File: | llvm/lib/Analysis/ScalarEvolution.cpp |
Warning: | line 6434, column 23 Called C++ object pointer is null |
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1 | //===- ScalarEvolution.cpp - Scalar Evolution Analysis --------------------===// | ||||||
2 | // | ||||||
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||||||
4 | // See https://llvm.org/LICENSE.txt for license information. | ||||||
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||||||
6 | // | ||||||
7 | //===----------------------------------------------------------------------===// | ||||||
8 | // | ||||||
9 | // This file contains the implementation of the scalar evolution analysis | ||||||
10 | // engine, which is used primarily to analyze expressions involving induction | ||||||
11 | // variables in loops. | ||||||
12 | // | ||||||
13 | // There are several aspects to this library. First is the representation of | ||||||
14 | // scalar expressions, which are represented as subclasses of the SCEV class. | ||||||
15 | // These classes are used to represent certain types of subexpressions that we | ||||||
16 | // can handle. We only create one SCEV of a particular shape, so | ||||||
17 | // pointer-comparisons for equality are legal. | ||||||
18 | // | ||||||
19 | // One important aspect of the SCEV objects is that they are never cyclic, even | ||||||
20 | // if there is a cycle in the dataflow for an expression (ie, a PHI node). If | ||||||
21 | // the PHI node is one of the idioms that we can represent (e.g., a polynomial | ||||||
22 | // recurrence) then we represent it directly as a recurrence node, otherwise we | ||||||
23 | // represent it as a SCEVUnknown node. | ||||||
24 | // | ||||||
25 | // In addition to being able to represent expressions of various types, we also | ||||||
26 | // have folders that are used to build the *canonical* representation for a | ||||||
27 | // particular expression. These folders are capable of using a variety of | ||||||
28 | // rewrite rules to simplify the expressions. | ||||||
29 | // | ||||||
30 | // Once the folders are defined, we can implement the more interesting | ||||||
31 | // higher-level code, such as the code that recognizes PHI nodes of various | ||||||
32 | // types, computes the execution count of a loop, etc. | ||||||
33 | // | ||||||
34 | // TODO: We should use these routines and value representations to implement | ||||||
35 | // dependence analysis! | ||||||
36 | // | ||||||
37 | //===----------------------------------------------------------------------===// | ||||||
38 | // | ||||||
39 | // There are several good references for the techniques used in this analysis. | ||||||
40 | // | ||||||
41 | // Chains of recurrences -- a method to expedite the evaluation | ||||||
42 | // of closed-form functions | ||||||
43 | // Olaf Bachmann, Paul S. Wang, Eugene V. Zima | ||||||
44 | // | ||||||
45 | // On computational properties of chains of recurrences | ||||||
46 | // Eugene V. Zima | ||||||
47 | // | ||||||
48 | // Symbolic Evaluation of Chains of Recurrences for Loop Optimization | ||||||
49 | // Robert A. van Engelen | ||||||
50 | // | ||||||
51 | // Efficient Symbolic Analysis for Optimizing Compilers | ||||||
52 | // Robert A. van Engelen | ||||||
53 | // | ||||||
54 | // Using the chains of recurrences algebra for data dependence testing and | ||||||
55 | // induction variable substitution | ||||||
56 | // MS Thesis, Johnie Birch | ||||||
57 | // | ||||||
58 | //===----------------------------------------------------------------------===// | ||||||
59 | |||||||
60 | #include "llvm/Analysis/ScalarEvolution.h" | ||||||
61 | #include "llvm/ADT/APInt.h" | ||||||
62 | #include "llvm/ADT/ArrayRef.h" | ||||||
63 | #include "llvm/ADT/DenseMap.h" | ||||||
64 | #include "llvm/ADT/DepthFirstIterator.h" | ||||||
65 | #include "llvm/ADT/EquivalenceClasses.h" | ||||||
66 | #include "llvm/ADT/FoldingSet.h" | ||||||
67 | #include "llvm/ADT/None.h" | ||||||
68 | #include "llvm/ADT/Optional.h" | ||||||
69 | #include "llvm/ADT/STLExtras.h" | ||||||
70 | #include "llvm/ADT/ScopeExit.h" | ||||||
71 | #include "llvm/ADT/Sequence.h" | ||||||
72 | #include "llvm/ADT/SetVector.h" | ||||||
73 | #include "llvm/ADT/SmallPtrSet.h" | ||||||
74 | #include "llvm/ADT/SmallSet.h" | ||||||
75 | #include "llvm/ADT/SmallVector.h" | ||||||
76 | #include "llvm/ADT/Statistic.h" | ||||||
77 | #include "llvm/ADT/StringRef.h" | ||||||
78 | #include "llvm/Analysis/AssumptionCache.h" | ||||||
79 | #include "llvm/Analysis/ConstantFolding.h" | ||||||
80 | #include "llvm/Analysis/InstructionSimplify.h" | ||||||
81 | #include "llvm/Analysis/LoopInfo.h" | ||||||
82 | #include "llvm/Analysis/ScalarEvolutionExpressions.h" | ||||||
83 | #include "llvm/Analysis/TargetLibraryInfo.h" | ||||||
84 | #include "llvm/Analysis/ValueTracking.h" | ||||||
85 | #include "llvm/Config/llvm-config.h" | ||||||
86 | #include "llvm/IR/Argument.h" | ||||||
87 | #include "llvm/IR/BasicBlock.h" | ||||||
88 | #include "llvm/IR/CFG.h" | ||||||
89 | #include "llvm/IR/CallSite.h" | ||||||
90 | #include "llvm/IR/Constant.h" | ||||||
91 | #include "llvm/IR/ConstantRange.h" | ||||||
92 | #include "llvm/IR/Constants.h" | ||||||
93 | #include "llvm/IR/DataLayout.h" | ||||||
94 | #include "llvm/IR/DerivedTypes.h" | ||||||
95 | #include "llvm/IR/Dominators.h" | ||||||
96 | #include "llvm/IR/Function.h" | ||||||
97 | #include "llvm/IR/GlobalAlias.h" | ||||||
98 | #include "llvm/IR/GlobalValue.h" | ||||||
99 | #include "llvm/IR/GlobalVariable.h" | ||||||
100 | #include "llvm/IR/InstIterator.h" | ||||||
101 | #include "llvm/IR/InstrTypes.h" | ||||||
102 | #include "llvm/IR/Instruction.h" | ||||||
103 | #include "llvm/IR/Instructions.h" | ||||||
104 | #include "llvm/IR/IntrinsicInst.h" | ||||||
105 | #include "llvm/IR/Intrinsics.h" | ||||||
106 | #include "llvm/IR/LLVMContext.h" | ||||||
107 | #include "llvm/IR/Metadata.h" | ||||||
108 | #include "llvm/IR/Operator.h" | ||||||
109 | #include "llvm/IR/PatternMatch.h" | ||||||
110 | #include "llvm/IR/Type.h" | ||||||
111 | #include "llvm/IR/Use.h" | ||||||
112 | #include "llvm/IR/User.h" | ||||||
113 | #include "llvm/IR/Value.h" | ||||||
114 | #include "llvm/IR/Verifier.h" | ||||||
115 | #include "llvm/InitializePasses.h" | ||||||
116 | #include "llvm/Pass.h" | ||||||
117 | #include "llvm/Support/Casting.h" | ||||||
118 | #include "llvm/Support/CommandLine.h" | ||||||
119 | #include "llvm/Support/Compiler.h" | ||||||
120 | #include "llvm/Support/Debug.h" | ||||||
121 | #include "llvm/Support/ErrorHandling.h" | ||||||
122 | #include "llvm/Support/KnownBits.h" | ||||||
123 | #include "llvm/Support/SaveAndRestore.h" | ||||||
124 | #include "llvm/Support/raw_ostream.h" | ||||||
125 | #include <algorithm> | ||||||
126 | #include <cassert> | ||||||
127 | #include <climits> | ||||||
128 | #include <cstddef> | ||||||
129 | #include <cstdint> | ||||||
130 | #include <cstdlib> | ||||||
131 | #include <map> | ||||||
132 | #include <memory> | ||||||
133 | #include <tuple> | ||||||
134 | #include <utility> | ||||||
135 | #include <vector> | ||||||
136 | |||||||
137 | using namespace llvm; | ||||||
138 | |||||||
139 | #define DEBUG_TYPE"scalar-evolution" "scalar-evolution" | ||||||
140 | |||||||
141 | STATISTIC(NumArrayLenItCounts,static llvm::Statistic NumArrayLenItCounts = {"scalar-evolution" , "NumArrayLenItCounts", "Number of trip counts computed with array length" } | ||||||
142 | "Number of trip counts computed with array length")static llvm::Statistic NumArrayLenItCounts = {"scalar-evolution" , "NumArrayLenItCounts", "Number of trip counts computed with array length" }; | ||||||
143 | STATISTIC(NumTripCountsComputed,static llvm::Statistic NumTripCountsComputed = {"scalar-evolution" , "NumTripCountsComputed", "Number of loops with predictable loop counts" } | ||||||
144 | "Number of loops with predictable loop counts")static llvm::Statistic NumTripCountsComputed = {"scalar-evolution" , "NumTripCountsComputed", "Number of loops with predictable loop counts" }; | ||||||
145 | STATISTIC(NumTripCountsNotComputed,static llvm::Statistic NumTripCountsNotComputed = {"scalar-evolution" , "NumTripCountsNotComputed", "Number of loops without predictable loop counts" } | ||||||
146 | "Number of loops without predictable loop counts")static llvm::Statistic NumTripCountsNotComputed = {"scalar-evolution" , "NumTripCountsNotComputed", "Number of loops without predictable loop counts" }; | ||||||
147 | STATISTIC(NumBruteForceTripCountsComputed,static llvm::Statistic NumBruteForceTripCountsComputed = {"scalar-evolution" , "NumBruteForceTripCountsComputed", "Number of loops with trip counts computed by force" } | ||||||
148 | "Number of loops with trip counts computed by force")static llvm::Statistic NumBruteForceTripCountsComputed = {"scalar-evolution" , "NumBruteForceTripCountsComputed", "Number of loops with trip counts computed by force" }; | ||||||
149 | |||||||
150 | static cl::opt<unsigned> | ||||||
151 | MaxBruteForceIterations("scalar-evolution-max-iterations", cl::ReallyHidden, | ||||||
152 | cl::ZeroOrMore, | ||||||
153 | cl::desc("Maximum number of iterations SCEV will " | ||||||
154 | "symbolically execute a constant " | ||||||
155 | "derived loop"), | ||||||
156 | cl::init(100)); | ||||||
157 | |||||||
158 | // FIXME: Enable this with EXPENSIVE_CHECKS when the test suite is clean. | ||||||
159 | static cl::opt<bool> VerifySCEV( | ||||||
160 | "verify-scev", cl::Hidden, | ||||||
161 | cl::desc("Verify ScalarEvolution's backedge taken counts (slow)")); | ||||||
162 | static cl::opt<bool> VerifySCEVStrict( | ||||||
163 | "verify-scev-strict", cl::Hidden, | ||||||
164 | cl::desc("Enable stricter verification with -verify-scev is passed")); | ||||||
165 | static cl::opt<bool> | ||||||
166 | VerifySCEVMap("verify-scev-maps", cl::Hidden, | ||||||
167 | cl::desc("Verify no dangling value in ScalarEvolution's " | ||||||
168 | "ExprValueMap (slow)")); | ||||||
169 | |||||||
170 | static cl::opt<bool> VerifyIR( | ||||||
171 | "scev-verify-ir", cl::Hidden, | ||||||
172 | cl::desc("Verify IR correctness when making sensitive SCEV queries (slow)"), | ||||||
173 | cl::init(false)); | ||||||
174 | |||||||
175 | static cl::opt<unsigned> MulOpsInlineThreshold( | ||||||
176 | "scev-mulops-inline-threshold", cl::Hidden, | ||||||
177 | cl::desc("Threshold for inlining multiplication operands into a SCEV"), | ||||||
178 | cl::init(32)); | ||||||
179 | |||||||
180 | static cl::opt<unsigned> AddOpsInlineThreshold( | ||||||
181 | "scev-addops-inline-threshold", cl::Hidden, | ||||||
182 | cl::desc("Threshold for inlining addition operands into a SCEV"), | ||||||
183 | cl::init(500)); | ||||||
184 | |||||||
185 | static cl::opt<unsigned> MaxSCEVCompareDepth( | ||||||
186 | "scalar-evolution-max-scev-compare-depth", cl::Hidden, | ||||||
187 | cl::desc("Maximum depth of recursive SCEV complexity comparisons"), | ||||||
188 | cl::init(32)); | ||||||
189 | |||||||
190 | static cl::opt<unsigned> MaxSCEVOperationsImplicationDepth( | ||||||
191 | "scalar-evolution-max-scev-operations-implication-depth", cl::Hidden, | ||||||
192 | cl::desc("Maximum depth of recursive SCEV operations implication analysis"), | ||||||
193 | cl::init(2)); | ||||||
194 | |||||||
195 | static cl::opt<unsigned> MaxValueCompareDepth( | ||||||
196 | "scalar-evolution-max-value-compare-depth", cl::Hidden, | ||||||
197 | cl::desc("Maximum depth of recursive value complexity comparisons"), | ||||||
198 | cl::init(2)); | ||||||
199 | |||||||
200 | static cl::opt<unsigned> | ||||||
201 | MaxArithDepth("scalar-evolution-max-arith-depth", cl::Hidden, | ||||||
202 | cl::desc("Maximum depth of recursive arithmetics"), | ||||||
203 | cl::init(32)); | ||||||
204 | |||||||
205 | static cl::opt<unsigned> MaxConstantEvolvingDepth( | ||||||
206 | "scalar-evolution-max-constant-evolving-depth", cl::Hidden, | ||||||
207 | cl::desc("Maximum depth of recursive constant evolving"), cl::init(32)); | ||||||
208 | |||||||
209 | static cl::opt<unsigned> | ||||||
210 | MaxCastDepth("scalar-evolution-max-cast-depth", cl::Hidden, | ||||||
211 | cl::desc("Maximum depth of recursive SExt/ZExt/Trunc"), | ||||||
212 | cl::init(8)); | ||||||
213 | |||||||
214 | static cl::opt<unsigned> | ||||||
215 | MaxAddRecSize("scalar-evolution-max-add-rec-size", cl::Hidden, | ||||||
216 | cl::desc("Max coefficients in AddRec during evolving"), | ||||||
217 | cl::init(8)); | ||||||
218 | |||||||
219 | static cl::opt<unsigned> | ||||||
220 | HugeExprThreshold("scalar-evolution-huge-expr-threshold", cl::Hidden, | ||||||
221 | cl::desc("Size of the expression which is considered huge"), | ||||||
222 | cl::init(4096)); | ||||||
223 | |||||||
224 | static cl::opt<bool> | ||||||
225 | ClassifyExpressions("scalar-evolution-classify-expressions", | ||||||
226 | cl::Hidden, cl::init(true), | ||||||
227 | cl::desc("When printing analysis, include information on every instruction")); | ||||||
228 | |||||||
229 | |||||||
230 | //===----------------------------------------------------------------------===// | ||||||
231 | // SCEV class definitions | ||||||
232 | //===----------------------------------------------------------------------===// | ||||||
233 | |||||||
234 | //===----------------------------------------------------------------------===// | ||||||
235 | // Implementation of the SCEV class. | ||||||
236 | // | ||||||
237 | |||||||
238 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | ||||||
239 | LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void SCEV::dump() const { | ||||||
240 | print(dbgs()); | ||||||
241 | dbgs() << '\n'; | ||||||
242 | } | ||||||
243 | #endif | ||||||
244 | |||||||
245 | void SCEV::print(raw_ostream &OS) const { | ||||||
246 | switch (static_cast<SCEVTypes>(getSCEVType())) { | ||||||
247 | case scConstant: | ||||||
248 | cast<SCEVConstant>(this)->getValue()->printAsOperand(OS, false); | ||||||
249 | return; | ||||||
250 | case scTruncate: { | ||||||
251 | const SCEVTruncateExpr *Trunc = cast<SCEVTruncateExpr>(this); | ||||||
252 | const SCEV *Op = Trunc->getOperand(); | ||||||
253 | OS << "(trunc " << *Op->getType() << " " << *Op << " to " | ||||||
254 | << *Trunc->getType() << ")"; | ||||||
255 | return; | ||||||
256 | } | ||||||
257 | case scZeroExtend: { | ||||||
258 | const SCEVZeroExtendExpr *ZExt = cast<SCEVZeroExtendExpr>(this); | ||||||
259 | const SCEV *Op = ZExt->getOperand(); | ||||||
260 | OS << "(zext " << *Op->getType() << " " << *Op << " to " | ||||||
261 | << *ZExt->getType() << ")"; | ||||||
262 | return; | ||||||
263 | } | ||||||
264 | case scSignExtend: { | ||||||
265 | const SCEVSignExtendExpr *SExt = cast<SCEVSignExtendExpr>(this); | ||||||
266 | const SCEV *Op = SExt->getOperand(); | ||||||
267 | OS << "(sext " << *Op->getType() << " " << *Op << " to " | ||||||
268 | << *SExt->getType() << ")"; | ||||||
269 | return; | ||||||
270 | } | ||||||
271 | case scAddRecExpr: { | ||||||
272 | const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(this); | ||||||
273 | OS << "{" << *AR->getOperand(0); | ||||||
274 | for (unsigned i = 1, e = AR->getNumOperands(); i != e; ++i) | ||||||
275 | OS << ",+," << *AR->getOperand(i); | ||||||
276 | OS << "}<"; | ||||||
277 | if (AR->hasNoUnsignedWrap()) | ||||||
278 | OS << "nuw><"; | ||||||
279 | if (AR->hasNoSignedWrap()) | ||||||
280 | OS << "nsw><"; | ||||||
281 | if (AR->hasNoSelfWrap() && | ||||||
282 | !AR->getNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW))) | ||||||
283 | OS << "nw><"; | ||||||
284 | AR->getLoop()->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
285 | OS << ">"; | ||||||
286 | return; | ||||||
287 | } | ||||||
288 | case scAddExpr: | ||||||
289 | case scMulExpr: | ||||||
290 | case scUMaxExpr: | ||||||
291 | case scSMaxExpr: | ||||||
292 | case scUMinExpr: | ||||||
293 | case scSMinExpr: { | ||||||
294 | const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(this); | ||||||
295 | const char *OpStr = nullptr; | ||||||
296 | switch (NAry->getSCEVType()) { | ||||||
297 | case scAddExpr: OpStr = " + "; break; | ||||||
298 | case scMulExpr: OpStr = " * "; break; | ||||||
299 | case scUMaxExpr: OpStr = " umax "; break; | ||||||
300 | case scSMaxExpr: OpStr = " smax "; break; | ||||||
301 | case scUMinExpr: | ||||||
302 | OpStr = " umin "; | ||||||
303 | break; | ||||||
304 | case scSMinExpr: | ||||||
305 | OpStr = " smin "; | ||||||
306 | break; | ||||||
307 | } | ||||||
308 | OS << "("; | ||||||
309 | for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end(); | ||||||
310 | I != E; ++I) { | ||||||
311 | OS << **I; | ||||||
312 | if (std::next(I) != E) | ||||||
313 | OS << OpStr; | ||||||
314 | } | ||||||
315 | OS << ")"; | ||||||
316 | switch (NAry->getSCEVType()) { | ||||||
317 | case scAddExpr: | ||||||
318 | case scMulExpr: | ||||||
319 | if (NAry->hasNoUnsignedWrap()) | ||||||
320 | OS << "<nuw>"; | ||||||
321 | if (NAry->hasNoSignedWrap()) | ||||||
322 | OS << "<nsw>"; | ||||||
323 | } | ||||||
324 | return; | ||||||
325 | } | ||||||
326 | case scUDivExpr: { | ||||||
327 | const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(this); | ||||||
328 | OS << "(" << *UDiv->getLHS() << " /u " << *UDiv->getRHS() << ")"; | ||||||
329 | return; | ||||||
330 | } | ||||||
331 | case scUnknown: { | ||||||
332 | const SCEVUnknown *U = cast<SCEVUnknown>(this); | ||||||
333 | Type *AllocTy; | ||||||
334 | if (U->isSizeOf(AllocTy)) { | ||||||
335 | OS << "sizeof(" << *AllocTy << ")"; | ||||||
336 | return; | ||||||
337 | } | ||||||
338 | if (U->isAlignOf(AllocTy)) { | ||||||
339 | OS << "alignof(" << *AllocTy << ")"; | ||||||
340 | return; | ||||||
341 | } | ||||||
342 | |||||||
343 | Type *CTy; | ||||||
344 | Constant *FieldNo; | ||||||
345 | if (U->isOffsetOf(CTy, FieldNo)) { | ||||||
346 | OS << "offsetof(" << *CTy << ", "; | ||||||
347 | FieldNo->printAsOperand(OS, false); | ||||||
348 | OS << ")"; | ||||||
349 | return; | ||||||
350 | } | ||||||
351 | |||||||
352 | // Otherwise just print it normally. | ||||||
353 | U->getValue()->printAsOperand(OS, false); | ||||||
354 | return; | ||||||
355 | } | ||||||
356 | case scCouldNotCompute: | ||||||
357 | OS << "***COULDNOTCOMPUTE***"; | ||||||
358 | return; | ||||||
359 | } | ||||||
360 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 360); | ||||||
361 | } | ||||||
362 | |||||||
363 | Type *SCEV::getType() const { | ||||||
364 | switch (static_cast<SCEVTypes>(getSCEVType())) { | ||||||
365 | case scConstant: | ||||||
366 | return cast<SCEVConstant>(this)->getType(); | ||||||
367 | case scTruncate: | ||||||
368 | case scZeroExtend: | ||||||
369 | case scSignExtend: | ||||||
370 | return cast<SCEVCastExpr>(this)->getType(); | ||||||
371 | case scAddRecExpr: | ||||||
372 | case scMulExpr: | ||||||
373 | case scUMaxExpr: | ||||||
374 | case scSMaxExpr: | ||||||
375 | case scUMinExpr: | ||||||
376 | case scSMinExpr: | ||||||
377 | return cast<SCEVNAryExpr>(this)->getType(); | ||||||
378 | case scAddExpr: | ||||||
379 | return cast<SCEVAddExpr>(this)->getType(); | ||||||
380 | case scUDivExpr: | ||||||
381 | return cast<SCEVUDivExpr>(this)->getType(); | ||||||
382 | case scUnknown: | ||||||
383 | return cast<SCEVUnknown>(this)->getType(); | ||||||
384 | case scCouldNotCompute: | ||||||
385 | llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 385); | ||||||
386 | } | ||||||
387 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 387); | ||||||
388 | } | ||||||
389 | |||||||
390 | bool SCEV::isZero() const { | ||||||
391 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this)) | ||||||
392 | return SC->getValue()->isZero(); | ||||||
393 | return false; | ||||||
394 | } | ||||||
395 | |||||||
396 | bool SCEV::isOne() const { | ||||||
397 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this)) | ||||||
398 | return SC->getValue()->isOne(); | ||||||
399 | return false; | ||||||
400 | } | ||||||
401 | |||||||
402 | bool SCEV::isAllOnesValue() const { | ||||||
403 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this)) | ||||||
404 | return SC->getValue()->isMinusOne(); | ||||||
405 | return false; | ||||||
406 | } | ||||||
407 | |||||||
408 | bool SCEV::isNonConstantNegative() const { | ||||||
409 | const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(this); | ||||||
410 | if (!Mul) return false; | ||||||
411 | |||||||
412 | // If there is a constant factor, it will be first. | ||||||
413 | const SCEVConstant *SC = dyn_cast<SCEVConstant>(Mul->getOperand(0)); | ||||||
414 | if (!SC) return false; | ||||||
415 | |||||||
416 | // Return true if the value is negative, this matches things like (-42 * V). | ||||||
417 | return SC->getAPInt().isNegative(); | ||||||
418 | } | ||||||
419 | |||||||
420 | SCEVCouldNotCompute::SCEVCouldNotCompute() : | ||||||
421 | SCEV(FoldingSetNodeIDRef(), scCouldNotCompute, 0) {} | ||||||
422 | |||||||
423 | bool SCEVCouldNotCompute::classof(const SCEV *S) { | ||||||
424 | return S->getSCEVType() == scCouldNotCompute; | ||||||
425 | } | ||||||
426 | |||||||
427 | const SCEV *ScalarEvolution::getConstant(ConstantInt *V) { | ||||||
428 | FoldingSetNodeID ID; | ||||||
429 | ID.AddInteger(scConstant); | ||||||
430 | ID.AddPointer(V); | ||||||
431 | void *IP = nullptr; | ||||||
432 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
433 | SCEV *S = new (SCEVAllocator) SCEVConstant(ID.Intern(SCEVAllocator), V); | ||||||
434 | UniqueSCEVs.InsertNode(S, IP); | ||||||
435 | return S; | ||||||
436 | } | ||||||
437 | |||||||
438 | const SCEV *ScalarEvolution::getConstant(const APInt &Val) { | ||||||
439 | return getConstant(ConstantInt::get(getContext(), Val)); | ||||||
440 | } | ||||||
441 | |||||||
442 | const SCEV * | ||||||
443 | ScalarEvolution::getConstant(Type *Ty, uint64_t V, bool isSigned) { | ||||||
444 | IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty)); | ||||||
445 | return getConstant(ConstantInt::get(ITy, V, isSigned)); | ||||||
446 | } | ||||||
447 | |||||||
448 | SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeIDRef ID, | ||||||
449 | unsigned SCEVTy, const SCEV *op, Type *ty) | ||||||
450 | : SCEV(ID, SCEVTy, computeExpressionSize(op)), Op(op), Ty(ty) {} | ||||||
451 | |||||||
452 | SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeIDRef ID, | ||||||
453 | const SCEV *op, Type *ty) | ||||||
454 | : SCEVCastExpr(ID, scTruncate, op, ty) { | ||||||
455 | assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot truncate non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate non-integer value!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 456, __PRETTY_FUNCTION__)) | ||||||
456 | "Cannot truncate non-integer value!")((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot truncate non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate non-integer value!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 456, __PRETTY_FUNCTION__)); | ||||||
457 | } | ||||||
458 | |||||||
459 | SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID, | ||||||
460 | const SCEV *op, Type *ty) | ||||||
461 | : SCEVCastExpr(ID, scZeroExtend, op, ty) { | ||||||
462 | assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot zero extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot zero extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 463, __PRETTY_FUNCTION__)) | ||||||
463 | "Cannot zero extend non-integer value!")((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot zero extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot zero extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 463, __PRETTY_FUNCTION__)); | ||||||
464 | } | ||||||
465 | |||||||
466 | SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeIDRef ID, | ||||||
467 | const SCEV *op, Type *ty) | ||||||
468 | : SCEVCastExpr(ID, scSignExtend, op, ty) { | ||||||
469 | assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot sign extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot sign extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 470, __PRETTY_FUNCTION__)) | ||||||
470 | "Cannot sign extend non-integer value!")((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot sign extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot sign extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 470, __PRETTY_FUNCTION__)); | ||||||
471 | } | ||||||
472 | |||||||
473 | void SCEVUnknown::deleted() { | ||||||
474 | // Clear this SCEVUnknown from various maps. | ||||||
475 | SE->forgetMemoizedResults(this); | ||||||
476 | |||||||
477 | // Remove this SCEVUnknown from the uniquing map. | ||||||
478 | SE->UniqueSCEVs.RemoveNode(this); | ||||||
479 | |||||||
480 | // Release the value. | ||||||
481 | setValPtr(nullptr); | ||||||
482 | } | ||||||
483 | |||||||
484 | void SCEVUnknown::allUsesReplacedWith(Value *New) { | ||||||
485 | // Remove this SCEVUnknown from the uniquing map. | ||||||
486 | SE->UniqueSCEVs.RemoveNode(this); | ||||||
487 | |||||||
488 | // Update this SCEVUnknown to point to the new value. This is needed | ||||||
489 | // because there may still be outstanding SCEVs which still point to | ||||||
490 | // this SCEVUnknown. | ||||||
491 | setValPtr(New); | ||||||
492 | } | ||||||
493 | |||||||
494 | bool SCEVUnknown::isSizeOf(Type *&AllocTy) const { | ||||||
495 | if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue())) | ||||||
496 | if (VCE->getOpcode() == Instruction::PtrToInt) | ||||||
497 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0))) | ||||||
498 | if (CE->getOpcode() == Instruction::GetElementPtr && | ||||||
499 | CE->getOperand(0)->isNullValue() && | ||||||
500 | CE->getNumOperands() == 2) | ||||||
501 | if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(1))) | ||||||
502 | if (CI->isOne()) { | ||||||
503 | AllocTy = cast<PointerType>(CE->getOperand(0)->getType()) | ||||||
504 | ->getElementType(); | ||||||
505 | return true; | ||||||
506 | } | ||||||
507 | |||||||
508 | return false; | ||||||
509 | } | ||||||
510 | |||||||
511 | bool SCEVUnknown::isAlignOf(Type *&AllocTy) const { | ||||||
512 | if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue())) | ||||||
513 | if (VCE->getOpcode() == Instruction::PtrToInt) | ||||||
514 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0))) | ||||||
515 | if (CE->getOpcode() == Instruction::GetElementPtr && | ||||||
516 | CE->getOperand(0)->isNullValue()) { | ||||||
517 | Type *Ty = | ||||||
518 | cast<PointerType>(CE->getOperand(0)->getType())->getElementType(); | ||||||
519 | if (StructType *STy = dyn_cast<StructType>(Ty)) | ||||||
520 | if (!STy->isPacked() && | ||||||
521 | CE->getNumOperands() == 3 && | ||||||
522 | CE->getOperand(1)->isNullValue()) { | ||||||
523 | if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(2))) | ||||||
524 | if (CI->isOne() && | ||||||
525 | STy->getNumElements() == 2 && | ||||||
526 | STy->getElementType(0)->isIntegerTy(1)) { | ||||||
527 | AllocTy = STy->getElementType(1); | ||||||
528 | return true; | ||||||
529 | } | ||||||
530 | } | ||||||
531 | } | ||||||
532 | |||||||
533 | return false; | ||||||
534 | } | ||||||
535 | |||||||
536 | bool SCEVUnknown::isOffsetOf(Type *&CTy, Constant *&FieldNo) const { | ||||||
537 | if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue())) | ||||||
538 | if (VCE->getOpcode() == Instruction::PtrToInt) | ||||||
539 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0))) | ||||||
540 | if (CE->getOpcode() == Instruction::GetElementPtr && | ||||||
541 | CE->getNumOperands() == 3 && | ||||||
542 | CE->getOperand(0)->isNullValue() && | ||||||
543 | CE->getOperand(1)->isNullValue()) { | ||||||
544 | Type *Ty = | ||||||
545 | cast<PointerType>(CE->getOperand(0)->getType())->getElementType(); | ||||||
546 | // Ignore vector types here so that ScalarEvolutionExpander doesn't | ||||||
547 | // emit getelementptrs that index into vectors. | ||||||
548 | if (Ty->isStructTy() || Ty->isArrayTy()) { | ||||||
549 | CTy = Ty; | ||||||
550 | FieldNo = CE->getOperand(2); | ||||||
551 | return true; | ||||||
552 | } | ||||||
553 | } | ||||||
554 | |||||||
555 | return false; | ||||||
556 | } | ||||||
557 | |||||||
558 | //===----------------------------------------------------------------------===// | ||||||
559 | // SCEV Utilities | ||||||
560 | //===----------------------------------------------------------------------===// | ||||||
561 | |||||||
562 | /// Compare the two values \p LV and \p RV in terms of their "complexity" where | ||||||
563 | /// "complexity" is a partial (and somewhat ad-hoc) relation used to order | ||||||
564 | /// operands in SCEV expressions. \p EqCache is a set of pairs of values that | ||||||
565 | /// have been previously deemed to be "equally complex" by this routine. It is | ||||||
566 | /// intended to avoid exponential time complexity in cases like: | ||||||
567 | /// | ||||||
568 | /// %a = f(%x, %y) | ||||||
569 | /// %b = f(%a, %a) | ||||||
570 | /// %c = f(%b, %b) | ||||||
571 | /// | ||||||
572 | /// %d = f(%x, %y) | ||||||
573 | /// %e = f(%d, %d) | ||||||
574 | /// %f = f(%e, %e) | ||||||
575 | /// | ||||||
576 | /// CompareValueComplexity(%f, %c) | ||||||
577 | /// | ||||||
578 | /// Since we do not continue running this routine on expression trees once we | ||||||
579 | /// have seen unequal values, there is no need to track them in the cache. | ||||||
580 | static int | ||||||
581 | CompareValueComplexity(EquivalenceClasses<const Value *> &EqCacheValue, | ||||||
582 | const LoopInfo *const LI, Value *LV, Value *RV, | ||||||
583 | unsigned Depth) { | ||||||
584 | if (Depth > MaxValueCompareDepth || EqCacheValue.isEquivalent(LV, RV)) | ||||||
585 | return 0; | ||||||
586 | |||||||
587 | // Order pointer values after integer values. This helps SCEVExpander form | ||||||
588 | // GEPs. | ||||||
589 | bool LIsPointer = LV->getType()->isPointerTy(), | ||||||
590 | RIsPointer = RV->getType()->isPointerTy(); | ||||||
591 | if (LIsPointer != RIsPointer) | ||||||
592 | return (int)LIsPointer - (int)RIsPointer; | ||||||
593 | |||||||
594 | // Compare getValueID values. | ||||||
595 | unsigned LID = LV->getValueID(), RID = RV->getValueID(); | ||||||
596 | if (LID != RID) | ||||||
597 | return (int)LID - (int)RID; | ||||||
598 | |||||||
599 | // Sort arguments by their position. | ||||||
600 | if (const auto *LA = dyn_cast<Argument>(LV)) { | ||||||
601 | const auto *RA = cast<Argument>(RV); | ||||||
602 | unsigned LArgNo = LA->getArgNo(), RArgNo = RA->getArgNo(); | ||||||
603 | return (int)LArgNo - (int)RArgNo; | ||||||
604 | } | ||||||
605 | |||||||
606 | if (const auto *LGV = dyn_cast<GlobalValue>(LV)) { | ||||||
607 | const auto *RGV = cast<GlobalValue>(RV); | ||||||
608 | |||||||
609 | const auto IsGVNameSemantic = [&](const GlobalValue *GV) { | ||||||
610 | auto LT = GV->getLinkage(); | ||||||
611 | return !(GlobalValue::isPrivateLinkage(LT) || | ||||||
612 | GlobalValue::isInternalLinkage(LT)); | ||||||
613 | }; | ||||||
614 | |||||||
615 | // Use the names to distinguish the two values, but only if the | ||||||
616 | // names are semantically important. | ||||||
617 | if (IsGVNameSemantic(LGV) && IsGVNameSemantic(RGV)) | ||||||
618 | return LGV->getName().compare(RGV->getName()); | ||||||
619 | } | ||||||
620 | |||||||
621 | // For instructions, compare their loop depth, and their operand count. This | ||||||
622 | // is pretty loose. | ||||||
623 | if (const auto *LInst = dyn_cast<Instruction>(LV)) { | ||||||
624 | const auto *RInst = cast<Instruction>(RV); | ||||||
625 | |||||||
626 | // Compare loop depths. | ||||||
627 | const BasicBlock *LParent = LInst->getParent(), | ||||||
628 | *RParent = RInst->getParent(); | ||||||
629 | if (LParent != RParent) { | ||||||
630 | unsigned LDepth = LI->getLoopDepth(LParent), | ||||||
631 | RDepth = LI->getLoopDepth(RParent); | ||||||
632 | if (LDepth != RDepth) | ||||||
633 | return (int)LDepth - (int)RDepth; | ||||||
634 | } | ||||||
635 | |||||||
636 | // Compare the number of operands. | ||||||
637 | unsigned LNumOps = LInst->getNumOperands(), | ||||||
638 | RNumOps = RInst->getNumOperands(); | ||||||
639 | if (LNumOps != RNumOps) | ||||||
640 | return (int)LNumOps - (int)RNumOps; | ||||||
641 | |||||||
642 | for (unsigned Idx : seq(0u, LNumOps)) { | ||||||
643 | int Result = | ||||||
644 | CompareValueComplexity(EqCacheValue, LI, LInst->getOperand(Idx), | ||||||
645 | RInst->getOperand(Idx), Depth + 1); | ||||||
646 | if (Result != 0) | ||||||
647 | return Result; | ||||||
648 | } | ||||||
649 | } | ||||||
650 | |||||||
651 | EqCacheValue.unionSets(LV, RV); | ||||||
652 | return 0; | ||||||
653 | } | ||||||
654 | |||||||
655 | // Return negative, zero, or positive, if LHS is less than, equal to, or greater | ||||||
656 | // than RHS, respectively. A three-way result allows recursive comparisons to be | ||||||
657 | // more efficient. | ||||||
658 | static int CompareSCEVComplexity( | ||||||
659 | EquivalenceClasses<const SCEV *> &EqCacheSCEV, | ||||||
660 | EquivalenceClasses<const Value *> &EqCacheValue, | ||||||
661 | const LoopInfo *const LI, const SCEV *LHS, const SCEV *RHS, | ||||||
662 | DominatorTree &DT, unsigned Depth = 0) { | ||||||
663 | // Fast-path: SCEVs are uniqued so we can do a quick equality check. | ||||||
664 | if (LHS == RHS) | ||||||
665 | return 0; | ||||||
666 | |||||||
667 | // Primarily, sort the SCEVs by their getSCEVType(). | ||||||
668 | unsigned LType = LHS->getSCEVType(), RType = RHS->getSCEVType(); | ||||||
669 | if (LType != RType) | ||||||
670 | return (int)LType - (int)RType; | ||||||
671 | |||||||
672 | if (Depth > MaxSCEVCompareDepth || EqCacheSCEV.isEquivalent(LHS, RHS)) | ||||||
673 | return 0; | ||||||
674 | // Aside from the getSCEVType() ordering, the particular ordering | ||||||
675 | // isn't very important except that it's beneficial to be consistent, | ||||||
676 | // so that (a + b) and (b + a) don't end up as different expressions. | ||||||
677 | switch (static_cast<SCEVTypes>(LType)) { | ||||||
678 | case scUnknown: { | ||||||
679 | const SCEVUnknown *LU = cast<SCEVUnknown>(LHS); | ||||||
680 | const SCEVUnknown *RU = cast<SCEVUnknown>(RHS); | ||||||
681 | |||||||
682 | int X = CompareValueComplexity(EqCacheValue, LI, LU->getValue(), | ||||||
683 | RU->getValue(), Depth + 1); | ||||||
684 | if (X == 0) | ||||||
685 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
686 | return X; | ||||||
687 | } | ||||||
688 | |||||||
689 | case scConstant: { | ||||||
690 | const SCEVConstant *LC = cast<SCEVConstant>(LHS); | ||||||
691 | const SCEVConstant *RC = cast<SCEVConstant>(RHS); | ||||||
692 | |||||||
693 | // Compare constant values. | ||||||
694 | const APInt &LA = LC->getAPInt(); | ||||||
695 | const APInt &RA = RC->getAPInt(); | ||||||
696 | unsigned LBitWidth = LA.getBitWidth(), RBitWidth = RA.getBitWidth(); | ||||||
697 | if (LBitWidth != RBitWidth) | ||||||
698 | return (int)LBitWidth - (int)RBitWidth; | ||||||
699 | return LA.ult(RA) ? -1 : 1; | ||||||
700 | } | ||||||
701 | |||||||
702 | case scAddRecExpr: { | ||||||
703 | const SCEVAddRecExpr *LA = cast<SCEVAddRecExpr>(LHS); | ||||||
704 | const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS); | ||||||
705 | |||||||
706 | // There is always a dominance between two recs that are used by one SCEV, | ||||||
707 | // so we can safely sort recs by loop header dominance. We require such | ||||||
708 | // order in getAddExpr. | ||||||
709 | const Loop *LLoop = LA->getLoop(), *RLoop = RA->getLoop(); | ||||||
710 | if (LLoop != RLoop) { | ||||||
711 | const BasicBlock *LHead = LLoop->getHeader(), *RHead = RLoop->getHeader(); | ||||||
712 | assert(LHead != RHead && "Two loops share the same header?")((LHead != RHead && "Two loops share the same header?" ) ? static_cast<void> (0) : __assert_fail ("LHead != RHead && \"Two loops share the same header?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 712, __PRETTY_FUNCTION__)); | ||||||
713 | if (DT.dominates(LHead, RHead)) | ||||||
714 | return 1; | ||||||
715 | else | ||||||
716 | assert(DT.dominates(RHead, LHead) &&((DT.dominates(RHead, LHead) && "No dominance between recurrences used by one SCEV?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(RHead, LHead) && \"No dominance between recurrences used by one SCEV?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 717, __PRETTY_FUNCTION__)) | ||||||
717 | "No dominance between recurrences used by one SCEV?")((DT.dominates(RHead, LHead) && "No dominance between recurrences used by one SCEV?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(RHead, LHead) && \"No dominance between recurrences used by one SCEV?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 717, __PRETTY_FUNCTION__)); | ||||||
718 | return -1; | ||||||
719 | } | ||||||
720 | |||||||
721 | // Addrec complexity grows with operand count. | ||||||
722 | unsigned LNumOps = LA->getNumOperands(), RNumOps = RA->getNumOperands(); | ||||||
723 | if (LNumOps != RNumOps) | ||||||
724 | return (int)LNumOps - (int)RNumOps; | ||||||
725 | |||||||
726 | // Lexicographically compare. | ||||||
727 | for (unsigned i = 0; i != LNumOps; ++i) { | ||||||
728 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, | ||||||
729 | LA->getOperand(i), RA->getOperand(i), DT, | ||||||
730 | Depth + 1); | ||||||
731 | if (X != 0) | ||||||
732 | return X; | ||||||
733 | } | ||||||
734 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
735 | return 0; | ||||||
736 | } | ||||||
737 | |||||||
738 | case scAddExpr: | ||||||
739 | case scMulExpr: | ||||||
740 | case scSMaxExpr: | ||||||
741 | case scUMaxExpr: | ||||||
742 | case scSMinExpr: | ||||||
743 | case scUMinExpr: { | ||||||
744 | const SCEVNAryExpr *LC = cast<SCEVNAryExpr>(LHS); | ||||||
745 | const SCEVNAryExpr *RC = cast<SCEVNAryExpr>(RHS); | ||||||
746 | |||||||
747 | // Lexicographically compare n-ary expressions. | ||||||
748 | unsigned LNumOps = LC->getNumOperands(), RNumOps = RC->getNumOperands(); | ||||||
749 | if (LNumOps != RNumOps) | ||||||
750 | return (int)LNumOps - (int)RNumOps; | ||||||
751 | |||||||
752 | for (unsigned i = 0; i != LNumOps; ++i) { | ||||||
753 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, | ||||||
754 | LC->getOperand(i), RC->getOperand(i), DT, | ||||||
755 | Depth + 1); | ||||||
756 | if (X != 0) | ||||||
757 | return X; | ||||||
758 | } | ||||||
759 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
760 | return 0; | ||||||
761 | } | ||||||
762 | |||||||
763 | case scUDivExpr: { | ||||||
764 | const SCEVUDivExpr *LC = cast<SCEVUDivExpr>(LHS); | ||||||
765 | const SCEVUDivExpr *RC = cast<SCEVUDivExpr>(RHS); | ||||||
766 | |||||||
767 | // Lexicographically compare udiv expressions. | ||||||
768 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getLHS(), | ||||||
769 | RC->getLHS(), DT, Depth + 1); | ||||||
770 | if (X != 0) | ||||||
771 | return X; | ||||||
772 | X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getRHS(), | ||||||
773 | RC->getRHS(), DT, Depth + 1); | ||||||
774 | if (X == 0) | ||||||
775 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
776 | return X; | ||||||
777 | } | ||||||
778 | |||||||
779 | case scTruncate: | ||||||
780 | case scZeroExtend: | ||||||
781 | case scSignExtend: { | ||||||
782 | const SCEVCastExpr *LC = cast<SCEVCastExpr>(LHS); | ||||||
783 | const SCEVCastExpr *RC = cast<SCEVCastExpr>(RHS); | ||||||
784 | |||||||
785 | // Compare cast expressions by operand. | ||||||
786 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, | ||||||
787 | LC->getOperand(), RC->getOperand(), DT, | ||||||
788 | Depth + 1); | ||||||
789 | if (X == 0) | ||||||
790 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
791 | return X; | ||||||
792 | } | ||||||
793 | |||||||
794 | case scCouldNotCompute: | ||||||
795 | llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 795); | ||||||
796 | } | ||||||
797 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 797); | ||||||
798 | } | ||||||
799 | |||||||
800 | /// Given a list of SCEV objects, order them by their complexity, and group | ||||||
801 | /// objects of the same complexity together by value. When this routine is | ||||||
802 | /// finished, we know that any duplicates in the vector are consecutive and that | ||||||
803 | /// complexity is monotonically increasing. | ||||||
804 | /// | ||||||
805 | /// Note that we go take special precautions to ensure that we get deterministic | ||||||
806 | /// results from this routine. In other words, we don't want the results of | ||||||
807 | /// this to depend on where the addresses of various SCEV objects happened to | ||||||
808 | /// land in memory. | ||||||
809 | static void GroupByComplexity(SmallVectorImpl<const SCEV *> &Ops, | ||||||
810 | LoopInfo *LI, DominatorTree &DT) { | ||||||
811 | if (Ops.size() < 2) return; // Noop | ||||||
812 | |||||||
813 | EquivalenceClasses<const SCEV *> EqCacheSCEV; | ||||||
814 | EquivalenceClasses<const Value *> EqCacheValue; | ||||||
815 | if (Ops.size() == 2) { | ||||||
816 | // This is the common case, which also happens to be trivially simple. | ||||||
817 | // Special case it. | ||||||
818 | const SCEV *&LHS = Ops[0], *&RHS = Ops[1]; | ||||||
819 | if (CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, RHS, LHS, DT) < 0) | ||||||
820 | std::swap(LHS, RHS); | ||||||
821 | return; | ||||||
822 | } | ||||||
823 | |||||||
824 | // Do the rough sort by complexity. | ||||||
825 | llvm::stable_sort(Ops, [&](const SCEV *LHS, const SCEV *RHS) { | ||||||
826 | return CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LHS, RHS, DT) < | ||||||
827 | 0; | ||||||
828 | }); | ||||||
829 | |||||||
830 | // Now that we are sorted by complexity, group elements of the same | ||||||
831 | // complexity. Note that this is, at worst, N^2, but the vector is likely to | ||||||
832 | // be extremely short in practice. Note that we take this approach because we | ||||||
833 | // do not want to depend on the addresses of the objects we are grouping. | ||||||
834 | for (unsigned i = 0, e = Ops.size(); i != e-2; ++i) { | ||||||
835 | const SCEV *S = Ops[i]; | ||||||
836 | unsigned Complexity = S->getSCEVType(); | ||||||
837 | |||||||
838 | // If there are any objects of the same complexity and same value as this | ||||||
839 | // one, group them. | ||||||
840 | for (unsigned j = i+1; j != e && Ops[j]->getSCEVType() == Complexity; ++j) { | ||||||
841 | if (Ops[j] == S) { // Found a duplicate. | ||||||
842 | // Move it to immediately after i'th element. | ||||||
843 | std::swap(Ops[i+1], Ops[j]); | ||||||
844 | ++i; // no need to rescan it. | ||||||
845 | if (i == e-2) return; // Done! | ||||||
846 | } | ||||||
847 | } | ||||||
848 | } | ||||||
849 | } | ||||||
850 | |||||||
851 | // Returns the size of the SCEV S. | ||||||
852 | static inline int sizeOfSCEV(const SCEV *S) { | ||||||
853 | struct FindSCEVSize { | ||||||
854 | int Size = 0; | ||||||
855 | |||||||
856 | FindSCEVSize() = default; | ||||||
857 | |||||||
858 | bool follow(const SCEV *S) { | ||||||
859 | ++Size; | ||||||
860 | // Keep looking at all operands of S. | ||||||
861 | return true; | ||||||
862 | } | ||||||
863 | |||||||
864 | bool isDone() const { | ||||||
865 | return false; | ||||||
866 | } | ||||||
867 | }; | ||||||
868 | |||||||
869 | FindSCEVSize F; | ||||||
870 | SCEVTraversal<FindSCEVSize> ST(F); | ||||||
871 | ST.visitAll(S); | ||||||
872 | return F.Size; | ||||||
873 | } | ||||||
874 | |||||||
875 | /// Returns true if \p Ops contains a huge SCEV (the subtree of S contains at | ||||||
876 | /// least HugeExprThreshold nodes). | ||||||
877 | static bool hasHugeExpression(ArrayRef<const SCEV *> Ops) { | ||||||
878 | return any_of(Ops, [](const SCEV *S) { | ||||||
879 | return S->getExpressionSize() >= HugeExprThreshold; | ||||||
880 | }); | ||||||
881 | } | ||||||
882 | |||||||
883 | namespace { | ||||||
884 | |||||||
885 | struct SCEVDivision : public SCEVVisitor<SCEVDivision, void> { | ||||||
886 | public: | ||||||
887 | // Computes the Quotient and Remainder of the division of Numerator by | ||||||
888 | // Denominator. | ||||||
889 | static void divide(ScalarEvolution &SE, const SCEV *Numerator, | ||||||
890 | const SCEV *Denominator, const SCEV **Quotient, | ||||||
891 | const SCEV **Remainder) { | ||||||
892 | assert(Numerator && Denominator && "Uninitialized SCEV")((Numerator && Denominator && "Uninitialized SCEV" ) ? static_cast<void> (0) : __assert_fail ("Numerator && Denominator && \"Uninitialized SCEV\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 892, __PRETTY_FUNCTION__)); | ||||||
893 | |||||||
894 | SCEVDivision D(SE, Numerator, Denominator); | ||||||
895 | |||||||
896 | // Check for the trivial case here to avoid having to check for it in the | ||||||
897 | // rest of the code. | ||||||
898 | if (Numerator == Denominator) { | ||||||
899 | *Quotient = D.One; | ||||||
900 | *Remainder = D.Zero; | ||||||
901 | return; | ||||||
902 | } | ||||||
903 | |||||||
904 | if (Numerator->isZero()) { | ||||||
905 | *Quotient = D.Zero; | ||||||
906 | *Remainder = D.Zero; | ||||||
907 | return; | ||||||
908 | } | ||||||
909 | |||||||
910 | // A simple case when N/1. The quotient is N. | ||||||
911 | if (Denominator->isOne()) { | ||||||
912 | *Quotient = Numerator; | ||||||
913 | *Remainder = D.Zero; | ||||||
914 | return; | ||||||
915 | } | ||||||
916 | |||||||
917 | // Split the Denominator when it is a product. | ||||||
918 | if (const SCEVMulExpr *T = dyn_cast<SCEVMulExpr>(Denominator)) { | ||||||
919 | const SCEV *Q, *R; | ||||||
920 | *Quotient = Numerator; | ||||||
921 | for (const SCEV *Op : T->operands()) { | ||||||
922 | divide(SE, *Quotient, Op, &Q, &R); | ||||||
923 | *Quotient = Q; | ||||||
924 | |||||||
925 | // Bail out when the Numerator is not divisible by one of the terms of | ||||||
926 | // the Denominator. | ||||||
927 | if (!R->isZero()) { | ||||||
928 | *Quotient = D.Zero; | ||||||
929 | *Remainder = Numerator; | ||||||
930 | return; | ||||||
931 | } | ||||||
932 | } | ||||||
933 | *Remainder = D.Zero; | ||||||
934 | return; | ||||||
935 | } | ||||||
936 | |||||||
937 | D.visit(Numerator); | ||||||
938 | *Quotient = D.Quotient; | ||||||
939 | *Remainder = D.Remainder; | ||||||
940 | } | ||||||
941 | |||||||
942 | // Except in the trivial case described above, we do not know how to divide | ||||||
943 | // Expr by Denominator for the following functions with empty implementation. | ||||||
944 | void visitTruncateExpr(const SCEVTruncateExpr *Numerator) {} | ||||||
945 | void visitZeroExtendExpr(const SCEVZeroExtendExpr *Numerator) {} | ||||||
946 | void visitSignExtendExpr(const SCEVSignExtendExpr *Numerator) {} | ||||||
947 | void visitUDivExpr(const SCEVUDivExpr *Numerator) {} | ||||||
948 | void visitSMaxExpr(const SCEVSMaxExpr *Numerator) {} | ||||||
949 | void visitUMaxExpr(const SCEVUMaxExpr *Numerator) {} | ||||||
950 | void visitSMinExpr(const SCEVSMinExpr *Numerator) {} | ||||||
951 | void visitUMinExpr(const SCEVUMinExpr *Numerator) {} | ||||||
952 | void visitUnknown(const SCEVUnknown *Numerator) {} | ||||||
953 | void visitCouldNotCompute(const SCEVCouldNotCompute *Numerator) {} | ||||||
954 | |||||||
955 | void visitConstant(const SCEVConstant *Numerator) { | ||||||
956 | if (const SCEVConstant *D = dyn_cast<SCEVConstant>(Denominator)) { | ||||||
957 | APInt NumeratorVal = Numerator->getAPInt(); | ||||||
958 | APInt DenominatorVal = D->getAPInt(); | ||||||
959 | uint32_t NumeratorBW = NumeratorVal.getBitWidth(); | ||||||
960 | uint32_t DenominatorBW = DenominatorVal.getBitWidth(); | ||||||
961 | |||||||
962 | if (NumeratorBW > DenominatorBW) | ||||||
963 | DenominatorVal = DenominatorVal.sext(NumeratorBW); | ||||||
964 | else if (NumeratorBW < DenominatorBW) | ||||||
965 | NumeratorVal = NumeratorVal.sext(DenominatorBW); | ||||||
966 | |||||||
967 | APInt QuotientVal(NumeratorVal.getBitWidth(), 0); | ||||||
968 | APInt RemainderVal(NumeratorVal.getBitWidth(), 0); | ||||||
969 | APInt::sdivrem(NumeratorVal, DenominatorVal, QuotientVal, RemainderVal); | ||||||
970 | Quotient = SE.getConstant(QuotientVal); | ||||||
971 | Remainder = SE.getConstant(RemainderVal); | ||||||
972 | return; | ||||||
973 | } | ||||||
974 | } | ||||||
975 | |||||||
976 | void visitAddRecExpr(const SCEVAddRecExpr *Numerator) { | ||||||
977 | const SCEV *StartQ, *StartR, *StepQ, *StepR; | ||||||
978 | if (!Numerator->isAffine()) | ||||||
979 | return cannotDivide(Numerator); | ||||||
980 | divide(SE, Numerator->getStart(), Denominator, &StartQ, &StartR); | ||||||
981 | divide(SE, Numerator->getStepRecurrence(SE), Denominator, &StepQ, &StepR); | ||||||
982 | // Bail out if the types do not match. | ||||||
983 | Type *Ty = Denominator->getType(); | ||||||
984 | if (Ty != StartQ->getType() || Ty != StartR->getType() || | ||||||
985 | Ty != StepQ->getType() || Ty != StepR->getType()) | ||||||
986 | return cannotDivide(Numerator); | ||||||
987 | Quotient = SE.getAddRecExpr(StartQ, StepQ, Numerator->getLoop(), | ||||||
988 | Numerator->getNoWrapFlags()); | ||||||
989 | Remainder = SE.getAddRecExpr(StartR, StepR, Numerator->getLoop(), | ||||||
990 | Numerator->getNoWrapFlags()); | ||||||
991 | } | ||||||
992 | |||||||
993 | void visitAddExpr(const SCEVAddExpr *Numerator) { | ||||||
994 | SmallVector<const SCEV *, 2> Qs, Rs; | ||||||
995 | Type *Ty = Denominator->getType(); | ||||||
996 | |||||||
997 | for (const SCEV *Op : Numerator->operands()) { | ||||||
998 | const SCEV *Q, *R; | ||||||
999 | divide(SE, Op, Denominator, &Q, &R); | ||||||
1000 | |||||||
1001 | // Bail out if types do not match. | ||||||
1002 | if (Ty != Q->getType() || Ty != R->getType()) | ||||||
1003 | return cannotDivide(Numerator); | ||||||
1004 | |||||||
1005 | Qs.push_back(Q); | ||||||
1006 | Rs.push_back(R); | ||||||
1007 | } | ||||||
1008 | |||||||
1009 | if (Qs.size() == 1) { | ||||||
1010 | Quotient = Qs[0]; | ||||||
1011 | Remainder = Rs[0]; | ||||||
1012 | return; | ||||||
1013 | } | ||||||
1014 | |||||||
1015 | Quotient = SE.getAddExpr(Qs); | ||||||
1016 | Remainder = SE.getAddExpr(Rs); | ||||||
1017 | } | ||||||
1018 | |||||||
1019 | void visitMulExpr(const SCEVMulExpr *Numerator) { | ||||||
1020 | SmallVector<const SCEV *, 2> Qs; | ||||||
1021 | Type *Ty = Denominator->getType(); | ||||||
1022 | |||||||
1023 | bool FoundDenominatorTerm = false; | ||||||
1024 | for (const SCEV *Op : Numerator->operands()) { | ||||||
1025 | // Bail out if types do not match. | ||||||
1026 | if (Ty != Op->getType()) | ||||||
1027 | return cannotDivide(Numerator); | ||||||
1028 | |||||||
1029 | if (FoundDenominatorTerm) { | ||||||
1030 | Qs.push_back(Op); | ||||||
1031 | continue; | ||||||
1032 | } | ||||||
1033 | |||||||
1034 | // Check whether Denominator divides one of the product operands. | ||||||
1035 | const SCEV *Q, *R; | ||||||
1036 | divide(SE, Op, Denominator, &Q, &R); | ||||||
1037 | if (!R->isZero()) { | ||||||
1038 | Qs.push_back(Op); | ||||||
1039 | continue; | ||||||
1040 | } | ||||||
1041 | |||||||
1042 | // Bail out if types do not match. | ||||||
1043 | if (Ty != Q->getType()) | ||||||
1044 | return cannotDivide(Numerator); | ||||||
1045 | |||||||
1046 | FoundDenominatorTerm = true; | ||||||
1047 | Qs.push_back(Q); | ||||||
1048 | } | ||||||
1049 | |||||||
1050 | if (FoundDenominatorTerm) { | ||||||
1051 | Remainder = Zero; | ||||||
1052 | if (Qs.size() == 1) | ||||||
1053 | Quotient = Qs[0]; | ||||||
1054 | else | ||||||
1055 | Quotient = SE.getMulExpr(Qs); | ||||||
1056 | return; | ||||||
1057 | } | ||||||
1058 | |||||||
1059 | if (!isa<SCEVUnknown>(Denominator)) | ||||||
1060 | return cannotDivide(Numerator); | ||||||
1061 | |||||||
1062 | // The Remainder is obtained by replacing Denominator by 0 in Numerator. | ||||||
1063 | ValueToValueMap RewriteMap; | ||||||
1064 | RewriteMap[cast<SCEVUnknown>(Denominator)->getValue()] = | ||||||
1065 | cast<SCEVConstant>(Zero)->getValue(); | ||||||
1066 | Remainder = SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true); | ||||||
1067 | |||||||
1068 | if (Remainder->isZero()) { | ||||||
1069 | // The Quotient is obtained by replacing Denominator by 1 in Numerator. | ||||||
1070 | RewriteMap[cast<SCEVUnknown>(Denominator)->getValue()] = | ||||||
1071 | cast<SCEVConstant>(One)->getValue(); | ||||||
1072 | Quotient = | ||||||
1073 | SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true); | ||||||
1074 | return; | ||||||
1075 | } | ||||||
1076 | |||||||
1077 | // Quotient is (Numerator - Remainder) divided by Denominator. | ||||||
1078 | const SCEV *Q, *R; | ||||||
1079 | const SCEV *Diff = SE.getMinusSCEV(Numerator, Remainder); | ||||||
1080 | // This SCEV does not seem to simplify: fail the division here. | ||||||
1081 | if (sizeOfSCEV(Diff) > sizeOfSCEV(Numerator)) | ||||||
1082 | return cannotDivide(Numerator); | ||||||
1083 | divide(SE, Diff, Denominator, &Q, &R); | ||||||
1084 | if (R != Zero) | ||||||
1085 | return cannotDivide(Numerator); | ||||||
1086 | Quotient = Q; | ||||||
1087 | } | ||||||
1088 | |||||||
1089 | private: | ||||||
1090 | SCEVDivision(ScalarEvolution &S, const SCEV *Numerator, | ||||||
1091 | const SCEV *Denominator) | ||||||
1092 | : SE(S), Denominator(Denominator) { | ||||||
1093 | Zero = SE.getZero(Denominator->getType()); | ||||||
1094 | One = SE.getOne(Denominator->getType()); | ||||||
1095 | |||||||
1096 | // We generally do not know how to divide Expr by Denominator. We | ||||||
1097 | // initialize the division to a "cannot divide" state to simplify the rest | ||||||
1098 | // of the code. | ||||||
1099 | cannotDivide(Numerator); | ||||||
1100 | } | ||||||
1101 | |||||||
1102 | // Convenience function for giving up on the division. We set the quotient to | ||||||
1103 | // be equal to zero and the remainder to be equal to the numerator. | ||||||
1104 | void cannotDivide(const SCEV *Numerator) { | ||||||
1105 | Quotient = Zero; | ||||||
1106 | Remainder = Numerator; | ||||||
1107 | } | ||||||
1108 | |||||||
1109 | ScalarEvolution &SE; | ||||||
1110 | const SCEV *Denominator, *Quotient, *Remainder, *Zero, *One; | ||||||
1111 | }; | ||||||
1112 | |||||||
1113 | } // end anonymous namespace | ||||||
1114 | |||||||
1115 | //===----------------------------------------------------------------------===// | ||||||
1116 | // Simple SCEV method implementations | ||||||
1117 | //===----------------------------------------------------------------------===// | ||||||
1118 | |||||||
1119 | /// Compute BC(It, K). The result has width W. Assume, K > 0. | ||||||
1120 | static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K, | ||||||
1121 | ScalarEvolution &SE, | ||||||
1122 | Type *ResultTy) { | ||||||
1123 | // Handle the simplest case efficiently. | ||||||
1124 | if (K == 1) | ||||||
1125 | return SE.getTruncateOrZeroExtend(It, ResultTy); | ||||||
1126 | |||||||
1127 | // We are using the following formula for BC(It, K): | ||||||
1128 | // | ||||||
1129 | // BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / K! | ||||||
1130 | // | ||||||
1131 | // Suppose, W is the bitwidth of the return value. We must be prepared for | ||||||
1132 | // overflow. Hence, we must assure that the result of our computation is | ||||||
1133 | // equal to the accurate one modulo 2^W. Unfortunately, division isn't | ||||||
1134 | // safe in modular arithmetic. | ||||||
1135 | // | ||||||
1136 | // However, this code doesn't use exactly that formula; the formula it uses | ||||||
1137 | // is something like the following, where T is the number of factors of 2 in | ||||||
1138 | // K! (i.e. trailing zeros in the binary representation of K!), and ^ is | ||||||
1139 | // exponentiation: | ||||||
1140 | // | ||||||
1141 | // BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / 2^T / (K! / 2^T) | ||||||
1142 | // | ||||||
1143 | // This formula is trivially equivalent to the previous formula. However, | ||||||
1144 | // this formula can be implemented much more efficiently. The trick is that | ||||||
1145 | // K! / 2^T is odd, and exact division by an odd number *is* safe in modular | ||||||
1146 | // arithmetic. To do exact division in modular arithmetic, all we have | ||||||
1147 | // to do is multiply by the inverse. Therefore, this step can be done at | ||||||
1148 | // width W. | ||||||
1149 | // | ||||||
1150 | // The next issue is how to safely do the division by 2^T. The way this | ||||||
1151 | // is done is by doing the multiplication step at a width of at least W + T | ||||||
1152 | // bits. This way, the bottom W+T bits of the product are accurate. Then, | ||||||
1153 | // when we perform the division by 2^T (which is equivalent to a right shift | ||||||
1154 | // by T), the bottom W bits are accurate. Extra bits are okay; they'll get | ||||||
1155 | // truncated out after the division by 2^T. | ||||||
1156 | // | ||||||
1157 | // In comparison to just directly using the first formula, this technique | ||||||
1158 | // is much more efficient; using the first formula requires W * K bits, | ||||||
1159 | // but this formula less than W + K bits. Also, the first formula requires | ||||||
1160 | // a division step, whereas this formula only requires multiplies and shifts. | ||||||
1161 | // | ||||||
1162 | // It doesn't matter whether the subtraction step is done in the calculation | ||||||
1163 | // width or the input iteration count's width; if the subtraction overflows, | ||||||
1164 | // the result must be zero anyway. We prefer here to do it in the width of | ||||||
1165 | // the induction variable because it helps a lot for certain cases; CodeGen | ||||||
1166 | // isn't smart enough to ignore the overflow, which leads to much less | ||||||
1167 | // efficient code if the width of the subtraction is wider than the native | ||||||
1168 | // register width. | ||||||
1169 | // | ||||||
1170 | // (It's possible to not widen at all by pulling out factors of 2 before | ||||||
1171 | // the multiplication; for example, K=2 can be calculated as | ||||||
1172 | // It/2*(It+(It*INT_MIN/INT_MIN)+-1). However, it requires | ||||||
1173 | // extra arithmetic, so it's not an obvious win, and it gets | ||||||
1174 | // much more complicated for K > 3.) | ||||||
1175 | |||||||
1176 | // Protection from insane SCEVs; this bound is conservative, | ||||||
1177 | // but it probably doesn't matter. | ||||||
1178 | if (K > 1000) | ||||||
1179 | return SE.getCouldNotCompute(); | ||||||
1180 | |||||||
1181 | unsigned W = SE.getTypeSizeInBits(ResultTy); | ||||||
1182 | |||||||
1183 | // Calculate K! / 2^T and T; we divide out the factors of two before | ||||||
1184 | // multiplying for calculating K! / 2^T to avoid overflow. | ||||||
1185 | // Other overflow doesn't matter because we only care about the bottom | ||||||
1186 | // W bits of the result. | ||||||
1187 | APInt OddFactorial(W, 1); | ||||||
1188 | unsigned T = 1; | ||||||
1189 | for (unsigned i = 3; i <= K; ++i) { | ||||||
1190 | APInt Mult(W, i); | ||||||
1191 | unsigned TwoFactors = Mult.countTrailingZeros(); | ||||||
1192 | T += TwoFactors; | ||||||
1193 | Mult.lshrInPlace(TwoFactors); | ||||||
1194 | OddFactorial *= Mult; | ||||||
1195 | } | ||||||
1196 | |||||||
1197 | // We need at least W + T bits for the multiplication step | ||||||
1198 | unsigned CalculationBits = W + T; | ||||||
1199 | |||||||
1200 | // Calculate 2^T, at width T+W. | ||||||
1201 | APInt DivFactor = APInt::getOneBitSet(CalculationBits, T); | ||||||
1202 | |||||||
1203 | // Calculate the multiplicative inverse of K! / 2^T; | ||||||
1204 | // this multiplication factor will perform the exact division by | ||||||
1205 | // K! / 2^T. | ||||||
1206 | APInt Mod = APInt::getSignedMinValue(W+1); | ||||||
1207 | APInt MultiplyFactor = OddFactorial.zext(W+1); | ||||||
1208 | MultiplyFactor = MultiplyFactor.multiplicativeInverse(Mod); | ||||||
1209 | MultiplyFactor = MultiplyFactor.trunc(W); | ||||||
1210 | |||||||
1211 | // Calculate the product, at width T+W | ||||||
1212 | IntegerType *CalculationTy = IntegerType::get(SE.getContext(), | ||||||
1213 | CalculationBits); | ||||||
1214 | const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy); | ||||||
1215 | for (unsigned i = 1; i != K; ++i) { | ||||||
1216 | const SCEV *S = SE.getMinusSCEV(It, SE.getConstant(It->getType(), i)); | ||||||
1217 | Dividend = SE.getMulExpr(Dividend, | ||||||
1218 | SE.getTruncateOrZeroExtend(S, CalculationTy)); | ||||||
1219 | } | ||||||
1220 | |||||||
1221 | // Divide by 2^T | ||||||
1222 | const SCEV *DivResult = SE.getUDivExpr(Dividend, SE.getConstant(DivFactor)); | ||||||
1223 | |||||||
1224 | // Truncate the result, and divide by K! / 2^T. | ||||||
1225 | |||||||
1226 | return SE.getMulExpr(SE.getConstant(MultiplyFactor), | ||||||
1227 | SE.getTruncateOrZeroExtend(DivResult, ResultTy)); | ||||||
1228 | } | ||||||
1229 | |||||||
1230 | /// Return the value of this chain of recurrences at the specified iteration | ||||||
1231 | /// number. We can evaluate this recurrence by multiplying each element in the | ||||||
1232 | /// chain by the binomial coefficient corresponding to it. In other words, we | ||||||
1233 | /// can evaluate {A,+,B,+,C,+,D} as: | ||||||
1234 | /// | ||||||
1235 | /// A*BC(It, 0) + B*BC(It, 1) + C*BC(It, 2) + D*BC(It, 3) | ||||||
1236 | /// | ||||||
1237 | /// where BC(It, k) stands for binomial coefficient. | ||||||
1238 | const SCEV *SCEVAddRecExpr::evaluateAtIteration(const SCEV *It, | ||||||
1239 | ScalarEvolution &SE) const { | ||||||
1240 | const SCEV *Result = getStart(); | ||||||
1241 | for (unsigned i = 1, e = getNumOperands(); i != e; ++i) { | ||||||
1242 | // The computation is correct in the face of overflow provided that the | ||||||
1243 | // multiplication is performed _after_ the evaluation of the binomial | ||||||
1244 | // coefficient. | ||||||
1245 | const SCEV *Coeff = BinomialCoefficient(It, i, SE, getType()); | ||||||
1246 | if (isa<SCEVCouldNotCompute>(Coeff)) | ||||||
1247 | return Coeff; | ||||||
1248 | |||||||
1249 | Result = SE.getAddExpr(Result, SE.getMulExpr(getOperand(i), Coeff)); | ||||||
1250 | } | ||||||
1251 | return Result; | ||||||
1252 | } | ||||||
1253 | |||||||
1254 | //===----------------------------------------------------------------------===// | ||||||
1255 | // SCEV Expression folder implementations | ||||||
1256 | //===----------------------------------------------------------------------===// | ||||||
1257 | |||||||
1258 | const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op, Type *Ty, | ||||||
1259 | unsigned Depth) { | ||||||
1260 | assert(getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) > getTypeSizeInBits( Ty) && "This is not a truncating conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) && \"This is not a truncating conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1261, __PRETTY_FUNCTION__)) | ||||||
1261 | "This is not a truncating conversion!")((getTypeSizeInBits(Op->getType()) > getTypeSizeInBits( Ty) && "This is not a truncating conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) && \"This is not a truncating conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1261, __PRETTY_FUNCTION__)); | ||||||
1262 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1263, __PRETTY_FUNCTION__)) | ||||||
1263 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1263, __PRETTY_FUNCTION__)); | ||||||
1264 | Ty = getEffectiveSCEVType(Ty); | ||||||
1265 | |||||||
1266 | FoldingSetNodeID ID; | ||||||
1267 | ID.AddInteger(scTruncate); | ||||||
1268 | ID.AddPointer(Op); | ||||||
1269 | ID.AddPointer(Ty); | ||||||
1270 | void *IP = nullptr; | ||||||
1271 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
1272 | |||||||
1273 | // Fold if the operand is constant. | ||||||
1274 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
1275 | return getConstant( | ||||||
1276 | cast<ConstantInt>(ConstantExpr::getTrunc(SC->getValue(), Ty))); | ||||||
1277 | |||||||
1278 | // trunc(trunc(x)) --> trunc(x) | ||||||
1279 | if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) | ||||||
1280 | return getTruncateExpr(ST->getOperand(), Ty, Depth + 1); | ||||||
1281 | |||||||
1282 | // trunc(sext(x)) --> sext(x) if widening or trunc(x) if narrowing | ||||||
1283 | if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op)) | ||||||
1284 | return getTruncateOrSignExtend(SS->getOperand(), Ty, Depth + 1); | ||||||
1285 | |||||||
1286 | // trunc(zext(x)) --> zext(x) if widening or trunc(x) if narrowing | ||||||
1287 | if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op)) | ||||||
1288 | return getTruncateOrZeroExtend(SZ->getOperand(), Ty, Depth + 1); | ||||||
1289 | |||||||
1290 | if (Depth > MaxCastDepth) { | ||||||
1291 | SCEV *S = | ||||||
1292 | new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator), Op, Ty); | ||||||
1293 | UniqueSCEVs.InsertNode(S, IP); | ||||||
1294 | addToLoopUseLists(S); | ||||||
1295 | return S; | ||||||
1296 | } | ||||||
1297 | |||||||
1298 | // trunc(x1 + ... + xN) --> trunc(x1) + ... + trunc(xN) and | ||||||
1299 | // trunc(x1 * ... * xN) --> trunc(x1) * ... * trunc(xN), | ||||||
1300 | // if after transforming we have at most one truncate, not counting truncates | ||||||
1301 | // that replace other casts. | ||||||
1302 | if (isa<SCEVAddExpr>(Op) || isa<SCEVMulExpr>(Op)) { | ||||||
1303 | auto *CommOp = cast<SCEVCommutativeExpr>(Op); | ||||||
1304 | SmallVector<const SCEV *, 4> Operands; | ||||||
1305 | unsigned numTruncs = 0; | ||||||
1306 | for (unsigned i = 0, e = CommOp->getNumOperands(); i != e && numTruncs < 2; | ||||||
1307 | ++i) { | ||||||
1308 | const SCEV *S = getTruncateExpr(CommOp->getOperand(i), Ty, Depth + 1); | ||||||
1309 | if (!isa<SCEVCastExpr>(CommOp->getOperand(i)) && isa<SCEVTruncateExpr>(S)) | ||||||
1310 | numTruncs++; | ||||||
1311 | Operands.push_back(S); | ||||||
1312 | } | ||||||
1313 | if (numTruncs < 2) { | ||||||
1314 | if (isa<SCEVAddExpr>(Op)) | ||||||
1315 | return getAddExpr(Operands); | ||||||
1316 | else if (isa<SCEVMulExpr>(Op)) | ||||||
1317 | return getMulExpr(Operands); | ||||||
1318 | else | ||||||
1319 | llvm_unreachable("Unexpected SCEV type for Op.")::llvm::llvm_unreachable_internal("Unexpected SCEV type for Op." , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1319); | ||||||
1320 | } | ||||||
1321 | // Although we checked in the beginning that ID is not in the cache, it is | ||||||
1322 | // possible that during recursion and different modification ID was inserted | ||||||
1323 | // into the cache. So if we find it, just return it. | ||||||
1324 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) | ||||||
1325 | return S; | ||||||
1326 | } | ||||||
1327 | |||||||
1328 | // If the input value is a chrec scev, truncate the chrec's operands. | ||||||
1329 | if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) { | ||||||
1330 | SmallVector<const SCEV *, 4> Operands; | ||||||
1331 | for (const SCEV *Op : AddRec->operands()) | ||||||
1332 | Operands.push_back(getTruncateExpr(Op, Ty, Depth + 1)); | ||||||
1333 | return getAddRecExpr(Operands, AddRec->getLoop(), SCEV::FlagAnyWrap); | ||||||
1334 | } | ||||||
1335 | |||||||
1336 | // The cast wasn't folded; create an explicit cast node. We can reuse | ||||||
1337 | // the existing insert position since if we get here, we won't have | ||||||
1338 | // made any changes which would invalidate it. | ||||||
1339 | SCEV *S = new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator), | ||||||
1340 | Op, Ty); | ||||||
1341 | UniqueSCEVs.InsertNode(S, IP); | ||||||
1342 | addToLoopUseLists(S); | ||||||
1343 | return S; | ||||||
1344 | } | ||||||
1345 | |||||||
1346 | // Get the limit of a recurrence such that incrementing by Step cannot cause | ||||||
1347 | // signed overflow as long as the value of the recurrence within the | ||||||
1348 | // loop does not exceed this limit before incrementing. | ||||||
1349 | static const SCEV *getSignedOverflowLimitForStep(const SCEV *Step, | ||||||
1350 | ICmpInst::Predicate *Pred, | ||||||
1351 | ScalarEvolution *SE) { | ||||||
1352 | unsigned BitWidth = SE->getTypeSizeInBits(Step->getType()); | ||||||
1353 | if (SE->isKnownPositive(Step)) { | ||||||
1354 | *Pred = ICmpInst::ICMP_SLT; | ||||||
1355 | return SE->getConstant(APInt::getSignedMinValue(BitWidth) - | ||||||
1356 | SE->getSignedRangeMax(Step)); | ||||||
1357 | } | ||||||
1358 | if (SE->isKnownNegative(Step)) { | ||||||
1359 | *Pred = ICmpInst::ICMP_SGT; | ||||||
1360 | return SE->getConstant(APInt::getSignedMaxValue(BitWidth) - | ||||||
1361 | SE->getSignedRangeMin(Step)); | ||||||
1362 | } | ||||||
1363 | return nullptr; | ||||||
1364 | } | ||||||
1365 | |||||||
1366 | // Get the limit of a recurrence such that incrementing by Step cannot cause | ||||||
1367 | // unsigned overflow as long as the value of the recurrence within the loop does | ||||||
1368 | // not exceed this limit before incrementing. | ||||||
1369 | static const SCEV *getUnsignedOverflowLimitForStep(const SCEV *Step, | ||||||
1370 | ICmpInst::Predicate *Pred, | ||||||
1371 | ScalarEvolution *SE) { | ||||||
1372 | unsigned BitWidth = SE->getTypeSizeInBits(Step->getType()); | ||||||
1373 | *Pred = ICmpInst::ICMP_ULT; | ||||||
1374 | |||||||
1375 | return SE->getConstant(APInt::getMinValue(BitWidth) - | ||||||
1376 | SE->getUnsignedRangeMax(Step)); | ||||||
1377 | } | ||||||
1378 | |||||||
1379 | namespace { | ||||||
1380 | |||||||
1381 | struct ExtendOpTraitsBase { | ||||||
1382 | typedef const SCEV *(ScalarEvolution::*GetExtendExprTy)(const SCEV *, Type *, | ||||||
1383 | unsigned); | ||||||
1384 | }; | ||||||
1385 | |||||||
1386 | // Used to make code generic over signed and unsigned overflow. | ||||||
1387 | template <typename ExtendOp> struct ExtendOpTraits { | ||||||
1388 | // Members present: | ||||||
1389 | // | ||||||
1390 | // static const SCEV::NoWrapFlags WrapType; | ||||||
1391 | // | ||||||
1392 | // static const ExtendOpTraitsBase::GetExtendExprTy GetExtendExpr; | ||||||
1393 | // | ||||||
1394 | // static const SCEV *getOverflowLimitForStep(const SCEV *Step, | ||||||
1395 | // ICmpInst::Predicate *Pred, | ||||||
1396 | // ScalarEvolution *SE); | ||||||
1397 | }; | ||||||
1398 | |||||||
1399 | template <> | ||||||
1400 | struct ExtendOpTraits<SCEVSignExtendExpr> : public ExtendOpTraitsBase { | ||||||
1401 | static const SCEV::NoWrapFlags WrapType = SCEV::FlagNSW; | ||||||
1402 | |||||||
1403 | static const GetExtendExprTy GetExtendExpr; | ||||||
1404 | |||||||
1405 | static const SCEV *getOverflowLimitForStep(const SCEV *Step, | ||||||
1406 | ICmpInst::Predicate *Pred, | ||||||
1407 | ScalarEvolution *SE) { | ||||||
1408 | return getSignedOverflowLimitForStep(Step, Pred, SE); | ||||||
1409 | } | ||||||
1410 | }; | ||||||
1411 | |||||||
1412 | const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits< | ||||||
1413 | SCEVSignExtendExpr>::GetExtendExpr = &ScalarEvolution::getSignExtendExpr; | ||||||
1414 | |||||||
1415 | template <> | ||||||
1416 | struct ExtendOpTraits<SCEVZeroExtendExpr> : public ExtendOpTraitsBase { | ||||||
1417 | static const SCEV::NoWrapFlags WrapType = SCEV::FlagNUW; | ||||||
1418 | |||||||
1419 | static const GetExtendExprTy GetExtendExpr; | ||||||
1420 | |||||||
1421 | static const SCEV *getOverflowLimitForStep(const SCEV *Step, | ||||||
1422 | ICmpInst::Predicate *Pred, | ||||||
1423 | ScalarEvolution *SE) { | ||||||
1424 | return getUnsignedOverflowLimitForStep(Step, Pred, SE); | ||||||
1425 | } | ||||||
1426 | }; | ||||||
1427 | |||||||
1428 | const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits< | ||||||
1429 | SCEVZeroExtendExpr>::GetExtendExpr = &ScalarEvolution::getZeroExtendExpr; | ||||||
1430 | |||||||
1431 | } // end anonymous namespace | ||||||
1432 | |||||||
1433 | // The recurrence AR has been shown to have no signed/unsigned wrap or something | ||||||
1434 | // close to it. Typically, if we can prove NSW/NUW for AR, then we can just as | ||||||
1435 | // easily prove NSW/NUW for its preincrement or postincrement sibling. This | ||||||
1436 | // allows normalizing a sign/zero extended AddRec as such: {sext/zext(Step + | ||||||
1437 | // Start),+,Step} => {(Step + sext/zext(Start),+,Step} As a result, the | ||||||
1438 | // expression "Step + sext/zext(PreIncAR)" is congruent with | ||||||
1439 | // "sext/zext(PostIncAR)" | ||||||
1440 | template <typename ExtendOpTy> | ||||||
1441 | static const SCEV *getPreStartForExtend(const SCEVAddRecExpr *AR, Type *Ty, | ||||||
1442 | ScalarEvolution *SE, unsigned Depth) { | ||||||
1443 | auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType; | ||||||
1444 | auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr; | ||||||
1445 | |||||||
1446 | const Loop *L = AR->getLoop(); | ||||||
1447 | const SCEV *Start = AR->getStart(); | ||||||
1448 | const SCEV *Step = AR->getStepRecurrence(*SE); | ||||||
1449 | |||||||
1450 | // Check for a simple looking step prior to loop entry. | ||||||
1451 | const SCEVAddExpr *SA = dyn_cast<SCEVAddExpr>(Start); | ||||||
1452 | if (!SA) | ||||||
1453 | return nullptr; | ||||||
1454 | |||||||
1455 | // Create an AddExpr for "PreStart" after subtracting Step. Full SCEV | ||||||
1456 | // subtraction is expensive. For this purpose, perform a quick and dirty | ||||||
1457 | // difference, by checking for Step in the operand list. | ||||||
1458 | SmallVector<const SCEV *, 4> DiffOps; | ||||||
1459 | for (const SCEV *Op : SA->operands()) | ||||||
1460 | if (Op != Step) | ||||||
1461 | DiffOps.push_back(Op); | ||||||
1462 | |||||||
1463 | if (DiffOps.size() == SA->getNumOperands()) | ||||||
1464 | return nullptr; | ||||||
1465 | |||||||
1466 | // Try to prove `WrapType` (SCEV::FlagNSW or SCEV::FlagNUW) on `PreStart` + | ||||||
1467 | // `Step`: | ||||||
1468 | |||||||
1469 | // 1. NSW/NUW flags on the step increment. | ||||||
1470 | auto PreStartFlags = | ||||||
1471 | ScalarEvolution::maskFlags(SA->getNoWrapFlags(), SCEV::FlagNUW); | ||||||
1472 | const SCEV *PreStart = SE->getAddExpr(DiffOps, PreStartFlags); | ||||||
1473 | const SCEVAddRecExpr *PreAR = dyn_cast<SCEVAddRecExpr>( | ||||||
1474 | SE->getAddRecExpr(PreStart, Step, L, SCEV::FlagAnyWrap)); | ||||||
1475 | |||||||
1476 | // "{S,+,X} is <nsw>/<nuw>" and "the backedge is taken at least once" implies | ||||||
1477 | // "S+X does not sign/unsign-overflow". | ||||||
1478 | // | ||||||
1479 | |||||||
1480 | const SCEV *BECount = SE->getBackedgeTakenCount(L); | ||||||
1481 | if (PreAR && PreAR->getNoWrapFlags(WrapType) && | ||||||
1482 | !isa<SCEVCouldNotCompute>(BECount) && SE->isKnownPositive(BECount)) | ||||||
1483 | return PreStart; | ||||||
1484 | |||||||
1485 | // 2. Direct overflow check on the step operation's expression. | ||||||
1486 | unsigned BitWidth = SE->getTypeSizeInBits(AR->getType()); | ||||||
1487 | Type *WideTy = IntegerType::get(SE->getContext(), BitWidth * 2); | ||||||
1488 | const SCEV *OperandExtendedStart = | ||||||
1489 | SE->getAddExpr((SE->*GetExtendExpr)(PreStart, WideTy, Depth), | ||||||
1490 | (SE->*GetExtendExpr)(Step, WideTy, Depth)); | ||||||
1491 | if ((SE->*GetExtendExpr)(Start, WideTy, Depth) == OperandExtendedStart) { | ||||||
1492 | if (PreAR && AR->getNoWrapFlags(WrapType)) { | ||||||
1493 | // If we know `AR` == {`PreStart`+`Step`,+,`Step`} is `WrapType` (FlagNSW | ||||||
1494 | // or FlagNUW) and that `PreStart` + `Step` is `WrapType` too, then | ||||||
1495 | // `PreAR` == {`PreStart`,+,`Step`} is also `WrapType`. Cache this fact. | ||||||
1496 | const_cast<SCEVAddRecExpr *>(PreAR)->setNoWrapFlags(WrapType); | ||||||
1497 | } | ||||||
1498 | return PreStart; | ||||||
1499 | } | ||||||
1500 | |||||||
1501 | // 3. Loop precondition. | ||||||
1502 | ICmpInst::Predicate Pred; | ||||||
1503 | const SCEV *OverflowLimit = | ||||||
1504 | ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(Step, &Pred, SE); | ||||||
1505 | |||||||
1506 | if (OverflowLimit && | ||||||
1507 | SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit)) | ||||||
1508 | return PreStart; | ||||||
1509 | |||||||
1510 | return nullptr; | ||||||
1511 | } | ||||||
1512 | |||||||
1513 | // Get the normalized zero or sign extended expression for this AddRec's Start. | ||||||
1514 | template <typename ExtendOpTy> | ||||||
1515 | static const SCEV *getExtendAddRecStart(const SCEVAddRecExpr *AR, Type *Ty, | ||||||
1516 | ScalarEvolution *SE, | ||||||
1517 | unsigned Depth) { | ||||||
1518 | auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr; | ||||||
1519 | |||||||
1520 | const SCEV *PreStart = getPreStartForExtend<ExtendOpTy>(AR, Ty, SE, Depth); | ||||||
1521 | if (!PreStart) | ||||||
1522 | return (SE->*GetExtendExpr)(AR->getStart(), Ty, Depth); | ||||||
1523 | |||||||
1524 | return SE->getAddExpr((SE->*GetExtendExpr)(AR->getStepRecurrence(*SE), Ty, | ||||||
1525 | Depth), | ||||||
1526 | (SE->*GetExtendExpr)(PreStart, Ty, Depth)); | ||||||
1527 | } | ||||||
1528 | |||||||
1529 | // Try to prove away overflow by looking at "nearby" add recurrences. A | ||||||
1530 | // motivating example for this rule: if we know `{0,+,4}` is `ult` `-1` and it | ||||||
1531 | // does not itself wrap then we can conclude that `{1,+,4}` is `nuw`. | ||||||
1532 | // | ||||||
1533 | // Formally: | ||||||
1534 | // | ||||||
1535 | // {S,+,X} == {S-T,+,X} + T | ||||||
1536 | // => Ext({S,+,X}) == Ext({S-T,+,X} + T) | ||||||
1537 | // | ||||||
1538 | // If ({S-T,+,X} + T) does not overflow ... (1) | ||||||
1539 | // | ||||||
1540 | // RHS == Ext({S-T,+,X} + T) == Ext({S-T,+,X}) + Ext(T) | ||||||
1541 | // | ||||||
1542 | // If {S-T,+,X} does not overflow ... (2) | ||||||
1543 | // | ||||||
1544 | // RHS == Ext({S-T,+,X}) + Ext(T) == {Ext(S-T),+,Ext(X)} + Ext(T) | ||||||
1545 | // == {Ext(S-T)+Ext(T),+,Ext(X)} | ||||||
1546 | // | ||||||
1547 | // If (S-T)+T does not overflow ... (3) | ||||||
1548 | // | ||||||
1549 | // RHS == {Ext(S-T)+Ext(T),+,Ext(X)} == {Ext(S-T+T),+,Ext(X)} | ||||||
1550 | // == {Ext(S),+,Ext(X)} == LHS | ||||||
1551 | // | ||||||
1552 | // Thus, if (1), (2) and (3) are true for some T, then | ||||||
1553 | // Ext({S,+,X}) == {Ext(S),+,Ext(X)} | ||||||
1554 | // | ||||||
1555 | // (3) is implied by (1) -- "(S-T)+T does not overflow" is simply "({S-T,+,X}+T) | ||||||
1556 | // does not overflow" restricted to the 0th iteration. Therefore we only need | ||||||
1557 | // to check for (1) and (2). | ||||||
1558 | // | ||||||
1559 | // In the current context, S is `Start`, X is `Step`, Ext is `ExtendOpTy` and T | ||||||
1560 | // is `Delta` (defined below). | ||||||
1561 | template <typename ExtendOpTy> | ||||||
1562 | bool ScalarEvolution::proveNoWrapByVaryingStart(const SCEV *Start, | ||||||
1563 | const SCEV *Step, | ||||||
1564 | const Loop *L) { | ||||||
1565 | auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType; | ||||||
1566 | |||||||
1567 | // We restrict `Start` to a constant to prevent SCEV from spending too much | ||||||
1568 | // time here. It is correct (but more expensive) to continue with a | ||||||
1569 | // non-constant `Start` and do a general SCEV subtraction to compute | ||||||
1570 | // `PreStart` below. | ||||||
1571 | const SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start); | ||||||
1572 | if (!StartC) | ||||||
1573 | return false; | ||||||
1574 | |||||||
1575 | APInt StartAI = StartC->getAPInt(); | ||||||
1576 | |||||||
1577 | for (unsigned Delta : {-2, -1, 1, 2}) { | ||||||
1578 | const SCEV *PreStart = getConstant(StartAI - Delta); | ||||||
1579 | |||||||
1580 | FoldingSetNodeID ID; | ||||||
1581 | ID.AddInteger(scAddRecExpr); | ||||||
1582 | ID.AddPointer(PreStart); | ||||||
1583 | ID.AddPointer(Step); | ||||||
1584 | ID.AddPointer(L); | ||||||
1585 | void *IP = nullptr; | ||||||
1586 | const auto *PreAR = | ||||||
1587 | static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
1588 | |||||||
1589 | // Give up if we don't already have the add recurrence we need because | ||||||
1590 | // actually constructing an add recurrence is relatively expensive. | ||||||
1591 | if (PreAR && PreAR->getNoWrapFlags(WrapType)) { // proves (2) | ||||||
1592 | const SCEV *DeltaS = getConstant(StartC->getType(), Delta); | ||||||
1593 | ICmpInst::Predicate Pred = ICmpInst::BAD_ICMP_PREDICATE; | ||||||
1594 | const SCEV *Limit = ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep( | ||||||
1595 | DeltaS, &Pred, this); | ||||||
1596 | if (Limit && isKnownPredicate(Pred, PreAR, Limit)) // proves (1) | ||||||
1597 | return true; | ||||||
1598 | } | ||||||
1599 | } | ||||||
1600 | |||||||
1601 | return false; | ||||||
1602 | } | ||||||
1603 | |||||||
1604 | // Finds an integer D for an expression (C + x + y + ...) such that the top | ||||||
1605 | // level addition in (D + (C - D + x + y + ...)) would not wrap (signed or | ||||||
1606 | // unsigned) and the number of trailing zeros of (C - D + x + y + ...) is | ||||||
1607 | // maximized, where C is the \p ConstantTerm, x, y, ... are arbitrary SCEVs, and | ||||||
1608 | // the (C + x + y + ...) expression is \p WholeAddExpr. | ||||||
1609 | static APInt extractConstantWithoutWrapping(ScalarEvolution &SE, | ||||||
1610 | const SCEVConstant *ConstantTerm, | ||||||
1611 | const SCEVAddExpr *WholeAddExpr) { | ||||||
1612 | const APInt C = ConstantTerm->getAPInt(); | ||||||
1613 | const unsigned BitWidth = C.getBitWidth(); | ||||||
1614 | // Find number of trailing zeros of (x + y + ...) w/o the C first: | ||||||
1615 | uint32_t TZ = BitWidth; | ||||||
1616 | for (unsigned I = 1, E = WholeAddExpr->getNumOperands(); I < E && TZ; ++I) | ||||||
1617 | TZ = std::min(TZ, SE.GetMinTrailingZeros(WholeAddExpr->getOperand(I))); | ||||||
1618 | if (TZ) { | ||||||
1619 | // Set D to be as many least significant bits of C as possible while still | ||||||
1620 | // guaranteeing that adding D to (C - D + x + y + ...) won't cause a wrap: | ||||||
1621 | return TZ < BitWidth ? C.trunc(TZ).zext(BitWidth) : C; | ||||||
1622 | } | ||||||
1623 | return APInt(BitWidth, 0); | ||||||
1624 | } | ||||||
1625 | |||||||
1626 | // Finds an integer D for an affine AddRec expression {C,+,x} such that the top | ||||||
1627 | // level addition in (D + {C-D,+,x}) would not wrap (signed or unsigned) and the | ||||||
1628 | // number of trailing zeros of (C - D + x * n) is maximized, where C is the \p | ||||||
1629 | // ConstantStart, x is an arbitrary \p Step, and n is the loop trip count. | ||||||
1630 | static APInt extractConstantWithoutWrapping(ScalarEvolution &SE, | ||||||
1631 | const APInt &ConstantStart, | ||||||
1632 | const SCEV *Step) { | ||||||
1633 | const unsigned BitWidth = ConstantStart.getBitWidth(); | ||||||
1634 | const uint32_t TZ = SE.GetMinTrailingZeros(Step); | ||||||
1635 | if (TZ) | ||||||
1636 | return TZ < BitWidth ? ConstantStart.trunc(TZ).zext(BitWidth) | ||||||
1637 | : ConstantStart; | ||||||
1638 | return APInt(BitWidth, 0); | ||||||
1639 | } | ||||||
1640 | |||||||
1641 | const SCEV * | ||||||
1642 | ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) { | ||||||
1643 | assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1644, __PRETTY_FUNCTION__)) | ||||||
1644 | "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1644, __PRETTY_FUNCTION__)); | ||||||
1645 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1646, __PRETTY_FUNCTION__)) | ||||||
1646 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1646, __PRETTY_FUNCTION__)); | ||||||
1647 | Ty = getEffectiveSCEVType(Ty); | ||||||
1648 | |||||||
1649 | // Fold if the operand is constant. | ||||||
1650 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
1651 | return getConstant( | ||||||
1652 | cast<ConstantInt>(ConstantExpr::getZExt(SC->getValue(), Ty))); | ||||||
1653 | |||||||
1654 | // zext(zext(x)) --> zext(x) | ||||||
1655 | if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op)) | ||||||
1656 | return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1); | ||||||
1657 | |||||||
1658 | // Before doing any expensive analysis, check to see if we've already | ||||||
1659 | // computed a SCEV for this Op and Ty. | ||||||
1660 | FoldingSetNodeID ID; | ||||||
1661 | ID.AddInteger(scZeroExtend); | ||||||
1662 | ID.AddPointer(Op); | ||||||
1663 | ID.AddPointer(Ty); | ||||||
1664 | void *IP = nullptr; | ||||||
1665 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
1666 | if (Depth > MaxCastDepth) { | ||||||
1667 | SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator), | ||||||
1668 | Op, Ty); | ||||||
1669 | UniqueSCEVs.InsertNode(S, IP); | ||||||
1670 | addToLoopUseLists(S); | ||||||
1671 | return S; | ||||||
1672 | } | ||||||
1673 | |||||||
1674 | // zext(trunc(x)) --> zext(x) or x or trunc(x) | ||||||
1675 | if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) { | ||||||
1676 | // It's possible the bits taken off by the truncate were all zero bits. If | ||||||
1677 | // so, we should be able to simplify this further. | ||||||
1678 | const SCEV *X = ST->getOperand(); | ||||||
1679 | ConstantRange CR = getUnsignedRange(X); | ||||||
1680 | unsigned TruncBits = getTypeSizeInBits(ST->getType()); | ||||||
1681 | unsigned NewBits = getTypeSizeInBits(Ty); | ||||||
1682 | if (CR.truncate(TruncBits).zeroExtend(NewBits).contains( | ||||||
1683 | CR.zextOrTrunc(NewBits))) | ||||||
1684 | return getTruncateOrZeroExtend(X, Ty, Depth); | ||||||
1685 | } | ||||||
1686 | |||||||
1687 | // If the input value is a chrec scev, and we can prove that the value | ||||||
1688 | // did not overflow the old, smaller, value, we can zero extend all of the | ||||||
1689 | // operands (often constants). This allows analysis of something like | ||||||
1690 | // this: for (unsigned char X = 0; X < 100; ++X) { int Y = X; } | ||||||
1691 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) | ||||||
1692 | if (AR->isAffine()) { | ||||||
1693 | const SCEV *Start = AR->getStart(); | ||||||
1694 | const SCEV *Step = AR->getStepRecurrence(*this); | ||||||
1695 | unsigned BitWidth = getTypeSizeInBits(AR->getType()); | ||||||
1696 | const Loop *L = AR->getLoop(); | ||||||
1697 | |||||||
1698 | if (!AR->hasNoUnsignedWrap()) { | ||||||
1699 | auto NewFlags = proveNoWrapViaConstantRanges(AR); | ||||||
1700 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags); | ||||||
1701 | } | ||||||
1702 | |||||||
1703 | // If we have special knowledge that this addrec won't overflow, | ||||||
1704 | // we don't need to do any further analysis. | ||||||
1705 | if (AR->hasNoUnsignedWrap()) | ||||||
1706 | return getAddRecExpr( | ||||||
1707 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
1708 | getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
1709 | |||||||
1710 | // Check whether the backedge-taken count is SCEVCouldNotCompute. | ||||||
1711 | // Note that this serves two purposes: It filters out loops that are | ||||||
1712 | // simply not analyzable, and it covers the case where this code is | ||||||
1713 | // being called from within backedge-taken count analysis, such that | ||||||
1714 | // attempting to ask for the backedge-taken count would likely result | ||||||
1715 | // in infinite recursion. In the later case, the analysis code will | ||||||
1716 | // cope with a conservative value, and it will take care to purge | ||||||
1717 | // that value once it has finished. | ||||||
1718 | const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L); | ||||||
1719 | if (!isa<SCEVCouldNotCompute>(MaxBECount)) { | ||||||
1720 | // Manually compute the final value for AR, checking for | ||||||
1721 | // overflow. | ||||||
1722 | |||||||
1723 | // Check whether the backedge-taken count can be losslessly casted to | ||||||
1724 | // the addrec's type. The count is always unsigned. | ||||||
1725 | const SCEV *CastedMaxBECount = | ||||||
1726 | getTruncateOrZeroExtend(MaxBECount, Start->getType(), Depth); | ||||||
1727 | const SCEV *RecastedMaxBECount = getTruncateOrZeroExtend( | ||||||
1728 | CastedMaxBECount, MaxBECount->getType(), Depth); | ||||||
1729 | if (MaxBECount == RecastedMaxBECount) { | ||||||
1730 | Type *WideTy = IntegerType::get(getContext(), BitWidth * 2); | ||||||
1731 | // Check whether Start+Step*MaxBECount has no unsigned overflow. | ||||||
1732 | const SCEV *ZMul = getMulExpr(CastedMaxBECount, Step, | ||||||
1733 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
1734 | const SCEV *ZAdd = getZeroExtendExpr(getAddExpr(Start, ZMul, | ||||||
1735 | SCEV::FlagAnyWrap, | ||||||
1736 | Depth + 1), | ||||||
1737 | WideTy, Depth + 1); | ||||||
1738 | const SCEV *WideStart = getZeroExtendExpr(Start, WideTy, Depth + 1); | ||||||
1739 | const SCEV *WideMaxBECount = | ||||||
1740 | getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1); | ||||||
1741 | const SCEV *OperandExtendedAdd = | ||||||
1742 | getAddExpr(WideStart, | ||||||
1743 | getMulExpr(WideMaxBECount, | ||||||
1744 | getZeroExtendExpr(Step, WideTy, Depth + 1), | ||||||
1745 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
1746 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
1747 | if (ZAdd == OperandExtendedAdd) { | ||||||
1748 | // Cache knowledge of AR NUW, which is propagated to this AddRec. | ||||||
1749 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW); | ||||||
1750 | // Return the expression with the addrec on the outside. | ||||||
1751 | return getAddRecExpr( | ||||||
1752 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
1753 | Depth + 1), | ||||||
1754 | getZeroExtendExpr(Step, Ty, Depth + 1), L, | ||||||
1755 | AR->getNoWrapFlags()); | ||||||
1756 | } | ||||||
1757 | // Similar to above, only this time treat the step value as signed. | ||||||
1758 | // This covers loops that count down. | ||||||
1759 | OperandExtendedAdd = | ||||||
1760 | getAddExpr(WideStart, | ||||||
1761 | getMulExpr(WideMaxBECount, | ||||||
1762 | getSignExtendExpr(Step, WideTy, Depth + 1), | ||||||
1763 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
1764 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
1765 | if (ZAdd == OperandExtendedAdd) { | ||||||
1766 | // Cache knowledge of AR NW, which is propagated to this AddRec. | ||||||
1767 | // Negative step causes unsigned wrap, but it still can't self-wrap. | ||||||
1768 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW); | ||||||
1769 | // Return the expression with the addrec on the outside. | ||||||
1770 | return getAddRecExpr( | ||||||
1771 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
1772 | Depth + 1), | ||||||
1773 | getSignExtendExpr(Step, Ty, Depth + 1), L, | ||||||
1774 | AR->getNoWrapFlags()); | ||||||
1775 | } | ||||||
1776 | } | ||||||
1777 | } | ||||||
1778 | |||||||
1779 | // Normally, in the cases we can prove no-overflow via a | ||||||
1780 | // backedge guarding condition, we can also compute a backedge | ||||||
1781 | // taken count for the loop. The exceptions are assumptions and | ||||||
1782 | // guards present in the loop -- SCEV is not great at exploiting | ||||||
1783 | // these to compute max backedge taken counts, but can still use | ||||||
1784 | // these to prove lack of overflow. Use this fact to avoid | ||||||
1785 | // doing extra work that may not pay off. | ||||||
1786 | if (!isa<SCEVCouldNotCompute>(MaxBECount) || HasGuards || | ||||||
1787 | !AC.assumptions().empty()) { | ||||||
1788 | // If the backedge is guarded by a comparison with the pre-inc | ||||||
1789 | // value the addrec is safe. Also, if the entry is guarded by | ||||||
1790 | // a comparison with the start value and the backedge is | ||||||
1791 | // guarded by a comparison with the post-inc value, the addrec | ||||||
1792 | // is safe. | ||||||
1793 | if (isKnownPositive(Step)) { | ||||||
1794 | const SCEV *N = getConstant(APInt::getMinValue(BitWidth) - | ||||||
1795 | getUnsignedRangeMax(Step)); | ||||||
1796 | if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT, AR, N) || | ||||||
1797 | isKnownOnEveryIteration(ICmpInst::ICMP_ULT, AR, N)) { | ||||||
1798 | // Cache knowledge of AR NUW, which is propagated to this | ||||||
1799 | // AddRec. | ||||||
1800 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW); | ||||||
1801 | // Return the expression with the addrec on the outside. | ||||||
1802 | return getAddRecExpr( | ||||||
1803 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
1804 | Depth + 1), | ||||||
1805 | getZeroExtendExpr(Step, Ty, Depth + 1), L, | ||||||
1806 | AR->getNoWrapFlags()); | ||||||
1807 | } | ||||||
1808 | } else if (isKnownNegative(Step)) { | ||||||
1809 | const SCEV *N = getConstant(APInt::getMaxValue(BitWidth) - | ||||||
1810 | getSignedRangeMin(Step)); | ||||||
1811 | if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT, AR, N) || | ||||||
1812 | isKnownOnEveryIteration(ICmpInst::ICMP_UGT, AR, N)) { | ||||||
1813 | // Cache knowledge of AR NW, which is propagated to this | ||||||
1814 | // AddRec. Negative step causes unsigned wrap, but it | ||||||
1815 | // still can't self-wrap. | ||||||
1816 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW); | ||||||
1817 | // Return the expression with the addrec on the outside. | ||||||
1818 | return getAddRecExpr( | ||||||
1819 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
1820 | Depth + 1), | ||||||
1821 | getSignExtendExpr(Step, Ty, Depth + 1), L, | ||||||
1822 | AR->getNoWrapFlags()); | ||||||
1823 | } | ||||||
1824 | } | ||||||
1825 | } | ||||||
1826 | |||||||
1827 | // zext({C,+,Step}) --> (zext(D) + zext({C-D,+,Step}))<nuw><nsw> | ||||||
1828 | // if D + (C - D + Step * n) could be proven to not unsigned wrap | ||||||
1829 | // where D maximizes the number of trailing zeros of (C - D + Step * n) | ||||||
1830 | if (const auto *SC = dyn_cast<SCEVConstant>(Start)) { | ||||||
1831 | const APInt &C = SC->getAPInt(); | ||||||
1832 | const APInt &D = extractConstantWithoutWrapping(*this, C, Step); | ||||||
1833 | if (D != 0) { | ||||||
1834 | const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth); | ||||||
1835 | const SCEV *SResidual = | ||||||
1836 | getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags()); | ||||||
1837 | const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1); | ||||||
1838 | return getAddExpr(SZExtD, SZExtR, | ||||||
1839 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
1840 | Depth + 1); | ||||||
1841 | } | ||||||
1842 | } | ||||||
1843 | |||||||
1844 | if (proveNoWrapByVaryingStart<SCEVZeroExtendExpr>(Start, Step, L)) { | ||||||
1845 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW); | ||||||
1846 | return getAddRecExpr( | ||||||
1847 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
1848 | getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
1849 | } | ||||||
1850 | } | ||||||
1851 | |||||||
1852 | // zext(A % B) --> zext(A) % zext(B) | ||||||
1853 | { | ||||||
1854 | const SCEV *LHS; | ||||||
1855 | const SCEV *RHS; | ||||||
1856 | if (matchURem(Op, LHS, RHS)) | ||||||
1857 | return getURemExpr(getZeroExtendExpr(LHS, Ty, Depth + 1), | ||||||
1858 | getZeroExtendExpr(RHS, Ty, Depth + 1)); | ||||||
1859 | } | ||||||
1860 | |||||||
1861 | // zext(A / B) --> zext(A) / zext(B). | ||||||
1862 | if (auto *Div = dyn_cast<SCEVUDivExpr>(Op)) | ||||||
1863 | return getUDivExpr(getZeroExtendExpr(Div->getLHS(), Ty, Depth + 1), | ||||||
1864 | getZeroExtendExpr(Div->getRHS(), Ty, Depth + 1)); | ||||||
1865 | |||||||
1866 | if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) { | ||||||
1867 | // zext((A + B + ...)<nuw>) --> (zext(A) + zext(B) + ...)<nuw> | ||||||
1868 | if (SA->hasNoUnsignedWrap()) { | ||||||
1869 | // If the addition does not unsign overflow then we can, by definition, | ||||||
1870 | // commute the zero extension with the addition operation. | ||||||
1871 | SmallVector<const SCEV *, 4> Ops; | ||||||
1872 | for (const auto *Op : SA->operands()) | ||||||
1873 | Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1)); | ||||||
1874 | return getAddExpr(Ops, SCEV::FlagNUW, Depth + 1); | ||||||
1875 | } | ||||||
1876 | |||||||
1877 | // zext(C + x + y + ...) --> (zext(D) + zext((C - D) + x + y + ...)) | ||||||
1878 | // if D + (C - D + x + y + ...) could be proven to not unsigned wrap | ||||||
1879 | // where D maximizes the number of trailing zeros of (C - D + x + y + ...) | ||||||
1880 | // | ||||||
1881 | // Often address arithmetics contain expressions like | ||||||
1882 | // (zext (add (shl X, C1), C2)), for instance, (zext (5 + (4 * X))). | ||||||
1883 | // This transformation is useful while proving that such expressions are | ||||||
1884 | // equal or differ by a small constant amount, see LoadStoreVectorizer pass. | ||||||
1885 | if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) { | ||||||
1886 | const APInt &D = extractConstantWithoutWrapping(*this, SC, SA); | ||||||
1887 | if (D != 0) { | ||||||
1888 | const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth); | ||||||
1889 | const SCEV *SResidual = | ||||||
1890 | getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth); | ||||||
1891 | const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1); | ||||||
1892 | return getAddExpr(SZExtD, SZExtR, | ||||||
1893 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
1894 | Depth + 1); | ||||||
1895 | } | ||||||
1896 | } | ||||||
1897 | } | ||||||
1898 | |||||||
1899 | if (auto *SM = dyn_cast<SCEVMulExpr>(Op)) { | ||||||
1900 | // zext((A * B * ...)<nuw>) --> (zext(A) * zext(B) * ...)<nuw> | ||||||
1901 | if (SM->hasNoUnsignedWrap()) { | ||||||
1902 | // If the multiply does not unsign overflow then we can, by definition, | ||||||
1903 | // commute the zero extension with the multiply operation. | ||||||
1904 | SmallVector<const SCEV *, 4> Ops; | ||||||
1905 | for (const auto *Op : SM->operands()) | ||||||
1906 | Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1)); | ||||||
1907 | return getMulExpr(Ops, SCEV::FlagNUW, Depth + 1); | ||||||
1908 | } | ||||||
1909 | |||||||
1910 | // zext(2^K * (trunc X to iN)) to iM -> | ||||||
1911 | // 2^K * (zext(trunc X to i{N-K}) to iM)<nuw> | ||||||
1912 | // | ||||||
1913 | // Proof: | ||||||
1914 | // | ||||||
1915 | // zext(2^K * (trunc X to iN)) to iM | ||||||
1916 | // = zext((trunc X to iN) << K) to iM | ||||||
1917 | // = zext((trunc X to i{N-K}) << K)<nuw> to iM | ||||||
1918 | // (because shl removes the top K bits) | ||||||
1919 | // = zext((2^K * (trunc X to i{N-K}))<nuw>) to iM | ||||||
1920 | // = (2^K * (zext(trunc X to i{N-K}) to iM))<nuw>. | ||||||
1921 | // | ||||||
1922 | if (SM->getNumOperands() == 2) | ||||||
1923 | if (auto *MulLHS = dyn_cast<SCEVConstant>(SM->getOperand(0))) | ||||||
1924 | if (MulLHS->getAPInt().isPowerOf2()) | ||||||
1925 | if (auto *TruncRHS = dyn_cast<SCEVTruncateExpr>(SM->getOperand(1))) { | ||||||
1926 | int NewTruncBits = getTypeSizeInBits(TruncRHS->getType()) - | ||||||
1927 | MulLHS->getAPInt().logBase2(); | ||||||
1928 | Type *NewTruncTy = IntegerType::get(getContext(), NewTruncBits); | ||||||
1929 | return getMulExpr( | ||||||
1930 | getZeroExtendExpr(MulLHS, Ty), | ||||||
1931 | getZeroExtendExpr( | ||||||
1932 | getTruncateExpr(TruncRHS->getOperand(), NewTruncTy), Ty), | ||||||
1933 | SCEV::FlagNUW, Depth + 1); | ||||||
1934 | } | ||||||
1935 | } | ||||||
1936 | |||||||
1937 | // The cast wasn't folded; create an explicit cast node. | ||||||
1938 | // Recompute the insert position, as it may have been invalidated. | ||||||
1939 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
1940 | SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator), | ||||||
1941 | Op, Ty); | ||||||
1942 | UniqueSCEVs.InsertNode(S, IP); | ||||||
1943 | addToLoopUseLists(S); | ||||||
1944 | return S; | ||||||
1945 | } | ||||||
1946 | |||||||
1947 | const SCEV * | ||||||
1948 | ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) { | ||||||
1949 | assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1950, __PRETTY_FUNCTION__)) | ||||||
1950 | "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1950, __PRETTY_FUNCTION__)); | ||||||
1951 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1952, __PRETTY_FUNCTION__)) | ||||||
1952 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 1952, __PRETTY_FUNCTION__)); | ||||||
1953 | Ty = getEffectiveSCEVType(Ty); | ||||||
1954 | |||||||
1955 | // Fold if the operand is constant. | ||||||
1956 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
1957 | return getConstant( | ||||||
1958 | cast<ConstantInt>(ConstantExpr::getSExt(SC->getValue(), Ty))); | ||||||
1959 | |||||||
1960 | // sext(sext(x)) --> sext(x) | ||||||
1961 | if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op)) | ||||||
1962 | return getSignExtendExpr(SS->getOperand(), Ty, Depth + 1); | ||||||
1963 | |||||||
1964 | // sext(zext(x)) --> zext(x) | ||||||
1965 | if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op)) | ||||||
1966 | return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1); | ||||||
1967 | |||||||
1968 | // Before doing any expensive analysis, check to see if we've already | ||||||
1969 | // computed a SCEV for this Op and Ty. | ||||||
1970 | FoldingSetNodeID ID; | ||||||
1971 | ID.AddInteger(scSignExtend); | ||||||
1972 | ID.AddPointer(Op); | ||||||
1973 | ID.AddPointer(Ty); | ||||||
1974 | void *IP = nullptr; | ||||||
1975 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
1976 | // Limit recursion depth. | ||||||
1977 | if (Depth > MaxCastDepth) { | ||||||
1978 | SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator), | ||||||
1979 | Op, Ty); | ||||||
1980 | UniqueSCEVs.InsertNode(S, IP); | ||||||
1981 | addToLoopUseLists(S); | ||||||
1982 | return S; | ||||||
1983 | } | ||||||
1984 | |||||||
1985 | // sext(trunc(x)) --> sext(x) or x or trunc(x) | ||||||
1986 | if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) { | ||||||
1987 | // It's possible the bits taken off by the truncate were all sign bits. If | ||||||
1988 | // so, we should be able to simplify this further. | ||||||
1989 | const SCEV *X = ST->getOperand(); | ||||||
1990 | ConstantRange CR = getSignedRange(X); | ||||||
1991 | unsigned TruncBits = getTypeSizeInBits(ST->getType()); | ||||||
1992 | unsigned NewBits = getTypeSizeInBits(Ty); | ||||||
1993 | if (CR.truncate(TruncBits).signExtend(NewBits).contains( | ||||||
1994 | CR.sextOrTrunc(NewBits))) | ||||||
1995 | return getTruncateOrSignExtend(X, Ty, Depth); | ||||||
1996 | } | ||||||
1997 | |||||||
1998 | if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) { | ||||||
1999 | // sext((A + B + ...)<nsw>) --> (sext(A) + sext(B) + ...)<nsw> | ||||||
2000 | if (SA->hasNoSignedWrap()) { | ||||||
2001 | // If the addition does not sign overflow then we can, by definition, | ||||||
2002 | // commute the sign extension with the addition operation. | ||||||
2003 | SmallVector<const SCEV *, 4> Ops; | ||||||
2004 | for (const auto *Op : SA->operands()) | ||||||
2005 | Ops.push_back(getSignExtendExpr(Op, Ty, Depth + 1)); | ||||||
2006 | return getAddExpr(Ops, SCEV::FlagNSW, Depth + 1); | ||||||
2007 | } | ||||||
2008 | |||||||
2009 | // sext(C + x + y + ...) --> (sext(D) + sext((C - D) + x + y + ...)) | ||||||
2010 | // if D + (C - D + x + y + ...) could be proven to not signed wrap | ||||||
2011 | // where D maximizes the number of trailing zeros of (C - D + x + y + ...) | ||||||
2012 | // | ||||||
2013 | // For instance, this will bring two seemingly different expressions: | ||||||
2014 | // 1 + sext(5 + 20 * %x + 24 * %y) and | ||||||
2015 | // sext(6 + 20 * %x + 24 * %y) | ||||||
2016 | // to the same form: | ||||||
2017 | // 2 + sext(4 + 20 * %x + 24 * %y) | ||||||
2018 | if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) { | ||||||
2019 | const APInt &D = extractConstantWithoutWrapping(*this, SC, SA); | ||||||
2020 | if (D != 0) { | ||||||
2021 | const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth); | ||||||
2022 | const SCEV *SResidual = | ||||||
2023 | getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth); | ||||||
2024 | const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1); | ||||||
2025 | return getAddExpr(SSExtD, SSExtR, | ||||||
2026 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
2027 | Depth + 1); | ||||||
2028 | } | ||||||
2029 | } | ||||||
2030 | } | ||||||
2031 | // If the input value is a chrec scev, and we can prove that the value | ||||||
2032 | // did not overflow the old, smaller, value, we can sign extend all of the | ||||||
2033 | // operands (often constants). This allows analysis of something like | ||||||
2034 | // this: for (signed char X = 0; X < 100; ++X) { int Y = X; } | ||||||
2035 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) | ||||||
2036 | if (AR->isAffine()) { | ||||||
2037 | const SCEV *Start = AR->getStart(); | ||||||
2038 | const SCEV *Step = AR->getStepRecurrence(*this); | ||||||
2039 | unsigned BitWidth = getTypeSizeInBits(AR->getType()); | ||||||
2040 | const Loop *L = AR->getLoop(); | ||||||
2041 | |||||||
2042 | if (!AR->hasNoSignedWrap()) { | ||||||
2043 | auto NewFlags = proveNoWrapViaConstantRanges(AR); | ||||||
2044 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags); | ||||||
2045 | } | ||||||
2046 | |||||||
2047 | // If we have special knowledge that this addrec won't overflow, | ||||||
2048 | // we don't need to do any further analysis. | ||||||
2049 | if (AR->hasNoSignedWrap()) | ||||||
2050 | return getAddRecExpr( | ||||||
2051 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
2052 | getSignExtendExpr(Step, Ty, Depth + 1), L, SCEV::FlagNSW); | ||||||
2053 | |||||||
2054 | // Check whether the backedge-taken count is SCEVCouldNotCompute. | ||||||
2055 | // Note that this serves two purposes: It filters out loops that are | ||||||
2056 | // simply not analyzable, and it covers the case where this code is | ||||||
2057 | // being called from within backedge-taken count analysis, such that | ||||||
2058 | // attempting to ask for the backedge-taken count would likely result | ||||||
2059 | // in infinite recursion. In the later case, the analysis code will | ||||||
2060 | // cope with a conservative value, and it will take care to purge | ||||||
2061 | // that value once it has finished. | ||||||
2062 | const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L); | ||||||
2063 | if (!isa<SCEVCouldNotCompute>(MaxBECount)) { | ||||||
2064 | // Manually compute the final value for AR, checking for | ||||||
2065 | // overflow. | ||||||
2066 | |||||||
2067 | // Check whether the backedge-taken count can be losslessly casted to | ||||||
2068 | // the addrec's type. The count is always unsigned. | ||||||
2069 | const SCEV *CastedMaxBECount = | ||||||
2070 | getTruncateOrZeroExtend(MaxBECount, Start->getType(), Depth); | ||||||
2071 | const SCEV *RecastedMaxBECount = getTruncateOrZeroExtend( | ||||||
2072 | CastedMaxBECount, MaxBECount->getType(), Depth); | ||||||
2073 | if (MaxBECount == RecastedMaxBECount) { | ||||||
2074 | Type *WideTy = IntegerType::get(getContext(), BitWidth * 2); | ||||||
2075 | // Check whether Start+Step*MaxBECount has no signed overflow. | ||||||
2076 | const SCEV *SMul = getMulExpr(CastedMaxBECount, Step, | ||||||
2077 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
2078 | const SCEV *SAdd = getSignExtendExpr(getAddExpr(Start, SMul, | ||||||
2079 | SCEV::FlagAnyWrap, | ||||||
2080 | Depth + 1), | ||||||
2081 | WideTy, Depth + 1); | ||||||
2082 | const SCEV *WideStart = getSignExtendExpr(Start, WideTy, Depth + 1); | ||||||
2083 | const SCEV *WideMaxBECount = | ||||||
2084 | getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1); | ||||||
2085 | const SCEV *OperandExtendedAdd = | ||||||
2086 | getAddExpr(WideStart, | ||||||
2087 | getMulExpr(WideMaxBECount, | ||||||
2088 | getSignExtendExpr(Step, WideTy, Depth + 1), | ||||||
2089 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
2090 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
2091 | if (SAdd == OperandExtendedAdd) { | ||||||
2092 | // Cache knowledge of AR NSW, which is propagated to this AddRec. | ||||||
2093 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW); | ||||||
2094 | // Return the expression with the addrec on the outside. | ||||||
2095 | return getAddRecExpr( | ||||||
2096 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, | ||||||
2097 | Depth + 1), | ||||||
2098 | getSignExtendExpr(Step, Ty, Depth + 1), L, | ||||||
2099 | AR->getNoWrapFlags()); | ||||||
2100 | } | ||||||
2101 | // Similar to above, only this time treat the step value as unsigned. | ||||||
2102 | // This covers loops that count up with an unsigned step. | ||||||
2103 | OperandExtendedAdd = | ||||||
2104 | getAddExpr(WideStart, | ||||||
2105 | getMulExpr(WideMaxBECount, | ||||||
2106 | getZeroExtendExpr(Step, WideTy, Depth + 1), | ||||||
2107 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
2108 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
2109 | if (SAdd == OperandExtendedAdd) { | ||||||
2110 | // If AR wraps around then | ||||||
2111 | // | ||||||
2112 | // abs(Step) * MaxBECount > unsigned-max(AR->getType()) | ||||||
2113 | // => SAdd != OperandExtendedAdd | ||||||
2114 | // | ||||||
2115 | // Thus (AR is not NW => SAdd != OperandExtendedAdd) <=> | ||||||
2116 | // (SAdd == OperandExtendedAdd => AR is NW) | ||||||
2117 | |||||||
2118 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW); | ||||||
2119 | |||||||
2120 | // Return the expression with the addrec on the outside. | ||||||
2121 | return getAddRecExpr( | ||||||
2122 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, | ||||||
2123 | Depth + 1), | ||||||
2124 | getZeroExtendExpr(Step, Ty, Depth + 1), L, | ||||||
2125 | AR->getNoWrapFlags()); | ||||||
2126 | } | ||||||
2127 | } | ||||||
2128 | } | ||||||
2129 | |||||||
2130 | // Normally, in the cases we can prove no-overflow via a | ||||||
2131 | // backedge guarding condition, we can also compute a backedge | ||||||
2132 | // taken count for the loop. The exceptions are assumptions and | ||||||
2133 | // guards present in the loop -- SCEV is not great at exploiting | ||||||
2134 | // these to compute max backedge taken counts, but can still use | ||||||
2135 | // these to prove lack of overflow. Use this fact to avoid | ||||||
2136 | // doing extra work that may not pay off. | ||||||
2137 | |||||||
2138 | if (!isa<SCEVCouldNotCompute>(MaxBECount) || HasGuards || | ||||||
2139 | !AC.assumptions().empty()) { | ||||||
2140 | // If the backedge is guarded by a comparison with the pre-inc | ||||||
2141 | // value the addrec is safe. Also, if the entry is guarded by | ||||||
2142 | // a comparison with the start value and the backedge is | ||||||
2143 | // guarded by a comparison with the post-inc value, the addrec | ||||||
2144 | // is safe. | ||||||
2145 | ICmpInst::Predicate Pred; | ||||||
2146 | const SCEV *OverflowLimit = | ||||||
2147 | getSignedOverflowLimitForStep(Step, &Pred, this); | ||||||
2148 | if (OverflowLimit && | ||||||
2149 | (isLoopBackedgeGuardedByCond(L, Pred, AR, OverflowLimit) || | ||||||
2150 | isKnownOnEveryIteration(Pred, AR, OverflowLimit))) { | ||||||
2151 | // Cache knowledge of AR NSW, then propagate NSW to the wide AddRec. | ||||||
2152 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW); | ||||||
2153 | return getAddRecExpr( | ||||||
2154 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
2155 | getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
2156 | } | ||||||
2157 | } | ||||||
2158 | |||||||
2159 | // sext({C,+,Step}) --> (sext(D) + sext({C-D,+,Step}))<nuw><nsw> | ||||||
2160 | // if D + (C - D + Step * n) could be proven to not signed wrap | ||||||
2161 | // where D maximizes the number of trailing zeros of (C - D + Step * n) | ||||||
2162 | if (const auto *SC = dyn_cast<SCEVConstant>(Start)) { | ||||||
2163 | const APInt &C = SC->getAPInt(); | ||||||
2164 | const APInt &D = extractConstantWithoutWrapping(*this, C, Step); | ||||||
2165 | if (D != 0) { | ||||||
2166 | const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth); | ||||||
2167 | const SCEV *SResidual = | ||||||
2168 | getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags()); | ||||||
2169 | const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1); | ||||||
2170 | return getAddExpr(SSExtD, SSExtR, | ||||||
2171 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
2172 | Depth + 1); | ||||||
2173 | } | ||||||
2174 | } | ||||||
2175 | |||||||
2176 | if (proveNoWrapByVaryingStart<SCEVSignExtendExpr>(Start, Step, L)) { | ||||||
2177 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW); | ||||||
2178 | return getAddRecExpr( | ||||||
2179 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
2180 | getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
2181 | } | ||||||
2182 | } | ||||||
2183 | |||||||
2184 | // If the input value is provably positive and we could not simplify | ||||||
2185 | // away the sext build a zext instead. | ||||||
2186 | if (isKnownNonNegative(Op)) | ||||||
2187 | return getZeroExtendExpr(Op, Ty, Depth + 1); | ||||||
2188 | |||||||
2189 | // The cast wasn't folded; create an explicit cast node. | ||||||
2190 | // Recompute the insert position, as it may have been invalidated. | ||||||
2191 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
2192 | SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator), | ||||||
2193 | Op, Ty); | ||||||
2194 | UniqueSCEVs.InsertNode(S, IP); | ||||||
2195 | addToLoopUseLists(S); | ||||||
2196 | return S; | ||||||
2197 | } | ||||||
2198 | |||||||
2199 | /// getAnyExtendExpr - Return a SCEV for the given operand extended with | ||||||
2200 | /// unspecified bits out to the given type. | ||||||
2201 | const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op, | ||||||
2202 | Type *Ty) { | ||||||
2203 | assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2204, __PRETTY_FUNCTION__)) | ||||||
2204 | "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2204, __PRETTY_FUNCTION__)); | ||||||
2205 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2206, __PRETTY_FUNCTION__)) | ||||||
2206 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2206, __PRETTY_FUNCTION__)); | ||||||
2207 | Ty = getEffectiveSCEVType(Ty); | ||||||
2208 | |||||||
2209 | // Sign-extend negative constants. | ||||||
2210 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
2211 | if (SC->getAPInt().isNegative()) | ||||||
2212 | return getSignExtendExpr(Op, Ty); | ||||||
2213 | |||||||
2214 | // Peel off a truncate cast. | ||||||
2215 | if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Op)) { | ||||||
2216 | const SCEV *NewOp = T->getOperand(); | ||||||
2217 | if (getTypeSizeInBits(NewOp->getType()) < getTypeSizeInBits(Ty)) | ||||||
2218 | return getAnyExtendExpr(NewOp, Ty); | ||||||
2219 | return getTruncateOrNoop(NewOp, Ty); | ||||||
2220 | } | ||||||
2221 | |||||||
2222 | // Next try a zext cast. If the cast is folded, use it. | ||||||
2223 | const SCEV *ZExt = getZeroExtendExpr(Op, Ty); | ||||||
2224 | if (!isa<SCEVZeroExtendExpr>(ZExt)) | ||||||
2225 | return ZExt; | ||||||
2226 | |||||||
2227 | // Next try a sext cast. If the cast is folded, use it. | ||||||
2228 | const SCEV *SExt = getSignExtendExpr(Op, Ty); | ||||||
2229 | if (!isa<SCEVSignExtendExpr>(SExt)) | ||||||
2230 | return SExt; | ||||||
2231 | |||||||
2232 | // Force the cast to be folded into the operands of an addrec. | ||||||
2233 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) { | ||||||
2234 | SmallVector<const SCEV *, 4> Ops; | ||||||
2235 | for (const SCEV *Op : AR->operands()) | ||||||
2236 | Ops.push_back(getAnyExtendExpr(Op, Ty)); | ||||||
2237 | return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagNW); | ||||||
2238 | } | ||||||
2239 | |||||||
2240 | // If the expression is obviously signed, use the sext cast value. | ||||||
2241 | if (isa<SCEVSMaxExpr>(Op)) | ||||||
2242 | return SExt; | ||||||
2243 | |||||||
2244 | // Absent any other information, use the zext cast value. | ||||||
2245 | return ZExt; | ||||||
2246 | } | ||||||
2247 | |||||||
2248 | /// Process the given Ops list, which is a list of operands to be added under | ||||||
2249 | /// the given scale, update the given map. This is a helper function for | ||||||
2250 | /// getAddRecExpr. As an example of what it does, given a sequence of operands | ||||||
2251 | /// that would form an add expression like this: | ||||||
2252 | /// | ||||||
2253 | /// m + n + 13 + (A * (o + p + (B * (q + m + 29)))) + r + (-1 * r) | ||||||
2254 | /// | ||||||
2255 | /// where A and B are constants, update the map with these values: | ||||||
2256 | /// | ||||||
2257 | /// (m, 1+A*B), (n, 1), (o, A), (p, A), (q, A*B), (r, 0) | ||||||
2258 | /// | ||||||
2259 | /// and add 13 + A*B*29 to AccumulatedConstant. | ||||||
2260 | /// This will allow getAddRecExpr to produce this: | ||||||
2261 | /// | ||||||
2262 | /// 13+A*B*29 + n + (m * (1+A*B)) + ((o + p) * A) + (q * A*B) | ||||||
2263 | /// | ||||||
2264 | /// This form often exposes folding opportunities that are hidden in | ||||||
2265 | /// the original operand list. | ||||||
2266 | /// | ||||||
2267 | /// Return true iff it appears that any interesting folding opportunities | ||||||
2268 | /// may be exposed. This helps getAddRecExpr short-circuit extra work in | ||||||
2269 | /// the common case where no interesting opportunities are present, and | ||||||
2270 | /// is also used as a check to avoid infinite recursion. | ||||||
2271 | static bool | ||||||
2272 | CollectAddOperandsWithScales(DenseMap<const SCEV *, APInt> &M, | ||||||
2273 | SmallVectorImpl<const SCEV *> &NewOps, | ||||||
2274 | APInt &AccumulatedConstant, | ||||||
2275 | const SCEV *const *Ops, size_t NumOperands, | ||||||
2276 | const APInt &Scale, | ||||||
2277 | ScalarEvolution &SE) { | ||||||
2278 | bool Interesting = false; | ||||||
2279 | |||||||
2280 | // Iterate over the add operands. They are sorted, with constants first. | ||||||
2281 | unsigned i = 0; | ||||||
2282 | while (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) { | ||||||
2283 | ++i; | ||||||
2284 | // Pull a buried constant out to the outside. | ||||||
2285 | if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero()) | ||||||
2286 | Interesting = true; | ||||||
2287 | AccumulatedConstant += Scale * C->getAPInt(); | ||||||
2288 | } | ||||||
2289 | |||||||
2290 | // Next comes everything else. We're especially interested in multiplies | ||||||
2291 | // here, but they're in the middle, so just visit the rest with one loop. | ||||||
2292 | for (; i != NumOperands; ++i) { | ||||||
2293 | const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[i]); | ||||||
2294 | if (Mul && isa<SCEVConstant>(Mul->getOperand(0))) { | ||||||
2295 | APInt NewScale = | ||||||
2296 | Scale * cast<SCEVConstant>(Mul->getOperand(0))->getAPInt(); | ||||||
2297 | if (Mul->getNumOperands() == 2 && isa<SCEVAddExpr>(Mul->getOperand(1))) { | ||||||
2298 | // A multiplication of a constant with another add; recurse. | ||||||
2299 | const SCEVAddExpr *Add = cast<SCEVAddExpr>(Mul->getOperand(1)); | ||||||
2300 | Interesting |= | ||||||
2301 | CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant, | ||||||
2302 | Add->op_begin(), Add->getNumOperands(), | ||||||
2303 | NewScale, SE); | ||||||
2304 | } else { | ||||||
2305 | // A multiplication of a constant with some other value. Update | ||||||
2306 | // the map. | ||||||
2307 | SmallVector<const SCEV *, 4> MulOps(Mul->op_begin()+1, Mul->op_end()); | ||||||
2308 | const SCEV *Key = SE.getMulExpr(MulOps); | ||||||
2309 | auto Pair = M.insert({Key, NewScale}); | ||||||
2310 | if (Pair.second) { | ||||||
2311 | NewOps.push_back(Pair.first->first); | ||||||
2312 | } else { | ||||||
2313 | Pair.first->second += NewScale; | ||||||
2314 | // The map already had an entry for this value, which may indicate | ||||||
2315 | // a folding opportunity. | ||||||
2316 | Interesting = true; | ||||||
2317 | } | ||||||
2318 | } | ||||||
2319 | } else { | ||||||
2320 | // An ordinary operand. Update the map. | ||||||
2321 | std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair = | ||||||
2322 | M.insert({Ops[i], Scale}); | ||||||
2323 | if (Pair.second) { | ||||||
2324 | NewOps.push_back(Pair.first->first); | ||||||
2325 | } else { | ||||||
2326 | Pair.first->second += Scale; | ||||||
2327 | // The map already had an entry for this value, which may indicate | ||||||
2328 | // a folding opportunity. | ||||||
2329 | Interesting = true; | ||||||
2330 | } | ||||||
2331 | } | ||||||
2332 | } | ||||||
2333 | |||||||
2334 | return Interesting; | ||||||
2335 | } | ||||||
2336 | |||||||
2337 | // We're trying to construct a SCEV of type `Type' with `Ops' as operands and | ||||||
2338 | // `OldFlags' as can't-wrap behavior. Infer a more aggressive set of | ||||||
2339 | // can't-overflow flags for the operation if possible. | ||||||
2340 | static SCEV::NoWrapFlags | ||||||
2341 | StrengthenNoWrapFlags(ScalarEvolution *SE, SCEVTypes Type, | ||||||
2342 | const ArrayRef<const SCEV *> Ops, | ||||||
2343 | SCEV::NoWrapFlags Flags) { | ||||||
2344 | using namespace std::placeholders; | ||||||
2345 | |||||||
2346 | using OBO = OverflowingBinaryOperator; | ||||||
2347 | |||||||
2348 | bool CanAnalyze = | ||||||
2349 | Type == scAddExpr || Type == scAddRecExpr || Type == scMulExpr; | ||||||
2350 | (void)CanAnalyze; | ||||||
2351 | assert(CanAnalyze && "don't call from other places!")((CanAnalyze && "don't call from other places!") ? static_cast <void> (0) : __assert_fail ("CanAnalyze && \"don't call from other places!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2351, __PRETTY_FUNCTION__)); | ||||||
2352 | |||||||
2353 | int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW; | ||||||
2354 | SCEV::NoWrapFlags SignOrUnsignWrap = | ||||||
2355 | ScalarEvolution::maskFlags(Flags, SignOrUnsignMask); | ||||||
2356 | |||||||
2357 | // If FlagNSW is true and all the operands are non-negative, infer FlagNUW. | ||||||
2358 | auto IsKnownNonNegative = [&](const SCEV *S) { | ||||||
2359 | return SE->isKnownNonNegative(S); | ||||||
2360 | }; | ||||||
2361 | |||||||
2362 | if (SignOrUnsignWrap == SCEV::FlagNSW && all_of(Ops, IsKnownNonNegative)) | ||||||
2363 | Flags = | ||||||
2364 | ScalarEvolution::setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask); | ||||||
2365 | |||||||
2366 | SignOrUnsignWrap = ScalarEvolution::maskFlags(Flags, SignOrUnsignMask); | ||||||
2367 | |||||||
2368 | if (SignOrUnsignWrap != SignOrUnsignMask && | ||||||
2369 | (Type == scAddExpr || Type == scMulExpr) && Ops.size() == 2 && | ||||||
2370 | isa<SCEVConstant>(Ops[0])) { | ||||||
2371 | |||||||
2372 | auto Opcode = [&] { | ||||||
2373 | switch (Type) { | ||||||
2374 | case scAddExpr: | ||||||
2375 | return Instruction::Add; | ||||||
2376 | case scMulExpr: | ||||||
2377 | return Instruction::Mul; | ||||||
2378 | default: | ||||||
2379 | llvm_unreachable("Unexpected SCEV op.")::llvm::llvm_unreachable_internal("Unexpected SCEV op.", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2379); | ||||||
2380 | } | ||||||
2381 | }(); | ||||||
2382 | |||||||
2383 | const APInt &C = cast<SCEVConstant>(Ops[0])->getAPInt(); | ||||||
2384 | |||||||
2385 | // (A <opcode> C) --> (A <opcode> C)<nsw> if the op doesn't sign overflow. | ||||||
2386 | if (!(SignOrUnsignWrap & SCEV::FlagNSW)) { | ||||||
2387 | auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
2388 | Opcode, C, OBO::NoSignedWrap); | ||||||
2389 | if (NSWRegion.contains(SE->getSignedRange(Ops[1]))) | ||||||
2390 | Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW); | ||||||
2391 | } | ||||||
2392 | |||||||
2393 | // (A <opcode> C) --> (A <opcode> C)<nuw> if the op doesn't unsign overflow. | ||||||
2394 | if (!(SignOrUnsignWrap & SCEV::FlagNUW)) { | ||||||
2395 | auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
2396 | Opcode, C, OBO::NoUnsignedWrap); | ||||||
2397 | if (NUWRegion.contains(SE->getUnsignedRange(Ops[1]))) | ||||||
2398 | Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW); | ||||||
2399 | } | ||||||
2400 | } | ||||||
2401 | |||||||
2402 | return Flags; | ||||||
2403 | } | ||||||
2404 | |||||||
2405 | bool ScalarEvolution::isAvailableAtLoopEntry(const SCEV *S, const Loop *L) { | ||||||
2406 | return isLoopInvariant(S, L) && properlyDominates(S, L->getHeader()); | ||||||
2407 | } | ||||||
2408 | |||||||
2409 | /// Get a canonical add expression, or something simpler if possible. | ||||||
2410 | const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops, | ||||||
2411 | SCEV::NoWrapFlags Flags, | ||||||
2412 | unsigned Depth) { | ||||||
2413 | assert(!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) &&((!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && "only nuw or nsw allowed" ) ? static_cast<void> (0) : __assert_fail ("!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2414, __PRETTY_FUNCTION__)) | ||||||
2414 | "only nuw or nsw allowed")((!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && "only nuw or nsw allowed" ) ? static_cast<void> (0) : __assert_fail ("!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2414, __PRETTY_FUNCTION__)); | ||||||
2415 | assert(!Ops.empty() && "Cannot get empty add!")((!Ops.empty() && "Cannot get empty add!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty add!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2415, __PRETTY_FUNCTION__)); | ||||||
2416 | if (Ops.size() == 1) return Ops[0]; | ||||||
2417 | #ifndef NDEBUG | ||||||
2418 | Type *ETy = getEffectiveSCEVType(Ops[0]->getType()); | ||||||
2419 | for (unsigned i = 1, e = Ops.size(); i != e; ++i) | ||||||
2420 | assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVAddExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVAddExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2421, __PRETTY_FUNCTION__)) | ||||||
2421 | "SCEVAddExpr operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVAddExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVAddExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2421, __PRETTY_FUNCTION__)); | ||||||
2422 | #endif | ||||||
2423 | |||||||
2424 | // Sort by complexity, this groups all similar expression types together. | ||||||
2425 | GroupByComplexity(Ops, &LI, DT); | ||||||
2426 | |||||||
2427 | Flags = StrengthenNoWrapFlags(this, scAddExpr, Ops, Flags); | ||||||
2428 | |||||||
2429 | // If there are any constants, fold them together. | ||||||
2430 | unsigned Idx = 0; | ||||||
2431 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) { | ||||||
2432 | ++Idx; | ||||||
2433 | assert(Idx < Ops.size())((Idx < Ops.size()) ? static_cast<void> (0) : __assert_fail ("Idx < Ops.size()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2433, __PRETTY_FUNCTION__)); | ||||||
2434 | while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) { | ||||||
2435 | // We found two constants, fold them together! | ||||||
2436 | Ops[0] = getConstant(LHSC->getAPInt() + RHSC->getAPInt()); | ||||||
2437 | if (Ops.size() == 2) return Ops[0]; | ||||||
2438 | Ops.erase(Ops.begin()+1); // Erase the folded element | ||||||
2439 | LHSC = cast<SCEVConstant>(Ops[0]); | ||||||
2440 | } | ||||||
2441 | |||||||
2442 | // If we are left with a constant zero being added, strip it off. | ||||||
2443 | if (LHSC->getValue()->isZero()) { | ||||||
2444 | Ops.erase(Ops.begin()); | ||||||
2445 | --Idx; | ||||||
2446 | } | ||||||
2447 | |||||||
2448 | if (Ops.size() == 1) return Ops[0]; | ||||||
2449 | } | ||||||
2450 | |||||||
2451 | // Limit recursion calls depth. | ||||||
2452 | if (Depth > MaxArithDepth || hasHugeExpression(Ops)) | ||||||
2453 | return getOrCreateAddExpr(Ops, Flags); | ||||||
2454 | |||||||
2455 | // Okay, check to see if the same value occurs in the operand list more than | ||||||
2456 | // once. If so, merge them together into an multiply expression. Since we | ||||||
2457 | // sorted the list, these values are required to be adjacent. | ||||||
2458 | Type *Ty = Ops[0]->getType(); | ||||||
2459 | bool FoundMatch = false; | ||||||
2460 | for (unsigned i = 0, e = Ops.size(); i != e-1; ++i) | ||||||
2461 | if (Ops[i] == Ops[i+1]) { // X + Y + Y --> X + Y*2 | ||||||
2462 | // Scan ahead to count how many equal operands there are. | ||||||
2463 | unsigned Count = 2; | ||||||
2464 | while (i+Count != e && Ops[i+Count] == Ops[i]) | ||||||
2465 | ++Count; | ||||||
2466 | // Merge the values into a multiply. | ||||||
2467 | const SCEV *Scale = getConstant(Ty, Count); | ||||||
2468 | const SCEV *Mul = getMulExpr(Scale, Ops[i], SCEV::FlagAnyWrap, Depth + 1); | ||||||
2469 | if (Ops.size() == Count) | ||||||
2470 | return Mul; | ||||||
2471 | Ops[i] = Mul; | ||||||
2472 | Ops.erase(Ops.begin()+i+1, Ops.begin()+i+Count); | ||||||
2473 | --i; e -= Count - 1; | ||||||
2474 | FoundMatch = true; | ||||||
2475 | } | ||||||
2476 | if (FoundMatch) | ||||||
2477 | return getAddExpr(Ops, Flags, Depth + 1); | ||||||
2478 | |||||||
2479 | // Check for truncates. If all the operands are truncated from the same | ||||||
2480 | // type, see if factoring out the truncate would permit the result to be | ||||||
2481 | // folded. eg., n*trunc(x) + m*trunc(y) --> trunc(trunc(m)*x + trunc(n)*y) | ||||||
2482 | // if the contents of the resulting outer trunc fold to something simple. | ||||||
2483 | auto FindTruncSrcType = [&]() -> Type * { | ||||||
2484 | // We're ultimately looking to fold an addrec of truncs and muls of only | ||||||
2485 | // constants and truncs, so if we find any other types of SCEV | ||||||
2486 | // as operands of the addrec then we bail and return nullptr here. | ||||||
2487 | // Otherwise, we return the type of the operand of a trunc that we find. | ||||||
2488 | if (auto *T = dyn_cast<SCEVTruncateExpr>(Ops[Idx])) | ||||||
2489 | return T->getOperand()->getType(); | ||||||
2490 | if (const auto *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) { | ||||||
2491 | const auto *LastOp = Mul->getOperand(Mul->getNumOperands() - 1); | ||||||
2492 | if (const auto *T = dyn_cast<SCEVTruncateExpr>(LastOp)) | ||||||
2493 | return T->getOperand()->getType(); | ||||||
2494 | } | ||||||
2495 | return nullptr; | ||||||
2496 | }; | ||||||
2497 | if (auto *SrcType = FindTruncSrcType()) { | ||||||
2498 | SmallVector<const SCEV *, 8> LargeOps; | ||||||
2499 | bool Ok = true; | ||||||
2500 | // Check all the operands to see if they can be represented in the | ||||||
2501 | // source type of the truncate. | ||||||
2502 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) { | ||||||
2503 | if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Ops[i])) { | ||||||
2504 | if (T->getOperand()->getType() != SrcType) { | ||||||
2505 | Ok = false; | ||||||
2506 | break; | ||||||
2507 | } | ||||||
2508 | LargeOps.push_back(T->getOperand()); | ||||||
2509 | } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) { | ||||||
2510 | LargeOps.push_back(getAnyExtendExpr(C, SrcType)); | ||||||
2511 | } else if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Ops[i])) { | ||||||
2512 | SmallVector<const SCEV *, 8> LargeMulOps; | ||||||
2513 | for (unsigned j = 0, f = M->getNumOperands(); j != f && Ok; ++j) { | ||||||
2514 | if (const SCEVTruncateExpr *T = | ||||||
2515 | dyn_cast<SCEVTruncateExpr>(M->getOperand(j))) { | ||||||
2516 | if (T->getOperand()->getType() != SrcType) { | ||||||
2517 | Ok = false; | ||||||
2518 | break; | ||||||
2519 | } | ||||||
2520 | LargeMulOps.push_back(T->getOperand()); | ||||||
2521 | } else if (const auto *C = dyn_cast<SCEVConstant>(M->getOperand(j))) { | ||||||
2522 | LargeMulOps.push_back(getAnyExtendExpr(C, SrcType)); | ||||||
2523 | } else { | ||||||
2524 | Ok = false; | ||||||
2525 | break; | ||||||
2526 | } | ||||||
2527 | } | ||||||
2528 | if (Ok) | ||||||
2529 | LargeOps.push_back(getMulExpr(LargeMulOps, SCEV::FlagAnyWrap, Depth + 1)); | ||||||
2530 | } else { | ||||||
2531 | Ok = false; | ||||||
2532 | break; | ||||||
2533 | } | ||||||
2534 | } | ||||||
2535 | if (Ok) { | ||||||
2536 | // Evaluate the expression in the larger type. | ||||||
2537 | const SCEV *Fold = getAddExpr(LargeOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2538 | // If it folds to something simple, use it. Otherwise, don't. | ||||||
2539 | if (isa<SCEVConstant>(Fold) || isa<SCEVUnknown>(Fold)) | ||||||
2540 | return getTruncateExpr(Fold, Ty); | ||||||
2541 | } | ||||||
2542 | } | ||||||
2543 | |||||||
2544 | // Skip past any other cast SCEVs. | ||||||
2545 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddExpr) | ||||||
2546 | ++Idx; | ||||||
2547 | |||||||
2548 | // If there are add operands they would be next. | ||||||
2549 | if (Idx < Ops.size()) { | ||||||
2550 | bool DeletedAdd = false; | ||||||
2551 | while (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[Idx])) { | ||||||
2552 | if (Ops.size() > AddOpsInlineThreshold || | ||||||
2553 | Add->getNumOperands() > AddOpsInlineThreshold) | ||||||
2554 | break; | ||||||
2555 | // If we have an add, expand the add operands onto the end of the operands | ||||||
2556 | // list. | ||||||
2557 | Ops.erase(Ops.begin()+Idx); | ||||||
2558 | Ops.append(Add->op_begin(), Add->op_end()); | ||||||
2559 | DeletedAdd = true; | ||||||
2560 | } | ||||||
2561 | |||||||
2562 | // If we deleted at least one add, we added operands to the end of the list, | ||||||
2563 | // and they are not necessarily sorted. Recurse to resort and resimplify | ||||||
2564 | // any operands we just acquired. | ||||||
2565 | if (DeletedAdd) | ||||||
2566 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2567 | } | ||||||
2568 | |||||||
2569 | // Skip over the add expression until we get to a multiply. | ||||||
2570 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr) | ||||||
2571 | ++Idx; | ||||||
2572 | |||||||
2573 | // Check to see if there are any folding opportunities present with | ||||||
2574 | // operands multiplied by constant values. | ||||||
2575 | if (Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx])) { | ||||||
2576 | uint64_t BitWidth = getTypeSizeInBits(Ty); | ||||||
2577 | DenseMap<const SCEV *, APInt> M; | ||||||
2578 | SmallVector<const SCEV *, 8> NewOps; | ||||||
2579 | APInt AccumulatedConstant(BitWidth, 0); | ||||||
2580 | if (CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant, | ||||||
2581 | Ops.data(), Ops.size(), | ||||||
2582 | APInt(BitWidth, 1), *this)) { | ||||||
2583 | struct APIntCompare { | ||||||
2584 | bool operator()(const APInt &LHS, const APInt &RHS) const { | ||||||
2585 | return LHS.ult(RHS); | ||||||
2586 | } | ||||||
2587 | }; | ||||||
2588 | |||||||
2589 | // Some interesting folding opportunity is present, so its worthwhile to | ||||||
2590 | // re-generate the operands list. Group the operands by constant scale, | ||||||
2591 | // to avoid multiplying by the same constant scale multiple times. | ||||||
2592 | std::map<APInt, SmallVector<const SCEV *, 4>, APIntCompare> MulOpLists; | ||||||
2593 | for (const SCEV *NewOp : NewOps) | ||||||
2594 | MulOpLists[M.find(NewOp)->second].push_back(NewOp); | ||||||
2595 | // Re-generate the operands list. | ||||||
2596 | Ops.clear(); | ||||||
2597 | if (AccumulatedConstant != 0) | ||||||
2598 | Ops.push_back(getConstant(AccumulatedConstant)); | ||||||
2599 | for (auto &MulOp : MulOpLists) | ||||||
2600 | if (MulOp.first != 0) | ||||||
2601 | Ops.push_back(getMulExpr( | ||||||
2602 | getConstant(MulOp.first), | ||||||
2603 | getAddExpr(MulOp.second, SCEV::FlagAnyWrap, Depth + 1), | ||||||
2604 | SCEV::FlagAnyWrap, Depth + 1)); | ||||||
2605 | if (Ops.empty()) | ||||||
2606 | return getZero(Ty); | ||||||
2607 | if (Ops.size() == 1) | ||||||
2608 | return Ops[0]; | ||||||
2609 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2610 | } | ||||||
2611 | } | ||||||
2612 | |||||||
2613 | // If we are adding something to a multiply expression, make sure the | ||||||
2614 | // something is not already an operand of the multiply. If so, merge it into | ||||||
2615 | // the multiply. | ||||||
2616 | for (; Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx]); ++Idx) { | ||||||
2617 | const SCEVMulExpr *Mul = cast<SCEVMulExpr>(Ops[Idx]); | ||||||
2618 | for (unsigned MulOp = 0, e = Mul->getNumOperands(); MulOp != e; ++MulOp) { | ||||||
2619 | const SCEV *MulOpSCEV = Mul->getOperand(MulOp); | ||||||
2620 | if (isa<SCEVConstant>(MulOpSCEV)) | ||||||
2621 | continue; | ||||||
2622 | for (unsigned AddOp = 0, e = Ops.size(); AddOp != e; ++AddOp) | ||||||
2623 | if (MulOpSCEV == Ops[AddOp]) { | ||||||
2624 | // Fold W + X + (X * Y * Z) --> W + (X * ((Y*Z)+1)) | ||||||
2625 | const SCEV *InnerMul = Mul->getOperand(MulOp == 0); | ||||||
2626 | if (Mul->getNumOperands() != 2) { | ||||||
2627 | // If the multiply has more than two operands, we must get the | ||||||
2628 | // Y*Z term. | ||||||
2629 | SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(), | ||||||
2630 | Mul->op_begin()+MulOp); | ||||||
2631 | MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end()); | ||||||
2632 | InnerMul = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2633 | } | ||||||
2634 | SmallVector<const SCEV *, 2> TwoOps = {getOne(Ty), InnerMul}; | ||||||
2635 | const SCEV *AddOne = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2636 | const SCEV *OuterMul = getMulExpr(AddOne, MulOpSCEV, | ||||||
2637 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
2638 | if (Ops.size() == 2) return OuterMul; | ||||||
2639 | if (AddOp < Idx) { | ||||||
2640 | Ops.erase(Ops.begin()+AddOp); | ||||||
2641 | Ops.erase(Ops.begin()+Idx-1); | ||||||
2642 | } else { | ||||||
2643 | Ops.erase(Ops.begin()+Idx); | ||||||
2644 | Ops.erase(Ops.begin()+AddOp-1); | ||||||
2645 | } | ||||||
2646 | Ops.push_back(OuterMul); | ||||||
2647 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2648 | } | ||||||
2649 | |||||||
2650 | // Check this multiply against other multiplies being added together. | ||||||
2651 | for (unsigned OtherMulIdx = Idx+1; | ||||||
2652 | OtherMulIdx < Ops.size() && isa<SCEVMulExpr>(Ops[OtherMulIdx]); | ||||||
2653 | ++OtherMulIdx) { | ||||||
2654 | const SCEVMulExpr *OtherMul = cast<SCEVMulExpr>(Ops[OtherMulIdx]); | ||||||
2655 | // If MulOp occurs in OtherMul, we can fold the two multiplies | ||||||
2656 | // together. | ||||||
2657 | for (unsigned OMulOp = 0, e = OtherMul->getNumOperands(); | ||||||
2658 | OMulOp != e; ++OMulOp) | ||||||
2659 | if (OtherMul->getOperand(OMulOp) == MulOpSCEV) { | ||||||
2660 | // Fold X + (A*B*C) + (A*D*E) --> X + (A*(B*C+D*E)) | ||||||
2661 | const SCEV *InnerMul1 = Mul->getOperand(MulOp == 0); | ||||||
2662 | if (Mul->getNumOperands() != 2) { | ||||||
2663 | SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(), | ||||||
2664 | Mul->op_begin()+MulOp); | ||||||
2665 | MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end()); | ||||||
2666 | InnerMul1 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2667 | } | ||||||
2668 | const SCEV *InnerMul2 = OtherMul->getOperand(OMulOp == 0); | ||||||
2669 | if (OtherMul->getNumOperands() != 2) { | ||||||
2670 | SmallVector<const SCEV *, 4> MulOps(OtherMul->op_begin(), | ||||||
2671 | OtherMul->op_begin()+OMulOp); | ||||||
2672 | MulOps.append(OtherMul->op_begin()+OMulOp+1, OtherMul->op_end()); | ||||||
2673 | InnerMul2 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2674 | } | ||||||
2675 | SmallVector<const SCEV *, 2> TwoOps = {InnerMul1, InnerMul2}; | ||||||
2676 | const SCEV *InnerMulSum = | ||||||
2677 | getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2678 | const SCEV *OuterMul = getMulExpr(MulOpSCEV, InnerMulSum, | ||||||
2679 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
2680 | if (Ops.size() == 2) return OuterMul; | ||||||
2681 | Ops.erase(Ops.begin()+Idx); | ||||||
2682 | Ops.erase(Ops.begin()+OtherMulIdx-1); | ||||||
2683 | Ops.push_back(OuterMul); | ||||||
2684 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2685 | } | ||||||
2686 | } | ||||||
2687 | } | ||||||
2688 | } | ||||||
2689 | |||||||
2690 | // If there are any add recurrences in the operands list, see if any other | ||||||
2691 | // added values are loop invariant. If so, we can fold them into the | ||||||
2692 | // recurrence. | ||||||
2693 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr) | ||||||
2694 | ++Idx; | ||||||
2695 | |||||||
2696 | // Scan over all recurrences, trying to fold loop invariants into them. | ||||||
2697 | for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) { | ||||||
2698 | // Scan all of the other operands to this add and add them to the vector if | ||||||
2699 | // they are loop invariant w.r.t. the recurrence. | ||||||
2700 | SmallVector<const SCEV *, 8> LIOps; | ||||||
2701 | const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]); | ||||||
2702 | const Loop *AddRecLoop = AddRec->getLoop(); | ||||||
2703 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
2704 | if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) { | ||||||
2705 | LIOps.push_back(Ops[i]); | ||||||
2706 | Ops.erase(Ops.begin()+i); | ||||||
2707 | --i; --e; | ||||||
2708 | } | ||||||
2709 | |||||||
2710 | // If we found some loop invariants, fold them into the recurrence. | ||||||
2711 | if (!LIOps.empty()) { | ||||||
2712 | // NLI + LI + {Start,+,Step} --> NLI + {LI+Start,+,Step} | ||||||
2713 | LIOps.push_back(AddRec->getStart()); | ||||||
2714 | |||||||
2715 | SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(), | ||||||
2716 | AddRec->op_end()); | ||||||
2717 | // This follows from the fact that the no-wrap flags on the outer add | ||||||
2718 | // expression are applicable on the 0th iteration, when the add recurrence | ||||||
2719 | // will be equal to its start value. | ||||||
2720 | AddRecOps[0] = getAddExpr(LIOps, Flags, Depth + 1); | ||||||
2721 | |||||||
2722 | // Build the new addrec. Propagate the NUW and NSW flags if both the | ||||||
2723 | // outer add and the inner addrec are guaranteed to have no overflow. | ||||||
2724 | // Always propagate NW. | ||||||
2725 | Flags = AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW)); | ||||||
2726 | const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, Flags); | ||||||
2727 | |||||||
2728 | // If all of the other operands were loop invariant, we are done. | ||||||
2729 | if (Ops.size() == 1) return NewRec; | ||||||
2730 | |||||||
2731 | // Otherwise, add the folded AddRec by the non-invariant parts. | ||||||
2732 | for (unsigned i = 0;; ++i) | ||||||
2733 | if (Ops[i] == AddRec) { | ||||||
2734 | Ops[i] = NewRec; | ||||||
2735 | break; | ||||||
2736 | } | ||||||
2737 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2738 | } | ||||||
2739 | |||||||
2740 | // Okay, if there weren't any loop invariants to be folded, check to see if | ||||||
2741 | // there are multiple AddRec's with the same loop induction variable being | ||||||
2742 | // added together. If so, we can fold them. | ||||||
2743 | for (unsigned OtherIdx = Idx+1; | ||||||
2744 | OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
2745 | ++OtherIdx) { | ||||||
2746 | // We expect the AddRecExpr's to be sorted in reverse dominance order, | ||||||
2747 | // so that the 1st found AddRecExpr is dominated by all others. | ||||||
2748 | assert(DT.dominates(((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2751, __PRETTY_FUNCTION__)) | ||||||
2749 | cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(),((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2751, __PRETTY_FUNCTION__)) | ||||||
2750 | AddRec->getLoop()->getHeader()) &&((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2751, __PRETTY_FUNCTION__)) | ||||||
2751 | "AddRecExprs are not sorted in reverse dominance order?")((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2751, __PRETTY_FUNCTION__)); | ||||||
2752 | if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) { | ||||||
2753 | // Other + {A,+,B}<L> + {C,+,D}<L> --> Other + {A+C,+,B+D}<L> | ||||||
2754 | SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(), | ||||||
2755 | AddRec->op_end()); | ||||||
2756 | for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
2757 | ++OtherIdx) { | ||||||
2758 | const auto *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
2759 | if (OtherAddRec->getLoop() == AddRecLoop) { | ||||||
2760 | for (unsigned i = 0, e = OtherAddRec->getNumOperands(); | ||||||
2761 | i != e; ++i) { | ||||||
2762 | if (i >= AddRecOps.size()) { | ||||||
2763 | AddRecOps.append(OtherAddRec->op_begin()+i, | ||||||
2764 | OtherAddRec->op_end()); | ||||||
2765 | break; | ||||||
2766 | } | ||||||
2767 | SmallVector<const SCEV *, 2> TwoOps = { | ||||||
2768 | AddRecOps[i], OtherAddRec->getOperand(i)}; | ||||||
2769 | AddRecOps[i] = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2770 | } | ||||||
2771 | Ops.erase(Ops.begin() + OtherIdx); --OtherIdx; | ||||||
2772 | } | ||||||
2773 | } | ||||||
2774 | // Step size has changed, so we cannot guarantee no self-wraparound. | ||||||
2775 | Ops[Idx] = getAddRecExpr(AddRecOps, AddRecLoop, SCEV::FlagAnyWrap); | ||||||
2776 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2777 | } | ||||||
2778 | } | ||||||
2779 | |||||||
2780 | // Otherwise couldn't fold anything into this recurrence. Move onto the | ||||||
2781 | // next one. | ||||||
2782 | } | ||||||
2783 | |||||||
2784 | // Okay, it looks like we really DO need an add expr. Check to see if we | ||||||
2785 | // already have one, otherwise create a new one. | ||||||
2786 | return getOrCreateAddExpr(Ops, Flags); | ||||||
2787 | } | ||||||
2788 | |||||||
2789 | const SCEV * | ||||||
2790 | ScalarEvolution::getOrCreateAddExpr(ArrayRef<const SCEV *> Ops, | ||||||
2791 | SCEV::NoWrapFlags Flags) { | ||||||
2792 | FoldingSetNodeID ID; | ||||||
2793 | ID.AddInteger(scAddExpr); | ||||||
2794 | for (const SCEV *Op : Ops) | ||||||
2795 | ID.AddPointer(Op); | ||||||
2796 | void *IP = nullptr; | ||||||
2797 | SCEVAddExpr *S = | ||||||
2798 | static_cast<SCEVAddExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
2799 | if (!S) { | ||||||
2800 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
2801 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
2802 | S = new (SCEVAllocator) | ||||||
2803 | SCEVAddExpr(ID.Intern(SCEVAllocator), O, Ops.size()); | ||||||
2804 | UniqueSCEVs.InsertNode(S, IP); | ||||||
2805 | addToLoopUseLists(S); | ||||||
2806 | } | ||||||
2807 | S->setNoWrapFlags(Flags); | ||||||
2808 | return S; | ||||||
2809 | } | ||||||
2810 | |||||||
2811 | const SCEV * | ||||||
2812 | ScalarEvolution::getOrCreateAddRecExpr(ArrayRef<const SCEV *> Ops, | ||||||
2813 | const Loop *L, SCEV::NoWrapFlags Flags) { | ||||||
2814 | FoldingSetNodeID ID; | ||||||
2815 | ID.AddInteger(scAddRecExpr); | ||||||
2816 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
2817 | ID.AddPointer(Ops[i]); | ||||||
2818 | ID.AddPointer(L); | ||||||
2819 | void *IP = nullptr; | ||||||
2820 | SCEVAddRecExpr *S = | ||||||
2821 | static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
2822 | if (!S) { | ||||||
2823 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
2824 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
2825 | S = new (SCEVAllocator) | ||||||
2826 | SCEVAddRecExpr(ID.Intern(SCEVAllocator), O, Ops.size(), L); | ||||||
2827 | UniqueSCEVs.InsertNode(S, IP); | ||||||
2828 | addToLoopUseLists(S); | ||||||
2829 | } | ||||||
2830 | S->setNoWrapFlags(Flags); | ||||||
2831 | return S; | ||||||
2832 | } | ||||||
2833 | |||||||
2834 | const SCEV * | ||||||
2835 | ScalarEvolution::getOrCreateMulExpr(ArrayRef<const SCEV *> Ops, | ||||||
2836 | SCEV::NoWrapFlags Flags) { | ||||||
2837 | FoldingSetNodeID ID; | ||||||
2838 | ID.AddInteger(scMulExpr); | ||||||
2839 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
2840 | ID.AddPointer(Ops[i]); | ||||||
2841 | void *IP = nullptr; | ||||||
2842 | SCEVMulExpr *S = | ||||||
2843 | static_cast<SCEVMulExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
2844 | if (!S) { | ||||||
2845 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
2846 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
2847 | S = new (SCEVAllocator) SCEVMulExpr(ID.Intern(SCEVAllocator), | ||||||
2848 | O, Ops.size()); | ||||||
2849 | UniqueSCEVs.InsertNode(S, IP); | ||||||
2850 | addToLoopUseLists(S); | ||||||
2851 | } | ||||||
2852 | S->setNoWrapFlags(Flags); | ||||||
2853 | return S; | ||||||
2854 | } | ||||||
2855 | |||||||
2856 | static uint64_t umul_ov(uint64_t i, uint64_t j, bool &Overflow) { | ||||||
2857 | uint64_t k = i*j; | ||||||
2858 | if (j > 1 && k / j != i) Overflow = true; | ||||||
2859 | return k; | ||||||
2860 | } | ||||||
2861 | |||||||
2862 | /// Compute the result of "n choose k", the binomial coefficient. If an | ||||||
2863 | /// intermediate computation overflows, Overflow will be set and the return will | ||||||
2864 | /// be garbage. Overflow is not cleared on absence of overflow. | ||||||
2865 | static uint64_t Choose(uint64_t n, uint64_t k, bool &Overflow) { | ||||||
2866 | // We use the multiplicative formula: | ||||||
2867 | // n(n-1)(n-2)...(n-(k-1)) / k(k-1)(k-2)...1 . | ||||||
2868 | // At each iteration, we take the n-th term of the numeral and divide by the | ||||||
2869 | // (k-n)th term of the denominator. This division will always produce an | ||||||
2870 | // integral result, and helps reduce the chance of overflow in the | ||||||
2871 | // intermediate computations. However, we can still overflow even when the | ||||||
2872 | // final result would fit. | ||||||
2873 | |||||||
2874 | if (n == 0 || n == k) return 1; | ||||||
2875 | if (k > n) return 0; | ||||||
2876 | |||||||
2877 | if (k > n/2) | ||||||
2878 | k = n-k; | ||||||
2879 | |||||||
2880 | uint64_t r = 1; | ||||||
2881 | for (uint64_t i = 1; i <= k; ++i) { | ||||||
2882 | r = umul_ov(r, n-(i-1), Overflow); | ||||||
2883 | r /= i; | ||||||
2884 | } | ||||||
2885 | return r; | ||||||
2886 | } | ||||||
2887 | |||||||
2888 | /// Determine if any of the operands in this SCEV are a constant or if | ||||||
2889 | /// any of the add or multiply expressions in this SCEV contain a constant. | ||||||
2890 | static bool containsConstantInAddMulChain(const SCEV *StartExpr) { | ||||||
2891 | struct FindConstantInAddMulChain { | ||||||
2892 | bool FoundConstant = false; | ||||||
2893 | |||||||
2894 | bool follow(const SCEV *S) { | ||||||
2895 | FoundConstant |= isa<SCEVConstant>(S); | ||||||
2896 | return isa<SCEVAddExpr>(S) || isa<SCEVMulExpr>(S); | ||||||
2897 | } | ||||||
2898 | |||||||
2899 | bool isDone() const { | ||||||
2900 | return FoundConstant; | ||||||
2901 | } | ||||||
2902 | }; | ||||||
2903 | |||||||
2904 | FindConstantInAddMulChain F; | ||||||
2905 | SCEVTraversal<FindConstantInAddMulChain> ST(F); | ||||||
2906 | ST.visitAll(StartExpr); | ||||||
2907 | return F.FoundConstant; | ||||||
2908 | } | ||||||
2909 | |||||||
2910 | /// Get a canonical multiply expression, or something simpler if possible. | ||||||
2911 | const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops, | ||||||
2912 | SCEV::NoWrapFlags Flags, | ||||||
2913 | unsigned Depth) { | ||||||
2914 | assert(Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) &&((Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && "only nuw or nsw allowed") ? static_cast<void> (0) : __assert_fail ("Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2915, __PRETTY_FUNCTION__)) | ||||||
2915 | "only nuw or nsw allowed")((Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && "only nuw or nsw allowed") ? static_cast<void> (0) : __assert_fail ("Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2915, __PRETTY_FUNCTION__)); | ||||||
2916 | assert(!Ops.empty() && "Cannot get empty mul!")((!Ops.empty() && "Cannot get empty mul!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty mul!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2916, __PRETTY_FUNCTION__)); | ||||||
2917 | if (Ops.size() == 1) return Ops[0]; | ||||||
2918 | #ifndef NDEBUG | ||||||
2919 | Type *ETy = getEffectiveSCEVType(Ops[0]->getType()); | ||||||
2920 | for (unsigned i = 1, e = Ops.size(); i != e; ++i) | ||||||
2921 | assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVMulExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVMulExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2922, __PRETTY_FUNCTION__)) | ||||||
2922 | "SCEVMulExpr operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVMulExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVMulExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 2922, __PRETTY_FUNCTION__)); | ||||||
2923 | #endif | ||||||
2924 | |||||||
2925 | // Sort by complexity, this groups all similar expression types together. | ||||||
2926 | GroupByComplexity(Ops, &LI, DT); | ||||||
2927 | |||||||
2928 | Flags = StrengthenNoWrapFlags(this, scMulExpr, Ops, Flags); | ||||||
2929 | |||||||
2930 | // Limit recursion calls depth. | ||||||
2931 | if (Depth > MaxArithDepth || hasHugeExpression(Ops)) | ||||||
2932 | return getOrCreateMulExpr(Ops, Flags); | ||||||
2933 | |||||||
2934 | // If there are any constants, fold them together. | ||||||
2935 | unsigned Idx = 0; | ||||||
2936 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) { | ||||||
2937 | |||||||
2938 | if (Ops.size() == 2) | ||||||
2939 | // C1*(C2+V) -> C1*C2 + C1*V | ||||||
2940 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) | ||||||
2941 | // If any of Add's ops are Adds or Muls with a constant, apply this | ||||||
2942 | // transformation as well. | ||||||
2943 | // | ||||||
2944 | // TODO: There are some cases where this transformation is not | ||||||
2945 | // profitable; for example, Add = (C0 + X) * Y + Z. Maybe the scope of | ||||||
2946 | // this transformation should be narrowed down. | ||||||
2947 | if (Add->getNumOperands() == 2 && containsConstantInAddMulChain(Add)) | ||||||
2948 | return getAddExpr(getMulExpr(LHSC, Add->getOperand(0), | ||||||
2949 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
2950 | getMulExpr(LHSC, Add->getOperand(1), | ||||||
2951 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
2952 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
2953 | |||||||
2954 | ++Idx; | ||||||
2955 | while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) { | ||||||
2956 | // We found two constants, fold them together! | ||||||
2957 | ConstantInt *Fold = | ||||||
2958 | ConstantInt::get(getContext(), LHSC->getAPInt() * RHSC->getAPInt()); | ||||||
2959 | Ops[0] = getConstant(Fold); | ||||||
2960 | Ops.erase(Ops.begin()+1); // Erase the folded element | ||||||
2961 | if (Ops.size() == 1) return Ops[0]; | ||||||
2962 | LHSC = cast<SCEVConstant>(Ops[0]); | ||||||
2963 | } | ||||||
2964 | |||||||
2965 | // If we are left with a constant one being multiplied, strip it off. | ||||||
2966 | if (cast<SCEVConstant>(Ops[0])->getValue()->isOne()) { | ||||||
2967 | Ops.erase(Ops.begin()); | ||||||
2968 | --Idx; | ||||||
2969 | } else if (cast<SCEVConstant>(Ops[0])->getValue()->isZero()) { | ||||||
2970 | // If we have a multiply of zero, it will always be zero. | ||||||
2971 | return Ops[0]; | ||||||
2972 | } else if (Ops[0]->isAllOnesValue()) { | ||||||
2973 | // If we have a mul by -1 of an add, try distributing the -1 among the | ||||||
2974 | // add operands. | ||||||
2975 | if (Ops.size() == 2) { | ||||||
2976 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) { | ||||||
2977 | SmallVector<const SCEV *, 4> NewOps; | ||||||
2978 | bool AnyFolded = false; | ||||||
2979 | for (const SCEV *AddOp : Add->operands()) { | ||||||
2980 | const SCEV *Mul = getMulExpr(Ops[0], AddOp, SCEV::FlagAnyWrap, | ||||||
2981 | Depth + 1); | ||||||
2982 | if (!isa<SCEVMulExpr>(Mul)) AnyFolded = true; | ||||||
2983 | NewOps.push_back(Mul); | ||||||
2984 | } | ||||||
2985 | if (AnyFolded) | ||||||
2986 | return getAddExpr(NewOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
2987 | } else if (const auto *AddRec = dyn_cast<SCEVAddRecExpr>(Ops[1])) { | ||||||
2988 | // Negation preserves a recurrence's no self-wrap property. | ||||||
2989 | SmallVector<const SCEV *, 4> Operands; | ||||||
2990 | for (const SCEV *AddRecOp : AddRec->operands()) | ||||||
2991 | Operands.push_back(getMulExpr(Ops[0], AddRecOp, SCEV::FlagAnyWrap, | ||||||
2992 | Depth + 1)); | ||||||
2993 | |||||||
2994 | return getAddRecExpr(Operands, AddRec->getLoop(), | ||||||
2995 | AddRec->getNoWrapFlags(SCEV::FlagNW)); | ||||||
2996 | } | ||||||
2997 | } | ||||||
2998 | } | ||||||
2999 | |||||||
3000 | if (Ops.size() == 1) | ||||||
3001 | return Ops[0]; | ||||||
3002 | } | ||||||
3003 | |||||||
3004 | // Skip over the add expression until we get to a multiply. | ||||||
3005 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr) | ||||||
3006 | ++Idx; | ||||||
3007 | |||||||
3008 | // If there are mul operands inline them all into this expression. | ||||||
3009 | if (Idx < Ops.size()) { | ||||||
3010 | bool DeletedMul = false; | ||||||
3011 | while (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) { | ||||||
3012 | if (Ops.size() > MulOpsInlineThreshold) | ||||||
3013 | break; | ||||||
3014 | // If we have an mul, expand the mul operands onto the end of the | ||||||
3015 | // operands list. | ||||||
3016 | Ops.erase(Ops.begin()+Idx); | ||||||
3017 | Ops.append(Mul->op_begin(), Mul->op_end()); | ||||||
3018 | DeletedMul = true; | ||||||
3019 | } | ||||||
3020 | |||||||
3021 | // If we deleted at least one mul, we added operands to the end of the | ||||||
3022 | // list, and they are not necessarily sorted. Recurse to resort and | ||||||
3023 | // resimplify any operands we just acquired. | ||||||
3024 | if (DeletedMul) | ||||||
3025 | return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
3026 | } | ||||||
3027 | |||||||
3028 | // If there are any add recurrences in the operands list, see if any other | ||||||
3029 | // added values are loop invariant. If so, we can fold them into the | ||||||
3030 | // recurrence. | ||||||
3031 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr) | ||||||
3032 | ++Idx; | ||||||
3033 | |||||||
3034 | // Scan over all recurrences, trying to fold loop invariants into them. | ||||||
3035 | for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) { | ||||||
3036 | // Scan all of the other operands to this mul and add them to the vector | ||||||
3037 | // if they are loop invariant w.r.t. the recurrence. | ||||||
3038 | SmallVector<const SCEV *, 8> LIOps; | ||||||
3039 | const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]); | ||||||
3040 | const Loop *AddRecLoop = AddRec->getLoop(); | ||||||
3041 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
3042 | if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) { | ||||||
3043 | LIOps.push_back(Ops[i]); | ||||||
3044 | Ops.erase(Ops.begin()+i); | ||||||
3045 | --i; --e; | ||||||
3046 | } | ||||||
3047 | |||||||
3048 | // If we found some loop invariants, fold them into the recurrence. | ||||||
3049 | if (!LIOps.empty()) { | ||||||
3050 | // NLI * LI * {Start,+,Step} --> NLI * {LI*Start,+,LI*Step} | ||||||
3051 | SmallVector<const SCEV *, 4> NewOps; | ||||||
3052 | NewOps.reserve(AddRec->getNumOperands()); | ||||||
3053 | const SCEV *Scale = getMulExpr(LIOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
3054 | for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) | ||||||
3055 | NewOps.push_back(getMulExpr(Scale, AddRec->getOperand(i), | ||||||
3056 | SCEV::FlagAnyWrap, Depth + 1)); | ||||||
3057 | |||||||
3058 | // Build the new addrec. Propagate the NUW and NSW flags if both the | ||||||
3059 | // outer mul and the inner addrec are guaranteed to have no overflow. | ||||||
3060 | // | ||||||
3061 | // No self-wrap cannot be guaranteed after changing the step size, but | ||||||
3062 | // will be inferred if either NUW or NSW is true. | ||||||
3063 | Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW)); | ||||||
3064 | const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags); | ||||||
3065 | |||||||
3066 | // If all of the other operands were loop invariant, we are done. | ||||||
3067 | if (Ops.size() == 1) return NewRec; | ||||||
3068 | |||||||
3069 | // Otherwise, multiply the folded AddRec by the non-invariant parts. | ||||||
3070 | for (unsigned i = 0;; ++i) | ||||||
3071 | if (Ops[i] == AddRec) { | ||||||
3072 | Ops[i] = NewRec; | ||||||
3073 | break; | ||||||
3074 | } | ||||||
3075 | return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
3076 | } | ||||||
3077 | |||||||
3078 | // Okay, if there weren't any loop invariants to be folded, check to see | ||||||
3079 | // if there are multiple AddRec's with the same loop induction variable | ||||||
3080 | // being multiplied together. If so, we can fold them. | ||||||
3081 | |||||||
3082 | // {A1,+,A2,+,...,+,An}<L> * {B1,+,B2,+,...,+,Bn}<L> | ||||||
3083 | // = {x=1 in [ sum y=x..2x [ sum z=max(y-x, y-n)..min(x,n) [ | ||||||
3084 | // choose(x, 2x)*choose(2x-y, x-z)*A_{y-z}*B_z | ||||||
3085 | // ]]],+,...up to x=2n}. | ||||||
3086 | // Note that the arguments to choose() are always integers with values | ||||||
3087 | // known at compile time, never SCEV objects. | ||||||
3088 | // | ||||||
3089 | // The implementation avoids pointless extra computations when the two | ||||||
3090 | // addrec's are of different length (mathematically, it's equivalent to | ||||||
3091 | // an infinite stream of zeros on the right). | ||||||
3092 | bool OpsModified = false; | ||||||
3093 | for (unsigned OtherIdx = Idx+1; | ||||||
3094 | OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
3095 | ++OtherIdx) { | ||||||
3096 | const SCEVAddRecExpr *OtherAddRec = | ||||||
3097 | dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
3098 | if (!OtherAddRec || OtherAddRec->getLoop() != AddRecLoop) | ||||||
3099 | continue; | ||||||
3100 | |||||||
3101 | // Limit max number of arguments to avoid creation of unreasonably big | ||||||
3102 | // SCEVAddRecs with very complex operands. | ||||||
3103 | if (AddRec->getNumOperands() + OtherAddRec->getNumOperands() - 1 > | ||||||
3104 | MaxAddRecSize || hasHugeExpression({AddRec, OtherAddRec})) | ||||||
3105 | continue; | ||||||
3106 | |||||||
3107 | bool Overflow = false; | ||||||
3108 | Type *Ty = AddRec->getType(); | ||||||
3109 | bool LargerThan64Bits = getTypeSizeInBits(Ty) > 64; | ||||||
3110 | SmallVector<const SCEV*, 7> AddRecOps; | ||||||
3111 | for (int x = 0, xe = AddRec->getNumOperands() + | ||||||
3112 | OtherAddRec->getNumOperands() - 1; x != xe && !Overflow; ++x) { | ||||||
3113 | SmallVector <const SCEV *, 7> SumOps; | ||||||
3114 | for (int y = x, ye = 2*x+1; y != ye && !Overflow; ++y) { | ||||||
3115 | uint64_t Coeff1 = Choose(x, 2*x - y, Overflow); | ||||||
3116 | for (int z = std::max(y-x, y-(int)AddRec->getNumOperands()+1), | ||||||
3117 | ze = std::min(x+1, (int)OtherAddRec->getNumOperands()); | ||||||
3118 | z < ze && !Overflow; ++z) { | ||||||
3119 | uint64_t Coeff2 = Choose(2*x - y, x-z, Overflow); | ||||||
3120 | uint64_t Coeff; | ||||||
3121 | if (LargerThan64Bits) | ||||||
3122 | Coeff = umul_ov(Coeff1, Coeff2, Overflow); | ||||||
3123 | else | ||||||
3124 | Coeff = Coeff1*Coeff2; | ||||||
3125 | const SCEV *CoeffTerm = getConstant(Ty, Coeff); | ||||||
3126 | const SCEV *Term1 = AddRec->getOperand(y-z); | ||||||
3127 | const SCEV *Term2 = OtherAddRec->getOperand(z); | ||||||
3128 | SumOps.push_back(getMulExpr(CoeffTerm, Term1, Term2, | ||||||
3129 | SCEV::FlagAnyWrap, Depth + 1)); | ||||||
3130 | } | ||||||
3131 | } | ||||||
3132 | if (SumOps.empty()) | ||||||
3133 | SumOps.push_back(getZero(Ty)); | ||||||
3134 | AddRecOps.push_back(getAddExpr(SumOps, SCEV::FlagAnyWrap, Depth + 1)); | ||||||
3135 | } | ||||||
3136 | if (!Overflow) { | ||||||
3137 | const SCEV *NewAddRec = getAddRecExpr(AddRecOps, AddRecLoop, | ||||||
3138 | SCEV::FlagAnyWrap); | ||||||
3139 | if (Ops.size() == 2) return NewAddRec; | ||||||
3140 | Ops[Idx] = NewAddRec; | ||||||
3141 | Ops.erase(Ops.begin() + OtherIdx); --OtherIdx; | ||||||
3142 | OpsModified = true; | ||||||
3143 | AddRec = dyn_cast<SCEVAddRecExpr>(NewAddRec); | ||||||
3144 | if (!AddRec) | ||||||
3145 | break; | ||||||
3146 | } | ||||||
3147 | } | ||||||
3148 | if (OpsModified) | ||||||
3149 | return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
3150 | |||||||
3151 | // Otherwise couldn't fold anything into this recurrence. Move onto the | ||||||
3152 | // next one. | ||||||
3153 | } | ||||||
3154 | |||||||
3155 | // Okay, it looks like we really DO need an mul expr. Check to see if we | ||||||
3156 | // already have one, otherwise create a new one. | ||||||
3157 | return getOrCreateMulExpr(Ops, Flags); | ||||||
3158 | } | ||||||
3159 | |||||||
3160 | /// Represents an unsigned remainder expression based on unsigned division. | ||||||
3161 | const SCEV *ScalarEvolution::getURemExpr(const SCEV *LHS, | ||||||
3162 | const SCEV *RHS) { | ||||||
3163 | assert(getEffectiveSCEVType(LHS->getType()) ==((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVURemExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3165, __PRETTY_FUNCTION__)) | ||||||
3164 | getEffectiveSCEVType(RHS->getType()) &&((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVURemExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3165, __PRETTY_FUNCTION__)) | ||||||
3165 | "SCEVURemExpr operand types don't match!")((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVURemExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3165, __PRETTY_FUNCTION__)); | ||||||
3166 | |||||||
3167 | // Short-circuit easy cases | ||||||
3168 | if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) { | ||||||
3169 | // If constant is one, the result is trivial | ||||||
3170 | if (RHSC->getValue()->isOne()) | ||||||
3171 | return getZero(LHS->getType()); // X urem 1 --> 0 | ||||||
3172 | |||||||
3173 | // If constant is a power of two, fold into a zext(trunc(LHS)). | ||||||
3174 | if (RHSC->getAPInt().isPowerOf2()) { | ||||||
3175 | Type *FullTy = LHS->getType(); | ||||||
3176 | Type *TruncTy = | ||||||
3177 | IntegerType::get(getContext(), RHSC->getAPInt().logBase2()); | ||||||
3178 | return getZeroExtendExpr(getTruncateExpr(LHS, TruncTy), FullTy); | ||||||
3179 | } | ||||||
3180 | } | ||||||
3181 | |||||||
3182 | // Fallback to %a == %x urem %y == %x -<nuw> ((%x udiv %y) *<nuw> %y) | ||||||
3183 | const SCEV *UDiv = getUDivExpr(LHS, RHS); | ||||||
3184 | const SCEV *Mult = getMulExpr(UDiv, RHS, SCEV::FlagNUW); | ||||||
3185 | return getMinusSCEV(LHS, Mult, SCEV::FlagNUW); | ||||||
3186 | } | ||||||
3187 | |||||||
3188 | /// Get a canonical unsigned division expression, or something simpler if | ||||||
3189 | /// possible. | ||||||
3190 | const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS, | ||||||
3191 | const SCEV *RHS) { | ||||||
3192 | assert(getEffectiveSCEVType(LHS->getType()) ==((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVUDivExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3194, __PRETTY_FUNCTION__)) | ||||||
3193 | getEffectiveSCEVType(RHS->getType()) &&((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVUDivExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3194, __PRETTY_FUNCTION__)) | ||||||
3194 | "SCEVUDivExpr operand types don't match!")((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVUDivExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3194, __PRETTY_FUNCTION__)); | ||||||
3195 | |||||||
3196 | if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) { | ||||||
3197 | if (RHSC->getValue()->isOne()) | ||||||
3198 | return LHS; // X udiv 1 --> x | ||||||
3199 | // If the denominator is zero, the result of the udiv is undefined. Don't | ||||||
3200 | // try to analyze it, because the resolution chosen here may differ from | ||||||
3201 | // the resolution chosen in other parts of the compiler. | ||||||
3202 | if (!RHSC->getValue()->isZero()) { | ||||||
3203 | // Determine if the division can be folded into the operands of | ||||||
3204 | // its operands. | ||||||
3205 | // TODO: Generalize this to non-constants by using known-bits information. | ||||||
3206 | Type *Ty = LHS->getType(); | ||||||
3207 | unsigned LZ = RHSC->getAPInt().countLeadingZeros(); | ||||||
3208 | unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ - 1; | ||||||
3209 | // For non-power-of-two values, effectively round the value up to the | ||||||
3210 | // nearest power of two. | ||||||
3211 | if (!RHSC->getAPInt().isPowerOf2()) | ||||||
3212 | ++MaxShiftAmt; | ||||||
3213 | IntegerType *ExtTy = | ||||||
3214 | IntegerType::get(getContext(), getTypeSizeInBits(Ty) + MaxShiftAmt); | ||||||
3215 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS)) | ||||||
3216 | if (const SCEVConstant *Step = | ||||||
3217 | dyn_cast<SCEVConstant>(AR->getStepRecurrence(*this))) { | ||||||
3218 | // {X,+,N}/C --> {X/C,+,N/C} if safe and N/C can be folded. | ||||||
3219 | const APInt &StepInt = Step->getAPInt(); | ||||||
3220 | const APInt &DivInt = RHSC->getAPInt(); | ||||||
3221 | if (!StepInt.urem(DivInt) && | ||||||
3222 | getZeroExtendExpr(AR, ExtTy) == | ||||||
3223 | getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy), | ||||||
3224 | getZeroExtendExpr(Step, ExtTy), | ||||||
3225 | AR->getLoop(), SCEV::FlagAnyWrap)) { | ||||||
3226 | SmallVector<const SCEV *, 4> Operands; | ||||||
3227 | for (const SCEV *Op : AR->operands()) | ||||||
3228 | Operands.push_back(getUDivExpr(Op, RHS)); | ||||||
3229 | return getAddRecExpr(Operands, AR->getLoop(), SCEV::FlagNW); | ||||||
3230 | } | ||||||
3231 | /// Get a canonical UDivExpr for a recurrence. | ||||||
3232 | /// {X,+,N}/C => {Y,+,N}/C where Y=X-(X%N). Safe when C%N=0. | ||||||
3233 | // We can currently only fold X%N if X is constant. | ||||||
3234 | const SCEVConstant *StartC = dyn_cast<SCEVConstant>(AR->getStart()); | ||||||
3235 | if (StartC && !DivInt.urem(StepInt) && | ||||||
3236 | getZeroExtendExpr(AR, ExtTy) == | ||||||
3237 | getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy), | ||||||
3238 | getZeroExtendExpr(Step, ExtTy), | ||||||
3239 | AR->getLoop(), SCEV::FlagAnyWrap)) { | ||||||
3240 | const APInt &StartInt = StartC->getAPInt(); | ||||||
3241 | const APInt &StartRem = StartInt.urem(StepInt); | ||||||
3242 | if (StartRem != 0) | ||||||
3243 | LHS = getAddRecExpr(getConstant(StartInt - StartRem), Step, | ||||||
3244 | AR->getLoop(), SCEV::FlagNW); | ||||||
3245 | } | ||||||
3246 | } | ||||||
3247 | // (A*B)/C --> A*(B/C) if safe and B/C can be folded. | ||||||
3248 | if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(LHS)) { | ||||||
3249 | SmallVector<const SCEV *, 4> Operands; | ||||||
3250 | for (const SCEV *Op : M->operands()) | ||||||
3251 | Operands.push_back(getZeroExtendExpr(Op, ExtTy)); | ||||||
3252 | if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands)) | ||||||
3253 | // Find an operand that's safely divisible. | ||||||
3254 | for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) { | ||||||
3255 | const SCEV *Op = M->getOperand(i); | ||||||
3256 | const SCEV *Div = getUDivExpr(Op, RHSC); | ||||||
3257 | if (!isa<SCEVUDivExpr>(Div) && getMulExpr(Div, RHSC) == Op) { | ||||||
3258 | Operands = SmallVector<const SCEV *, 4>(M->op_begin(), | ||||||
3259 | M->op_end()); | ||||||
3260 | Operands[i] = Div; | ||||||
3261 | return getMulExpr(Operands); | ||||||
3262 | } | ||||||
3263 | } | ||||||
3264 | } | ||||||
3265 | |||||||
3266 | // (A/B)/C --> A/(B*C) if safe and B*C can be folded. | ||||||
3267 | if (const SCEVUDivExpr *OtherDiv = dyn_cast<SCEVUDivExpr>(LHS)) { | ||||||
3268 | if (auto *DivisorConstant = | ||||||
3269 | dyn_cast<SCEVConstant>(OtherDiv->getRHS())) { | ||||||
3270 | bool Overflow = false; | ||||||
3271 | APInt NewRHS = | ||||||
3272 | DivisorConstant->getAPInt().umul_ov(RHSC->getAPInt(), Overflow); | ||||||
3273 | if (Overflow) { | ||||||
3274 | return getConstant(RHSC->getType(), 0, false); | ||||||
3275 | } | ||||||
3276 | return getUDivExpr(OtherDiv->getLHS(), getConstant(NewRHS)); | ||||||
3277 | } | ||||||
3278 | } | ||||||
3279 | |||||||
3280 | // (A+B)/C --> (A/C + B/C) if safe and A/C and B/C can be folded. | ||||||
3281 | if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(LHS)) { | ||||||
3282 | SmallVector<const SCEV *, 4> Operands; | ||||||
3283 | for (const SCEV *Op : A->operands()) | ||||||
3284 | Operands.push_back(getZeroExtendExpr(Op, ExtTy)); | ||||||
3285 | if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) { | ||||||
3286 | Operands.clear(); | ||||||
3287 | for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) { | ||||||
3288 | const SCEV *Op = getUDivExpr(A->getOperand(i), RHS); | ||||||
3289 | if (isa<SCEVUDivExpr>(Op) || | ||||||
3290 | getMulExpr(Op, RHS) != A->getOperand(i)) | ||||||
3291 | break; | ||||||
3292 | Operands.push_back(Op); | ||||||
3293 | } | ||||||
3294 | if (Operands.size() == A->getNumOperands()) | ||||||
3295 | return getAddExpr(Operands); | ||||||
3296 | } | ||||||
3297 | } | ||||||
3298 | |||||||
3299 | // Fold if both operands are constant. | ||||||
3300 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) { | ||||||
3301 | Constant *LHSCV = LHSC->getValue(); | ||||||
3302 | Constant *RHSCV = RHSC->getValue(); | ||||||
3303 | return getConstant(cast<ConstantInt>(ConstantExpr::getUDiv(LHSCV, | ||||||
3304 | RHSCV))); | ||||||
3305 | } | ||||||
3306 | } | ||||||
3307 | } | ||||||
3308 | |||||||
3309 | FoldingSetNodeID ID; | ||||||
3310 | ID.AddInteger(scUDivExpr); | ||||||
3311 | ID.AddPointer(LHS); | ||||||
3312 | ID.AddPointer(RHS); | ||||||
3313 | void *IP = nullptr; | ||||||
3314 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
3315 | SCEV *S = new (SCEVAllocator) SCEVUDivExpr(ID.Intern(SCEVAllocator), | ||||||
3316 | LHS, RHS); | ||||||
3317 | UniqueSCEVs.InsertNode(S, IP); | ||||||
3318 | addToLoopUseLists(S); | ||||||
3319 | return S; | ||||||
3320 | } | ||||||
3321 | |||||||
3322 | static const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) { | ||||||
3323 | APInt A = C1->getAPInt().abs(); | ||||||
3324 | APInt B = C2->getAPInt().abs(); | ||||||
3325 | uint32_t ABW = A.getBitWidth(); | ||||||
3326 | uint32_t BBW = B.getBitWidth(); | ||||||
3327 | |||||||
3328 | if (ABW > BBW) | ||||||
3329 | B = B.zext(ABW); | ||||||
3330 | else if (ABW < BBW) | ||||||
3331 | A = A.zext(BBW); | ||||||
3332 | |||||||
3333 | return APIntOps::GreatestCommonDivisor(std::move(A), std::move(B)); | ||||||
3334 | } | ||||||
3335 | |||||||
3336 | /// Get a canonical unsigned division expression, or something simpler if | ||||||
3337 | /// possible. There is no representation for an exact udiv in SCEV IR, but we | ||||||
3338 | /// can attempt to remove factors from the LHS and RHS. We can't do this when | ||||||
3339 | /// it's not exact because the udiv may be clearing bits. | ||||||
3340 | const SCEV *ScalarEvolution::getUDivExactExpr(const SCEV *LHS, | ||||||
3341 | const SCEV *RHS) { | ||||||
3342 | // TODO: we could try to find factors in all sorts of things, but for now we | ||||||
3343 | // just deal with u/exact (multiply, constant). See SCEVDivision towards the | ||||||
3344 | // end of this file for inspiration. | ||||||
3345 | |||||||
3346 | const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS); | ||||||
3347 | if (!Mul || !Mul->hasNoUnsignedWrap()) | ||||||
3348 | return getUDivExpr(LHS, RHS); | ||||||
3349 | |||||||
3350 | if (const SCEVConstant *RHSCst = dyn_cast<SCEVConstant>(RHS)) { | ||||||
3351 | // If the mulexpr multiplies by a constant, then that constant must be the | ||||||
3352 | // first element of the mulexpr. | ||||||
3353 | if (const auto *LHSCst = dyn_cast<SCEVConstant>(Mul->getOperand(0))) { | ||||||
3354 | if (LHSCst == RHSCst) { | ||||||
3355 | SmallVector<const SCEV *, 2> Operands; | ||||||
3356 | Operands.append(Mul->op_begin() + 1, Mul->op_end()); | ||||||
3357 | return getMulExpr(Operands); | ||||||
3358 | } | ||||||
3359 | |||||||
3360 | // We can't just assume that LHSCst divides RHSCst cleanly, it could be | ||||||
3361 | // that there's a factor provided by one of the other terms. We need to | ||||||
3362 | // check. | ||||||
3363 | APInt Factor = gcd(LHSCst, RHSCst); | ||||||
3364 | if (!Factor.isIntN(1)) { | ||||||
3365 | LHSCst = | ||||||
3366 | cast<SCEVConstant>(getConstant(LHSCst->getAPInt().udiv(Factor))); | ||||||
3367 | RHSCst = | ||||||
3368 | cast<SCEVConstant>(getConstant(RHSCst->getAPInt().udiv(Factor))); | ||||||
3369 | SmallVector<const SCEV *, 2> Operands; | ||||||
3370 | Operands.push_back(LHSCst); | ||||||
3371 | Operands.append(Mul->op_begin() + 1, Mul->op_end()); | ||||||
3372 | LHS = getMulExpr(Operands); | ||||||
3373 | RHS = RHSCst; | ||||||
3374 | Mul = dyn_cast<SCEVMulExpr>(LHS); | ||||||
3375 | if (!Mul) | ||||||
3376 | return getUDivExactExpr(LHS, RHS); | ||||||
3377 | } | ||||||
3378 | } | ||||||
3379 | } | ||||||
3380 | |||||||
3381 | for (int i = 0, e = Mul->getNumOperands(); i != e; ++i) { | ||||||
3382 | if (Mul->getOperand(i) == RHS) { | ||||||
3383 | SmallVector<const SCEV *, 2> Operands; | ||||||
3384 | Operands.append(Mul->op_begin(), Mul->op_begin() + i); | ||||||
3385 | Operands.append(Mul->op_begin() + i + 1, Mul->op_end()); | ||||||
3386 | return getMulExpr(Operands); | ||||||
3387 | } | ||||||
3388 | } | ||||||
3389 | |||||||
3390 | return getUDivExpr(LHS, RHS); | ||||||
3391 | } | ||||||
3392 | |||||||
3393 | /// Get an add recurrence expression for the specified loop. Simplify the | ||||||
3394 | /// expression as much as possible. | ||||||
3395 | const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start, const SCEV *Step, | ||||||
3396 | const Loop *L, | ||||||
3397 | SCEV::NoWrapFlags Flags) { | ||||||
3398 | SmallVector<const SCEV *, 4> Operands; | ||||||
3399 | Operands.push_back(Start); | ||||||
3400 | if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step)) | ||||||
3401 | if (StepChrec->getLoop() == L) { | ||||||
3402 | Operands.append(StepChrec->op_begin(), StepChrec->op_end()); | ||||||
3403 | return getAddRecExpr(Operands, L, maskFlags(Flags, SCEV::FlagNW)); | ||||||
3404 | } | ||||||
3405 | |||||||
3406 | Operands.push_back(Step); | ||||||
3407 | return getAddRecExpr(Operands, L, Flags); | ||||||
3408 | } | ||||||
3409 | |||||||
3410 | /// Get an add recurrence expression for the specified loop. Simplify the | ||||||
3411 | /// expression as much as possible. | ||||||
3412 | const SCEV * | ||||||
3413 | ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands, | ||||||
3414 | const Loop *L, SCEV::NoWrapFlags Flags) { | ||||||
3415 | if (Operands.size() == 1) return Operands[0]; | ||||||
3416 | #ifndef NDEBUG | ||||||
3417 | Type *ETy = getEffectiveSCEVType(Operands[0]->getType()); | ||||||
3418 | for (unsigned i = 1, e = Operands.size(); i != e; ++i) | ||||||
3419 | assert(getEffectiveSCEVType(Operands[i]->getType()) == ETy &&((getEffectiveSCEVType(Operands[i]->getType()) == ETy && "SCEVAddRecExpr operand types don't match!") ? static_cast< void> (0) : __assert_fail ("getEffectiveSCEVType(Operands[i]->getType()) == ETy && \"SCEVAddRecExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3420, __PRETTY_FUNCTION__)) | ||||||
3420 | "SCEVAddRecExpr operand types don't match!")((getEffectiveSCEVType(Operands[i]->getType()) == ETy && "SCEVAddRecExpr operand types don't match!") ? static_cast< void> (0) : __assert_fail ("getEffectiveSCEVType(Operands[i]->getType()) == ETy && \"SCEVAddRecExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3420, __PRETTY_FUNCTION__)); | ||||||
3421 | for (unsigned i = 0, e = Operands.size(); i != e; ++i) | ||||||
3422 | assert(isLoopInvariant(Operands[i], L) &&((isLoopInvariant(Operands[i], L) && "SCEVAddRecExpr operand is not loop-invariant!" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Operands[i], L) && \"SCEVAddRecExpr operand is not loop-invariant!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3423, __PRETTY_FUNCTION__)) | ||||||
3423 | "SCEVAddRecExpr operand is not loop-invariant!")((isLoopInvariant(Operands[i], L) && "SCEVAddRecExpr operand is not loop-invariant!" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Operands[i], L) && \"SCEVAddRecExpr operand is not loop-invariant!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3423, __PRETTY_FUNCTION__)); | ||||||
3424 | #endif | ||||||
3425 | |||||||
3426 | if (Operands.back()->isZero()) { | ||||||
3427 | Operands.pop_back(); | ||||||
3428 | return getAddRecExpr(Operands, L, SCEV::FlagAnyWrap); // {X,+,0} --> X | ||||||
3429 | } | ||||||
3430 | |||||||
3431 | // It's tempting to want to call getConstantMaxBackedgeTakenCount count here and | ||||||
3432 | // use that information to infer NUW and NSW flags. However, computing a | ||||||
3433 | // BE count requires calling getAddRecExpr, so we may not yet have a | ||||||
3434 | // meaningful BE count at this point (and if we don't, we'd be stuck | ||||||
3435 | // with a SCEVCouldNotCompute as the cached BE count). | ||||||
3436 | |||||||
3437 | Flags = StrengthenNoWrapFlags(this, scAddRecExpr, Operands, Flags); | ||||||
3438 | |||||||
3439 | // Canonicalize nested AddRecs in by nesting them in order of loop depth. | ||||||
3440 | if (const SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) { | ||||||
3441 | const Loop *NestedLoop = NestedAR->getLoop(); | ||||||
3442 | if (L->contains(NestedLoop) | ||||||
3443 | ? (L->getLoopDepth() < NestedLoop->getLoopDepth()) | ||||||
3444 | : (!NestedLoop->contains(L) && | ||||||
3445 | DT.dominates(L->getHeader(), NestedLoop->getHeader()))) { | ||||||
3446 | SmallVector<const SCEV *, 4> NestedOperands(NestedAR->op_begin(), | ||||||
3447 | NestedAR->op_end()); | ||||||
3448 | Operands[0] = NestedAR->getStart(); | ||||||
3449 | // AddRecs require their operands be loop-invariant with respect to their | ||||||
3450 | // loops. Don't perform this transformation if it would break this | ||||||
3451 | // requirement. | ||||||
3452 | bool AllInvariant = all_of( | ||||||
3453 | Operands, [&](const SCEV *Op) { return isLoopInvariant(Op, L); }); | ||||||
3454 | |||||||
3455 | if (AllInvariant) { | ||||||
3456 | // Create a recurrence for the outer loop with the same step size. | ||||||
3457 | // | ||||||
3458 | // The outer recurrence keeps its NW flag but only keeps NUW/NSW if the | ||||||
3459 | // inner recurrence has the same property. | ||||||
3460 | SCEV::NoWrapFlags OuterFlags = | ||||||
3461 | maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags()); | ||||||
3462 | |||||||
3463 | NestedOperands[0] = getAddRecExpr(Operands, L, OuterFlags); | ||||||
3464 | AllInvariant = all_of(NestedOperands, [&](const SCEV *Op) { | ||||||
3465 | return isLoopInvariant(Op, NestedLoop); | ||||||
3466 | }); | ||||||
3467 | |||||||
3468 | if (AllInvariant) { | ||||||
3469 | // Ok, both add recurrences are valid after the transformation. | ||||||
3470 | // | ||||||
3471 | // The inner recurrence keeps its NW flag but only keeps NUW/NSW if | ||||||
3472 | // the outer recurrence has the same property. | ||||||
3473 | SCEV::NoWrapFlags InnerFlags = | ||||||
3474 | maskFlags(NestedAR->getNoWrapFlags(), SCEV::FlagNW | Flags); | ||||||
3475 | return getAddRecExpr(NestedOperands, NestedLoop, InnerFlags); | ||||||
3476 | } | ||||||
3477 | } | ||||||
3478 | // Reset Operands to its original state. | ||||||
3479 | Operands[0] = NestedAR; | ||||||
3480 | } | ||||||
3481 | } | ||||||
3482 | |||||||
3483 | // Okay, it looks like we really DO need an addrec expr. Check to see if we | ||||||
3484 | // already have one, otherwise create a new one. | ||||||
3485 | return getOrCreateAddRecExpr(Operands, L, Flags); | ||||||
3486 | } | ||||||
3487 | |||||||
3488 | const SCEV * | ||||||
3489 | ScalarEvolution::getGEPExpr(GEPOperator *GEP, | ||||||
3490 | const SmallVectorImpl<const SCEV *> &IndexExprs) { | ||||||
3491 | const SCEV *BaseExpr = getSCEV(GEP->getPointerOperand()); | ||||||
3492 | // getSCEV(Base)->getType() has the same address space as Base->getType() | ||||||
3493 | // because SCEV::getType() preserves the address space. | ||||||
3494 | Type *IntIdxTy = getEffectiveSCEVType(BaseExpr->getType()); | ||||||
3495 | // FIXME(PR23527): Don't blindly transfer the inbounds flag from the GEP | ||||||
3496 | // instruction to its SCEV, because the Instruction may be guarded by control | ||||||
3497 | // flow and the no-overflow bits may not be valid for the expression in any | ||||||
3498 | // context. This can be fixed similarly to how these flags are handled for | ||||||
3499 | // adds. | ||||||
3500 | SCEV::NoWrapFlags Wrap = GEP->isInBounds() ? SCEV::FlagNSW | ||||||
3501 | : SCEV::FlagAnyWrap; | ||||||
3502 | |||||||
3503 | const SCEV *TotalOffset = getZero(IntIdxTy); | ||||||
3504 | // The array size is unimportant. The first thing we do on CurTy is getting | ||||||
3505 | // its element type. | ||||||
3506 | Type *CurTy = ArrayType::get(GEP->getSourceElementType(), 0); | ||||||
3507 | for (const SCEV *IndexExpr : IndexExprs) { | ||||||
3508 | // Compute the (potentially symbolic) offset in bytes for this index. | ||||||
3509 | if (StructType *STy = dyn_cast<StructType>(CurTy)) { | ||||||
3510 | // For a struct, add the member offset. | ||||||
3511 | ConstantInt *Index = cast<SCEVConstant>(IndexExpr)->getValue(); | ||||||
3512 | unsigned FieldNo = Index->getZExtValue(); | ||||||
3513 | const SCEV *FieldOffset = getOffsetOfExpr(IntIdxTy, STy, FieldNo); | ||||||
3514 | |||||||
3515 | // Add the field offset to the running total offset. | ||||||
3516 | TotalOffset = getAddExpr(TotalOffset, FieldOffset); | ||||||
3517 | |||||||
3518 | // Update CurTy to the type of the field at Index. | ||||||
3519 | CurTy = STy->getTypeAtIndex(Index); | ||||||
3520 | } else { | ||||||
3521 | // Update CurTy to its element type. | ||||||
3522 | CurTy = cast<SequentialType>(CurTy)->getElementType(); | ||||||
3523 | // For an array, add the element offset, explicitly scaled. | ||||||
3524 | const SCEV *ElementSize = getSizeOfExpr(IntIdxTy, CurTy); | ||||||
3525 | // Getelementptr indices are signed. | ||||||
3526 | IndexExpr = getTruncateOrSignExtend(IndexExpr, IntIdxTy); | ||||||
3527 | |||||||
3528 | // Multiply the index by the element size to compute the element offset. | ||||||
3529 | const SCEV *LocalOffset = getMulExpr(IndexExpr, ElementSize, Wrap); | ||||||
3530 | |||||||
3531 | // Add the element offset to the running total offset. | ||||||
3532 | TotalOffset = getAddExpr(TotalOffset, LocalOffset); | ||||||
3533 | } | ||||||
3534 | } | ||||||
3535 | |||||||
3536 | // Add the total offset from all the GEP indices to the base. | ||||||
3537 | return getAddExpr(BaseExpr, TotalOffset, Wrap); | ||||||
3538 | } | ||||||
3539 | |||||||
3540 | std::tuple<const SCEV *, FoldingSetNodeID, void *> | ||||||
3541 | ScalarEvolution::findExistingSCEVInCache(int SCEVType, | ||||||
3542 | ArrayRef<const SCEV *> Ops) { | ||||||
3543 | FoldingSetNodeID ID; | ||||||
3544 | void *IP = nullptr; | ||||||
3545 | ID.AddInteger(SCEVType); | ||||||
3546 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
3547 | ID.AddPointer(Ops[i]); | ||||||
3548 | return std::tuple<const SCEV *, FoldingSetNodeID, void *>( | ||||||
3549 | UniqueSCEVs.FindNodeOrInsertPos(ID, IP), std::move(ID), IP); | ||||||
3550 | } | ||||||
3551 | |||||||
3552 | const SCEV *ScalarEvolution::getMinMaxExpr(unsigned Kind, | ||||||
3553 | SmallVectorImpl<const SCEV *> &Ops) { | ||||||
3554 | assert(!Ops.empty() && "Cannot get empty (u|s)(min|max)!")((!Ops.empty() && "Cannot get empty (u|s)(min|max)!") ? static_cast<void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty (u|s)(min|max)!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3554, __PRETTY_FUNCTION__)); | ||||||
3555 | if (Ops.size() == 1) return Ops[0]; | ||||||
3556 | #ifndef NDEBUG | ||||||
3557 | Type *ETy = getEffectiveSCEVType(Ops[0]->getType()); | ||||||
3558 | for (unsigned i = 1, e = Ops.size(); i != e; ++i) | ||||||
3559 | assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "Operand types don't match!") ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"Operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3560, __PRETTY_FUNCTION__)) | ||||||
3560 | "Operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "Operand types don't match!") ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"Operand types don't match!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3560, __PRETTY_FUNCTION__)); | ||||||
3561 | #endif | ||||||
3562 | |||||||
3563 | bool IsSigned = Kind == scSMaxExpr || Kind == scSMinExpr; | ||||||
3564 | bool IsMax = Kind == scSMaxExpr || Kind == scUMaxExpr; | ||||||
3565 | |||||||
3566 | // Sort by complexity, this groups all similar expression types together. | ||||||
3567 | GroupByComplexity(Ops, &LI, DT); | ||||||
3568 | |||||||
3569 | // Check if we have created the same expression before. | ||||||
3570 | if (const SCEV *S = std::get<0>(findExistingSCEVInCache(Kind, Ops))) { | ||||||
3571 | return S; | ||||||
3572 | } | ||||||
3573 | |||||||
3574 | // If there are any constants, fold them together. | ||||||
3575 | unsigned Idx = 0; | ||||||
3576 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) { | ||||||
3577 | ++Idx; | ||||||
3578 | assert(Idx < Ops.size())((Idx < Ops.size()) ? static_cast<void> (0) : __assert_fail ("Idx < Ops.size()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3578, __PRETTY_FUNCTION__)); | ||||||
3579 | auto FoldOp = [&](const APInt &LHS, const APInt &RHS) { | ||||||
3580 | if (Kind == scSMaxExpr) | ||||||
3581 | return APIntOps::smax(LHS, RHS); | ||||||
3582 | else if (Kind == scSMinExpr) | ||||||
3583 | return APIntOps::smin(LHS, RHS); | ||||||
3584 | else if (Kind == scUMaxExpr) | ||||||
3585 | return APIntOps::umax(LHS, RHS); | ||||||
3586 | else if (Kind == scUMinExpr) | ||||||
3587 | return APIntOps::umin(LHS, RHS); | ||||||
3588 | llvm_unreachable("Unknown SCEV min/max opcode")::llvm::llvm_unreachable_internal("Unknown SCEV min/max opcode" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3588); | ||||||
3589 | }; | ||||||
3590 | |||||||
3591 | while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) { | ||||||
3592 | // We found two constants, fold them together! | ||||||
3593 | ConstantInt *Fold = ConstantInt::get( | ||||||
3594 | getContext(), FoldOp(LHSC->getAPInt(), RHSC->getAPInt())); | ||||||
3595 | Ops[0] = getConstant(Fold); | ||||||
3596 | Ops.erase(Ops.begin()+1); // Erase the folded element | ||||||
3597 | if (Ops.size() == 1) return Ops[0]; | ||||||
3598 | LHSC = cast<SCEVConstant>(Ops[0]); | ||||||
3599 | } | ||||||
3600 | |||||||
3601 | bool IsMinV = LHSC->getValue()->isMinValue(IsSigned); | ||||||
3602 | bool IsMaxV = LHSC->getValue()->isMaxValue(IsSigned); | ||||||
3603 | |||||||
3604 | if (IsMax ? IsMinV : IsMaxV) { | ||||||
3605 | // If we are left with a constant minimum(/maximum)-int, strip it off. | ||||||
3606 | Ops.erase(Ops.begin()); | ||||||
3607 | --Idx; | ||||||
3608 | } else if (IsMax ? IsMaxV : IsMinV) { | ||||||
3609 | // If we have a max(/min) with a constant maximum(/minimum)-int, | ||||||
3610 | // it will always be the extremum. | ||||||
3611 | return LHSC; | ||||||
3612 | } | ||||||
3613 | |||||||
3614 | if (Ops.size() == 1) return Ops[0]; | ||||||
3615 | } | ||||||
3616 | |||||||
3617 | // Find the first operation of the same kind | ||||||
3618 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < Kind) | ||||||
3619 | ++Idx; | ||||||
3620 | |||||||
3621 | // Check to see if one of the operands is of the same kind. If so, expand its | ||||||
3622 | // operands onto our operand list, and recurse to simplify. | ||||||
3623 | if (Idx < Ops.size()) { | ||||||
3624 | bool DeletedAny = false; | ||||||
3625 | while (Ops[Idx]->getSCEVType() == Kind) { | ||||||
3626 | const SCEVMinMaxExpr *SMME = cast<SCEVMinMaxExpr>(Ops[Idx]); | ||||||
3627 | Ops.erase(Ops.begin()+Idx); | ||||||
3628 | Ops.append(SMME->op_begin(), SMME->op_end()); | ||||||
3629 | DeletedAny = true; | ||||||
3630 | } | ||||||
3631 | |||||||
3632 | if (DeletedAny) | ||||||
3633 | return getMinMaxExpr(Kind, Ops); | ||||||
3634 | } | ||||||
3635 | |||||||
3636 | // Okay, check to see if the same value occurs in the operand list twice. If | ||||||
3637 | // so, delete one. Since we sorted the list, these values are required to | ||||||
3638 | // be adjacent. | ||||||
3639 | llvm::CmpInst::Predicate GEPred = | ||||||
3640 | IsSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; | ||||||
3641 | llvm::CmpInst::Predicate LEPred = | ||||||
3642 | IsSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; | ||||||
3643 | llvm::CmpInst::Predicate FirstPred = IsMax ? GEPred : LEPred; | ||||||
3644 | llvm::CmpInst::Predicate SecondPred = IsMax ? LEPred : GEPred; | ||||||
3645 | for (unsigned i = 0, e = Ops.size() - 1; i != e; ++i) { | ||||||
3646 | if (Ops[i] == Ops[i + 1] || | ||||||
3647 | isKnownViaNonRecursiveReasoning(FirstPred, Ops[i], Ops[i + 1])) { | ||||||
3648 | // X op Y op Y --> X op Y | ||||||
3649 | // X op Y --> X, if we know X, Y are ordered appropriately | ||||||
3650 | Ops.erase(Ops.begin() + i + 1, Ops.begin() + i + 2); | ||||||
3651 | --i; | ||||||
3652 | --e; | ||||||
3653 | } else if (isKnownViaNonRecursiveReasoning(SecondPred, Ops[i], | ||||||
3654 | Ops[i + 1])) { | ||||||
3655 | // X op Y --> Y, if we know X, Y are ordered appropriately | ||||||
3656 | Ops.erase(Ops.begin() + i, Ops.begin() + i + 1); | ||||||
3657 | --i; | ||||||
3658 | --e; | ||||||
3659 | } | ||||||
3660 | } | ||||||
3661 | |||||||
3662 | if (Ops.size() == 1) return Ops[0]; | ||||||
3663 | |||||||
3664 | assert(!Ops.empty() && "Reduced smax down to nothing!")((!Ops.empty() && "Reduced smax down to nothing!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"Reduced smax down to nothing!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3664, __PRETTY_FUNCTION__)); | ||||||
3665 | |||||||
3666 | // Okay, it looks like we really DO need an expr. Check to see if we | ||||||
3667 | // already have one, otherwise create a new one. | ||||||
3668 | const SCEV *ExistingSCEV; | ||||||
3669 | FoldingSetNodeID ID; | ||||||
3670 | void *IP; | ||||||
3671 | std::tie(ExistingSCEV, ID, IP) = findExistingSCEVInCache(Kind, Ops); | ||||||
3672 | if (ExistingSCEV) | ||||||
3673 | return ExistingSCEV; | ||||||
3674 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
3675 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
3676 | SCEV *S = new (SCEVAllocator) SCEVMinMaxExpr( | ||||||
3677 | ID.Intern(SCEVAllocator), static_cast<SCEVTypes>(Kind), O, Ops.size()); | ||||||
3678 | |||||||
3679 | UniqueSCEVs.InsertNode(S, IP); | ||||||
3680 | addToLoopUseLists(S); | ||||||
3681 | return S; | ||||||
3682 | } | ||||||
3683 | |||||||
3684 | const SCEV *ScalarEvolution::getSMaxExpr(const SCEV *LHS, const SCEV *RHS) { | ||||||
3685 | SmallVector<const SCEV *, 2> Ops = {LHS, RHS}; | ||||||
3686 | return getSMaxExpr(Ops); | ||||||
3687 | } | ||||||
3688 | |||||||
3689 | const SCEV *ScalarEvolution::getSMaxExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
3690 | return getMinMaxExpr(scSMaxExpr, Ops); | ||||||
3691 | } | ||||||
3692 | |||||||
3693 | const SCEV *ScalarEvolution::getUMaxExpr(const SCEV *LHS, const SCEV *RHS) { | ||||||
3694 | SmallVector<const SCEV *, 2> Ops = {LHS, RHS}; | ||||||
3695 | return getUMaxExpr(Ops); | ||||||
3696 | } | ||||||
3697 | |||||||
3698 | const SCEV *ScalarEvolution::getUMaxExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
3699 | return getMinMaxExpr(scUMaxExpr, Ops); | ||||||
3700 | } | ||||||
3701 | |||||||
3702 | const SCEV *ScalarEvolution::getSMinExpr(const SCEV *LHS, | ||||||
3703 | const SCEV *RHS) { | ||||||
3704 | SmallVector<const SCEV *, 2> Ops = { LHS, RHS }; | ||||||
3705 | return getSMinExpr(Ops); | ||||||
3706 | } | ||||||
3707 | |||||||
3708 | const SCEV *ScalarEvolution::getSMinExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
3709 | return getMinMaxExpr(scSMinExpr, Ops); | ||||||
3710 | } | ||||||
3711 | |||||||
3712 | const SCEV *ScalarEvolution::getUMinExpr(const SCEV *LHS, | ||||||
3713 | const SCEV *RHS) { | ||||||
3714 | SmallVector<const SCEV *, 2> Ops = { LHS, RHS }; | ||||||
3715 | return getUMinExpr(Ops); | ||||||
3716 | } | ||||||
3717 | |||||||
3718 | const SCEV *ScalarEvolution::getUMinExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
3719 | return getMinMaxExpr(scUMinExpr, Ops); | ||||||
3720 | } | ||||||
3721 | |||||||
3722 | const SCEV *ScalarEvolution::getSizeOfExpr(Type *IntTy, Type *AllocTy) { | ||||||
3723 | // We can bypass creating a target-independent | ||||||
3724 | // constant expression and then folding it back into a ConstantInt. | ||||||
3725 | // This is just a compile-time optimization. | ||||||
3726 | return getConstant(IntTy, getDataLayout().getTypeAllocSize(AllocTy)); | ||||||
3727 | } | ||||||
3728 | |||||||
3729 | const SCEV *ScalarEvolution::getOffsetOfExpr(Type *IntTy, | ||||||
3730 | StructType *STy, | ||||||
3731 | unsigned FieldNo) { | ||||||
3732 | // We can bypass creating a target-independent | ||||||
3733 | // constant expression and then folding it back into a ConstantInt. | ||||||
3734 | // This is just a compile-time optimization. | ||||||
3735 | return getConstant( | ||||||
3736 | IntTy, getDataLayout().getStructLayout(STy)->getElementOffset(FieldNo)); | ||||||
3737 | } | ||||||
3738 | |||||||
3739 | const SCEV *ScalarEvolution::getUnknown(Value *V) { | ||||||
3740 | // Don't attempt to do anything other than create a SCEVUnknown object | ||||||
3741 | // here. createSCEV only calls getUnknown after checking for all other | ||||||
3742 | // interesting possibilities, and any other code that calls getUnknown | ||||||
3743 | // is doing so in order to hide a value from SCEV canonicalization. | ||||||
3744 | |||||||
3745 | FoldingSetNodeID ID; | ||||||
3746 | ID.AddInteger(scUnknown); | ||||||
3747 | ID.AddPointer(V); | ||||||
3748 | void *IP = nullptr; | ||||||
3749 | if (SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) { | ||||||
3750 | assert(cast<SCEVUnknown>(S)->getValue() == V &&((cast<SCEVUnknown>(S)->getValue() == V && "Stale SCEVUnknown in uniquing map!" ) ? static_cast<void> (0) : __assert_fail ("cast<SCEVUnknown>(S)->getValue() == V && \"Stale SCEVUnknown in uniquing map!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3751, __PRETTY_FUNCTION__)) | ||||||
3751 | "Stale SCEVUnknown in uniquing map!")((cast<SCEVUnknown>(S)->getValue() == V && "Stale SCEVUnknown in uniquing map!" ) ? static_cast<void> (0) : __assert_fail ("cast<SCEVUnknown>(S)->getValue() == V && \"Stale SCEVUnknown in uniquing map!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3751, __PRETTY_FUNCTION__)); | ||||||
3752 | return S; | ||||||
3753 | } | ||||||
3754 | SCEV *S = new (SCEVAllocator) SCEVUnknown(ID.Intern(SCEVAllocator), V, this, | ||||||
3755 | FirstUnknown); | ||||||
3756 | FirstUnknown = cast<SCEVUnknown>(S); | ||||||
3757 | UniqueSCEVs.InsertNode(S, IP); | ||||||
3758 | return S; | ||||||
3759 | } | ||||||
3760 | |||||||
3761 | //===----------------------------------------------------------------------===// | ||||||
3762 | // Basic SCEV Analysis and PHI Idiom Recognition Code | ||||||
3763 | // | ||||||
3764 | |||||||
3765 | /// Test if values of the given type are analyzable within the SCEV | ||||||
3766 | /// framework. This primarily includes integer types, and it can optionally | ||||||
3767 | /// include pointer types if the ScalarEvolution class has access to | ||||||
3768 | /// target-specific information. | ||||||
3769 | bool ScalarEvolution::isSCEVable(Type *Ty) const { | ||||||
3770 | // Integers and pointers are always SCEVable. | ||||||
3771 | return Ty->isIntOrPtrTy(); | ||||||
3772 | } | ||||||
3773 | |||||||
3774 | /// Return the size in bits of the specified type, for which isSCEVable must | ||||||
3775 | /// return true. | ||||||
3776 | uint64_t ScalarEvolution::getTypeSizeInBits(Type *Ty) const { | ||||||
3777 | assert(isSCEVable(Ty) && "Type is not SCEVable!")((isSCEVable(Ty) && "Type is not SCEVable!") ? static_cast <void> (0) : __assert_fail ("isSCEVable(Ty) && \"Type is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3777, __PRETTY_FUNCTION__)); | ||||||
3778 | if (Ty->isPointerTy()) | ||||||
3779 | return getDataLayout().getIndexTypeSizeInBits(Ty); | ||||||
3780 | return getDataLayout().getTypeSizeInBits(Ty); | ||||||
3781 | } | ||||||
3782 | |||||||
3783 | /// Return a type with the same bitwidth as the given type and which represents | ||||||
3784 | /// how SCEV will treat the given type, for which isSCEVable must return | ||||||
3785 | /// true. For pointer types, this is the pointer index sized integer type. | ||||||
3786 | Type *ScalarEvolution::getEffectiveSCEVType(Type *Ty) const { | ||||||
3787 | assert(isSCEVable(Ty) && "Type is not SCEVable!")((isSCEVable(Ty) && "Type is not SCEVable!") ? static_cast <void> (0) : __assert_fail ("isSCEVable(Ty) && \"Type is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3787, __PRETTY_FUNCTION__)); | ||||||
3788 | |||||||
3789 | if (Ty->isIntegerTy()) | ||||||
3790 | return Ty; | ||||||
3791 | |||||||
3792 | // The only other support type is pointer. | ||||||
3793 | assert(Ty->isPointerTy() && "Unexpected non-pointer non-integer type!")((Ty->isPointerTy() && "Unexpected non-pointer non-integer type!" ) ? static_cast<void> (0) : __assert_fail ("Ty->isPointerTy() && \"Unexpected non-pointer non-integer type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3793, __PRETTY_FUNCTION__)); | ||||||
3794 | return getDataLayout().getIndexType(Ty); | ||||||
3795 | } | ||||||
3796 | |||||||
3797 | Type *ScalarEvolution::getWiderType(Type *T1, Type *T2) const { | ||||||
3798 | return getTypeSizeInBits(T1) >= getTypeSizeInBits(T2) ? T1 : T2; | ||||||
3799 | } | ||||||
3800 | |||||||
3801 | const SCEV *ScalarEvolution::getCouldNotCompute() { | ||||||
3802 | return CouldNotCompute.get(); | ||||||
3803 | } | ||||||
3804 | |||||||
3805 | bool ScalarEvolution::checkValidity(const SCEV *S) const { | ||||||
3806 | bool ContainsNulls = SCEVExprContains(S, [](const SCEV *S) { | ||||||
3807 | auto *SU = dyn_cast<SCEVUnknown>(S); | ||||||
3808 | return SU && SU->getValue() == nullptr; | ||||||
3809 | }); | ||||||
3810 | |||||||
3811 | return !ContainsNulls; | ||||||
3812 | } | ||||||
3813 | |||||||
3814 | bool ScalarEvolution::containsAddRecurrence(const SCEV *S) { | ||||||
3815 | HasRecMapType::iterator I = HasRecMap.find(S); | ||||||
3816 | if (I != HasRecMap.end()) | ||||||
3817 | return I->second; | ||||||
3818 | |||||||
3819 | bool FoundAddRec = SCEVExprContains(S, isa<SCEVAddRecExpr, const SCEV *>); | ||||||
3820 | HasRecMap.insert({S, FoundAddRec}); | ||||||
3821 | return FoundAddRec; | ||||||
3822 | } | ||||||
3823 | |||||||
3824 | /// Try to split a SCEVAddExpr into a pair of {SCEV, ConstantInt}. | ||||||
3825 | /// If \p S is a SCEVAddExpr and is composed of a sub SCEV S' and an | ||||||
3826 | /// offset I, then return {S', I}, else return {\p S, nullptr}. | ||||||
3827 | static std::pair<const SCEV *, ConstantInt *> splitAddExpr(const SCEV *S) { | ||||||
3828 | const auto *Add = dyn_cast<SCEVAddExpr>(S); | ||||||
3829 | if (!Add) | ||||||
3830 | return {S, nullptr}; | ||||||
3831 | |||||||
3832 | if (Add->getNumOperands() != 2) | ||||||
3833 | return {S, nullptr}; | ||||||
3834 | |||||||
3835 | auto *ConstOp = dyn_cast<SCEVConstant>(Add->getOperand(0)); | ||||||
3836 | if (!ConstOp) | ||||||
3837 | return {S, nullptr}; | ||||||
3838 | |||||||
3839 | return {Add->getOperand(1), ConstOp->getValue()}; | ||||||
3840 | } | ||||||
3841 | |||||||
3842 | /// Return the ValueOffsetPair set for \p S. \p S can be represented | ||||||
3843 | /// by the value and offset from any ValueOffsetPair in the set. | ||||||
3844 | SetVector<ScalarEvolution::ValueOffsetPair> * | ||||||
3845 | ScalarEvolution::getSCEVValues(const SCEV *S) { | ||||||
3846 | ExprValueMapType::iterator SI = ExprValueMap.find_as(S); | ||||||
3847 | if (SI == ExprValueMap.end()) | ||||||
3848 | return nullptr; | ||||||
3849 | #ifndef NDEBUG | ||||||
3850 | if (VerifySCEVMap) { | ||||||
3851 | // Check there is no dangling Value in the set returned. | ||||||
3852 | for (const auto &VE : SI->second) | ||||||
3853 | assert(ValueExprMap.count(VE.first))((ValueExprMap.count(VE.first)) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.count(VE.first)", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3853, __PRETTY_FUNCTION__)); | ||||||
3854 | } | ||||||
3855 | #endif | ||||||
3856 | return &SI->second; | ||||||
3857 | } | ||||||
3858 | |||||||
3859 | /// Erase Value from ValueExprMap and ExprValueMap. ValueExprMap.erase(V) | ||||||
3860 | /// cannot be used separately. eraseValueFromMap should be used to remove | ||||||
3861 | /// V from ValueExprMap and ExprValueMap at the same time. | ||||||
3862 | void ScalarEvolution::eraseValueFromMap(Value *V) { | ||||||
3863 | ValueExprMapType::iterator I = ValueExprMap.find_as(V); | ||||||
3864 | if (I != ValueExprMap.end()) { | ||||||
3865 | const SCEV *S = I->second; | ||||||
3866 | // Remove {V, 0} from the set of ExprValueMap[S] | ||||||
3867 | if (SetVector<ValueOffsetPair> *SV = getSCEVValues(S)) | ||||||
3868 | SV->remove({V, nullptr}); | ||||||
3869 | |||||||
3870 | // Remove {V, Offset} from the set of ExprValueMap[Stripped] | ||||||
3871 | const SCEV *Stripped; | ||||||
3872 | ConstantInt *Offset; | ||||||
3873 | std::tie(Stripped, Offset) = splitAddExpr(S); | ||||||
3874 | if (Offset != nullptr) { | ||||||
3875 | if (SetVector<ValueOffsetPair> *SV = getSCEVValues(Stripped)) | ||||||
3876 | SV->remove({V, Offset}); | ||||||
3877 | } | ||||||
3878 | ValueExprMap.erase(V); | ||||||
3879 | } | ||||||
3880 | } | ||||||
3881 | |||||||
3882 | /// Check whether value has nuw/nsw/exact set but SCEV does not. | ||||||
3883 | /// TODO: In reality it is better to check the poison recursively | ||||||
3884 | /// but this is better than nothing. | ||||||
3885 | static bool SCEVLostPoisonFlags(const SCEV *S, const Value *V) { | ||||||
3886 | if (auto *I = dyn_cast<Instruction>(V)) { | ||||||
3887 | if (isa<OverflowingBinaryOperator>(I)) { | ||||||
3888 | if (auto *NS = dyn_cast<SCEVNAryExpr>(S)) { | ||||||
3889 | if (I->hasNoSignedWrap() && !NS->hasNoSignedWrap()) | ||||||
3890 | return true; | ||||||
3891 | if (I->hasNoUnsignedWrap() && !NS->hasNoUnsignedWrap()) | ||||||
3892 | return true; | ||||||
3893 | } | ||||||
3894 | } else if (isa<PossiblyExactOperator>(I) && I->isExact()) | ||||||
3895 | return true; | ||||||
3896 | } | ||||||
3897 | return false; | ||||||
3898 | } | ||||||
3899 | |||||||
3900 | /// Return an existing SCEV if it exists, otherwise analyze the expression and | ||||||
3901 | /// create a new one. | ||||||
3902 | const SCEV *ScalarEvolution::getSCEV(Value *V) { | ||||||
3903 | assert(isSCEVable(V->getType()) && "Value is not SCEVable!")((isSCEVable(V->getType()) && "Value is not SCEVable!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(V->getType()) && \"Value is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3903, __PRETTY_FUNCTION__)); | ||||||
3904 | |||||||
3905 | const SCEV *S = getExistingSCEV(V); | ||||||
3906 | if (S == nullptr) { | ||||||
3907 | S = createSCEV(V); | ||||||
3908 | // During PHI resolution, it is possible to create two SCEVs for the same | ||||||
3909 | // V, so it is needed to double check whether V->S is inserted into | ||||||
3910 | // ValueExprMap before insert S->{V, 0} into ExprValueMap. | ||||||
3911 | std::pair<ValueExprMapType::iterator, bool> Pair = | ||||||
3912 | ValueExprMap.insert({SCEVCallbackVH(V, this), S}); | ||||||
3913 | if (Pair.second && !SCEVLostPoisonFlags(S, V)) { | ||||||
3914 | ExprValueMap[S].insert({V, nullptr}); | ||||||
3915 | |||||||
3916 | // If S == Stripped + Offset, add Stripped -> {V, Offset} into | ||||||
3917 | // ExprValueMap. | ||||||
3918 | const SCEV *Stripped = S; | ||||||
3919 | ConstantInt *Offset = nullptr; | ||||||
3920 | std::tie(Stripped, Offset) = splitAddExpr(S); | ||||||
3921 | // If stripped is SCEVUnknown, don't bother to save | ||||||
3922 | // Stripped -> {V, offset}. It doesn't simplify and sometimes even | ||||||
3923 | // increase the complexity of the expansion code. | ||||||
3924 | // If V is GetElementPtrInst, don't save Stripped -> {V, offset} | ||||||
3925 | // because it may generate add/sub instead of GEP in SCEV expansion. | ||||||
3926 | if (Offset != nullptr && !isa<SCEVUnknown>(Stripped) && | ||||||
3927 | !isa<GetElementPtrInst>(V)) | ||||||
3928 | ExprValueMap[Stripped].insert({V, Offset}); | ||||||
3929 | } | ||||||
3930 | } | ||||||
3931 | return S; | ||||||
3932 | } | ||||||
3933 | |||||||
3934 | const SCEV *ScalarEvolution::getExistingSCEV(Value *V) { | ||||||
3935 | assert(isSCEVable(V->getType()) && "Value is not SCEVable!")((isSCEVable(V->getType()) && "Value is not SCEVable!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(V->getType()) && \"Value is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 3935, __PRETTY_FUNCTION__)); | ||||||
3936 | |||||||
3937 | ValueExprMapType::iterator I = ValueExprMap.find_as(V); | ||||||
3938 | if (I != ValueExprMap.end()) { | ||||||
3939 | const SCEV *S = I->second; | ||||||
3940 | if (checkValidity(S)) | ||||||
3941 | return S; | ||||||
3942 | eraseValueFromMap(V); | ||||||
3943 | forgetMemoizedResults(S); | ||||||
3944 | } | ||||||
3945 | return nullptr; | ||||||
3946 | } | ||||||
3947 | |||||||
3948 | /// Return a SCEV corresponding to -V = -1*V | ||||||
3949 | const SCEV *ScalarEvolution::getNegativeSCEV(const SCEV *V, | ||||||
3950 | SCEV::NoWrapFlags Flags) { | ||||||
3951 | if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V)) | ||||||
3952 | return getConstant( | ||||||
3953 | cast<ConstantInt>(ConstantExpr::getNeg(VC->getValue()))); | ||||||
3954 | |||||||
3955 | Type *Ty = V->getType(); | ||||||
3956 | Ty = getEffectiveSCEVType(Ty); | ||||||
3957 | return getMulExpr( | ||||||
3958 | V, getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))), Flags); | ||||||
3959 | } | ||||||
3960 | |||||||
3961 | /// If Expr computes ~A, return A else return nullptr | ||||||
3962 | static const SCEV *MatchNotExpr(const SCEV *Expr) { | ||||||
3963 | const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Expr); | ||||||
3964 | if (!Add || Add->getNumOperands() != 2 || | ||||||
3965 | !Add->getOperand(0)->isAllOnesValue()) | ||||||
3966 | return nullptr; | ||||||
3967 | |||||||
3968 | const SCEVMulExpr *AddRHS = dyn_cast<SCEVMulExpr>(Add->getOperand(1)); | ||||||
3969 | if (!AddRHS || AddRHS->getNumOperands() != 2 || | ||||||
3970 | !AddRHS->getOperand(0)->isAllOnesValue()) | ||||||
3971 | return nullptr; | ||||||
3972 | |||||||
3973 | return AddRHS->getOperand(1); | ||||||
3974 | } | ||||||
3975 | |||||||
3976 | /// Return a SCEV corresponding to ~V = -1-V | ||||||
3977 | const SCEV *ScalarEvolution::getNotSCEV(const SCEV *V) { | ||||||
3978 | if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V)) | ||||||
3979 | return getConstant( | ||||||
3980 | cast<ConstantInt>(ConstantExpr::getNot(VC->getValue()))); | ||||||
3981 | |||||||
3982 | // Fold ~(u|s)(min|max)(~x, ~y) to (u|s)(max|min)(x, y) | ||||||
3983 | if (const SCEVMinMaxExpr *MME = dyn_cast<SCEVMinMaxExpr>(V)) { | ||||||
3984 | auto MatchMinMaxNegation = [&](const SCEVMinMaxExpr *MME) { | ||||||
3985 | SmallVector<const SCEV *, 2> MatchedOperands; | ||||||
3986 | for (const SCEV *Operand : MME->operands()) { | ||||||
3987 | const SCEV *Matched = MatchNotExpr(Operand); | ||||||
3988 | if (!Matched) | ||||||
3989 | return (const SCEV *)nullptr; | ||||||
3990 | MatchedOperands.push_back(Matched); | ||||||
3991 | } | ||||||
3992 | return getMinMaxExpr( | ||||||
3993 | SCEVMinMaxExpr::negate(static_cast<SCEVTypes>(MME->getSCEVType())), | ||||||
3994 | MatchedOperands); | ||||||
3995 | }; | ||||||
3996 | if (const SCEV *Replaced = MatchMinMaxNegation(MME)) | ||||||
3997 | return Replaced; | ||||||
3998 | } | ||||||
3999 | |||||||
4000 | Type *Ty = V->getType(); | ||||||
4001 | Ty = getEffectiveSCEVType(Ty); | ||||||
4002 | const SCEV *AllOnes = | ||||||
4003 | getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))); | ||||||
4004 | return getMinusSCEV(AllOnes, V); | ||||||
4005 | } | ||||||
4006 | |||||||
4007 | const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS, | ||||||
4008 | SCEV::NoWrapFlags Flags, | ||||||
4009 | unsigned Depth) { | ||||||
4010 | // Fast path: X - X --> 0. | ||||||
4011 | if (LHS == RHS) | ||||||
4012 | return getZero(LHS->getType()); | ||||||
4013 | |||||||
4014 | // We represent LHS - RHS as LHS + (-1)*RHS. This transformation | ||||||
4015 | // makes it so that we cannot make much use of NUW. | ||||||
4016 | auto AddFlags = SCEV::FlagAnyWrap; | ||||||
4017 | const bool RHSIsNotMinSigned = | ||||||
4018 | !getSignedRangeMin(RHS).isMinSignedValue(); | ||||||
4019 | if (maskFlags(Flags, SCEV::FlagNSW) == SCEV::FlagNSW) { | ||||||
4020 | // Let M be the minimum representable signed value. Then (-1)*RHS | ||||||
4021 | // signed-wraps if and only if RHS is M. That can happen even for | ||||||
4022 | // a NSW subtraction because e.g. (-1)*M signed-wraps even though | ||||||
4023 | // -1 - M does not. So to transfer NSW from LHS - RHS to LHS + | ||||||
4024 | // (-1)*RHS, we need to prove that RHS != M. | ||||||
4025 | // | ||||||
4026 | // If LHS is non-negative and we know that LHS - RHS does not | ||||||
4027 | // signed-wrap, then RHS cannot be M. So we can rule out signed-wrap | ||||||
4028 | // either by proving that RHS > M or that LHS >= 0. | ||||||
4029 | if (RHSIsNotMinSigned || isKnownNonNegative(LHS)) { | ||||||
4030 | AddFlags = SCEV::FlagNSW; | ||||||
4031 | } | ||||||
4032 | } | ||||||
4033 | |||||||
4034 | // FIXME: Find a correct way to transfer NSW to (-1)*M when LHS - | ||||||
4035 | // RHS is NSW and LHS >= 0. | ||||||
4036 | // | ||||||
4037 | // The difficulty here is that the NSW flag may have been proven | ||||||
4038 | // relative to a loop that is to be found in a recurrence in LHS and | ||||||
4039 | // not in RHS. Applying NSW to (-1)*M may then let the NSW have a | ||||||
4040 | // larger scope than intended. | ||||||
4041 | auto NegFlags = RHSIsNotMinSigned ? SCEV::FlagNSW : SCEV::FlagAnyWrap; | ||||||
4042 | |||||||
4043 | return getAddExpr(LHS, getNegativeSCEV(RHS, NegFlags), AddFlags, Depth); | ||||||
4044 | } | ||||||
4045 | |||||||
4046 | const SCEV *ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V, Type *Ty, | ||||||
4047 | unsigned Depth) { | ||||||
4048 | Type *SrcTy = V->getType(); | ||||||
4049 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4050, __PRETTY_FUNCTION__)) | ||||||
4050 | "Cannot truncate or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4050, __PRETTY_FUNCTION__)); | ||||||
4051 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
4052 | return V; // No conversion | ||||||
4053 | if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty)) | ||||||
4054 | return getTruncateExpr(V, Ty, Depth); | ||||||
4055 | return getZeroExtendExpr(V, Ty, Depth); | ||||||
4056 | } | ||||||
4057 | |||||||
4058 | const SCEV *ScalarEvolution::getTruncateOrSignExtend(const SCEV *V, Type *Ty, | ||||||
4059 | unsigned Depth) { | ||||||
4060 | Type *SrcTy = V->getType(); | ||||||
4061 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4062, __PRETTY_FUNCTION__)) | ||||||
4062 | "Cannot truncate or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4062, __PRETTY_FUNCTION__)); | ||||||
4063 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
4064 | return V; // No conversion | ||||||
4065 | if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty)) | ||||||
4066 | return getTruncateExpr(V, Ty, Depth); | ||||||
4067 | return getSignExtendExpr(V, Ty, Depth); | ||||||
4068 | } | ||||||
4069 | |||||||
4070 | const SCEV * | ||||||
4071 | ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, Type *Ty) { | ||||||
4072 | Type *SrcTy = V->getType(); | ||||||
4073 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or zero extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4074, __PRETTY_FUNCTION__)) | ||||||
4074 | "Cannot noop or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or zero extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4074, __PRETTY_FUNCTION__)); | ||||||
4075 | assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrZeroExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrZeroExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4076, __PRETTY_FUNCTION__)) | ||||||
4076 | "getNoopOrZeroExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrZeroExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrZeroExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4076, __PRETTY_FUNCTION__)); | ||||||
4077 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
4078 | return V; // No conversion | ||||||
4079 | return getZeroExtendExpr(V, Ty); | ||||||
4080 | } | ||||||
4081 | |||||||
4082 | const SCEV * | ||||||
4083 | ScalarEvolution::getNoopOrSignExtend(const SCEV *V, Type *Ty) { | ||||||
4084 | Type *SrcTy = V->getType(); | ||||||
4085 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or sign extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or sign extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4086, __PRETTY_FUNCTION__)) | ||||||
4086 | "Cannot noop or sign extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or sign extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or sign extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4086, __PRETTY_FUNCTION__)); | ||||||
4087 | assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrSignExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrSignExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4088, __PRETTY_FUNCTION__)) | ||||||
4088 | "getNoopOrSignExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrSignExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrSignExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4088, __PRETTY_FUNCTION__)); | ||||||
4089 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
4090 | return V; // No conversion | ||||||
4091 | return getSignExtendExpr(V, Ty); | ||||||
4092 | } | ||||||
4093 | |||||||
4094 | const SCEV * | ||||||
4095 | ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, Type *Ty) { | ||||||
4096 | Type *SrcTy = V->getType(); | ||||||
4097 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or any extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or any extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4098, __PRETTY_FUNCTION__)) | ||||||
4098 | "Cannot noop or any extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or any extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or any extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4098, __PRETTY_FUNCTION__)); | ||||||
4099 | assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrAnyExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrAnyExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4100, __PRETTY_FUNCTION__)) | ||||||
4100 | "getNoopOrAnyExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrAnyExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrAnyExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4100, __PRETTY_FUNCTION__)); | ||||||
4101 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
4102 | return V; // No conversion | ||||||
4103 | return getAnyExtendExpr(V, Ty); | ||||||
4104 | } | ||||||
4105 | |||||||
4106 | const SCEV * | ||||||
4107 | ScalarEvolution::getTruncateOrNoop(const SCEV *V, Type *Ty) { | ||||||
4108 | Type *SrcTy = V->getType(); | ||||||
4109 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or noop with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or noop with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4110, __PRETTY_FUNCTION__)) | ||||||
4110 | "Cannot truncate or noop with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or noop with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or noop with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4110, __PRETTY_FUNCTION__)); | ||||||
4111 | assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && "getTruncateOrNoop cannot extend!") ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && \"getTruncateOrNoop cannot extend!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4112, __PRETTY_FUNCTION__)) | ||||||
4112 | "getTruncateOrNoop cannot extend!")((getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && "getTruncateOrNoop cannot extend!") ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && \"getTruncateOrNoop cannot extend!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4112, __PRETTY_FUNCTION__)); | ||||||
4113 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
4114 | return V; // No conversion | ||||||
4115 | return getTruncateExpr(V, Ty); | ||||||
4116 | } | ||||||
4117 | |||||||
4118 | const SCEV *ScalarEvolution::getUMaxFromMismatchedTypes(const SCEV *LHS, | ||||||
4119 | const SCEV *RHS) { | ||||||
4120 | const SCEV *PromotedLHS = LHS; | ||||||
4121 | const SCEV *PromotedRHS = RHS; | ||||||
4122 | |||||||
4123 | if (getTypeSizeInBits(LHS->getType()) > getTypeSizeInBits(RHS->getType())) | ||||||
4124 | PromotedRHS = getZeroExtendExpr(RHS, LHS->getType()); | ||||||
4125 | else | ||||||
4126 | PromotedLHS = getNoopOrZeroExtend(LHS, RHS->getType()); | ||||||
4127 | |||||||
4128 | return getUMaxExpr(PromotedLHS, PromotedRHS); | ||||||
4129 | } | ||||||
4130 | |||||||
4131 | const SCEV *ScalarEvolution::getUMinFromMismatchedTypes(const SCEV *LHS, | ||||||
4132 | const SCEV *RHS) { | ||||||
4133 | SmallVector<const SCEV *, 2> Ops = { LHS, RHS }; | ||||||
4134 | return getUMinFromMismatchedTypes(Ops); | ||||||
4135 | } | ||||||
4136 | |||||||
4137 | const SCEV *ScalarEvolution::getUMinFromMismatchedTypes( | ||||||
4138 | SmallVectorImpl<const SCEV *> &Ops) { | ||||||
4139 | assert(!Ops.empty() && "At least one operand must be!")((!Ops.empty() && "At least one operand must be!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"At least one operand must be!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4139, __PRETTY_FUNCTION__)); | ||||||
4140 | // Trivial case. | ||||||
4141 | if (Ops.size() == 1) | ||||||
4142 | return Ops[0]; | ||||||
4143 | |||||||
4144 | // Find the max type first. | ||||||
4145 | Type *MaxType = nullptr; | ||||||
4146 | for (auto *S : Ops) | ||||||
4147 | if (MaxType) | ||||||
4148 | MaxType = getWiderType(MaxType, S->getType()); | ||||||
4149 | else | ||||||
4150 | MaxType = S->getType(); | ||||||
4151 | |||||||
4152 | // Extend all ops to max type. | ||||||
4153 | SmallVector<const SCEV *, 2> PromotedOps; | ||||||
4154 | for (auto *S : Ops) | ||||||
4155 | PromotedOps.push_back(getNoopOrZeroExtend(S, MaxType)); | ||||||
4156 | |||||||
4157 | // Generate umin. | ||||||
4158 | return getUMinExpr(PromotedOps); | ||||||
4159 | } | ||||||
4160 | |||||||
4161 | const SCEV *ScalarEvolution::getPointerBase(const SCEV *V) { | ||||||
4162 | // A pointer operand may evaluate to a nonpointer expression, such as null. | ||||||
4163 | if (!V->getType()->isPointerTy()) | ||||||
4164 | return V; | ||||||
4165 | |||||||
4166 | if (const SCEVCastExpr *Cast = dyn_cast<SCEVCastExpr>(V)) { | ||||||
4167 | return getPointerBase(Cast->getOperand()); | ||||||
4168 | } else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) { | ||||||
4169 | const SCEV *PtrOp = nullptr; | ||||||
4170 | for (const SCEV *NAryOp : NAry->operands()) { | ||||||
4171 | if (NAryOp->getType()->isPointerTy()) { | ||||||
4172 | // Cannot find the base of an expression with multiple pointer operands. | ||||||
4173 | if (PtrOp) | ||||||
4174 | return V; | ||||||
4175 | PtrOp = NAryOp; | ||||||
4176 | } | ||||||
4177 | } | ||||||
4178 | if (!PtrOp) | ||||||
4179 | return V; | ||||||
4180 | return getPointerBase(PtrOp); | ||||||
4181 | } | ||||||
4182 | return V; | ||||||
4183 | } | ||||||
4184 | |||||||
4185 | /// Push users of the given Instruction onto the given Worklist. | ||||||
4186 | static void | ||||||
4187 | PushDefUseChildren(Instruction *I, | ||||||
4188 | SmallVectorImpl<Instruction *> &Worklist) { | ||||||
4189 | // Push the def-use children onto the Worklist stack. | ||||||
4190 | for (User *U : I->users()) | ||||||
4191 | Worklist.push_back(cast<Instruction>(U)); | ||||||
4192 | } | ||||||
4193 | |||||||
4194 | void ScalarEvolution::forgetSymbolicName(Instruction *PN, const SCEV *SymName) { | ||||||
4195 | SmallVector<Instruction *, 16> Worklist; | ||||||
4196 | PushDefUseChildren(PN, Worklist); | ||||||
4197 | |||||||
4198 | SmallPtrSet<Instruction *, 8> Visited; | ||||||
4199 | Visited.insert(PN); | ||||||
4200 | while (!Worklist.empty()) { | ||||||
4201 | Instruction *I = Worklist.pop_back_val(); | ||||||
4202 | if (!Visited.insert(I).second) | ||||||
4203 | continue; | ||||||
4204 | |||||||
4205 | auto It = ValueExprMap.find_as(static_cast<Value *>(I)); | ||||||
4206 | if (It != ValueExprMap.end()) { | ||||||
4207 | const SCEV *Old = It->second; | ||||||
4208 | |||||||
4209 | // Short-circuit the def-use traversal if the symbolic name | ||||||
4210 | // ceases to appear in expressions. | ||||||
4211 | if (Old != SymName && !hasOperand(Old, SymName)) | ||||||
4212 | continue; | ||||||
4213 | |||||||
4214 | // SCEVUnknown for a PHI either means that it has an unrecognized | ||||||
4215 | // structure, it's a PHI that's in the progress of being computed | ||||||
4216 | // by createNodeForPHI, or it's a single-value PHI. In the first case, | ||||||
4217 | // additional loop trip count information isn't going to change anything. | ||||||
4218 | // In the second case, createNodeForPHI will perform the necessary | ||||||
4219 | // updates on its own when it gets to that point. In the third, we do | ||||||
4220 | // want to forget the SCEVUnknown. | ||||||
4221 | if (!isa<PHINode>(I) || | ||||||
4222 | !isa<SCEVUnknown>(Old) || | ||||||
4223 | (I != PN && Old == SymName)) { | ||||||
4224 | eraseValueFromMap(It->first); | ||||||
4225 | forgetMemoizedResults(Old); | ||||||
4226 | } | ||||||
4227 | } | ||||||
4228 | |||||||
4229 | PushDefUseChildren(I, Worklist); | ||||||
4230 | } | ||||||
4231 | } | ||||||
4232 | |||||||
4233 | namespace { | ||||||
4234 | |||||||
4235 | /// Takes SCEV S and Loop L. For each AddRec sub-expression, use its start | ||||||
4236 | /// expression in case its Loop is L. If it is not L then | ||||||
4237 | /// if IgnoreOtherLoops is true then use AddRec itself | ||||||
4238 | /// otherwise rewrite cannot be done. | ||||||
4239 | /// If SCEV contains non-invariant unknown SCEV rewrite cannot be done. | ||||||
4240 | class SCEVInitRewriter : public SCEVRewriteVisitor<SCEVInitRewriter> { | ||||||
4241 | public: | ||||||
4242 | static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE, | ||||||
4243 | bool IgnoreOtherLoops = true) { | ||||||
4244 | SCEVInitRewriter Rewriter(L, SE); | ||||||
4245 | const SCEV *Result = Rewriter.visit(S); | ||||||
4246 | if (Rewriter.hasSeenLoopVariantSCEVUnknown()) | ||||||
4247 | return SE.getCouldNotCompute(); | ||||||
4248 | return Rewriter.hasSeenOtherLoops() && !IgnoreOtherLoops | ||||||
4249 | ? SE.getCouldNotCompute() | ||||||
4250 | : Result; | ||||||
4251 | } | ||||||
4252 | |||||||
4253 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
4254 | if (!SE.isLoopInvariant(Expr, L)) | ||||||
4255 | SeenLoopVariantSCEVUnknown = true; | ||||||
4256 | return Expr; | ||||||
4257 | } | ||||||
4258 | |||||||
4259 | const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { | ||||||
4260 | // Only re-write AddRecExprs for this loop. | ||||||
4261 | if (Expr->getLoop() == L) | ||||||
4262 | return Expr->getStart(); | ||||||
4263 | SeenOtherLoops = true; | ||||||
4264 | return Expr; | ||||||
4265 | } | ||||||
4266 | |||||||
4267 | bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; } | ||||||
4268 | |||||||
4269 | bool hasSeenOtherLoops() { return SeenOtherLoops; } | ||||||
4270 | |||||||
4271 | private: | ||||||
4272 | explicit SCEVInitRewriter(const Loop *L, ScalarEvolution &SE) | ||||||
4273 | : SCEVRewriteVisitor(SE), L(L) {} | ||||||
4274 | |||||||
4275 | const Loop *L; | ||||||
4276 | bool SeenLoopVariantSCEVUnknown = false; | ||||||
4277 | bool SeenOtherLoops = false; | ||||||
4278 | }; | ||||||
4279 | |||||||
4280 | /// Takes SCEV S and Loop L. For each AddRec sub-expression, use its post | ||||||
4281 | /// increment expression in case its Loop is L. If it is not L then | ||||||
4282 | /// use AddRec itself. | ||||||
4283 | /// If SCEV contains non-invariant unknown SCEV rewrite cannot be done. | ||||||
4284 | class SCEVPostIncRewriter : public SCEVRewriteVisitor<SCEVPostIncRewriter> { | ||||||
4285 | public: | ||||||
4286 | static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE) { | ||||||
4287 | SCEVPostIncRewriter Rewriter(L, SE); | ||||||
4288 | const SCEV *Result = Rewriter.visit(S); | ||||||
4289 | return Rewriter.hasSeenLoopVariantSCEVUnknown() | ||||||
4290 | ? SE.getCouldNotCompute() | ||||||
4291 | : Result; | ||||||
4292 | } | ||||||
4293 | |||||||
4294 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
4295 | if (!SE.isLoopInvariant(Expr, L)) | ||||||
4296 | SeenLoopVariantSCEVUnknown = true; | ||||||
4297 | return Expr; | ||||||
4298 | } | ||||||
4299 | |||||||
4300 | const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { | ||||||
4301 | // Only re-write AddRecExprs for this loop. | ||||||
4302 | if (Expr->getLoop() == L) | ||||||
4303 | return Expr->getPostIncExpr(SE); | ||||||
4304 | SeenOtherLoops = true; | ||||||
4305 | return Expr; | ||||||
4306 | } | ||||||
4307 | |||||||
4308 | bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; } | ||||||
4309 | |||||||
4310 | bool hasSeenOtherLoops() { return SeenOtherLoops; } | ||||||
4311 | |||||||
4312 | private: | ||||||
4313 | explicit SCEVPostIncRewriter(const Loop *L, ScalarEvolution &SE) | ||||||
4314 | : SCEVRewriteVisitor(SE), L(L) {} | ||||||
4315 | |||||||
4316 | const Loop *L; | ||||||
4317 | bool SeenLoopVariantSCEVUnknown = false; | ||||||
4318 | bool SeenOtherLoops = false; | ||||||
4319 | }; | ||||||
4320 | |||||||
4321 | /// This class evaluates the compare condition by matching it against the | ||||||
4322 | /// condition of loop latch. If there is a match we assume a true value | ||||||
4323 | /// for the condition while building SCEV nodes. | ||||||
4324 | class SCEVBackedgeConditionFolder | ||||||
4325 | : public SCEVRewriteVisitor<SCEVBackedgeConditionFolder> { | ||||||
4326 | public: | ||||||
4327 | static const SCEV *rewrite(const SCEV *S, const Loop *L, | ||||||
4328 | ScalarEvolution &SE) { | ||||||
4329 | bool IsPosBECond = false; | ||||||
4330 | Value *BECond = nullptr; | ||||||
4331 | if (BasicBlock *Latch = L->getLoopLatch()) { | ||||||
4332 | BranchInst *BI = dyn_cast<BranchInst>(Latch->getTerminator()); | ||||||
4333 | if (BI && BI->isConditional()) { | ||||||
4334 | assert(BI->getSuccessor(0) != BI->getSuccessor(1) &&((BI->getSuccessor(0) != BI->getSuccessor(1) && "Both outgoing branches should not target same header!") ? static_cast <void> (0) : __assert_fail ("BI->getSuccessor(0) != BI->getSuccessor(1) && \"Both outgoing branches should not target same header!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4335, __PRETTY_FUNCTION__)) | ||||||
4335 | "Both outgoing branches should not target same header!")((BI->getSuccessor(0) != BI->getSuccessor(1) && "Both outgoing branches should not target same header!") ? static_cast <void> (0) : __assert_fail ("BI->getSuccessor(0) != BI->getSuccessor(1) && \"Both outgoing branches should not target same header!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4335, __PRETTY_FUNCTION__)); | ||||||
4336 | BECond = BI->getCondition(); | ||||||
4337 | IsPosBECond = BI->getSuccessor(0) == L->getHeader(); | ||||||
4338 | } else { | ||||||
4339 | return S; | ||||||
4340 | } | ||||||
4341 | } | ||||||
4342 | SCEVBackedgeConditionFolder Rewriter(L, BECond, IsPosBECond, SE); | ||||||
4343 | return Rewriter.visit(S); | ||||||
4344 | } | ||||||
4345 | |||||||
4346 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
4347 | const SCEV *Result = Expr; | ||||||
4348 | bool InvariantF = SE.isLoopInvariant(Expr, L); | ||||||
4349 | |||||||
4350 | if (!InvariantF) { | ||||||
4351 | Instruction *I = cast<Instruction>(Expr->getValue()); | ||||||
4352 | switch (I->getOpcode()) { | ||||||
4353 | case Instruction::Select: { | ||||||
4354 | SelectInst *SI = cast<SelectInst>(I); | ||||||
4355 | Optional<const SCEV *> Res = | ||||||
4356 | compareWithBackedgeCondition(SI->getCondition()); | ||||||
4357 | if (Res.hasValue()) { | ||||||
4358 | bool IsOne = cast<SCEVConstant>(Res.getValue())->getValue()->isOne(); | ||||||
4359 | Result = SE.getSCEV(IsOne ? SI->getTrueValue() : SI->getFalseValue()); | ||||||
4360 | } | ||||||
4361 | break; | ||||||
4362 | } | ||||||
4363 | default: { | ||||||
4364 | Optional<const SCEV *> Res = compareWithBackedgeCondition(I); | ||||||
4365 | if (Res.hasValue()) | ||||||
4366 | Result = Res.getValue(); | ||||||
4367 | break; | ||||||
4368 | } | ||||||
4369 | } | ||||||
4370 | } | ||||||
4371 | return Result; | ||||||
4372 | } | ||||||
4373 | |||||||
4374 | private: | ||||||
4375 | explicit SCEVBackedgeConditionFolder(const Loop *L, Value *BECond, | ||||||
4376 | bool IsPosBECond, ScalarEvolution &SE) | ||||||
4377 | : SCEVRewriteVisitor(SE), L(L), BackedgeCond(BECond), | ||||||
4378 | IsPositiveBECond(IsPosBECond) {} | ||||||
4379 | |||||||
4380 | Optional<const SCEV *> compareWithBackedgeCondition(Value *IC); | ||||||
4381 | |||||||
4382 | const Loop *L; | ||||||
4383 | /// Loop back condition. | ||||||
4384 | Value *BackedgeCond = nullptr; | ||||||
4385 | /// Set to true if loop back is on positive branch condition. | ||||||
4386 | bool IsPositiveBECond; | ||||||
4387 | }; | ||||||
4388 | |||||||
4389 | Optional<const SCEV *> | ||||||
4390 | SCEVBackedgeConditionFolder::compareWithBackedgeCondition(Value *IC) { | ||||||
4391 | |||||||
4392 | // If value matches the backedge condition for loop latch, | ||||||
4393 | // then return a constant evolution node based on loopback | ||||||
4394 | // branch taken. | ||||||
4395 | if (BackedgeCond == IC) | ||||||
4396 | return IsPositiveBECond ? SE.getOne(Type::getInt1Ty(SE.getContext())) | ||||||
4397 | : SE.getZero(Type::getInt1Ty(SE.getContext())); | ||||||
4398 | return None; | ||||||
4399 | } | ||||||
4400 | |||||||
4401 | class SCEVShiftRewriter : public SCEVRewriteVisitor<SCEVShiftRewriter> { | ||||||
4402 | public: | ||||||
4403 | static const SCEV *rewrite(const SCEV *S, const Loop *L, | ||||||
4404 | ScalarEvolution &SE) { | ||||||
4405 | SCEVShiftRewriter Rewriter(L, SE); | ||||||
4406 | const SCEV *Result = Rewriter.visit(S); | ||||||
4407 | return Rewriter.isValid() ? Result : SE.getCouldNotCompute(); | ||||||
4408 | } | ||||||
4409 | |||||||
4410 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
4411 | // Only allow AddRecExprs for this loop. | ||||||
4412 | if (!SE.isLoopInvariant(Expr, L)) | ||||||
4413 | Valid = false; | ||||||
4414 | return Expr; | ||||||
4415 | } | ||||||
4416 | |||||||
4417 | const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { | ||||||
4418 | if (Expr->getLoop() == L && Expr->isAffine()) | ||||||
4419 | return SE.getMinusSCEV(Expr, Expr->getStepRecurrence(SE)); | ||||||
4420 | Valid = false; | ||||||
4421 | return Expr; | ||||||
4422 | } | ||||||
4423 | |||||||
4424 | bool isValid() { return Valid; } | ||||||
4425 | |||||||
4426 | private: | ||||||
4427 | explicit SCEVShiftRewriter(const Loop *L, ScalarEvolution &SE) | ||||||
4428 | : SCEVRewriteVisitor(SE), L(L) {} | ||||||
4429 | |||||||
4430 | const Loop *L; | ||||||
4431 | bool Valid = true; | ||||||
4432 | }; | ||||||
4433 | |||||||
4434 | } // end anonymous namespace | ||||||
4435 | |||||||
4436 | SCEV::NoWrapFlags | ||||||
4437 | ScalarEvolution::proveNoWrapViaConstantRanges(const SCEVAddRecExpr *AR) { | ||||||
4438 | if (!AR->isAffine()) | ||||||
4439 | return SCEV::FlagAnyWrap; | ||||||
4440 | |||||||
4441 | using OBO = OverflowingBinaryOperator; | ||||||
4442 | |||||||
4443 | SCEV::NoWrapFlags Result = SCEV::FlagAnyWrap; | ||||||
4444 | |||||||
4445 | if (!AR->hasNoSignedWrap()) { | ||||||
4446 | ConstantRange AddRecRange = getSignedRange(AR); | ||||||
4447 | ConstantRange IncRange = getSignedRange(AR->getStepRecurrence(*this)); | ||||||
4448 | |||||||
4449 | auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
4450 | Instruction::Add, IncRange, OBO::NoSignedWrap); | ||||||
4451 | if (NSWRegion.contains(AddRecRange)) | ||||||
4452 | Result = ScalarEvolution::setFlags(Result, SCEV::FlagNSW); | ||||||
4453 | } | ||||||
4454 | |||||||
4455 | if (!AR->hasNoUnsignedWrap()) { | ||||||
4456 | ConstantRange AddRecRange = getUnsignedRange(AR); | ||||||
4457 | ConstantRange IncRange = getUnsignedRange(AR->getStepRecurrence(*this)); | ||||||
4458 | |||||||
4459 | auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
4460 | Instruction::Add, IncRange, OBO::NoUnsignedWrap); | ||||||
4461 | if (NUWRegion.contains(AddRecRange)) | ||||||
4462 | Result = ScalarEvolution::setFlags(Result, SCEV::FlagNUW); | ||||||
4463 | } | ||||||
4464 | |||||||
4465 | return Result; | ||||||
4466 | } | ||||||
4467 | |||||||
4468 | namespace { | ||||||
4469 | |||||||
4470 | /// Represents an abstract binary operation. This may exist as a | ||||||
4471 | /// normal instruction or constant expression, or may have been | ||||||
4472 | /// derived from an expression tree. | ||||||
4473 | struct BinaryOp { | ||||||
4474 | unsigned Opcode; | ||||||
4475 | Value *LHS; | ||||||
4476 | Value *RHS; | ||||||
4477 | bool IsNSW = false; | ||||||
4478 | bool IsNUW = false; | ||||||
4479 | |||||||
4480 | /// Op is set if this BinaryOp corresponds to a concrete LLVM instruction or | ||||||
4481 | /// constant expression. | ||||||
4482 | Operator *Op = nullptr; | ||||||
4483 | |||||||
4484 | explicit BinaryOp(Operator *Op) | ||||||
4485 | : Opcode(Op->getOpcode()), LHS(Op->getOperand(0)), RHS(Op->getOperand(1)), | ||||||
4486 | Op(Op) { | ||||||
4487 | if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(Op)) { | ||||||
4488 | IsNSW = OBO->hasNoSignedWrap(); | ||||||
4489 | IsNUW = OBO->hasNoUnsignedWrap(); | ||||||
4490 | } | ||||||
4491 | } | ||||||
4492 | |||||||
4493 | explicit BinaryOp(unsigned Opcode, Value *LHS, Value *RHS, bool IsNSW = false, | ||||||
4494 | bool IsNUW = false) | ||||||
4495 | : Opcode(Opcode), LHS(LHS), RHS(RHS), IsNSW(IsNSW), IsNUW(IsNUW) {} | ||||||
4496 | }; | ||||||
4497 | |||||||
4498 | } // end anonymous namespace | ||||||
4499 | |||||||
4500 | /// Try to map \p V into a BinaryOp, and return \c None on failure. | ||||||
4501 | static Optional<BinaryOp> MatchBinaryOp(Value *V, DominatorTree &DT) { | ||||||
4502 | auto *Op = dyn_cast<Operator>(V); | ||||||
4503 | if (!Op
| ||||||
4504 | return None; | ||||||
4505 | |||||||
4506 | // Implementation detail: all the cleverness here should happen without | ||||||
4507 | // creating new SCEV expressions -- our caller knowns tricks to avoid creating | ||||||
4508 | // SCEV expressions when possible, and we should not break that. | ||||||
4509 | |||||||
4510 | switch (Op->getOpcode()) { | ||||||
4511 | case Instruction::Add: | ||||||
4512 | case Instruction::Sub: | ||||||
4513 | case Instruction::Mul: | ||||||
4514 | case Instruction::UDiv: | ||||||
4515 | case Instruction::URem: | ||||||
4516 | case Instruction::And: | ||||||
4517 | case Instruction::Or: | ||||||
4518 | case Instruction::AShr: | ||||||
4519 | case Instruction::Shl: | ||||||
4520 | return BinaryOp(Op); | ||||||
4521 | |||||||
4522 | case Instruction::Xor: | ||||||
4523 | if (auto *RHSC = dyn_cast<ConstantInt>(Op->getOperand(1))) | ||||||
4524 | // If the RHS of the xor is a signmask, then this is just an add. | ||||||
4525 | // Instcombine turns add of signmask into xor as a strength reduction step. | ||||||
4526 | if (RHSC->getValue().isSignMask()) | ||||||
4527 | return BinaryOp(Instruction::Add, Op->getOperand(0), Op->getOperand(1)); | ||||||
4528 | return BinaryOp(Op); | ||||||
4529 | |||||||
4530 | case Instruction::LShr: | ||||||
4531 | // Turn logical shift right of a constant into a unsigned divide. | ||||||
4532 | if (ConstantInt *SA = dyn_cast<ConstantInt>(Op->getOperand(1))) { | ||||||
4533 | uint32_t BitWidth = cast<IntegerType>(Op->getType())->getBitWidth(); | ||||||
4534 | |||||||
4535 | // If the shift count is not less than the bitwidth, the result of | ||||||
4536 | // the shift is undefined. Don't try to analyze it, because the | ||||||
4537 | // resolution chosen here may differ from the resolution chosen in | ||||||
4538 | // other parts of the compiler. | ||||||
4539 | if (SA->getValue().ult(BitWidth)) { | ||||||
4540 | Constant *X = | ||||||
4541 | ConstantInt::get(SA->getContext(), | ||||||
4542 | APInt::getOneBitSet(BitWidth, SA->getZExtValue())); | ||||||
4543 | return BinaryOp(Instruction::UDiv, Op->getOperand(0), X); | ||||||
4544 | } | ||||||
4545 | } | ||||||
4546 | return BinaryOp(Op); | ||||||
4547 | |||||||
4548 | case Instruction::ExtractValue: { | ||||||
4549 | auto *EVI = cast<ExtractValueInst>(Op); | ||||||
4550 | if (EVI->getNumIndices() != 1 || EVI->getIndices()[0] != 0) | ||||||
4551 | break; | ||||||
4552 | |||||||
4553 | auto *WO = dyn_cast<WithOverflowInst>(EVI->getAggregateOperand()); | ||||||
4554 | if (!WO) | ||||||
4555 | break; | ||||||
4556 | |||||||
4557 | Instruction::BinaryOps BinOp = WO->getBinaryOp(); | ||||||
4558 | bool Signed = WO->isSigned(); | ||||||
4559 | // TODO: Should add nuw/nsw flags for mul as well. | ||||||
4560 | if (BinOp == Instruction::Mul || !isOverflowIntrinsicNoWrap(WO, DT)) | ||||||
4561 | return BinaryOp(BinOp, WO->getLHS(), WO->getRHS()); | ||||||
4562 | |||||||
4563 | // Now that we know that all uses of the arithmetic-result component of | ||||||
4564 | // CI are guarded by the overflow check, we can go ahead and pretend | ||||||
4565 | // that the arithmetic is non-overflowing. | ||||||
4566 | return BinaryOp(BinOp, WO->getLHS(), WO->getRHS(), | ||||||
4567 | /* IsNSW = */ Signed, /* IsNUW = */ !Signed); | ||||||
4568 | } | ||||||
4569 | |||||||
4570 | default: | ||||||
4571 | break; | ||||||
4572 | } | ||||||
4573 | |||||||
4574 | // Recognise intrinsic loop.decrement.reg, and as this has exactly the same | ||||||
4575 | // semantics as a Sub, return a binary sub expression. | ||||||
4576 | if (auto *II = dyn_cast<IntrinsicInst>(V)) | ||||||
4577 | if (II->getIntrinsicID() == Intrinsic::loop_decrement_reg) | ||||||
4578 | return BinaryOp(Instruction::Sub, II->getOperand(0), II->getOperand(1)); | ||||||
4579 | |||||||
4580 | return None; | ||||||
4581 | } | ||||||
4582 | |||||||
4583 | /// Helper function to createAddRecFromPHIWithCasts. We have a phi | ||||||
4584 | /// node whose symbolic (unknown) SCEV is \p SymbolicPHI, which is updated via | ||||||
4585 | /// the loop backedge by a SCEVAddExpr, possibly also with a few casts on the | ||||||
4586 | /// way. This function checks if \p Op, an operand of this SCEVAddExpr, | ||||||
4587 | /// follows one of the following patterns: | ||||||
4588 | /// Op == (SExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) | ||||||
4589 | /// Op == (ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) | ||||||
4590 | /// If the SCEV expression of \p Op conforms with one of the expected patterns | ||||||
4591 | /// we return the type of the truncation operation, and indicate whether the | ||||||
4592 | /// truncated type should be treated as signed/unsigned by setting | ||||||
4593 | /// \p Signed to true/false, respectively. | ||||||
4594 | static Type *isSimpleCastedPHI(const SCEV *Op, const SCEVUnknown *SymbolicPHI, | ||||||
4595 | bool &Signed, ScalarEvolution &SE) { | ||||||
4596 | // The case where Op == SymbolicPHI (that is, with no type conversions on | ||||||
4597 | // the way) is handled by the regular add recurrence creating logic and | ||||||
4598 | // would have already been triggered in createAddRecForPHI. Reaching it here | ||||||
4599 | // means that createAddRecFromPHI had failed for this PHI before (e.g., | ||||||
4600 | // because one of the other operands of the SCEVAddExpr updating this PHI is | ||||||
4601 | // not invariant). | ||||||
4602 | // | ||||||
4603 | // Here we look for the case where Op = (ext(trunc(SymbolicPHI))), and in | ||||||
4604 | // this case predicates that allow us to prove that Op == SymbolicPHI will | ||||||
4605 | // be added. | ||||||
4606 | if (Op == SymbolicPHI) | ||||||
4607 | return nullptr; | ||||||
4608 | |||||||
4609 | unsigned SourceBits = SE.getTypeSizeInBits(SymbolicPHI->getType()); | ||||||
4610 | unsigned NewBits = SE.getTypeSizeInBits(Op->getType()); | ||||||
4611 | if (SourceBits != NewBits) | ||||||
4612 | return nullptr; | ||||||
4613 | |||||||
4614 | const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(Op); | ||||||
4615 | const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(Op); | ||||||
4616 | if (!SExt && !ZExt) | ||||||
4617 | return nullptr; | ||||||
4618 | const SCEVTruncateExpr *Trunc = | ||||||
4619 | SExt ? dyn_cast<SCEVTruncateExpr>(SExt->getOperand()) | ||||||
4620 | : dyn_cast<SCEVTruncateExpr>(ZExt->getOperand()); | ||||||
4621 | if (!Trunc) | ||||||
4622 | return nullptr; | ||||||
4623 | const SCEV *X = Trunc->getOperand(); | ||||||
4624 | if (X != SymbolicPHI) | ||||||
4625 | return nullptr; | ||||||
4626 | Signed = SExt != nullptr; | ||||||
4627 | return Trunc->getType(); | ||||||
4628 | } | ||||||
4629 | |||||||
4630 | static const Loop *isIntegerLoopHeaderPHI(const PHINode *PN, LoopInfo &LI) { | ||||||
4631 | if (!PN->getType()->isIntegerTy()) | ||||||
4632 | return nullptr; | ||||||
4633 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
4634 | if (!L || L->getHeader() != PN->getParent()) | ||||||
4635 | return nullptr; | ||||||
4636 | return L; | ||||||
4637 | } | ||||||
4638 | |||||||
4639 | // Analyze \p SymbolicPHI, a SCEV expression of a phi node, and check if the | ||||||
4640 | // computation that updates the phi follows the following pattern: | ||||||
4641 | // (SExt/ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) + InvariantAccum | ||||||
4642 | // which correspond to a phi->trunc->sext/zext->add->phi update chain. | ||||||
4643 | // If so, try to see if it can be rewritten as an AddRecExpr under some | ||||||
4644 | // Predicates. If successful, return them as a pair. Also cache the results | ||||||
4645 | // of the analysis. | ||||||
4646 | // | ||||||
4647 | // Example usage scenario: | ||||||
4648 | // Say the Rewriter is called for the following SCEV: | ||||||
4649 | // 8 * ((sext i32 (trunc i64 %X to i32) to i64) + %Step) | ||||||
4650 | // where: | ||||||
4651 | // %X = phi i64 (%Start, %BEValue) | ||||||
4652 | // It will visitMul->visitAdd->visitSExt->visitTrunc->visitUnknown(%X), | ||||||
4653 | // and call this function with %SymbolicPHI = %X. | ||||||
4654 | // | ||||||
4655 | // The analysis will find that the value coming around the backedge has | ||||||
4656 | // the following SCEV: | ||||||
4657 | // BEValue = ((sext i32 (trunc i64 %X to i32) to i64) + %Step) | ||||||
4658 | // Upon concluding that this matches the desired pattern, the function | ||||||
4659 | // will return the pair {NewAddRec, SmallPredsVec} where: | ||||||
4660 | // NewAddRec = {%Start,+,%Step} | ||||||
4661 | // SmallPredsVec = {P1, P2, P3} as follows: | ||||||
4662 | // P1(WrapPred): AR: {trunc(%Start),+,(trunc %Step)}<nsw> Flags: <nssw> | ||||||
4663 | // P2(EqualPred): %Start == (sext i32 (trunc i64 %Start to i32) to i64) | ||||||
4664 | // P3(EqualPred): %Step == (sext i32 (trunc i64 %Step to i32) to i64) | ||||||
4665 | // The returned pair means that SymbolicPHI can be rewritten into NewAddRec | ||||||
4666 | // under the predicates {P1,P2,P3}. | ||||||
4667 | // This predicated rewrite will be cached in PredicatedSCEVRewrites: | ||||||
4668 | // PredicatedSCEVRewrites[{%X,L}] = {NewAddRec, {P1,P2,P3)} | ||||||
4669 | // | ||||||
4670 | // TODO's: | ||||||
4671 | // | ||||||
4672 | // 1) Extend the Induction descriptor to also support inductions that involve | ||||||
4673 | // casts: When needed (namely, when we are called in the context of the | ||||||
4674 | // vectorizer induction analysis), a Set of cast instructions will be | ||||||
4675 | // populated by this method, and provided back to isInductionPHI. This is | ||||||
4676 | // needed to allow the vectorizer to properly record them to be ignored by | ||||||
4677 | // the cost model and to avoid vectorizing them (otherwise these casts, | ||||||
4678 | // which are redundant under the runtime overflow checks, will be | ||||||
4679 | // vectorized, which can be costly). | ||||||
4680 | // | ||||||
4681 | // 2) Support additional induction/PHISCEV patterns: We also want to support | ||||||
4682 | // inductions where the sext-trunc / zext-trunc operations (partly) occur | ||||||
4683 | // after the induction update operation (the induction increment): | ||||||
4684 | // | ||||||
4685 | // (Trunc iy (SExt/ZExt ix (%SymbolicPHI + InvariantAccum) to iy) to ix) | ||||||
4686 | // which correspond to a phi->add->trunc->sext/zext->phi update chain. | ||||||
4687 | // | ||||||
4688 | // (Trunc iy ((SExt/ZExt ix (%SymbolicPhi) to iy) + InvariantAccum) to ix) | ||||||
4689 | // which correspond to a phi->trunc->add->sext/zext->phi update chain. | ||||||
4690 | // | ||||||
4691 | // 3) Outline common code with createAddRecFromPHI to avoid duplication. | ||||||
4692 | Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>> | ||||||
4693 | ScalarEvolution::createAddRecFromPHIWithCastsImpl(const SCEVUnknown *SymbolicPHI) { | ||||||
4694 | SmallVector<const SCEVPredicate *, 3> Predicates; | ||||||
4695 | |||||||
4696 | // *** Part1: Analyze if we have a phi-with-cast pattern for which we can | ||||||
4697 | // return an AddRec expression under some predicate. | ||||||
4698 | |||||||
4699 | auto *PN = cast<PHINode>(SymbolicPHI->getValue()); | ||||||
4700 | const Loop *L = isIntegerLoopHeaderPHI(PN, LI); | ||||||
4701 | assert(L && "Expecting an integer loop header phi")((L && "Expecting an integer loop header phi") ? static_cast <void> (0) : __assert_fail ("L && \"Expecting an integer loop header phi\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4701, __PRETTY_FUNCTION__)); | ||||||
4702 | |||||||
4703 | // The loop may have multiple entrances or multiple exits; we can analyze | ||||||
4704 | // this phi as an addrec if it has a unique entry value and a unique | ||||||
4705 | // backedge value. | ||||||
4706 | Value *BEValueV = nullptr, *StartValueV = nullptr; | ||||||
4707 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { | ||||||
4708 | Value *V = PN->getIncomingValue(i); | ||||||
4709 | if (L->contains(PN->getIncomingBlock(i))) { | ||||||
4710 | if (!BEValueV) { | ||||||
4711 | BEValueV = V; | ||||||
4712 | } else if (BEValueV != V) { | ||||||
4713 | BEValueV = nullptr; | ||||||
4714 | break; | ||||||
4715 | } | ||||||
4716 | } else if (!StartValueV) { | ||||||
4717 | StartValueV = V; | ||||||
4718 | } else if (StartValueV != V) { | ||||||
4719 | StartValueV = nullptr; | ||||||
4720 | break; | ||||||
4721 | } | ||||||
4722 | } | ||||||
4723 | if (!BEValueV || !StartValueV) | ||||||
4724 | return None; | ||||||
4725 | |||||||
4726 | const SCEV *BEValue = getSCEV(BEValueV); | ||||||
4727 | |||||||
4728 | // If the value coming around the backedge is an add with the symbolic | ||||||
4729 | // value we just inserted, possibly with casts that we can ignore under | ||||||
4730 | // an appropriate runtime guard, then we found a simple induction variable! | ||||||
4731 | const auto *Add = dyn_cast<SCEVAddExpr>(BEValue); | ||||||
4732 | if (!Add) | ||||||
4733 | return None; | ||||||
4734 | |||||||
4735 | // If there is a single occurrence of the symbolic value, possibly | ||||||
4736 | // casted, replace it with a recurrence. | ||||||
4737 | unsigned FoundIndex = Add->getNumOperands(); | ||||||
4738 | Type *TruncTy = nullptr; | ||||||
4739 | bool Signed; | ||||||
4740 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
4741 | if ((TruncTy = | ||||||
4742 | isSimpleCastedPHI(Add->getOperand(i), SymbolicPHI, Signed, *this))) | ||||||
4743 | if (FoundIndex == e) { | ||||||
4744 | FoundIndex = i; | ||||||
4745 | break; | ||||||
4746 | } | ||||||
4747 | |||||||
4748 | if (FoundIndex == Add->getNumOperands()) | ||||||
4749 | return None; | ||||||
4750 | |||||||
4751 | // Create an add with everything but the specified operand. | ||||||
4752 | SmallVector<const SCEV *, 8> Ops; | ||||||
4753 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
4754 | if (i != FoundIndex) | ||||||
4755 | Ops.push_back(Add->getOperand(i)); | ||||||
4756 | const SCEV *Accum = getAddExpr(Ops); | ||||||
4757 | |||||||
4758 | // The runtime checks will not be valid if the step amount is | ||||||
4759 | // varying inside the loop. | ||||||
4760 | if (!isLoopInvariant(Accum, L)) | ||||||
4761 | return None; | ||||||
4762 | |||||||
4763 | // *** Part2: Create the predicates | ||||||
4764 | |||||||
4765 | // Analysis was successful: we have a phi-with-cast pattern for which we | ||||||
4766 | // can return an AddRec expression under the following predicates: | ||||||
4767 | // | ||||||
4768 | // P1: A Wrap predicate that guarantees that Trunc(Start) + i*Trunc(Accum) | ||||||
4769 | // fits within the truncated type (does not overflow) for i = 0 to n-1. | ||||||
4770 | // P2: An Equal predicate that guarantees that | ||||||
4771 | // Start = (Ext ix (Trunc iy (Start) to ix) to iy) | ||||||
4772 | // P3: An Equal predicate that guarantees that | ||||||
4773 | // Accum = (Ext ix (Trunc iy (Accum) to ix) to iy) | ||||||
4774 | // | ||||||
4775 | // As we next prove, the above predicates guarantee that: | ||||||
4776 | // Start + i*Accum = (Ext ix (Trunc iy ( Start + i*Accum ) to ix) to iy) | ||||||
4777 | // | ||||||
4778 | // | ||||||
4779 | // More formally, we want to prove that: | ||||||
4780 | // Expr(i+1) = Start + (i+1) * Accum | ||||||
4781 | // = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum | ||||||
4782 | // | ||||||
4783 | // Given that: | ||||||
4784 | // 1) Expr(0) = Start | ||||||
4785 | // 2) Expr(1) = Start + Accum | ||||||
4786 | // = (Ext ix (Trunc iy (Start) to ix) to iy) + Accum :: from P2 | ||||||
4787 | // 3) Induction hypothesis (step i): | ||||||
4788 | // Expr(i) = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum | ||||||
4789 | // | ||||||
4790 | // Proof: | ||||||
4791 | // Expr(i+1) = | ||||||
4792 | // = Start + (i+1)*Accum | ||||||
4793 | // = (Start + i*Accum) + Accum | ||||||
4794 | // = Expr(i) + Accum | ||||||
4795 | // = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum + Accum | ||||||
4796 | // :: from step i | ||||||
4797 | // | ||||||
4798 | // = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy) + Accum + Accum | ||||||
4799 | // | ||||||
4800 | // = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy) | ||||||
4801 | // + (Ext ix (Trunc iy (Accum) to ix) to iy) | ||||||
4802 | // + Accum :: from P3 | ||||||
4803 | // | ||||||
4804 | // = (Ext ix (Trunc iy ((Start + (i-1)*Accum) + Accum) to ix) to iy) | ||||||
4805 | // + Accum :: from P1: Ext(x)+Ext(y)=>Ext(x+y) | ||||||
4806 | // | ||||||
4807 | // = (Ext ix (Trunc iy (Start + i*Accum) to ix) to iy) + Accum | ||||||
4808 | // = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum | ||||||
4809 | // | ||||||
4810 | // By induction, the same applies to all iterations 1<=i<n: | ||||||
4811 | // | ||||||
4812 | |||||||
4813 | // Create a truncated addrec for which we will add a no overflow check (P1). | ||||||
4814 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
4815 | const SCEV *PHISCEV = | ||||||
4816 | getAddRecExpr(getTruncateExpr(StartVal, TruncTy), | ||||||
4817 | getTruncateExpr(Accum, TruncTy), L, SCEV::FlagAnyWrap); | ||||||
4818 | |||||||
4819 | // PHISCEV can be either a SCEVConstant or a SCEVAddRecExpr. | ||||||
4820 | // ex: If truncated Accum is 0 and StartVal is a constant, then PHISCEV | ||||||
4821 | // will be constant. | ||||||
4822 | // | ||||||
4823 | // If PHISCEV is a constant, then P1 degenerates into P2 or P3, so we don't | ||||||
4824 | // add P1. | ||||||
4825 | if (const auto *AR = dyn_cast<SCEVAddRecExpr>(PHISCEV)) { | ||||||
4826 | SCEVWrapPredicate::IncrementWrapFlags AddedFlags = | ||||||
4827 | Signed ? SCEVWrapPredicate::IncrementNSSW | ||||||
4828 | : SCEVWrapPredicate::IncrementNUSW; | ||||||
4829 | const SCEVPredicate *AddRecPred = getWrapPredicate(AR, AddedFlags); | ||||||
4830 | Predicates.push_back(AddRecPred); | ||||||
4831 | } | ||||||
4832 | |||||||
4833 | // Create the Equal Predicates P2,P3: | ||||||
4834 | |||||||
4835 | // It is possible that the predicates P2 and/or P3 are computable at | ||||||
4836 | // compile time due to StartVal and/or Accum being constants. | ||||||
4837 | // If either one is, then we can check that now and escape if either P2 | ||||||
4838 | // or P3 is false. | ||||||
4839 | |||||||
4840 | // Construct the extended SCEV: (Ext ix (Trunc iy (Expr) to ix) to iy) | ||||||
4841 | // for each of StartVal and Accum | ||||||
4842 | auto getExtendedExpr = [&](const SCEV *Expr, | ||||||
4843 | bool CreateSignExtend) -> const SCEV * { | ||||||
4844 | assert(isLoopInvariant(Expr, L) && "Expr is expected to be invariant")((isLoopInvariant(Expr, L) && "Expr is expected to be invariant" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Expr, L) && \"Expr is expected to be invariant\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4844, __PRETTY_FUNCTION__)); | ||||||
4845 | const SCEV *TruncatedExpr = getTruncateExpr(Expr, TruncTy); | ||||||
4846 | const SCEV *ExtendedExpr = | ||||||
4847 | CreateSignExtend ? getSignExtendExpr(TruncatedExpr, Expr->getType()) | ||||||
4848 | : getZeroExtendExpr(TruncatedExpr, Expr->getType()); | ||||||
4849 | return ExtendedExpr; | ||||||
4850 | }; | ||||||
4851 | |||||||
4852 | // Given: | ||||||
4853 | // ExtendedExpr = (Ext ix (Trunc iy (Expr) to ix) to iy | ||||||
4854 | // = getExtendedExpr(Expr) | ||||||
4855 | // Determine whether the predicate P: Expr == ExtendedExpr | ||||||
4856 | // is known to be false at compile time | ||||||
4857 | auto PredIsKnownFalse = [&](const SCEV *Expr, | ||||||
4858 | const SCEV *ExtendedExpr) -> bool { | ||||||
4859 | return Expr != ExtendedExpr && | ||||||
4860 | isKnownPredicate(ICmpInst::ICMP_NE, Expr, ExtendedExpr); | ||||||
4861 | }; | ||||||
4862 | |||||||
4863 | const SCEV *StartExtended = getExtendedExpr(StartVal, Signed); | ||||||
4864 | if (PredIsKnownFalse(StartVal, StartExtended)) { | ||||||
4865 | LLVM_DEBUG(dbgs() << "P2 is compile-time false\n";)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "P2 is compile-time false\n" ;; } } while (false); | ||||||
4866 | return None; | ||||||
4867 | } | ||||||
4868 | |||||||
4869 | // The Step is always Signed (because the overflow checks are either | ||||||
4870 | // NSSW or NUSW) | ||||||
4871 | const SCEV *AccumExtended = getExtendedExpr(Accum, /*CreateSignExtend=*/true); | ||||||
4872 | if (PredIsKnownFalse(Accum, AccumExtended)) { | ||||||
4873 | LLVM_DEBUG(dbgs() << "P3 is compile-time false\n";)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "P3 is compile-time false\n" ;; } } while (false); | ||||||
4874 | return None; | ||||||
4875 | } | ||||||
4876 | |||||||
4877 | auto AppendPredicate = [&](const SCEV *Expr, | ||||||
4878 | const SCEV *ExtendedExpr) -> void { | ||||||
4879 | if (Expr != ExtendedExpr && | ||||||
4880 | !isKnownPredicate(ICmpInst::ICMP_EQ, Expr, ExtendedExpr)) { | ||||||
4881 | const SCEVPredicate *Pred = getEqualPredicate(Expr, ExtendedExpr); | ||||||
4882 | LLVM_DEBUG(dbgs() << "Added Predicate: " << *Pred)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "Added Predicate: " << *Pred; } } while (false); | ||||||
4883 | Predicates.push_back(Pred); | ||||||
4884 | } | ||||||
4885 | }; | ||||||
4886 | |||||||
4887 | AppendPredicate(StartVal, StartExtended); | ||||||
4888 | AppendPredicate(Accum, AccumExtended); | ||||||
4889 | |||||||
4890 | // *** Part3: Predicates are ready. Now go ahead and create the new addrec in | ||||||
4891 | // which the casts had been folded away. The caller can rewrite SymbolicPHI | ||||||
4892 | // into NewAR if it will also add the runtime overflow checks specified in | ||||||
4893 | // Predicates. | ||||||
4894 | auto *NewAR = getAddRecExpr(StartVal, Accum, L, SCEV::FlagAnyWrap); | ||||||
4895 | |||||||
4896 | std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> PredRewrite = | ||||||
4897 | std::make_pair(NewAR, Predicates); | ||||||
4898 | // Remember the result of the analysis for this SCEV at this locayyytion. | ||||||
4899 | PredicatedSCEVRewrites[{SymbolicPHI, L}] = PredRewrite; | ||||||
4900 | return PredRewrite; | ||||||
4901 | } | ||||||
4902 | |||||||
4903 | Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>> | ||||||
4904 | ScalarEvolution::createAddRecFromPHIWithCasts(const SCEVUnknown *SymbolicPHI) { | ||||||
4905 | auto *PN = cast<PHINode>(SymbolicPHI->getValue()); | ||||||
4906 | const Loop *L = isIntegerLoopHeaderPHI(PN, LI); | ||||||
4907 | if (!L) | ||||||
4908 | return None; | ||||||
4909 | |||||||
4910 | // Check to see if we already analyzed this PHI. | ||||||
4911 | auto I = PredicatedSCEVRewrites.find({SymbolicPHI, L}); | ||||||
4912 | if (I != PredicatedSCEVRewrites.end()) { | ||||||
4913 | std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> Rewrite = | ||||||
4914 | I->second; | ||||||
4915 | // Analysis was done before and failed to create an AddRec: | ||||||
4916 | if (Rewrite.first == SymbolicPHI) | ||||||
4917 | return None; | ||||||
4918 | // Analysis was done before and succeeded to create an AddRec under | ||||||
4919 | // a predicate: | ||||||
4920 | assert(isa<SCEVAddRecExpr>(Rewrite.first) && "Expected an AddRec")((isa<SCEVAddRecExpr>(Rewrite.first) && "Expected an AddRec" ) ? static_cast<void> (0) : __assert_fail ("isa<SCEVAddRecExpr>(Rewrite.first) && \"Expected an AddRec\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4920, __PRETTY_FUNCTION__)); | ||||||
4921 | assert(!(Rewrite.second).empty() && "Expected to find Predicates")((!(Rewrite.second).empty() && "Expected to find Predicates" ) ? static_cast<void> (0) : __assert_fail ("!(Rewrite.second).empty() && \"Expected to find Predicates\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4921, __PRETTY_FUNCTION__)); | ||||||
4922 | return Rewrite; | ||||||
4923 | } | ||||||
4924 | |||||||
4925 | Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>> | ||||||
4926 | Rewrite = createAddRecFromPHIWithCastsImpl(SymbolicPHI); | ||||||
4927 | |||||||
4928 | // Record in the cache that the analysis failed | ||||||
4929 | if (!Rewrite) { | ||||||
4930 | SmallVector<const SCEVPredicate *, 3> Predicates; | ||||||
4931 | PredicatedSCEVRewrites[{SymbolicPHI, L}] = {SymbolicPHI, Predicates}; | ||||||
4932 | return None; | ||||||
4933 | } | ||||||
4934 | |||||||
4935 | return Rewrite; | ||||||
4936 | } | ||||||
4937 | |||||||
4938 | // FIXME: This utility is currently required because the Rewriter currently | ||||||
4939 | // does not rewrite this expression: | ||||||
4940 | // {0, +, (sext ix (trunc iy to ix) to iy)} | ||||||
4941 | // into {0, +, %step}, | ||||||
4942 | // even when the following Equal predicate exists: | ||||||
4943 | // "%step == (sext ix (trunc iy to ix) to iy)". | ||||||
4944 | bool PredicatedScalarEvolution::areAddRecsEqualWithPreds( | ||||||
4945 | const SCEVAddRecExpr *AR1, const SCEVAddRecExpr *AR2) const { | ||||||
4946 | if (AR1 == AR2) | ||||||
4947 | return true; | ||||||
4948 | |||||||
4949 | auto areExprsEqual = [&](const SCEV *Expr1, const SCEV *Expr2) -> bool { | ||||||
4950 | if (Expr1 != Expr2 && !Preds.implies(SE.getEqualPredicate(Expr1, Expr2)) && | ||||||
4951 | !Preds.implies(SE.getEqualPredicate(Expr2, Expr1))) | ||||||
4952 | return false; | ||||||
4953 | return true; | ||||||
4954 | }; | ||||||
4955 | |||||||
4956 | if (!areExprsEqual(AR1->getStart(), AR2->getStart()) || | ||||||
4957 | !areExprsEqual(AR1->getStepRecurrence(SE), AR2->getStepRecurrence(SE))) | ||||||
4958 | return false; | ||||||
4959 | return true; | ||||||
4960 | } | ||||||
4961 | |||||||
4962 | /// A helper function for createAddRecFromPHI to handle simple cases. | ||||||
4963 | /// | ||||||
4964 | /// This function tries to find an AddRec expression for the simplest (yet most | ||||||
4965 | /// common) cases: PN = PHI(Start, OP(Self, LoopInvariant)). | ||||||
4966 | /// If it fails, createAddRecFromPHI will use a more general, but slow, | ||||||
4967 | /// technique for finding the AddRec expression. | ||||||
4968 | const SCEV *ScalarEvolution::createSimpleAffineAddRec(PHINode *PN, | ||||||
4969 | Value *BEValueV, | ||||||
4970 | Value *StartValueV) { | ||||||
4971 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
4972 | assert(L && L->getHeader() == PN->getParent())((L && L->getHeader() == PN->getParent()) ? static_cast <void> (0) : __assert_fail ("L && L->getHeader() == PN->getParent()" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4972, __PRETTY_FUNCTION__)); | ||||||
4973 | assert(BEValueV && StartValueV)((BEValueV && StartValueV) ? static_cast<void> ( 0) : __assert_fail ("BEValueV && StartValueV", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 4973, __PRETTY_FUNCTION__)); | ||||||
4974 | |||||||
4975 | auto BO = MatchBinaryOp(BEValueV, DT); | ||||||
4976 | if (!BO) | ||||||
4977 | return nullptr; | ||||||
4978 | |||||||
4979 | if (BO->Opcode != Instruction::Add) | ||||||
4980 | return nullptr; | ||||||
4981 | |||||||
4982 | const SCEV *Accum = nullptr; | ||||||
4983 | if (BO->LHS == PN && L->isLoopInvariant(BO->RHS)) | ||||||
4984 | Accum = getSCEV(BO->RHS); | ||||||
4985 | else if (BO->RHS == PN && L->isLoopInvariant(BO->LHS)) | ||||||
4986 | Accum = getSCEV(BO->LHS); | ||||||
4987 | |||||||
4988 | if (!Accum) | ||||||
4989 | return nullptr; | ||||||
4990 | |||||||
4991 | SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | ||||||
4992 | if (BO->IsNUW) | ||||||
4993 | Flags = setFlags(Flags, SCEV::FlagNUW); | ||||||
4994 | if (BO->IsNSW) | ||||||
4995 | Flags = setFlags(Flags, SCEV::FlagNSW); | ||||||
4996 | |||||||
4997 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
4998 | const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags); | ||||||
4999 | |||||||
5000 | ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV; | ||||||
5001 | |||||||
5002 | // We can add Flags to the post-inc expression only if we | ||||||
5003 | // know that it is *undefined behavior* for BEValueV to | ||||||
5004 | // overflow. | ||||||
5005 | if (auto *BEInst = dyn_cast<Instruction>(BEValueV)) | ||||||
5006 | if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L)) | ||||||
5007 | (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags); | ||||||
5008 | |||||||
5009 | return PHISCEV; | ||||||
5010 | } | ||||||
5011 | |||||||
5012 | const SCEV *ScalarEvolution::createAddRecFromPHI(PHINode *PN) { | ||||||
5013 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
5014 | if (!L || L->getHeader() != PN->getParent()) | ||||||
5015 | return nullptr; | ||||||
5016 | |||||||
5017 | // The loop may have multiple entrances or multiple exits; we can analyze | ||||||
5018 | // this phi as an addrec if it has a unique entry value and a unique | ||||||
5019 | // backedge value. | ||||||
5020 | Value *BEValueV = nullptr, *StartValueV = nullptr; | ||||||
5021 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { | ||||||
5022 | Value *V = PN->getIncomingValue(i); | ||||||
5023 | if (L->contains(PN->getIncomingBlock(i))) { | ||||||
5024 | if (!BEValueV) { | ||||||
5025 | BEValueV = V; | ||||||
5026 | } else if (BEValueV != V) { | ||||||
5027 | BEValueV = nullptr; | ||||||
5028 | break; | ||||||
5029 | } | ||||||
5030 | } else if (!StartValueV) { | ||||||
5031 | StartValueV = V; | ||||||
5032 | } else if (StartValueV != V) { | ||||||
5033 | StartValueV = nullptr; | ||||||
5034 | break; | ||||||
5035 | } | ||||||
5036 | } | ||||||
5037 | if (!BEValueV || !StartValueV) | ||||||
5038 | return nullptr; | ||||||
5039 | |||||||
5040 | assert(ValueExprMap.find_as(PN) == ValueExprMap.end() &&((ValueExprMap.find_as(PN) == ValueExprMap.end() && "PHI node already processed?" ) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.find_as(PN) == ValueExprMap.end() && \"PHI node already processed?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5041, __PRETTY_FUNCTION__)) | ||||||
5041 | "PHI node already processed?")((ValueExprMap.find_as(PN) == ValueExprMap.end() && "PHI node already processed?" ) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.find_as(PN) == ValueExprMap.end() && \"PHI node already processed?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5041, __PRETTY_FUNCTION__)); | ||||||
5042 | |||||||
5043 | // First, try to find AddRec expression without creating a fictituos symbolic | ||||||
5044 | // value for PN. | ||||||
5045 | if (auto *S = createSimpleAffineAddRec(PN, BEValueV, StartValueV)) | ||||||
5046 | return S; | ||||||
5047 | |||||||
5048 | // Handle PHI node value symbolically. | ||||||
5049 | const SCEV *SymbolicName = getUnknown(PN); | ||||||
5050 | ValueExprMap.insert({SCEVCallbackVH(PN, this), SymbolicName}); | ||||||
5051 | |||||||
5052 | // Using this symbolic name for the PHI, analyze the value coming around | ||||||
5053 | // the back-edge. | ||||||
5054 | const SCEV *BEValue = getSCEV(BEValueV); | ||||||
5055 | |||||||
5056 | // NOTE: If BEValue is loop invariant, we know that the PHI node just | ||||||
5057 | // has a special value for the first iteration of the loop. | ||||||
5058 | |||||||
5059 | // If the value coming around the backedge is an add with the symbolic | ||||||
5060 | // value we just inserted, then we found a simple induction variable! | ||||||
5061 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) { | ||||||
5062 | // If there is a single occurrence of the symbolic value, replace it | ||||||
5063 | // with a recurrence. | ||||||
5064 | unsigned FoundIndex = Add->getNumOperands(); | ||||||
5065 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
5066 | if (Add->getOperand(i) == SymbolicName) | ||||||
5067 | if (FoundIndex == e) { | ||||||
5068 | FoundIndex = i; | ||||||
5069 | break; | ||||||
5070 | } | ||||||
5071 | |||||||
5072 | if (FoundIndex != Add->getNumOperands()) { | ||||||
5073 | // Create an add with everything but the specified operand. | ||||||
5074 | SmallVector<const SCEV *, 8> Ops; | ||||||
5075 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
5076 | if (i != FoundIndex) | ||||||
5077 | Ops.push_back(SCEVBackedgeConditionFolder::rewrite(Add->getOperand(i), | ||||||
5078 | L, *this)); | ||||||
5079 | const SCEV *Accum = getAddExpr(Ops); | ||||||
5080 | |||||||
5081 | // This is not a valid addrec if the step amount is varying each | ||||||
5082 | // loop iteration, but is not itself an addrec in this loop. | ||||||
5083 | if (isLoopInvariant(Accum, L) || | ||||||
5084 | (isa<SCEVAddRecExpr>(Accum) && | ||||||
5085 | cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) { | ||||||
5086 | SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | ||||||
5087 | |||||||
5088 | if (auto BO = MatchBinaryOp(BEValueV, DT)) { | ||||||
5089 | if (BO->Opcode == Instruction::Add && BO->LHS == PN) { | ||||||
5090 | if (BO->IsNUW) | ||||||
5091 | Flags = setFlags(Flags, SCEV::FlagNUW); | ||||||
5092 | if (BO->IsNSW) | ||||||
5093 | Flags = setFlags(Flags, SCEV::FlagNSW); | ||||||
5094 | } | ||||||
5095 | } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(BEValueV)) { | ||||||
5096 | // If the increment is an inbounds GEP, then we know the address | ||||||
5097 | // space cannot be wrapped around. We cannot make any guarantee | ||||||
5098 | // about signed or unsigned overflow because pointers are | ||||||
5099 | // unsigned but we may have a negative index from the base | ||||||
5100 | // pointer. We can guarantee that no unsigned wrap occurs if the | ||||||
5101 | // indices form a positive value. | ||||||
5102 | if (GEP->isInBounds() && GEP->getOperand(0) == PN) { | ||||||
5103 | Flags = setFlags(Flags, SCEV::FlagNW); | ||||||
5104 | |||||||
5105 | const SCEV *Ptr = getSCEV(GEP->getPointerOperand()); | ||||||
5106 | if (isKnownPositive(getMinusSCEV(getSCEV(GEP), Ptr))) | ||||||
5107 | Flags = setFlags(Flags, SCEV::FlagNUW); | ||||||
5108 | } | ||||||
5109 | |||||||
5110 | // We cannot transfer nuw and nsw flags from subtraction | ||||||
5111 | // operations -- sub nuw X, Y is not the same as add nuw X, -Y | ||||||
5112 | // for instance. | ||||||
5113 | } | ||||||
5114 | |||||||
5115 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
5116 | const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags); | ||||||
5117 | |||||||
5118 | // Okay, for the entire analysis of this edge we assumed the PHI | ||||||
5119 | // to be symbolic. We now need to go back and purge all of the | ||||||
5120 | // entries for the scalars that use the symbolic expression. | ||||||
5121 | forgetSymbolicName(PN, SymbolicName); | ||||||
5122 | ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV; | ||||||
5123 | |||||||
5124 | // We can add Flags to the post-inc expression only if we | ||||||
5125 | // know that it is *undefined behavior* for BEValueV to | ||||||
5126 | // overflow. | ||||||
5127 | if (auto *BEInst = dyn_cast<Instruction>(BEValueV)) | ||||||
5128 | if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L)) | ||||||
5129 | (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags); | ||||||
5130 | |||||||
5131 | return PHISCEV; | ||||||
5132 | } | ||||||
5133 | } | ||||||
5134 | } else { | ||||||
5135 | // Otherwise, this could be a loop like this: | ||||||
5136 | // i = 0; for (j = 1; ..; ++j) { .... i = j; } | ||||||
5137 | // In this case, j = {1,+,1} and BEValue is j. | ||||||
5138 | // Because the other in-value of i (0) fits the evolution of BEValue | ||||||
5139 | // i really is an addrec evolution. | ||||||
5140 | // | ||||||
5141 | // We can generalize this saying that i is the shifted value of BEValue | ||||||
5142 | // by one iteration: | ||||||
5143 | // PHI(f(0), f({1,+,1})) --> f({0,+,1}) | ||||||
5144 | const SCEV *Shifted = SCEVShiftRewriter::rewrite(BEValue, L, *this); | ||||||
5145 | const SCEV *Start = SCEVInitRewriter::rewrite(Shifted, L, *this, false); | ||||||
5146 | if (Shifted != getCouldNotCompute() && | ||||||
5147 | Start != getCouldNotCompute()) { | ||||||
5148 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
5149 | if (Start == StartVal) { | ||||||
5150 | // Okay, for the entire analysis of this edge we assumed the PHI | ||||||
5151 | // to be symbolic. We now need to go back and purge all of the | ||||||
5152 | // entries for the scalars that use the symbolic expression. | ||||||
5153 | forgetSymbolicName(PN, SymbolicName); | ||||||
5154 | ValueExprMap[SCEVCallbackVH(PN, this)] = Shifted; | ||||||
5155 | return Shifted; | ||||||
5156 | } | ||||||
5157 | } | ||||||
5158 | } | ||||||
5159 | |||||||
5160 | // Remove the temporary PHI node SCEV that has been inserted while intending | ||||||
5161 | // to create an AddRecExpr for this PHI node. We can not keep this temporary | ||||||
5162 | // as it will prevent later (possibly simpler) SCEV expressions to be added | ||||||
5163 | // to the ValueExprMap. | ||||||
5164 | eraseValueFromMap(PN); | ||||||
5165 | |||||||
5166 | return nullptr; | ||||||
5167 | } | ||||||
5168 | |||||||
5169 | // Checks if the SCEV S is available at BB. S is considered available at BB | ||||||
5170 | // if S can be materialized at BB without introducing a fault. | ||||||
5171 | static bool IsAvailableOnEntry(const Loop *L, DominatorTree &DT, const SCEV *S, | ||||||
5172 | BasicBlock *BB) { | ||||||
5173 | struct CheckAvailable { | ||||||
5174 | bool TraversalDone = false; | ||||||
5175 | bool Available = true; | ||||||
5176 | |||||||
5177 | const Loop *L = nullptr; // The loop BB is in (can be nullptr) | ||||||
5178 | BasicBlock *BB = nullptr; | ||||||
5179 | DominatorTree &DT; | ||||||
5180 | |||||||
5181 | CheckAvailable(const Loop *L, BasicBlock *BB, DominatorTree &DT) | ||||||
5182 | : L(L), BB(BB), DT(DT) {} | ||||||
5183 | |||||||
5184 | bool setUnavailable() { | ||||||
5185 | TraversalDone = true; | ||||||
5186 | Available = false; | ||||||
5187 | return false; | ||||||
5188 | } | ||||||
5189 | |||||||
5190 | bool follow(const SCEV *S) { | ||||||
5191 | switch (S->getSCEVType()) { | ||||||
5192 | case scConstant: case scTruncate: case scZeroExtend: case scSignExtend: | ||||||
5193 | case scAddExpr: case scMulExpr: case scUMaxExpr: case scSMaxExpr: | ||||||
5194 | case scUMinExpr: | ||||||
5195 | case scSMinExpr: | ||||||
5196 | // These expressions are available if their operand(s) is/are. | ||||||
5197 | return true; | ||||||
5198 | |||||||
5199 | case scAddRecExpr: { | ||||||
5200 | // We allow add recurrences that are on the loop BB is in, or some | ||||||
5201 | // outer loop. This guarantees availability because the value of the | ||||||
5202 | // add recurrence at BB is simply the "current" value of the induction | ||||||
5203 | // variable. We can relax this in the future; for instance an add | ||||||
5204 | // recurrence on a sibling dominating loop is also available at BB. | ||||||
5205 | const auto *ARLoop = cast<SCEVAddRecExpr>(S)->getLoop(); | ||||||
5206 | if (L && (ARLoop == L || ARLoop->contains(L))) | ||||||
5207 | return true; | ||||||
5208 | |||||||
5209 | return setUnavailable(); | ||||||
5210 | } | ||||||
5211 | |||||||
5212 | case scUnknown: { | ||||||
5213 | // For SCEVUnknown, we check for simple dominance. | ||||||
5214 | const auto *SU = cast<SCEVUnknown>(S); | ||||||
5215 | Value *V = SU->getValue(); | ||||||
5216 | |||||||
5217 | if (isa<Argument>(V)) | ||||||
5218 | return false; | ||||||
5219 | |||||||
5220 | if (isa<Instruction>(V) && DT.dominates(cast<Instruction>(V), BB)) | ||||||
5221 | return false; | ||||||
5222 | |||||||
5223 | return setUnavailable(); | ||||||
5224 | } | ||||||
5225 | |||||||
5226 | case scUDivExpr: | ||||||
5227 | case scCouldNotCompute: | ||||||
5228 | // We do not try to smart about these at all. | ||||||
5229 | return setUnavailable(); | ||||||
5230 | } | ||||||
5231 | llvm_unreachable("switch should be fully covered!")::llvm::llvm_unreachable_internal("switch should be fully covered!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5231); | ||||||
5232 | } | ||||||
5233 | |||||||
5234 | bool isDone() { return TraversalDone; } | ||||||
5235 | }; | ||||||
5236 | |||||||
5237 | CheckAvailable CA(L, BB, DT); | ||||||
5238 | SCEVTraversal<CheckAvailable> ST(CA); | ||||||
5239 | |||||||
5240 | ST.visitAll(S); | ||||||
5241 | return CA.Available; | ||||||
5242 | } | ||||||
5243 | |||||||
5244 | // Try to match a control flow sequence that branches out at BI and merges back | ||||||
5245 | // at Merge into a "C ? LHS : RHS" select pattern. Return true on a successful | ||||||
5246 | // match. | ||||||
5247 | static bool BrPHIToSelect(DominatorTree &DT, BranchInst *BI, PHINode *Merge, | ||||||
5248 | Value *&C, Value *&LHS, Value *&RHS) { | ||||||
5249 | C = BI->getCondition(); | ||||||
5250 | |||||||
5251 | BasicBlockEdge LeftEdge(BI->getParent(), BI->getSuccessor(0)); | ||||||
5252 | BasicBlockEdge RightEdge(BI->getParent(), BI->getSuccessor(1)); | ||||||
5253 | |||||||
5254 | if (!LeftEdge.isSingleEdge()) | ||||||
5255 | return false; | ||||||
5256 | |||||||
5257 | assert(RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()")((RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()" ) ? static_cast<void> (0) : __assert_fail ("RightEdge.isSingleEdge() && \"Follows from LeftEdge.isSingleEdge()\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5257, __PRETTY_FUNCTION__)); | ||||||
5258 | |||||||
5259 | Use &LeftUse = Merge->getOperandUse(0); | ||||||
5260 | Use &RightUse = Merge->getOperandUse(1); | ||||||
5261 | |||||||
5262 | if (DT.dominates(LeftEdge, LeftUse) && DT.dominates(RightEdge, RightUse)) { | ||||||
5263 | LHS = LeftUse; | ||||||
5264 | RHS = RightUse; | ||||||
5265 | return true; | ||||||
5266 | } | ||||||
5267 | |||||||
5268 | if (DT.dominates(LeftEdge, RightUse) && DT.dominates(RightEdge, LeftUse)) { | ||||||
5269 | LHS = RightUse; | ||||||
5270 | RHS = LeftUse; | ||||||
5271 | return true; | ||||||
5272 | } | ||||||
5273 | |||||||
5274 | return false; | ||||||
5275 | } | ||||||
5276 | |||||||
5277 | const SCEV *ScalarEvolution::createNodeFromSelectLikePHI(PHINode *PN) { | ||||||
5278 | auto IsReachable = | ||||||
5279 | [&](BasicBlock *BB) { return DT.isReachableFromEntry(BB); }; | ||||||
5280 | if (PN->getNumIncomingValues() == 2 && all_of(PN->blocks(), IsReachable)) { | ||||||
5281 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
5282 | |||||||
5283 | // We don't want to break LCSSA, even in a SCEV expression tree. | ||||||
5284 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) | ||||||
5285 | if (LI.getLoopFor(PN->getIncomingBlock(i)) != L) | ||||||
5286 | return nullptr; | ||||||
5287 | |||||||
5288 | // Try to match | ||||||
5289 | // | ||||||
5290 | // br %cond, label %left, label %right | ||||||
5291 | // left: | ||||||
5292 | // br label %merge | ||||||
5293 | // right: | ||||||
5294 | // br label %merge | ||||||
5295 | // merge: | ||||||
5296 | // V = phi [ %x, %left ], [ %y, %right ] | ||||||
5297 | // | ||||||
5298 | // as "select %cond, %x, %y" | ||||||
5299 | |||||||
5300 | BasicBlock *IDom = DT[PN->getParent()]->getIDom()->getBlock(); | ||||||
5301 | assert(IDom && "At least the entry block should dominate PN")((IDom && "At least the entry block should dominate PN" ) ? static_cast<void> (0) : __assert_fail ("IDom && \"At least the entry block should dominate PN\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5301, __PRETTY_FUNCTION__)); | ||||||
5302 | |||||||
5303 | auto *BI = dyn_cast<BranchInst>(IDom->getTerminator()); | ||||||
5304 | Value *Cond = nullptr, *LHS = nullptr, *RHS = nullptr; | ||||||
5305 | |||||||
5306 | if (BI && BI->isConditional() && | ||||||
5307 | BrPHIToSelect(DT, BI, PN, Cond, LHS, RHS) && | ||||||
5308 | IsAvailableOnEntry(L, DT, getSCEV(LHS), PN->getParent()) && | ||||||
5309 | IsAvailableOnEntry(L, DT, getSCEV(RHS), PN->getParent())) | ||||||
5310 | return createNodeForSelectOrPHI(PN, Cond, LHS, RHS); | ||||||
5311 | } | ||||||
5312 | |||||||
5313 | return nullptr; | ||||||
5314 | } | ||||||
5315 | |||||||
5316 | const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) { | ||||||
5317 | if (const SCEV *S = createAddRecFromPHI(PN)) | ||||||
5318 | return S; | ||||||
5319 | |||||||
5320 | if (const SCEV *S = createNodeFromSelectLikePHI(PN)) | ||||||
5321 | return S; | ||||||
5322 | |||||||
5323 | // If the PHI has a single incoming value, follow that value, unless the | ||||||
5324 | // PHI's incoming blocks are in a different loop, in which case doing so | ||||||
5325 | // risks breaking LCSSA form. Instcombine would normally zap these, but | ||||||
5326 | // it doesn't have DominatorTree information, so it may miss cases. | ||||||
5327 | if (Value *V = SimplifyInstruction(PN, {getDataLayout(), &TLI, &DT, &AC})) | ||||||
5328 | if (LI.replacementPreservesLCSSAForm(PN, V)) | ||||||
5329 | return getSCEV(V); | ||||||
5330 | |||||||
5331 | // If it's not a loop phi, we can't handle it yet. | ||||||
5332 | return getUnknown(PN); | ||||||
5333 | } | ||||||
5334 | |||||||
5335 | const SCEV *ScalarEvolution::createNodeForSelectOrPHI(Instruction *I, | ||||||
5336 | Value *Cond, | ||||||
5337 | Value *TrueVal, | ||||||
5338 | Value *FalseVal) { | ||||||
5339 | // Handle "constant" branch or select. This can occur for instance when a | ||||||
5340 | // loop pass transforms an inner loop and moves on to process the outer loop. | ||||||
5341 | if (auto *CI = dyn_cast<ConstantInt>(Cond)) | ||||||
5342 | return getSCEV(CI->isOne() ? TrueVal : FalseVal); | ||||||
5343 | |||||||
5344 | // Try to match some simple smax or umax patterns. | ||||||
5345 | auto *ICI = dyn_cast<ICmpInst>(Cond); | ||||||
5346 | if (!ICI) | ||||||
5347 | return getUnknown(I); | ||||||
5348 | |||||||
5349 | Value *LHS = ICI->getOperand(0); | ||||||
5350 | Value *RHS = ICI->getOperand(1); | ||||||
5351 | |||||||
5352 | switch (ICI->getPredicate()) { | ||||||
5353 | case ICmpInst::ICMP_SLT: | ||||||
5354 | case ICmpInst::ICMP_SLE: | ||||||
5355 | std::swap(LHS, RHS); | ||||||
5356 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
5357 | case ICmpInst::ICMP_SGT: | ||||||
5358 | case ICmpInst::ICMP_SGE: | ||||||
5359 | // a >s b ? a+x : b+x -> smax(a, b)+x | ||||||
5360 | // a >s b ? b+x : a+x -> smin(a, b)+x | ||||||
5361 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) { | ||||||
5362 | const SCEV *LS = getNoopOrSignExtend(getSCEV(LHS), I->getType()); | ||||||
5363 | const SCEV *RS = getNoopOrSignExtend(getSCEV(RHS), I->getType()); | ||||||
5364 | const SCEV *LA = getSCEV(TrueVal); | ||||||
5365 | const SCEV *RA = getSCEV(FalseVal); | ||||||
5366 | const SCEV *LDiff = getMinusSCEV(LA, LS); | ||||||
5367 | const SCEV *RDiff = getMinusSCEV(RA, RS); | ||||||
5368 | if (LDiff == RDiff) | ||||||
5369 | return getAddExpr(getSMaxExpr(LS, RS), LDiff); | ||||||
5370 | LDiff = getMinusSCEV(LA, RS); | ||||||
5371 | RDiff = getMinusSCEV(RA, LS); | ||||||
5372 | if (LDiff == RDiff) | ||||||
5373 | return getAddExpr(getSMinExpr(LS, RS), LDiff); | ||||||
5374 | } | ||||||
5375 | break; | ||||||
5376 | case ICmpInst::ICMP_ULT: | ||||||
5377 | case ICmpInst::ICMP_ULE: | ||||||
5378 | std::swap(LHS, RHS); | ||||||
5379 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
5380 | case ICmpInst::ICMP_UGT: | ||||||
5381 | case ICmpInst::ICMP_UGE: | ||||||
5382 | // a >u b ? a+x : b+x -> umax(a, b)+x | ||||||
5383 | // a >u b ? b+x : a+x -> umin(a, b)+x | ||||||
5384 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) { | ||||||
5385 | const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType()); | ||||||
5386 | const SCEV *RS = getNoopOrZeroExtend(getSCEV(RHS), I->getType()); | ||||||
5387 | const SCEV *LA = getSCEV(TrueVal); | ||||||
5388 | const SCEV *RA = getSCEV(FalseVal); | ||||||
5389 | const SCEV *LDiff = getMinusSCEV(LA, LS); | ||||||
5390 | const SCEV *RDiff = getMinusSCEV(RA, RS); | ||||||
5391 | if (LDiff == RDiff) | ||||||
5392 | return getAddExpr(getUMaxExpr(LS, RS), LDiff); | ||||||
5393 | LDiff = getMinusSCEV(LA, RS); | ||||||
5394 | RDiff = getMinusSCEV(RA, LS); | ||||||
5395 | if (LDiff == RDiff) | ||||||
5396 | return getAddExpr(getUMinExpr(LS, RS), LDiff); | ||||||
5397 | } | ||||||
5398 | break; | ||||||
5399 | case ICmpInst::ICMP_NE: | ||||||
5400 | // n != 0 ? n+x : 1+x -> umax(n, 1)+x | ||||||
5401 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) && | ||||||
5402 | isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) { | ||||||
5403 | const SCEV *One = getOne(I->getType()); | ||||||
5404 | const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType()); | ||||||
5405 | const SCEV *LA = getSCEV(TrueVal); | ||||||
5406 | const SCEV *RA = getSCEV(FalseVal); | ||||||
5407 | const SCEV *LDiff = getMinusSCEV(LA, LS); | ||||||
5408 | const SCEV *RDiff = getMinusSCEV(RA, One); | ||||||
5409 | if (LDiff == RDiff) | ||||||
5410 | return getAddExpr(getUMaxExpr(One, LS), LDiff); | ||||||
5411 | } | ||||||
5412 | break; | ||||||
5413 | case ICmpInst::ICMP_EQ: | ||||||
5414 | // n == 0 ? 1+x : n+x -> umax(n, 1)+x | ||||||
5415 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) && | ||||||
5416 | isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) { | ||||||
5417 | const SCEV *One = getOne(I->getType()); | ||||||
5418 | const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType()); | ||||||
5419 | const SCEV *LA = getSCEV(TrueVal); | ||||||
5420 | const SCEV *RA = getSCEV(FalseVal); | ||||||
5421 | const SCEV *LDiff = getMinusSCEV(LA, One); | ||||||
5422 | const SCEV *RDiff = getMinusSCEV(RA, LS); | ||||||
5423 | if (LDiff == RDiff) | ||||||
5424 | return getAddExpr(getUMaxExpr(One, LS), LDiff); | ||||||
5425 | } | ||||||
5426 | break; | ||||||
5427 | default: | ||||||
5428 | break; | ||||||
5429 | } | ||||||
5430 | |||||||
5431 | return getUnknown(I); | ||||||
5432 | } | ||||||
5433 | |||||||
5434 | /// Expand GEP instructions into add and multiply operations. This allows them | ||||||
5435 | /// to be analyzed by regular SCEV code. | ||||||
5436 | const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) { | ||||||
5437 | // Don't attempt to analyze GEPs over unsized objects. | ||||||
5438 | if (!GEP->getSourceElementType()->isSized()) | ||||||
5439 | return getUnknown(GEP); | ||||||
5440 | |||||||
5441 | SmallVector<const SCEV *, 4> IndexExprs; | ||||||
5442 | for (auto Index = GEP->idx_begin(); Index != GEP->idx_end(); ++Index) | ||||||
5443 | IndexExprs.push_back(getSCEV(*Index)); | ||||||
5444 | return getGEPExpr(GEP, IndexExprs); | ||||||
5445 | } | ||||||
5446 | |||||||
5447 | uint32_t ScalarEvolution::GetMinTrailingZerosImpl(const SCEV *S) { | ||||||
5448 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) | ||||||
5449 | return C->getAPInt().countTrailingZeros(); | ||||||
5450 | |||||||
5451 | if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S)) | ||||||
5452 | return std::min(GetMinTrailingZeros(T->getOperand()), | ||||||
5453 | (uint32_t)getTypeSizeInBits(T->getType())); | ||||||
5454 | |||||||
5455 | if (const SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) { | ||||||
5456 | uint32_t OpRes = GetMinTrailingZeros(E->getOperand()); | ||||||
5457 | return OpRes == getTypeSizeInBits(E->getOperand()->getType()) | ||||||
5458 | ? getTypeSizeInBits(E->getType()) | ||||||
5459 | : OpRes; | ||||||
5460 | } | ||||||
5461 | |||||||
5462 | if (const SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) { | ||||||
5463 | uint32_t OpRes = GetMinTrailingZeros(E->getOperand()); | ||||||
5464 | return OpRes == getTypeSizeInBits(E->getOperand()->getType()) | ||||||
5465 | ? getTypeSizeInBits(E->getType()) | ||||||
5466 | : OpRes; | ||||||
5467 | } | ||||||
5468 | |||||||
5469 | if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) { | ||||||
5470 | // The result is the min of all operands results. | ||||||
5471 | uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0)); | ||||||
5472 | for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
5473 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i))); | ||||||
5474 | return MinOpRes; | ||||||
5475 | } | ||||||
5476 | |||||||
5477 | if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) { | ||||||
5478 | // The result is the sum of all operands results. | ||||||
5479 | uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0)); | ||||||
5480 | uint32_t BitWidth = getTypeSizeInBits(M->getType()); | ||||||
5481 | for (unsigned i = 1, e = M->getNumOperands(); | ||||||
5482 | SumOpRes != BitWidth && i != e; ++i) | ||||||
5483 | SumOpRes = | ||||||
5484 | std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i)), BitWidth); | ||||||
5485 | return SumOpRes; | ||||||
5486 | } | ||||||
5487 | |||||||
5488 | if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) { | ||||||
5489 | // The result is the min of all operands results. | ||||||
5490 | uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0)); | ||||||
5491 | for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
5492 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i))); | ||||||
5493 | return MinOpRes; | ||||||
5494 | } | ||||||
5495 | |||||||
5496 | if (const SCEVSMaxExpr *M = dyn_cast<SCEVSMaxExpr>(S)) { | ||||||
5497 | // The result is the min of all operands results. | ||||||
5498 | uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0)); | ||||||
5499 | for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
5500 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i))); | ||||||
5501 | return MinOpRes; | ||||||
5502 | } | ||||||
5503 | |||||||
5504 | if (const SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) { | ||||||
5505 | // The result is the min of all operands results. | ||||||
5506 | uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0)); | ||||||
5507 | for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
5508 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i))); | ||||||
5509 | return MinOpRes; | ||||||
5510 | } | ||||||
5511 | |||||||
5512 | if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { | ||||||
5513 | // For a SCEVUnknown, ask ValueTracking. | ||||||
5514 | KnownBits Known = computeKnownBits(U->getValue(), getDataLayout(), 0, &AC, nullptr, &DT); | ||||||
5515 | return Known.countMinTrailingZeros(); | ||||||
5516 | } | ||||||
5517 | |||||||
5518 | // SCEVUDivExpr | ||||||
5519 | return 0; | ||||||
5520 | } | ||||||
5521 | |||||||
5522 | uint32_t ScalarEvolution::GetMinTrailingZeros(const SCEV *S) { | ||||||
5523 | auto I = MinTrailingZerosCache.find(S); | ||||||
5524 | if (I != MinTrailingZerosCache.end()) | ||||||
5525 | return I->second; | ||||||
5526 | |||||||
5527 | uint32_t Result = GetMinTrailingZerosImpl(S); | ||||||
5528 | auto InsertPair = MinTrailingZerosCache.insert({S, Result}); | ||||||
5529 | assert(InsertPair.second && "Should insert a new key")((InsertPair.second && "Should insert a new key") ? static_cast <void> (0) : __assert_fail ("InsertPair.second && \"Should insert a new key\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5529, __PRETTY_FUNCTION__)); | ||||||
5530 | return InsertPair.first->second; | ||||||
5531 | } | ||||||
5532 | |||||||
5533 | /// Helper method to assign a range to V from metadata present in the IR. | ||||||
5534 | static Optional<ConstantRange> GetRangeFromMetadata(Value *V) { | ||||||
5535 | if (Instruction *I = dyn_cast<Instruction>(V)) | ||||||
5536 | if (MDNode *MD = I->getMetadata(LLVMContext::MD_range)) | ||||||
5537 | return getConstantRangeFromMetadata(*MD); | ||||||
5538 | |||||||
5539 | return None; | ||||||
5540 | } | ||||||
5541 | |||||||
5542 | /// Determine the range for a particular SCEV. If SignHint is | ||||||
5543 | /// HINT_RANGE_UNSIGNED (resp. HINT_RANGE_SIGNED) then getRange prefers ranges | ||||||
5544 | /// with a "cleaner" unsigned (resp. signed) representation. | ||||||
5545 | const ConstantRange & | ||||||
5546 | ScalarEvolution::getRangeRef(const SCEV *S, | ||||||
5547 | ScalarEvolution::RangeSignHint SignHint) { | ||||||
5548 | DenseMap<const SCEV *, ConstantRange> &Cache = | ||||||
5549 | SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED ? UnsignedRanges | ||||||
5550 | : SignedRanges; | ||||||
5551 | ConstantRange::PreferredRangeType RangeType = | ||||||
5552 | SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED | ||||||
5553 | ? ConstantRange::Unsigned : ConstantRange::Signed; | ||||||
5554 | |||||||
5555 | // See if we've computed this range already. | ||||||
5556 | DenseMap<const SCEV *, ConstantRange>::iterator I = Cache.find(S); | ||||||
5557 | if (I != Cache.end()) | ||||||
5558 | return I->second; | ||||||
5559 | |||||||
5560 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) | ||||||
5561 | return setRange(C, SignHint, ConstantRange(C->getAPInt())); | ||||||
5562 | |||||||
5563 | unsigned BitWidth = getTypeSizeInBits(S->getType()); | ||||||
5564 | ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true); | ||||||
5565 | using OBO = OverflowingBinaryOperator; | ||||||
5566 | |||||||
5567 | // If the value has known zeros, the maximum value will have those known zeros | ||||||
5568 | // as well. | ||||||
5569 | uint32_t TZ = GetMinTrailingZeros(S); | ||||||
5570 | if (TZ != 0) { | ||||||
5571 | if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) | ||||||
5572 | ConservativeResult = | ||||||
5573 | ConstantRange(APInt::getMinValue(BitWidth), | ||||||
5574 | APInt::getMaxValue(BitWidth).lshr(TZ).shl(TZ) + 1); | ||||||
5575 | else | ||||||
5576 | ConservativeResult = ConstantRange( | ||||||
5577 | APInt::getSignedMinValue(BitWidth), | ||||||
5578 | APInt::getSignedMaxValue(BitWidth).ashr(TZ).shl(TZ) + 1); | ||||||
5579 | } | ||||||
5580 | |||||||
5581 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | ||||||
5582 | ConstantRange X = getRangeRef(Add->getOperand(0), SignHint); | ||||||
5583 | unsigned WrapType = OBO::AnyWrap; | ||||||
5584 | if (Add->hasNoSignedWrap()) | ||||||
5585 | WrapType |= OBO::NoSignedWrap; | ||||||
5586 | if (Add->hasNoUnsignedWrap()) | ||||||
5587 | WrapType |= OBO::NoUnsignedWrap; | ||||||
5588 | for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i) | ||||||
5589 | X = X.addWithNoWrap(getRangeRef(Add->getOperand(i), SignHint), | ||||||
5590 | WrapType, RangeType); | ||||||
5591 | return setRange(Add, SignHint, | ||||||
5592 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
5593 | } | ||||||
5594 | |||||||
5595 | if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) { | ||||||
5596 | ConstantRange X = getRangeRef(Mul->getOperand(0), SignHint); | ||||||
5597 | for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i) | ||||||
5598 | X = X.multiply(getRangeRef(Mul->getOperand(i), SignHint)); | ||||||
5599 | return setRange(Mul, SignHint, | ||||||
5600 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
5601 | } | ||||||
5602 | |||||||
5603 | if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) { | ||||||
5604 | ConstantRange X = getRangeRef(SMax->getOperand(0), SignHint); | ||||||
5605 | for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i) | ||||||
5606 | X = X.smax(getRangeRef(SMax->getOperand(i), SignHint)); | ||||||
5607 | return setRange(SMax, SignHint, | ||||||
5608 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
5609 | } | ||||||
5610 | |||||||
5611 | if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) { | ||||||
5612 | ConstantRange X = getRangeRef(UMax->getOperand(0), SignHint); | ||||||
5613 | for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i) | ||||||
5614 | X = X.umax(getRangeRef(UMax->getOperand(i), SignHint)); | ||||||
5615 | return setRange(UMax, SignHint, | ||||||
5616 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
5617 | } | ||||||
5618 | |||||||
5619 | if (const SCEVSMinExpr *SMin = dyn_cast<SCEVSMinExpr>(S)) { | ||||||
5620 | ConstantRange X = getRangeRef(SMin->getOperand(0), SignHint); | ||||||
5621 | for (unsigned i = 1, e = SMin->getNumOperands(); i != e; ++i) | ||||||
5622 | X = X.smin(getRangeRef(SMin->getOperand(i), SignHint)); | ||||||
5623 | return setRange(SMin, SignHint, | ||||||
5624 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
5625 | } | ||||||
5626 | |||||||
5627 | if (const SCEVUMinExpr *UMin = dyn_cast<SCEVUMinExpr>(S)) { | ||||||
5628 | ConstantRange X = getRangeRef(UMin->getOperand(0), SignHint); | ||||||
5629 | for (unsigned i = 1, e = UMin->getNumOperands(); i != e; ++i) | ||||||
5630 | X = X.umin(getRangeRef(UMin->getOperand(i), SignHint)); | ||||||
5631 | return setRange(UMin, SignHint, | ||||||
5632 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
5633 | } | ||||||
5634 | |||||||
5635 | if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) { | ||||||
5636 | ConstantRange X = getRangeRef(UDiv->getLHS(), SignHint); | ||||||
5637 | ConstantRange Y = getRangeRef(UDiv->getRHS(), SignHint); | ||||||
5638 | return setRange(UDiv, SignHint, | ||||||
5639 | ConservativeResult.intersectWith(X.udiv(Y), RangeType)); | ||||||
5640 | } | ||||||
5641 | |||||||
5642 | if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) { | ||||||
5643 | ConstantRange X = getRangeRef(ZExt->getOperand(), SignHint); | ||||||
5644 | return setRange(ZExt, SignHint, | ||||||
5645 | ConservativeResult.intersectWith(X.zeroExtend(BitWidth), | ||||||
5646 | RangeType)); | ||||||
5647 | } | ||||||
5648 | |||||||
5649 | if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) { | ||||||
5650 | ConstantRange X = getRangeRef(SExt->getOperand(), SignHint); | ||||||
5651 | return setRange(SExt, SignHint, | ||||||
5652 | ConservativeResult.intersectWith(X.signExtend(BitWidth), | ||||||
5653 | RangeType)); | ||||||
5654 | } | ||||||
5655 | |||||||
5656 | if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) { | ||||||
5657 | ConstantRange X = getRangeRef(Trunc->getOperand(), SignHint); | ||||||
5658 | return setRange(Trunc, SignHint, | ||||||
5659 | ConservativeResult.intersectWith(X.truncate(BitWidth), | ||||||
5660 | RangeType)); | ||||||
5661 | } | ||||||
5662 | |||||||
5663 | if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) { | ||||||
5664 | // If there's no unsigned wrap, the value will never be less than its | ||||||
5665 | // initial value. | ||||||
5666 | if (AddRec->hasNoUnsignedWrap()) { | ||||||
5667 | APInt UnsignedMinValue = getUnsignedRangeMin(AddRec->getStart()); | ||||||
5668 | if (!UnsignedMinValue.isNullValue()) | ||||||
5669 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
5670 | ConstantRange(UnsignedMinValue, APInt(BitWidth, 0)), RangeType); | ||||||
5671 | } | ||||||
5672 | |||||||
5673 | // If there's no signed wrap, and all the operands except initial value have | ||||||
5674 | // the same sign or zero, the value won't ever be: | ||||||
5675 | // 1: smaller than initial value if operands are non negative, | ||||||
5676 | // 2: bigger than initial value if operands are non positive. | ||||||
5677 | // For both cases, value can not cross signed min/max boundary. | ||||||
5678 | if (AddRec->hasNoSignedWrap()) { | ||||||
5679 | bool AllNonNeg = true; | ||||||
5680 | bool AllNonPos = true; | ||||||
5681 | for (unsigned i = 1, e = AddRec->getNumOperands(); i != e; ++i) { | ||||||
5682 | if (!isKnownNonNegative(AddRec->getOperand(i))) | ||||||
5683 | AllNonNeg = false; | ||||||
5684 | if (!isKnownNonPositive(AddRec->getOperand(i))) | ||||||
5685 | AllNonPos = false; | ||||||
5686 | } | ||||||
5687 | if (AllNonNeg) | ||||||
5688 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
5689 | ConstantRange::getNonEmpty(getSignedRangeMin(AddRec->getStart()), | ||||||
5690 | APInt::getSignedMinValue(BitWidth)), | ||||||
5691 | RangeType); | ||||||
5692 | else if (AllNonPos) | ||||||
5693 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
5694 | ConstantRange::getNonEmpty( | ||||||
5695 | APInt::getSignedMinValue(BitWidth), | ||||||
5696 | getSignedRangeMax(AddRec->getStart()) + 1), | ||||||
5697 | RangeType); | ||||||
5698 | } | ||||||
5699 | |||||||
5700 | // TODO: non-affine addrec | ||||||
5701 | if (AddRec->isAffine()) { | ||||||
5702 | const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(AddRec->getLoop()); | ||||||
5703 | if (!isa<SCEVCouldNotCompute>(MaxBECount) && | ||||||
5704 | getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) { | ||||||
5705 | auto RangeFromAffine = getRangeForAffineAR( | ||||||
5706 | AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount, | ||||||
5707 | BitWidth); | ||||||
5708 | if (!RangeFromAffine.isFullSet()) | ||||||
5709 | ConservativeResult = | ||||||
5710 | ConservativeResult.intersectWith(RangeFromAffine, RangeType); | ||||||
5711 | |||||||
5712 | auto RangeFromFactoring = getRangeViaFactoring( | ||||||
5713 | AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount, | ||||||
5714 | BitWidth); | ||||||
5715 | if (!RangeFromFactoring.isFullSet()) | ||||||
5716 | ConservativeResult = | ||||||
5717 | ConservativeResult.intersectWith(RangeFromFactoring, RangeType); | ||||||
5718 | } | ||||||
5719 | } | ||||||
5720 | |||||||
5721 | return setRange(AddRec, SignHint, std::move(ConservativeResult)); | ||||||
5722 | } | ||||||
5723 | |||||||
5724 | if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { | ||||||
5725 | // Check if the IR explicitly contains !range metadata. | ||||||
5726 | Optional<ConstantRange> MDRange = GetRangeFromMetadata(U->getValue()); | ||||||
5727 | if (MDRange.hasValue()) | ||||||
5728 | ConservativeResult = ConservativeResult.intersectWith(MDRange.getValue(), | ||||||
5729 | RangeType); | ||||||
5730 | |||||||
5731 | // Split here to avoid paying the compile-time cost of calling both | ||||||
5732 | // computeKnownBits and ComputeNumSignBits. This restriction can be lifted | ||||||
5733 | // if needed. | ||||||
5734 | const DataLayout &DL = getDataLayout(); | ||||||
5735 | if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) { | ||||||
5736 | // For a SCEVUnknown, ask ValueTracking. | ||||||
5737 | KnownBits Known = computeKnownBits(U->getValue(), DL, 0, &AC, nullptr, &DT); | ||||||
5738 | if (Known.getBitWidth() != BitWidth) | ||||||
5739 | Known = Known.zextOrTrunc(BitWidth); | ||||||
5740 | // If Known does not result in full-set, intersect with it. | ||||||
5741 | if (Known.getMinValue() != Known.getMaxValue() + 1) | ||||||
5742 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
5743 | ConstantRange(Known.getMinValue(), Known.getMaxValue() + 1), | ||||||
5744 | RangeType); | ||||||
5745 | } else { | ||||||
5746 | assert(SignHint == ScalarEvolution::HINT_RANGE_SIGNED &&((SignHint == ScalarEvolution::HINT_RANGE_SIGNED && "generalize as needed!" ) ? static_cast<void> (0) : __assert_fail ("SignHint == ScalarEvolution::HINT_RANGE_SIGNED && \"generalize as needed!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5747, __PRETTY_FUNCTION__)) | ||||||
5747 | "generalize as needed!")((SignHint == ScalarEvolution::HINT_RANGE_SIGNED && "generalize as needed!" ) ? static_cast<void> (0) : __assert_fail ("SignHint == ScalarEvolution::HINT_RANGE_SIGNED && \"generalize as needed!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5747, __PRETTY_FUNCTION__)); | ||||||
5748 | unsigned NS = ComputeNumSignBits(U->getValue(), DL, 0, &AC, nullptr, &DT); | ||||||
5749 | // If the pointer size is larger than the index size type, this can cause | ||||||
5750 | // NS to be larger than BitWidth. So compensate for this. | ||||||
5751 | if (U->getType()->isPointerTy()) { | ||||||
5752 | unsigned ptrSize = DL.getPointerTypeSizeInBits(U->getType()); | ||||||
5753 | int ptrIdxDiff = ptrSize - BitWidth; | ||||||
5754 | if (ptrIdxDiff > 0 && ptrSize > BitWidth && NS > (unsigned)ptrIdxDiff) | ||||||
5755 | NS -= ptrIdxDiff; | ||||||
5756 | } | ||||||
5757 | |||||||
5758 | if (NS > 1) | ||||||
5759 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
5760 | ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1), | ||||||
5761 | APInt::getSignedMaxValue(BitWidth).ashr(NS - 1) + 1), | ||||||
5762 | RangeType); | ||||||
5763 | } | ||||||
5764 | |||||||
5765 | // A range of Phi is a subset of union of all ranges of its input. | ||||||
5766 | if (const PHINode *Phi = dyn_cast<PHINode>(U->getValue())) { | ||||||
5767 | // Make sure that we do not run over cycled Phis. | ||||||
5768 | if (PendingPhiRanges.insert(Phi).second) { | ||||||
5769 | ConstantRange RangeFromOps(BitWidth, /*isFullSet=*/false); | ||||||
5770 | for (auto &Op : Phi->operands()) { | ||||||
5771 | auto OpRange = getRangeRef(getSCEV(Op), SignHint); | ||||||
5772 | RangeFromOps = RangeFromOps.unionWith(OpRange); | ||||||
5773 | // No point to continue if we already have a full set. | ||||||
5774 | if (RangeFromOps.isFullSet()) | ||||||
5775 | break; | ||||||
5776 | } | ||||||
5777 | ConservativeResult = | ||||||
5778 | ConservativeResult.intersectWith(RangeFromOps, RangeType); | ||||||
5779 | bool Erased = PendingPhiRanges.erase(Phi); | ||||||
5780 | assert(Erased && "Failed to erase Phi properly?")((Erased && "Failed to erase Phi properly?") ? static_cast <void> (0) : __assert_fail ("Erased && \"Failed to erase Phi properly?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5780, __PRETTY_FUNCTION__)); | ||||||
5781 | (void) Erased; | ||||||
5782 | } | ||||||
5783 | } | ||||||
5784 | |||||||
5785 | return setRange(U, SignHint, std::move(ConservativeResult)); | ||||||
5786 | } | ||||||
5787 | |||||||
5788 | return setRange(S, SignHint, std::move(ConservativeResult)); | ||||||
5789 | } | ||||||
5790 | |||||||
5791 | // Given a StartRange, Step and MaxBECount for an expression compute a range of | ||||||
5792 | // values that the expression can take. Initially, the expression has a value | ||||||
5793 | // from StartRange and then is changed by Step up to MaxBECount times. Signed | ||||||
5794 | // argument defines if we treat Step as signed or unsigned. | ||||||
5795 | static ConstantRange getRangeForAffineARHelper(APInt Step, | ||||||
5796 | const ConstantRange &StartRange, | ||||||
5797 | const APInt &MaxBECount, | ||||||
5798 | unsigned BitWidth, bool Signed) { | ||||||
5799 | // If either Step or MaxBECount is 0, then the expression won't change, and we | ||||||
5800 | // just need to return the initial range. | ||||||
5801 | if (Step == 0 || MaxBECount == 0) | ||||||
5802 | return StartRange; | ||||||
5803 | |||||||
5804 | // If we don't know anything about the initial value (i.e. StartRange is | ||||||
5805 | // FullRange), then we don't know anything about the final range either. | ||||||
5806 | // Return FullRange. | ||||||
5807 | if (StartRange.isFullSet()) | ||||||
5808 | return ConstantRange::getFull(BitWidth); | ||||||
5809 | |||||||
5810 | // If Step is signed and negative, then we use its absolute value, but we also | ||||||
5811 | // note that we're moving in the opposite direction. | ||||||
5812 | bool Descending = Signed && Step.isNegative(); | ||||||
5813 | |||||||
5814 | if (Signed) | ||||||
5815 | // This is correct even for INT_SMIN. Let's look at i8 to illustrate this: | ||||||
5816 | // abs(INT_SMIN) = abs(-128) = abs(0x80) = -0x80 = 0x80 = 128. | ||||||
5817 | // This equations hold true due to the well-defined wrap-around behavior of | ||||||
5818 | // APInt. | ||||||
5819 | Step = Step.abs(); | ||||||
5820 | |||||||
5821 | // Check if Offset is more than full span of BitWidth. If it is, the | ||||||
5822 | // expression is guaranteed to overflow. | ||||||
5823 | if (APInt::getMaxValue(StartRange.getBitWidth()).udiv(Step).ult(MaxBECount)) | ||||||
5824 | return ConstantRange::getFull(BitWidth); | ||||||
5825 | |||||||
5826 | // Offset is by how much the expression can change. Checks above guarantee no | ||||||
5827 | // overflow here. | ||||||
5828 | APInt Offset = Step * MaxBECount; | ||||||
5829 | |||||||
5830 | // Minimum value of the final range will match the minimal value of StartRange | ||||||
5831 | // if the expression is increasing and will be decreased by Offset otherwise. | ||||||
5832 | // Maximum value of the final range will match the maximal value of StartRange | ||||||
5833 | // if the expression is decreasing and will be increased by Offset otherwise. | ||||||
5834 | APInt StartLower = StartRange.getLower(); | ||||||
5835 | APInt StartUpper = StartRange.getUpper() - 1; | ||||||
5836 | APInt MovedBoundary = Descending ? (StartLower - std::move(Offset)) | ||||||
5837 | : (StartUpper + std::move(Offset)); | ||||||
5838 | |||||||
5839 | // It's possible that the new minimum/maximum value will fall into the initial | ||||||
5840 | // range (due to wrap around). This means that the expression can take any | ||||||
5841 | // value in this bitwidth, and we have to return full range. | ||||||
5842 | if (StartRange.contains(MovedBoundary)) | ||||||
5843 | return ConstantRange::getFull(BitWidth); | ||||||
5844 | |||||||
5845 | APInt NewLower = | ||||||
5846 | Descending ? std::move(MovedBoundary) : std::move(StartLower); | ||||||
5847 | APInt NewUpper = | ||||||
5848 | Descending ? std::move(StartUpper) : std::move(MovedBoundary); | ||||||
5849 | NewUpper += 1; | ||||||
5850 | |||||||
5851 | // No overflow detected, return [StartLower, StartUpper + Offset + 1) range. | ||||||
5852 | return ConstantRange::getNonEmpty(std::move(NewLower), std::move(NewUpper)); | ||||||
5853 | } | ||||||
5854 | |||||||
5855 | ConstantRange ScalarEvolution::getRangeForAffineAR(const SCEV *Start, | ||||||
5856 | const SCEV *Step, | ||||||
5857 | const SCEV *MaxBECount, | ||||||
5858 | unsigned BitWidth) { | ||||||
5859 | assert(!isa<SCEVCouldNotCompute>(MaxBECount) &&((!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits (MaxBECount->getType()) <= BitWidth && "Precondition!" ) ? static_cast<void> (0) : __assert_fail ("!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits(MaxBECount->getType()) <= BitWidth && \"Precondition!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5861, __PRETTY_FUNCTION__)) | ||||||
5860 | getTypeSizeInBits(MaxBECount->getType()) <= BitWidth &&((!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits (MaxBECount->getType()) <= BitWidth && "Precondition!" ) ? static_cast<void> (0) : __assert_fail ("!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits(MaxBECount->getType()) <= BitWidth && \"Precondition!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5861, __PRETTY_FUNCTION__)) | ||||||
5861 | "Precondition!")((!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits (MaxBECount->getType()) <= BitWidth && "Precondition!" ) ? static_cast<void> (0) : __assert_fail ("!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits(MaxBECount->getType()) <= BitWidth && \"Precondition!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5861, __PRETTY_FUNCTION__)); | ||||||
5862 | |||||||
5863 | MaxBECount = getNoopOrZeroExtend(MaxBECount, Start->getType()); | ||||||
5864 | APInt MaxBECountValue = getUnsignedRangeMax(MaxBECount); | ||||||
5865 | |||||||
5866 | // First, consider step signed. | ||||||
5867 | ConstantRange StartSRange = getSignedRange(Start); | ||||||
5868 | ConstantRange StepSRange = getSignedRange(Step); | ||||||
5869 | |||||||
5870 | // If Step can be both positive and negative, we need to find ranges for the | ||||||
5871 | // maximum absolute step values in both directions and union them. | ||||||
5872 | ConstantRange SR = | ||||||
5873 | getRangeForAffineARHelper(StepSRange.getSignedMin(), StartSRange, | ||||||
5874 | MaxBECountValue, BitWidth, /* Signed = */ true); | ||||||
5875 | SR = SR.unionWith(getRangeForAffineARHelper(StepSRange.getSignedMax(), | ||||||
5876 | StartSRange, MaxBECountValue, | ||||||
5877 | BitWidth, /* Signed = */ true)); | ||||||
5878 | |||||||
5879 | // Next, consider step unsigned. | ||||||
5880 | ConstantRange UR = getRangeForAffineARHelper( | ||||||
5881 | getUnsignedRangeMax(Step), getUnsignedRange(Start), | ||||||
5882 | MaxBECountValue, BitWidth, /* Signed = */ false); | ||||||
5883 | |||||||
5884 | // Finally, intersect signed and unsigned ranges. | ||||||
5885 | return SR.intersectWith(UR, ConstantRange::Smallest); | ||||||
5886 | } | ||||||
5887 | |||||||
5888 | ConstantRange ScalarEvolution::getRangeViaFactoring(const SCEV *Start, | ||||||
5889 | const SCEV *Step, | ||||||
5890 | const SCEV *MaxBECount, | ||||||
5891 | unsigned BitWidth) { | ||||||
5892 | // RangeOf({C?A:B,+,C?P:Q}) == RangeOf(C?{A,+,P}:{B,+,Q}) | ||||||
5893 | // == RangeOf({A,+,P}) union RangeOf({B,+,Q}) | ||||||
5894 | |||||||
5895 | struct SelectPattern { | ||||||
5896 | Value *Condition = nullptr; | ||||||
5897 | APInt TrueValue; | ||||||
5898 | APInt FalseValue; | ||||||
5899 | |||||||
5900 | explicit SelectPattern(ScalarEvolution &SE, unsigned BitWidth, | ||||||
5901 | const SCEV *S) { | ||||||
5902 | Optional<unsigned> CastOp; | ||||||
5903 | APInt Offset(BitWidth, 0); | ||||||
5904 | |||||||
5905 | assert(SE.getTypeSizeInBits(S->getType()) == BitWidth &&((SE.getTypeSizeInBits(S->getType()) == BitWidth && "Should be!") ? static_cast<void> (0) : __assert_fail ( "SE.getTypeSizeInBits(S->getType()) == BitWidth && \"Should be!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5906, __PRETTY_FUNCTION__)) | ||||||
5906 | "Should be!")((SE.getTypeSizeInBits(S->getType()) == BitWidth && "Should be!") ? static_cast<void> (0) : __assert_fail ( "SE.getTypeSizeInBits(S->getType()) == BitWidth && \"Should be!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5906, __PRETTY_FUNCTION__)); | ||||||
5907 | |||||||
5908 | // Peel off a constant offset: | ||||||
5909 | if (auto *SA = dyn_cast<SCEVAddExpr>(S)) { | ||||||
5910 | // In the future we could consider being smarter here and handle | ||||||
5911 | // {Start+Step,+,Step} too. | ||||||
5912 | if (SA->getNumOperands() != 2 || !isa<SCEVConstant>(SA->getOperand(0))) | ||||||
5913 | return; | ||||||
5914 | |||||||
5915 | Offset = cast<SCEVConstant>(SA->getOperand(0))->getAPInt(); | ||||||
5916 | S = SA->getOperand(1); | ||||||
5917 | } | ||||||
5918 | |||||||
5919 | // Peel off a cast operation | ||||||
5920 | if (auto *SCast = dyn_cast<SCEVCastExpr>(S)) { | ||||||
5921 | CastOp = SCast->getSCEVType(); | ||||||
5922 | S = SCast->getOperand(); | ||||||
5923 | } | ||||||
5924 | |||||||
5925 | using namespace llvm::PatternMatch; | ||||||
5926 | |||||||
5927 | auto *SU = dyn_cast<SCEVUnknown>(S); | ||||||
5928 | const APInt *TrueVal, *FalseVal; | ||||||
5929 | if (!SU || | ||||||
5930 | !match(SU->getValue(), m_Select(m_Value(Condition), m_APInt(TrueVal), | ||||||
5931 | m_APInt(FalseVal)))) { | ||||||
5932 | Condition = nullptr; | ||||||
5933 | return; | ||||||
5934 | } | ||||||
5935 | |||||||
5936 | TrueValue = *TrueVal; | ||||||
5937 | FalseValue = *FalseVal; | ||||||
5938 | |||||||
5939 | // Re-apply the cast we peeled off earlier | ||||||
5940 | if (CastOp.hasValue()) | ||||||
5941 | switch (*CastOp) { | ||||||
5942 | default: | ||||||
5943 | llvm_unreachable("Unknown SCEV cast type!")::llvm::llvm_unreachable_internal("Unknown SCEV cast type!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 5943); | ||||||
5944 | |||||||
5945 | case scTruncate: | ||||||
5946 | TrueValue = TrueValue.trunc(BitWidth); | ||||||
5947 | FalseValue = FalseValue.trunc(BitWidth); | ||||||
5948 | break; | ||||||
5949 | case scZeroExtend: | ||||||
5950 | TrueValue = TrueValue.zext(BitWidth); | ||||||
5951 | FalseValue = FalseValue.zext(BitWidth); | ||||||
5952 | break; | ||||||
5953 | case scSignExtend: | ||||||
5954 | TrueValue = TrueValue.sext(BitWidth); | ||||||
5955 | FalseValue = FalseValue.sext(BitWidth); | ||||||
5956 | break; | ||||||
5957 | } | ||||||
5958 | |||||||
5959 | // Re-apply the constant offset we peeled off earlier | ||||||
5960 | TrueValue += Offset; | ||||||
5961 | FalseValue += Offset; | ||||||
5962 | } | ||||||
5963 | |||||||
5964 | bool isRecognized() { return Condition != nullptr; } | ||||||
5965 | }; | ||||||
5966 | |||||||
5967 | SelectPattern StartPattern(*this, BitWidth, Start); | ||||||
5968 | if (!StartPattern.isRecognized()) | ||||||
5969 | return ConstantRange::getFull(BitWidth); | ||||||
5970 | |||||||
5971 | SelectPattern StepPattern(*this, BitWidth, Step); | ||||||
5972 | if (!StepPattern.isRecognized()) | ||||||
5973 | return ConstantRange::getFull(BitWidth); | ||||||
5974 | |||||||
5975 | if (StartPattern.Condition != StepPattern.Condition) { | ||||||
5976 | // We don't handle this case today; but we could, by considering four | ||||||
5977 | // possibilities below instead of two. I'm not sure if there are cases where | ||||||
5978 | // that will help over what getRange already does, though. | ||||||
5979 | return ConstantRange::getFull(BitWidth); | ||||||
5980 | } | ||||||
5981 | |||||||
5982 | // NB! Calling ScalarEvolution::getConstant is fine, but we should not try to | ||||||
5983 | // construct arbitrary general SCEV expressions here. This function is called | ||||||
5984 | // from deep in the call stack, and calling getSCEV (on a sext instruction, | ||||||
5985 | // say) can end up caching a suboptimal value. | ||||||
5986 | |||||||
5987 | // FIXME: without the explicit `this` receiver below, MSVC errors out with | ||||||
5988 | // C2352 and C2512 (otherwise it isn't needed). | ||||||
5989 | |||||||
5990 | const SCEV *TrueStart = this->getConstant(StartPattern.TrueValue); | ||||||
5991 | const SCEV *TrueStep = this->getConstant(StepPattern.TrueValue); | ||||||
5992 | const SCEV *FalseStart = this->getConstant(StartPattern.FalseValue); | ||||||
5993 | const SCEV *FalseStep = this->getConstant(StepPattern.FalseValue); | ||||||
5994 | |||||||
5995 | ConstantRange TrueRange = | ||||||
5996 | this->getRangeForAffineAR(TrueStart, TrueStep, MaxBECount, BitWidth); | ||||||
5997 | ConstantRange FalseRange = | ||||||
5998 | this->getRangeForAffineAR(FalseStart, FalseStep, MaxBECount, BitWidth); | ||||||
5999 | |||||||
6000 | return TrueRange.unionWith(FalseRange); | ||||||
6001 | } | ||||||
6002 | |||||||
6003 | SCEV::NoWrapFlags ScalarEvolution::getNoWrapFlagsFromUB(const Value *V) { | ||||||
6004 | if (isa<ConstantExpr>(V)) return SCEV::FlagAnyWrap; | ||||||
6005 | const BinaryOperator *BinOp = cast<BinaryOperator>(V); | ||||||
6006 | |||||||
6007 | // Return early if there are no flags to propagate to the SCEV. | ||||||
6008 | SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | ||||||
6009 | if (BinOp->hasNoUnsignedWrap()) | ||||||
6010 | Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW); | ||||||
6011 | if (BinOp->hasNoSignedWrap()) | ||||||
6012 | Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW); | ||||||
6013 | if (Flags == SCEV::FlagAnyWrap) | ||||||
6014 | return SCEV::FlagAnyWrap; | ||||||
6015 | |||||||
6016 | return isSCEVExprNeverPoison(BinOp) ? Flags : SCEV::FlagAnyWrap; | ||||||
6017 | } | ||||||
6018 | |||||||
6019 | bool ScalarEvolution::isSCEVExprNeverPoison(const Instruction *I) { | ||||||
6020 | // Here we check that I is in the header of the innermost loop containing I, | ||||||
6021 | // since we only deal with instructions in the loop header. The actual loop we | ||||||
6022 | // need to check later will come from an add recurrence, but getting that | ||||||
6023 | // requires computing the SCEV of the operands, which can be expensive. This | ||||||
6024 | // check we can do cheaply to rule out some cases early. | ||||||
6025 | Loop *InnermostContainingLoop = LI.getLoopFor(I->getParent()); | ||||||
6026 | if (InnermostContainingLoop == nullptr || | ||||||
6027 | InnermostContainingLoop->getHeader() != I->getParent()) | ||||||
6028 | return false; | ||||||
6029 | |||||||
6030 | // Only proceed if we can prove that I does not yield poison. | ||||||
6031 | if (!programUndefinedIfFullPoison(I)) | ||||||
6032 | return false; | ||||||
6033 | |||||||
6034 | // At this point we know that if I is executed, then it does not wrap | ||||||
6035 | // according to at least one of NSW or NUW. If I is not executed, then we do | ||||||
6036 | // not know if the calculation that I represents would wrap. Multiple | ||||||
6037 | // instructions can map to the same SCEV. If we apply NSW or NUW from I to | ||||||
6038 | // the SCEV, we must guarantee no wrapping for that SCEV also when it is | ||||||
6039 | // derived from other instructions that map to the same SCEV. We cannot make | ||||||
6040 | // that guarantee for cases where I is not executed. So we need to find the | ||||||
6041 | // loop that I is considered in relation to and prove that I is executed for | ||||||
6042 | // every iteration of that loop. That implies that the value that I | ||||||
6043 | // calculates does not wrap anywhere in the loop, so then we can apply the | ||||||
6044 | // flags to the SCEV. | ||||||
6045 | // | ||||||
6046 | // We check isLoopInvariant to disambiguate in case we are adding recurrences | ||||||
6047 | // from different loops, so that we know which loop to prove that I is | ||||||
6048 | // executed in. | ||||||
6049 | for (unsigned OpIndex = 0; OpIndex < I->getNumOperands(); ++OpIndex) { | ||||||
6050 | // I could be an extractvalue from a call to an overflow intrinsic. | ||||||
6051 | // TODO: We can do better here in some cases. | ||||||
6052 | if (!isSCEVable(I->getOperand(OpIndex)->getType())) | ||||||
6053 | return false; | ||||||
6054 | const SCEV *Op = getSCEV(I->getOperand(OpIndex)); | ||||||
6055 | if (auto *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) { | ||||||
6056 | bool AllOtherOpsLoopInvariant = true; | ||||||
6057 | for (unsigned OtherOpIndex = 0; OtherOpIndex < I->getNumOperands(); | ||||||
6058 | ++OtherOpIndex) { | ||||||
6059 | if (OtherOpIndex != OpIndex) { | ||||||
6060 | const SCEV *OtherOp = getSCEV(I->getOperand(OtherOpIndex)); | ||||||
6061 | if (!isLoopInvariant(OtherOp, AddRec->getLoop())) { | ||||||
6062 | AllOtherOpsLoopInvariant = false; | ||||||
6063 | break; | ||||||
6064 | } | ||||||
6065 | } | ||||||
6066 | } | ||||||
6067 | if (AllOtherOpsLoopInvariant && | ||||||
6068 | isGuaranteedToExecuteForEveryIteration(I, AddRec->getLoop())) | ||||||
6069 | return true; | ||||||
6070 | } | ||||||
6071 | } | ||||||
6072 | return false; | ||||||
6073 | } | ||||||
6074 | |||||||
6075 | bool ScalarEvolution::isAddRecNeverPoison(const Instruction *I, const Loop *L) { | ||||||
6076 | // If we know that \c I can never be poison period, then that's enough. | ||||||
6077 | if (isSCEVExprNeverPoison(I)) | ||||||
6078 | return true; | ||||||
6079 | |||||||
6080 | // For an add recurrence specifically, we assume that infinite loops without | ||||||
6081 | // side effects are undefined behavior, and then reason as follows: | ||||||
6082 | // | ||||||
6083 | // If the add recurrence is poison in any iteration, it is poison on all | ||||||
6084 | // future iterations (since incrementing poison yields poison). If the result | ||||||
6085 | // of the add recurrence is fed into the loop latch condition and the loop | ||||||
6086 | // does not contain any throws or exiting blocks other than the latch, we now | ||||||
6087 | // have the ability to "choose" whether the backedge is taken or not (by | ||||||
6088 | // choosing a sufficiently evil value for the poison feeding into the branch) | ||||||
6089 | // for every iteration including and after the one in which \p I first became | ||||||
6090 | // poison. There are two possibilities (let's call the iteration in which \p | ||||||
6091 | // I first became poison as K): | ||||||
6092 | // | ||||||
6093 | // 1. In the set of iterations including and after K, the loop body executes | ||||||
6094 | // no side effects. In this case executing the backege an infinte number | ||||||
6095 | // of times will yield undefined behavior. | ||||||
6096 | // | ||||||
6097 | // 2. In the set of iterations including and after K, the loop body executes | ||||||
6098 | // at least one side effect. In this case, that specific instance of side | ||||||
6099 | // effect is control dependent on poison, which also yields undefined | ||||||
6100 | // behavior. | ||||||
6101 | |||||||
6102 | auto *ExitingBB = L->getExitingBlock(); | ||||||
6103 | auto *LatchBB = L->getLoopLatch(); | ||||||
6104 | if (!ExitingBB || !LatchBB || ExitingBB != LatchBB) | ||||||
6105 | return false; | ||||||
6106 | |||||||
6107 | SmallPtrSet<const Instruction *, 16> Pushed; | ||||||
6108 | SmallVector<const Instruction *, 8> PoisonStack; | ||||||
6109 | |||||||
6110 | // We start by assuming \c I, the post-inc add recurrence, is poison. Only | ||||||
6111 | // things that are known to be fully poison under that assumption go on the | ||||||
6112 | // PoisonStack. | ||||||
6113 | Pushed.insert(I); | ||||||
6114 | PoisonStack.push_back(I); | ||||||
6115 | |||||||
6116 | bool LatchControlDependentOnPoison = false; | ||||||
6117 | while (!PoisonStack.empty() && !LatchControlDependentOnPoison) { | ||||||
6118 | const Instruction *Poison = PoisonStack.pop_back_val(); | ||||||
6119 | |||||||
6120 | for (auto *PoisonUser : Poison->users()) { | ||||||
6121 | if (propagatesFullPoison(cast<Instruction>(PoisonUser))) { | ||||||
6122 | if (Pushed.insert(cast<Instruction>(PoisonUser)).second) | ||||||
6123 | PoisonStack.push_back(cast<Instruction>(PoisonUser)); | ||||||
6124 | } else if (auto *BI = dyn_cast<BranchInst>(PoisonUser)) { | ||||||
6125 | assert(BI->isConditional() && "Only possibility!")((BI->isConditional() && "Only possibility!") ? static_cast <void> (0) : __assert_fail ("BI->isConditional() && \"Only possibility!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6125, __PRETTY_FUNCTION__)); | ||||||
6126 | if (BI->getParent() == LatchBB) { | ||||||
6127 | LatchControlDependentOnPoison = true; | ||||||
6128 | break; | ||||||
6129 | } | ||||||
6130 | } | ||||||
6131 | } | ||||||
6132 | } | ||||||
6133 | |||||||
6134 | return LatchControlDependentOnPoison && loopHasNoAbnormalExits(L); | ||||||
6135 | } | ||||||
6136 | |||||||
6137 | ScalarEvolution::LoopProperties | ||||||
6138 | ScalarEvolution::getLoopProperties(const Loop *L) { | ||||||
6139 | using LoopProperties = ScalarEvolution::LoopProperties; | ||||||
6140 | |||||||
6141 | auto Itr = LoopPropertiesCache.find(L); | ||||||
6142 | if (Itr == LoopPropertiesCache.end()) { | ||||||
6143 | auto HasSideEffects = [](Instruction *I) { | ||||||
6144 | if (auto *SI = dyn_cast<StoreInst>(I)) | ||||||
6145 | return !SI->isSimple(); | ||||||
6146 | |||||||
6147 | return I->mayHaveSideEffects(); | ||||||
6148 | }; | ||||||
6149 | |||||||
6150 | LoopProperties LP = {/* HasNoAbnormalExits */ true, | ||||||
6151 | /*HasNoSideEffects*/ true}; | ||||||
6152 | |||||||
6153 | for (auto *BB : L->getBlocks()) | ||||||
6154 | for (auto &I : *BB) { | ||||||
6155 | if (!isGuaranteedToTransferExecutionToSuccessor(&I)) | ||||||
6156 | LP.HasNoAbnormalExits = false; | ||||||
6157 | if (HasSideEffects(&I)) | ||||||
6158 | LP.HasNoSideEffects = false; | ||||||
6159 | if (!LP.HasNoAbnormalExits && !LP.HasNoSideEffects) | ||||||
6160 | break; // We're already as pessimistic as we can get. | ||||||
6161 | } | ||||||
6162 | |||||||
6163 | auto InsertPair = LoopPropertiesCache.insert({L, LP}); | ||||||
6164 | assert(InsertPair.second && "We just checked!")((InsertPair.second && "We just checked!") ? static_cast <void> (0) : __assert_fail ("InsertPair.second && \"We just checked!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6164, __PRETTY_FUNCTION__)); | ||||||
6165 | Itr = InsertPair.first; | ||||||
6166 | } | ||||||
6167 | |||||||
6168 | return Itr->second; | ||||||
6169 | } | ||||||
6170 | |||||||
6171 | const SCEV *ScalarEvolution::createSCEV(Value *V) { | ||||||
6172 | if (!isSCEVable(V->getType())) | ||||||
| |||||||
6173 | return getUnknown(V); | ||||||
6174 | |||||||
6175 | if (Instruction *I
| ||||||
6176 | // Don't attempt to analyze instructions in blocks that aren't | ||||||
6177 | // reachable. Such instructions don't matter, and they aren't required | ||||||
6178 | // to obey basic rules for definitions dominating uses which this | ||||||
6179 | // analysis depends on. | ||||||
6180 | if (!DT.isReachableFromEntry(I->getParent())) | ||||||
6181 | return getUnknown(UndefValue::get(V->getType())); | ||||||
6182 | } else if (ConstantInt *CI
| ||||||
6183 | return getConstant(CI); | ||||||
6184 | else if (isa<ConstantPointerNull>(V)) | ||||||
6185 | return getZero(V->getType()); | ||||||
6186 | else if (GlobalAlias *GA
| ||||||
6187 | return GA->isInterposable() ? getUnknown(V) : getSCEV(GA->getAliasee()); | ||||||
6188 | else if (!isa<ConstantExpr>(V)) | ||||||
6189 | return getUnknown(V); | ||||||
6190 | |||||||
6191 | Operator *U = cast<Operator>(V); | ||||||
6192 | if (auto BO = MatchBinaryOp(U, DT)) { | ||||||
6193 | switch (BO->Opcode) { | ||||||
6194 | case Instruction::Add: { | ||||||
6195 | // The simple thing to do would be to just call getSCEV on both operands | ||||||
6196 | // and call getAddExpr with the result. However if we're looking at a | ||||||
6197 | // bunch of things all added together, this can be quite inefficient, | ||||||
6198 | // because it leads to N-1 getAddExpr calls for N ultimate operands. | ||||||
6199 | // Instead, gather up all the operands and make a single getAddExpr call. | ||||||
6200 | // LLVM IR canonical form means we need only traverse the left operands. | ||||||
6201 | SmallVector<const SCEV *, 4> AddOps; | ||||||
6202 | do { | ||||||
6203 | if (BO->Op) { | ||||||
6204 | if (auto *OpSCEV = getExistingSCEV(BO->Op)) { | ||||||
6205 | AddOps.push_back(OpSCEV); | ||||||
6206 | break; | ||||||
6207 | } | ||||||
6208 | |||||||
6209 | // If a NUW or NSW flag can be applied to the SCEV for this | ||||||
6210 | // addition, then compute the SCEV for this addition by itself | ||||||
6211 | // with a separate call to getAddExpr. We need to do that | ||||||
6212 | // instead of pushing the operands of the addition onto AddOps, | ||||||
6213 | // since the flags are only known to apply to this particular | ||||||
6214 | // addition - they may not apply to other additions that can be | ||||||
6215 | // formed with operands from AddOps. | ||||||
6216 | const SCEV *RHS = getSCEV(BO->RHS); | ||||||
6217 | SCEV::NoWrapFlags Flags = getNoWrapFlagsFromUB(BO->Op); | ||||||
6218 | if (Flags != SCEV::FlagAnyWrap) { | ||||||
6219 | const SCEV *LHS = getSCEV(BO->LHS); | ||||||
6220 | if (BO->Opcode == Instruction::Sub) | ||||||
6221 | AddOps.push_back(getMinusSCEV(LHS, RHS, Flags)); | ||||||
6222 | else | ||||||
6223 | AddOps.push_back(getAddExpr(LHS, RHS, Flags)); | ||||||
6224 | break; | ||||||
6225 | } | ||||||
6226 | } | ||||||
6227 | |||||||
6228 | if (BO->Opcode == Instruction::Sub) | ||||||
6229 | AddOps.push_back(getNegativeSCEV(getSCEV(BO->RHS))); | ||||||
6230 | else | ||||||
6231 | AddOps.push_back(getSCEV(BO->RHS)); | ||||||
6232 | |||||||
6233 | auto NewBO = MatchBinaryOp(BO->LHS, DT); | ||||||
6234 | if (!NewBO || (NewBO->Opcode != Instruction::Add && | ||||||
6235 | NewBO->Opcode != Instruction::Sub)) { | ||||||
6236 | AddOps.push_back(getSCEV(BO->LHS)); | ||||||
6237 | break; | ||||||
6238 | } | ||||||
6239 | BO = NewBO; | ||||||
6240 | } while (true); | ||||||
6241 | |||||||
6242 | return getAddExpr(AddOps); | ||||||
6243 | } | ||||||
6244 | |||||||
6245 | case Instruction::Mul: { | ||||||
6246 | SmallVector<const SCEV *, 4> MulOps; | ||||||
6247 | do { | ||||||
6248 | if (BO->Op) { | ||||||
6249 | if (auto *OpSCEV = getExistingSCEV(BO->Op)) { | ||||||
6250 | MulOps.push_back(OpSCEV); | ||||||
6251 | break; | ||||||
6252 | } | ||||||
6253 | |||||||
6254 | SCEV::NoWrapFlags Flags = getNoWrapFlagsFromUB(BO->Op); | ||||||
6255 | if (Flags != SCEV::FlagAnyWrap) { | ||||||
6256 | MulOps.push_back( | ||||||
6257 | getMulExpr(getSCEV(BO->LHS), getSCEV(BO->RHS), Flags)); | ||||||
6258 | break; | ||||||
6259 | } | ||||||
6260 | } | ||||||
6261 | |||||||
6262 | MulOps.push_back(getSCEV(BO->RHS)); | ||||||
6263 | auto NewBO = MatchBinaryOp(BO->LHS, DT); | ||||||
6264 | if (!NewBO || NewBO->Opcode != Instruction::Mul) { | ||||||
6265 | MulOps.push_back(getSCEV(BO->LHS)); | ||||||
6266 | break; | ||||||
6267 | } | ||||||
6268 | BO = NewBO; | ||||||
6269 | } while (true); | ||||||
6270 | |||||||
6271 | return getMulExpr(MulOps); | ||||||
6272 | } | ||||||
6273 | case Instruction::UDiv: | ||||||
6274 | return getUDivExpr(getSCEV(BO->LHS), getSCEV(BO->RHS)); | ||||||
6275 | case Instruction::URem: | ||||||
6276 | return getURemExpr(getSCEV(BO->LHS), getSCEV(BO->RHS)); | ||||||
6277 | case Instruction::Sub: { | ||||||
6278 | SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | ||||||
6279 | if (BO->Op) | ||||||
6280 | Flags = getNoWrapFlagsFromUB(BO->Op); | ||||||
6281 | return getMinusSCEV(getSCEV(BO->LHS), getSCEV(BO->RHS), Flags); | ||||||
6282 | } | ||||||
6283 | case Instruction::And: | ||||||
6284 | // For an expression like x&255 that merely masks off the high bits, | ||||||
6285 | // use zext(trunc(x)) as the SCEV expression. | ||||||
6286 | if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) { | ||||||
6287 | if (CI->isZero()) | ||||||
6288 | return getSCEV(BO->RHS); | ||||||
6289 | if (CI->isMinusOne()) | ||||||
6290 | return getSCEV(BO->LHS); | ||||||
6291 | const APInt &A = CI->getValue(); | ||||||
6292 | |||||||
6293 | // Instcombine's ShrinkDemandedConstant may strip bits out of | ||||||
6294 | // constants, obscuring what would otherwise be a low-bits mask. | ||||||
6295 | // Use computeKnownBits to compute what ShrinkDemandedConstant | ||||||
6296 | // knew about to reconstruct a low-bits mask value. | ||||||
6297 | unsigned LZ = A.countLeadingZeros(); | ||||||
6298 | unsigned TZ = A.countTrailingZeros(); | ||||||
6299 | unsigned BitWidth = A.getBitWidth(); | ||||||
6300 | KnownBits Known(BitWidth); | ||||||
6301 | computeKnownBits(BO->LHS, Known, getDataLayout(), | ||||||
6302 | 0, &AC, nullptr, &DT); | ||||||
6303 | |||||||
6304 | APInt EffectiveMask = | ||||||
6305 | APInt::getLowBitsSet(BitWidth, BitWidth - LZ - TZ).shl(TZ); | ||||||
6306 | if ((LZ != 0 || TZ != 0) && !((~A & ~Known.Zero) & EffectiveMask)) { | ||||||
6307 | const SCEV *MulCount = getConstant(APInt::getOneBitSet(BitWidth, TZ)); | ||||||
6308 | const SCEV *LHS = getSCEV(BO->LHS); | ||||||
6309 | const SCEV *ShiftedLHS = nullptr; | ||||||
6310 | if (auto *LHSMul = dyn_cast<SCEVMulExpr>(LHS)) { | ||||||
6311 | if (auto *OpC = dyn_cast<SCEVConstant>(LHSMul->getOperand(0))) { | ||||||
6312 | // For an expression like (x * 8) & 8, simplify the multiply. | ||||||
6313 | unsigned MulZeros = OpC->getAPInt().countTrailingZeros(); | ||||||
6314 | unsigned GCD = std::min(MulZeros, TZ); | ||||||
6315 | APInt DivAmt = APInt::getOneBitSet(BitWidth, TZ - GCD); | ||||||
6316 | SmallVector<const SCEV*, 4> MulOps; | ||||||
6317 | MulOps.push_back(getConstant(OpC->getAPInt().lshr(GCD))); | ||||||
6318 | MulOps.append(LHSMul->op_begin() + 1, LHSMul->op_end()); | ||||||
6319 | auto *NewMul = getMulExpr(MulOps, LHSMul->getNoWrapFlags()); | ||||||
6320 | ShiftedLHS = getUDivExpr(NewMul, getConstant(DivAmt)); | ||||||
6321 | } | ||||||
6322 | } | ||||||
6323 | if (!ShiftedLHS) | ||||||
6324 | ShiftedLHS = getUDivExpr(LHS, MulCount); | ||||||
6325 | return getMulExpr( | ||||||
6326 | getZeroExtendExpr( | ||||||
6327 | getTruncateExpr(ShiftedLHS, | ||||||
6328 | IntegerType::get(getContext(), BitWidth - LZ - TZ)), | ||||||
6329 | BO->LHS->getType()), | ||||||
6330 | MulCount); | ||||||
6331 | } | ||||||
6332 | } | ||||||
6333 | break; | ||||||
6334 | |||||||
6335 | case Instruction::Or: | ||||||
6336 | // If the RHS of the Or is a constant, we may have something like: | ||||||
6337 | // X*4+1 which got turned into X*4|1. Handle this as an Add so loop | ||||||
6338 | // optimizations will transparently handle this case. | ||||||
6339 | // | ||||||
6340 | // In order for this transformation to be safe, the LHS must be of the | ||||||
6341 | // form X*(2^n) and the Or constant must be less than 2^n. | ||||||
6342 | if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) { | ||||||
6343 | const SCEV *LHS = getSCEV(BO->LHS); | ||||||
6344 | const APInt &CIVal = CI->getValue(); | ||||||
6345 | if (GetMinTrailingZeros(LHS) >= | ||||||
6346 | (CIVal.getBitWidth() - CIVal.countLeadingZeros())) { | ||||||
6347 | // Build a plain add SCEV. | ||||||
6348 | const SCEV *S = getAddExpr(LHS, getSCEV(CI)); | ||||||
6349 | // If the LHS of the add was an addrec and it has no-wrap flags, | ||||||
6350 | // transfer the no-wrap flags, since an or won't introduce a wrap. | ||||||
6351 | if (const SCEVAddRecExpr *NewAR = dyn_cast<SCEVAddRecExpr>(S)) { | ||||||
6352 | const SCEVAddRecExpr *OldAR = cast<SCEVAddRecExpr>(LHS); | ||||||
6353 | const_cast<SCEVAddRecExpr *>(NewAR)->setNoWrapFlags( | ||||||
6354 | OldAR->getNoWrapFlags()); | ||||||
6355 | } | ||||||
6356 | return S; | ||||||
6357 | } | ||||||
6358 | } | ||||||
6359 | break; | ||||||
6360 | |||||||
6361 | case Instruction::Xor: | ||||||
6362 | if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) { | ||||||
6363 | // If the RHS of xor is -1, then this is a not operation. | ||||||
6364 | if (CI->isMinusOne()) | ||||||
6365 | return getNotSCEV(getSCEV(BO->LHS)); | ||||||
6366 | |||||||
6367 | // Model xor(and(x, C), C) as and(~x, C), if C is a low-bits mask. | ||||||
6368 | // This is a variant of the check for xor with -1, and it handles | ||||||
6369 | // the case where instcombine has trimmed non-demanded bits out | ||||||
6370 | // of an xor with -1. | ||||||
6371 | if (auto *LBO = dyn_cast<BinaryOperator>(BO->LHS)) | ||||||
6372 | if (ConstantInt *LCI = dyn_cast<ConstantInt>(LBO->getOperand(1))) | ||||||
6373 | if (LBO->getOpcode() == Instruction::And && | ||||||
6374 | LCI->getValue() == CI->getValue()) | ||||||
6375 | if (const SCEVZeroExtendExpr *Z = | ||||||
6376 | dyn_cast<SCEVZeroExtendExpr>(getSCEV(BO->LHS))) { | ||||||
6377 | Type *UTy = BO->LHS->getType(); | ||||||
6378 | const SCEV *Z0 = Z->getOperand(); | ||||||
6379 | Type *Z0Ty = Z0->getType(); | ||||||
6380 | unsigned Z0TySize = getTypeSizeInBits(Z0Ty); | ||||||
6381 | |||||||
6382 | // If C is a low-bits mask, the zero extend is serving to | ||||||
6383 | // mask off the high bits. Complement the operand and | ||||||
6384 | // re-apply the zext. | ||||||
6385 | if (CI->getValue().isMask(Z0TySize)) | ||||||
6386 | return getZeroExtendExpr(getNotSCEV(Z0), UTy); | ||||||
6387 | |||||||
6388 | // If C is a single bit, it may be in the sign-bit position | ||||||
6389 | // before the zero-extend. In this case, represent the xor | ||||||
6390 | // using an add, which is equivalent, and re-apply the zext. | ||||||
6391 | APInt Trunc = CI->getValue().trunc(Z0TySize); | ||||||
6392 | if (Trunc.zext(getTypeSizeInBits(UTy)) == CI->getValue() && | ||||||
6393 | Trunc.isSignMask()) | ||||||
6394 | return getZeroExtendExpr(getAddExpr(Z0, getConstant(Trunc)), | ||||||
6395 | UTy); | ||||||
6396 | } | ||||||
6397 | } | ||||||
6398 | break; | ||||||
6399 | |||||||
6400 | case Instruction::Shl: | ||||||
6401 | // Turn shift left of a constant amount into a multiply. | ||||||
6402 | if (ConstantInt *SA = dyn_cast<ConstantInt>(BO->RHS)) { | ||||||
6403 | uint32_t BitWidth = cast<IntegerType>(SA->getType())->getBitWidth(); | ||||||
6404 | |||||||
6405 | // If the shift count is not less than the bitwidth, the result of | ||||||
6406 | // the shift is undefined. Don't try to analyze it, because the | ||||||
6407 | // resolution chosen here may differ from the resolution chosen in | ||||||
6408 | // other parts of the compiler. | ||||||
6409 | if (SA->getValue().uge(BitWidth)) | ||||||
6410 | break; | ||||||
6411 | |||||||
6412 | // It is currently not resolved how to interpret NSW for left | ||||||
6413 | // shift by BitWidth - 1, so we avoid applying flags in that | ||||||
6414 | // case. Remove this check (or this comment) once the situation | ||||||
6415 | // is resolved. See | ||||||
6416 | // http://lists.llvm.org/pipermail/llvm-dev/2015-April/084195.html | ||||||
6417 | // and http://reviews.llvm.org/D8890 . | ||||||
6418 | auto Flags = SCEV::FlagAnyWrap; | ||||||
6419 | if (BO->Op && SA->getValue().ult(BitWidth - 1)) | ||||||
6420 | Flags = getNoWrapFlagsFromUB(BO->Op); | ||||||
6421 | |||||||
6422 | Constant *X = ConstantInt::get( | ||||||
6423 | getContext(), APInt::getOneBitSet(BitWidth, SA->getZExtValue())); | ||||||
6424 | return getMulExpr(getSCEV(BO->LHS), getSCEV(X), Flags); | ||||||
6425 | } | ||||||
6426 | break; | ||||||
6427 | |||||||
6428 | case Instruction::AShr: { | ||||||
6429 | // AShr X, C, where C is a constant. | ||||||
6430 | ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS); | ||||||
6431 | if (!CI) | ||||||
6432 | break; | ||||||
6433 | |||||||
6434 | Type *OuterTy = BO->LHS->getType(); | ||||||
| |||||||
6435 | uint64_t BitWidth = getTypeSizeInBits(OuterTy); | ||||||
6436 | // If the shift count is not less than the bitwidth, the result of | ||||||
6437 | // the shift is undefined. Don't try to analyze it, because the | ||||||
6438 | // resolution chosen here may differ from the resolution chosen in | ||||||
6439 | // other parts of the compiler. | ||||||
6440 | if (CI->getValue().uge(BitWidth)) | ||||||
6441 | break; | ||||||
6442 | |||||||
6443 | if (CI->isZero()) | ||||||
6444 | return getSCEV(BO->LHS); // shift by zero --> noop | ||||||
6445 | |||||||
6446 | uint64_t AShrAmt = CI->getZExtValue(); | ||||||
6447 | Type *TruncTy = IntegerType::get(getContext(), BitWidth - AShrAmt); | ||||||
6448 | |||||||
6449 | Operator *L = dyn_cast<Operator>(BO->LHS); | ||||||
6450 | if (L && L->getOpcode() == Instruction::Shl) { | ||||||
6451 | // X = Shl A, n | ||||||
6452 | // Y = AShr X, m | ||||||
6453 | // Both n and m are constant. | ||||||
6454 | |||||||
6455 | const SCEV *ShlOp0SCEV = getSCEV(L->getOperand(0)); | ||||||
6456 | if (L->getOperand(1) == BO->RHS) | ||||||
6457 | // For a two-shift sext-inreg, i.e. n = m, | ||||||
6458 | // use sext(trunc(x)) as the SCEV expression. | ||||||
6459 | return getSignExtendExpr( | ||||||
6460 | getTruncateExpr(ShlOp0SCEV, TruncTy), OuterTy); | ||||||
6461 | |||||||
6462 | ConstantInt *ShlAmtCI = dyn_cast<ConstantInt>(L->getOperand(1)); | ||||||
6463 | if (ShlAmtCI && ShlAmtCI->getValue().ult(BitWidth)) { | ||||||
6464 | uint64_t ShlAmt = ShlAmtCI->getZExtValue(); | ||||||
6465 | if (ShlAmt > AShrAmt) { | ||||||
6466 | // When n > m, use sext(mul(trunc(x), 2^(n-m)))) as the SCEV | ||||||
6467 | // expression. We already checked that ShlAmt < BitWidth, so | ||||||
6468 | // the multiplier, 1 << (ShlAmt - AShrAmt), fits into TruncTy as | ||||||
6469 | // ShlAmt - AShrAmt < Amt. | ||||||
6470 | APInt Mul = APInt::getOneBitSet(BitWidth - AShrAmt, | ||||||
6471 | ShlAmt - AShrAmt); | ||||||
6472 | return getSignExtendExpr( | ||||||
6473 | getMulExpr(getTruncateExpr(ShlOp0SCEV, TruncTy), | ||||||
6474 | getConstant(Mul)), OuterTy); | ||||||
6475 | } | ||||||
6476 | } | ||||||
6477 | } | ||||||
6478 | break; | ||||||
6479 | } | ||||||
6480 | } | ||||||
6481 | } | ||||||
6482 | |||||||
6483 | switch (U->getOpcode()) { | ||||||
6484 | case Instruction::Trunc: | ||||||
6485 | return getTruncateExpr(getSCEV(U->getOperand(0)), U->getType()); | ||||||
6486 | |||||||
6487 | case Instruction::ZExt: | ||||||
6488 | return getZeroExtendExpr(getSCEV(U->getOperand(0)), U->getType()); | ||||||
6489 | |||||||
6490 | case Instruction::SExt: | ||||||
6491 | if (auto BO = MatchBinaryOp(U->getOperand(0), DT)) { | ||||||
6492 | // The NSW flag of a subtract does not always survive the conversion to | ||||||
6493 | // A + (-1)*B. By pushing sign extension onto its operands we are much | ||||||
6494 | // more likely to preserve NSW and allow later AddRec optimisations. | ||||||
6495 | // | ||||||
6496 | // NOTE: This is effectively duplicating this logic from getSignExtend: | ||||||
6497 | // sext((A + B + ...)<nsw>) --> (sext(A) + sext(B) + ...)<nsw> | ||||||
6498 | // but by that point the NSW information has potentially been lost. | ||||||
6499 | if (BO->Opcode == Instruction::Sub && BO->IsNSW) { | ||||||
6500 | Type *Ty = U->getType(); | ||||||
6501 | auto *V1 = getSignExtendExpr(getSCEV(BO->LHS), Ty); | ||||||
6502 | auto *V2 = getSignExtendExpr(getSCEV(BO->RHS), Ty); | ||||||
6503 | return getMinusSCEV(V1, V2, SCEV::FlagNSW); | ||||||
6504 | } | ||||||
6505 | } | ||||||
6506 | return getSignExtendExpr(getSCEV(U->getOperand(0)), U->getType()); | ||||||
6507 | |||||||
6508 | case Instruction::BitCast: | ||||||
6509 | // BitCasts are no-op casts so we just eliminate the cast. | ||||||
6510 | if (isSCEVable(U->getType()) && isSCEVable(U->getOperand(0)->getType())) | ||||||
6511 | return getSCEV(U->getOperand(0)); | ||||||
6512 | break; | ||||||
6513 | |||||||
6514 | // It's tempting to handle inttoptr and ptrtoint as no-ops, however this can | ||||||
6515 | // lead to pointer expressions which cannot safely be expanded to GEPs, | ||||||
6516 | // because ScalarEvolution doesn't respect the GEP aliasing rules when | ||||||
6517 | // simplifying integer expressions. | ||||||
6518 | |||||||
6519 | case Instruction::GetElementPtr: | ||||||
6520 | return createNodeForGEP(cast<GEPOperator>(U)); | ||||||
6521 | |||||||
6522 | case Instruction::PHI: | ||||||
6523 | return createNodeForPHI(cast<PHINode>(U)); | ||||||
6524 | |||||||
6525 | case Instruction::Select: | ||||||
6526 | // U can also be a select constant expr, which let fall through. Since | ||||||
6527 | // createNodeForSelect only works for a condition that is an `ICmpInst`, and | ||||||
6528 | // constant expressions cannot have instructions as operands, we'd have | ||||||
6529 | // returned getUnknown for a select constant expressions anyway. | ||||||
6530 | if (isa<Instruction>(U)) | ||||||
6531 | return createNodeForSelectOrPHI(cast<Instruction>(U), U->getOperand(0), | ||||||
6532 | U->getOperand(1), U->getOperand(2)); | ||||||
6533 | break; | ||||||
6534 | |||||||
6535 | case Instruction::Call: | ||||||
6536 | case Instruction::Invoke: | ||||||
6537 | if (Value *RV = CallSite(U).getReturnedArgOperand()) | ||||||
6538 | return getSCEV(RV); | ||||||
6539 | break; | ||||||
6540 | } | ||||||
6541 | |||||||
6542 | return getUnknown(V); | ||||||
6543 | } | ||||||
6544 | |||||||
6545 | //===----------------------------------------------------------------------===// | ||||||
6546 | // Iteration Count Computation Code | ||||||
6547 | // | ||||||
6548 | |||||||
6549 | static unsigned getConstantTripCount(const SCEVConstant *ExitCount) { | ||||||
6550 | if (!ExitCount) | ||||||
6551 | return 0; | ||||||
6552 | |||||||
6553 | ConstantInt *ExitConst = ExitCount->getValue(); | ||||||
6554 | |||||||
6555 | // Guard against huge trip counts. | ||||||
6556 | if (ExitConst->getValue().getActiveBits() > 32) | ||||||
6557 | return 0; | ||||||
6558 | |||||||
6559 | // In case of integer overflow, this returns 0, which is correct. | ||||||
6560 | return ((unsigned)ExitConst->getZExtValue()) + 1; | ||||||
6561 | } | ||||||
6562 | |||||||
6563 | unsigned ScalarEvolution::getSmallConstantTripCount(const Loop *L) { | ||||||
6564 | if (BasicBlock *ExitingBB = L->getExitingBlock()) | ||||||
6565 | return getSmallConstantTripCount(L, ExitingBB); | ||||||
6566 | |||||||
6567 | // No trip count information for multiple exits. | ||||||
6568 | return 0; | ||||||
6569 | } | ||||||
6570 | |||||||
6571 | unsigned ScalarEvolution::getSmallConstantTripCount(const Loop *L, | ||||||
6572 | BasicBlock *ExitingBlock) { | ||||||
6573 | assert(ExitingBlock && "Must pass a non-null exiting block!")((ExitingBlock && "Must pass a non-null exiting block!" ) ? static_cast<void> (0) : __assert_fail ("ExitingBlock && \"Must pass a non-null exiting block!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6573, __PRETTY_FUNCTION__)); | ||||||
6574 | assert(L->isLoopExiting(ExitingBlock) &&((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!" ) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6575, __PRETTY_FUNCTION__)) | ||||||
6575 | "Exiting block must actually branch out of the loop!")((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!" ) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6575, __PRETTY_FUNCTION__)); | ||||||
6576 | const SCEVConstant *ExitCount = | ||||||
6577 | dyn_cast<SCEVConstant>(getExitCount(L, ExitingBlock)); | ||||||
6578 | return getConstantTripCount(ExitCount); | ||||||
6579 | } | ||||||
6580 | |||||||
6581 | unsigned ScalarEvolution::getSmallConstantMaxTripCount(const Loop *L) { | ||||||
6582 | const auto *MaxExitCount = | ||||||
6583 | dyn_cast<SCEVConstant>(getConstantMaxBackedgeTakenCount(L)); | ||||||
6584 | return getConstantTripCount(MaxExitCount); | ||||||
6585 | } | ||||||
6586 | |||||||
6587 | unsigned ScalarEvolution::getSmallConstantTripMultiple(const Loop *L) { | ||||||
6588 | if (BasicBlock *ExitingBB = L->getExitingBlock()) | ||||||
6589 | return getSmallConstantTripMultiple(L, ExitingBB); | ||||||
6590 | |||||||
6591 | // No trip multiple information for multiple exits. | ||||||
6592 | return 0; | ||||||
6593 | } | ||||||
6594 | |||||||
6595 | /// Returns the largest constant divisor of the trip count of this loop as a | ||||||
6596 | /// normal unsigned value, if possible. This means that the actual trip count is | ||||||
6597 | /// always a multiple of the returned value (don't forget the trip count could | ||||||
6598 | /// very well be zero as well!). | ||||||
6599 | /// | ||||||
6600 | /// Returns 1 if the trip count is unknown or not guaranteed to be the | ||||||
6601 | /// multiple of a constant (which is also the case if the trip count is simply | ||||||
6602 | /// constant, use getSmallConstantTripCount for that case), Will also return 1 | ||||||
6603 | /// if the trip count is very large (>= 2^32). | ||||||
6604 | /// | ||||||
6605 | /// As explained in the comments for getSmallConstantTripCount, this assumes | ||||||
6606 | /// that control exits the loop via ExitingBlock. | ||||||
6607 | unsigned | ||||||
6608 | ScalarEvolution::getSmallConstantTripMultiple(const Loop *L, | ||||||
6609 | BasicBlock *ExitingBlock) { | ||||||
6610 | assert(ExitingBlock && "Must pass a non-null exiting block!")((ExitingBlock && "Must pass a non-null exiting block!" ) ? static_cast<void> (0) : __assert_fail ("ExitingBlock && \"Must pass a non-null exiting block!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6610, __PRETTY_FUNCTION__)); | ||||||
6611 | assert(L->isLoopExiting(ExitingBlock) &&((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!" ) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6612, __PRETTY_FUNCTION__)) | ||||||
6612 | "Exiting block must actually branch out of the loop!")((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!" ) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6612, __PRETTY_FUNCTION__)); | ||||||
6613 | const SCEV *ExitCount = getExitCount(L, ExitingBlock); | ||||||
6614 | if (ExitCount == getCouldNotCompute()) | ||||||
6615 | return 1; | ||||||
6616 | |||||||
6617 | // Get the trip count from the BE count by adding 1. | ||||||
6618 | const SCEV *TCExpr = getAddExpr(ExitCount, getOne(ExitCount->getType())); | ||||||
6619 | |||||||
6620 | const SCEVConstant *TC = dyn_cast<SCEVConstant>(TCExpr); | ||||||
6621 | if (!TC) | ||||||
6622 | // Attempt to factor more general cases. Returns the greatest power of | ||||||
6623 | // two divisor. If overflow happens, the trip count expression is still | ||||||
6624 | // divisible by the greatest power of 2 divisor returned. | ||||||
6625 | return 1U << std::min((uint32_t)31, GetMinTrailingZeros(TCExpr)); | ||||||
6626 | |||||||
6627 | ConstantInt *Result = TC->getValue(); | ||||||
6628 | |||||||
6629 | // Guard against huge trip counts (this requires checking | ||||||
6630 | // for zero to handle the case where the trip count == -1 and the | ||||||
6631 | // addition wraps). | ||||||
6632 | if (!Result || Result->getValue().getActiveBits() > 32 || | ||||||
6633 | Result->getValue().getActiveBits() == 0) | ||||||
6634 | return 1; | ||||||
6635 | |||||||
6636 | return (unsigned)Result->getZExtValue(); | ||||||
6637 | } | ||||||
6638 | |||||||
6639 | const SCEV *ScalarEvolution::getExitCount(const Loop *L, | ||||||
6640 | BasicBlock *ExitingBlock, | ||||||
6641 | ExitCountKind Kind) { | ||||||
6642 | switch (Kind) { | ||||||
6643 | case Exact: | ||||||
6644 | return getBackedgeTakenInfo(L).getExact(ExitingBlock, this); | ||||||
6645 | case ConstantMaximum: | ||||||
6646 | return getBackedgeTakenInfo(L).getMax(ExitingBlock, this); | ||||||
6647 | }; | ||||||
6648 | llvm_unreachable("Invalid ExitCountKind!")::llvm::llvm_unreachable_internal("Invalid ExitCountKind!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6648); | ||||||
6649 | } | ||||||
6650 | |||||||
6651 | const SCEV * | ||||||
6652 | ScalarEvolution::getPredicatedBackedgeTakenCount(const Loop *L, | ||||||
6653 | SCEVUnionPredicate &Preds) { | ||||||
6654 | return getPredicatedBackedgeTakenInfo(L).getExact(L, this, &Preds); | ||||||
6655 | } | ||||||
6656 | |||||||
6657 | const SCEV *ScalarEvolution::getBackedgeTakenCount(const Loop *L, | ||||||
6658 | ExitCountKind Kind) { | ||||||
6659 | switch (Kind) { | ||||||
6660 | case Exact: | ||||||
6661 | return getBackedgeTakenInfo(L).getExact(L, this); | ||||||
6662 | case ConstantMaximum: | ||||||
6663 | return getBackedgeTakenInfo(L).getMax(this); | ||||||
6664 | }; | ||||||
6665 | llvm_unreachable("Invalid ExitCountKind!")::llvm::llvm_unreachable_internal("Invalid ExitCountKind!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6665); | ||||||
6666 | } | ||||||
6667 | |||||||
6668 | bool ScalarEvolution::isBackedgeTakenCountMaxOrZero(const Loop *L) { | ||||||
6669 | return getBackedgeTakenInfo(L).isMaxOrZero(this); | ||||||
6670 | } | ||||||
6671 | |||||||
6672 | /// Push PHI nodes in the header of the given loop onto the given Worklist. | ||||||
6673 | static void | ||||||
6674 | PushLoopPHIs(const Loop *L, SmallVectorImpl<Instruction *> &Worklist) { | ||||||
6675 | BasicBlock *Header = L->getHeader(); | ||||||
6676 | |||||||
6677 | // Push all Loop-header PHIs onto the Worklist stack. | ||||||
6678 | for (PHINode &PN : Header->phis()) | ||||||
6679 | Worklist.push_back(&PN); | ||||||
6680 | } | ||||||
6681 | |||||||
6682 | const ScalarEvolution::BackedgeTakenInfo & | ||||||
6683 | ScalarEvolution::getPredicatedBackedgeTakenInfo(const Loop *L) { | ||||||
6684 | auto &BTI = getBackedgeTakenInfo(L); | ||||||
6685 | if (BTI.hasFullInfo()) | ||||||
6686 | return BTI; | ||||||
6687 | |||||||
6688 | auto Pair = PredicatedBackedgeTakenCounts.insert({L, BackedgeTakenInfo()}); | ||||||
6689 | |||||||
6690 | if (!Pair.second) | ||||||
6691 | return Pair.first->second; | ||||||
6692 | |||||||
6693 | BackedgeTakenInfo Result = | ||||||
6694 | computeBackedgeTakenCount(L, /*AllowPredicates=*/true); | ||||||
6695 | |||||||
6696 | return PredicatedBackedgeTakenCounts.find(L)->second = std::move(Result); | ||||||
6697 | } | ||||||
6698 | |||||||
6699 | const ScalarEvolution::BackedgeTakenInfo & | ||||||
6700 | ScalarEvolution::getBackedgeTakenInfo(const Loop *L) { | ||||||
6701 | // Initially insert an invalid entry for this loop. If the insertion | ||||||
6702 | // succeeds, proceed to actually compute a backedge-taken count and | ||||||
6703 | // update the value. The temporary CouldNotCompute value tells SCEV | ||||||
6704 | // code elsewhere that it shouldn't attempt to request a new | ||||||
6705 | // backedge-taken count, which could result in infinite recursion. | ||||||
6706 | std::pair<DenseMap<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair = | ||||||
6707 | BackedgeTakenCounts.insert({L, BackedgeTakenInfo()}); | ||||||
6708 | if (!Pair.second) | ||||||
6709 | return Pair.first->second; | ||||||
6710 | |||||||
6711 | // computeBackedgeTakenCount may allocate memory for its result. Inserting it | ||||||
6712 | // into the BackedgeTakenCounts map transfers ownership. Otherwise, the result | ||||||
6713 | // must be cleared in this scope. | ||||||
6714 | BackedgeTakenInfo Result = computeBackedgeTakenCount(L); | ||||||
6715 | |||||||
6716 | // In product build, there are no usage of statistic. | ||||||
6717 | (void)NumTripCountsComputed; | ||||||
6718 | (void)NumTripCountsNotComputed; | ||||||
6719 | #if LLVM_ENABLE_STATS1 || !defined(NDEBUG) | ||||||
6720 | const SCEV *BEExact = Result.getExact(L, this); | ||||||
6721 | if (BEExact != getCouldNotCompute()) { | ||||||
6722 | assert(isLoopInvariant(BEExact, L) &&((isLoopInvariant(BEExact, L) && isLoopInvariant(Result .getMax(this), L) && "Computed backedge-taken count isn't loop invariant for loop!" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(BEExact, L) && isLoopInvariant(Result.getMax(this), L) && \"Computed backedge-taken count isn't loop invariant for loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6724, __PRETTY_FUNCTION__)) | ||||||
6723 | isLoopInvariant(Result.getMax(this), L) &&((isLoopInvariant(BEExact, L) && isLoopInvariant(Result .getMax(this), L) && "Computed backedge-taken count isn't loop invariant for loop!" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(BEExact, L) && isLoopInvariant(Result.getMax(this), L) && \"Computed backedge-taken count isn't loop invariant for loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6724, __PRETTY_FUNCTION__)) | ||||||
6724 | "Computed backedge-taken count isn't loop invariant for loop!")((isLoopInvariant(BEExact, L) && isLoopInvariant(Result .getMax(this), L) && "Computed backedge-taken count isn't loop invariant for loop!" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(BEExact, L) && isLoopInvariant(Result.getMax(this), L) && \"Computed backedge-taken count isn't loop invariant for loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6724, __PRETTY_FUNCTION__)); | ||||||
6725 | ++NumTripCountsComputed; | ||||||
6726 | } | ||||||
6727 | else if (Result.getMax(this) == getCouldNotCompute() && | ||||||
6728 | isa<PHINode>(L->getHeader()->begin())) { | ||||||
6729 | // Only count loops that have phi nodes as not being computable. | ||||||
6730 | ++NumTripCountsNotComputed; | ||||||
6731 | } | ||||||
6732 | #endif // LLVM_ENABLE_STATS || !defined(NDEBUG) | ||||||
6733 | |||||||
6734 | // Now that we know more about the trip count for this loop, forget any | ||||||
6735 | // existing SCEV values for PHI nodes in this loop since they are only | ||||||
6736 | // conservative estimates made without the benefit of trip count | ||||||
6737 | // information. This is similar to the code in forgetLoop, except that | ||||||
6738 | // it handles SCEVUnknown PHI nodes specially. | ||||||
6739 | if (Result.hasAnyInfo()) { | ||||||
6740 | SmallVector<Instruction *, 16> Worklist; | ||||||
6741 | PushLoopPHIs(L, Worklist); | ||||||
6742 | |||||||
6743 | SmallPtrSet<Instruction *, 8> Discovered; | ||||||
6744 | while (!Worklist.empty()) { | ||||||
6745 | Instruction *I = Worklist.pop_back_val(); | ||||||
6746 | |||||||
6747 | ValueExprMapType::iterator It = | ||||||
6748 | ValueExprMap.find_as(static_cast<Value *>(I)); | ||||||
6749 | if (It != ValueExprMap.end()) { | ||||||
6750 | const SCEV *Old = It->second; | ||||||
6751 | |||||||
6752 | // SCEVUnknown for a PHI either means that it has an unrecognized | ||||||
6753 | // structure, or it's a PHI that's in the progress of being computed | ||||||
6754 | // by createNodeForPHI. In the former case, additional loop trip | ||||||
6755 | // count information isn't going to change anything. In the later | ||||||
6756 | // case, createNodeForPHI will perform the necessary updates on its | ||||||
6757 | // own when it gets to that point. | ||||||
6758 | if (!isa<PHINode>(I) || !isa<SCEVUnknown>(Old)) { | ||||||
6759 | eraseValueFromMap(It->first); | ||||||
6760 | forgetMemoizedResults(Old); | ||||||
6761 | } | ||||||
6762 | if (PHINode *PN = dyn_cast<PHINode>(I)) | ||||||
6763 | ConstantEvolutionLoopExitValue.erase(PN); | ||||||
6764 | } | ||||||
6765 | |||||||
6766 | // Since we don't need to invalidate anything for correctness and we're | ||||||
6767 | // only invalidating to make SCEV's results more precise, we get to stop | ||||||
6768 | // early to avoid invalidating too much. This is especially important in | ||||||
6769 | // cases like: | ||||||
6770 | // | ||||||
6771 | // %v = f(pn0, pn1) // pn0 and pn1 used through some other phi node | ||||||
6772 | // loop0: | ||||||
6773 | // %pn0 = phi | ||||||
6774 | // ... | ||||||
6775 | // loop1: | ||||||
6776 | // %pn1 = phi | ||||||
6777 | // ... | ||||||
6778 | // | ||||||
6779 | // where both loop0 and loop1's backedge taken count uses the SCEV | ||||||
6780 | // expression for %v. If we don't have the early stop below then in cases | ||||||
6781 | // like the above, getBackedgeTakenInfo(loop1) will clear out the trip | ||||||
6782 | // count for loop0 and getBackedgeTakenInfo(loop0) will clear out the trip | ||||||
6783 | // count for loop1, effectively nullifying SCEV's trip count cache. | ||||||
6784 | for (auto *U : I->users()) | ||||||
6785 | if (auto *I = dyn_cast<Instruction>(U)) { | ||||||
6786 | auto *LoopForUser = LI.getLoopFor(I->getParent()); | ||||||
6787 | if (LoopForUser && L->contains(LoopForUser) && | ||||||
6788 | Discovered.insert(I).second) | ||||||
6789 | Worklist.push_back(I); | ||||||
6790 | } | ||||||
6791 | } | ||||||
6792 | } | ||||||
6793 | |||||||
6794 | // Re-lookup the insert position, since the call to | ||||||
6795 | // computeBackedgeTakenCount above could result in a | ||||||
6796 | // recusive call to getBackedgeTakenInfo (on a different | ||||||
6797 | // loop), which would invalidate the iterator computed | ||||||
6798 | // earlier. | ||||||
6799 | return BackedgeTakenCounts.find(L)->second = std::move(Result); | ||||||
6800 | } | ||||||
6801 | |||||||
6802 | void ScalarEvolution::forgetAllLoops() { | ||||||
6803 | // This method is intended to forget all info about loops. It should | ||||||
6804 | // invalidate caches as if the following happened: | ||||||
6805 | // - The trip counts of all loops have changed arbitrarily | ||||||
6806 | // - Every llvm::Value has been updated in place to produce a different | ||||||
6807 | // result. | ||||||
6808 | BackedgeTakenCounts.clear(); | ||||||
6809 | PredicatedBackedgeTakenCounts.clear(); | ||||||
6810 | LoopPropertiesCache.clear(); | ||||||
6811 | ConstantEvolutionLoopExitValue.clear(); | ||||||
6812 | ValueExprMap.clear(); | ||||||
6813 | ValuesAtScopes.clear(); | ||||||
6814 | LoopDispositions.clear(); | ||||||
6815 | BlockDispositions.clear(); | ||||||
6816 | UnsignedRanges.clear(); | ||||||
6817 | SignedRanges.clear(); | ||||||
6818 | ExprValueMap.clear(); | ||||||
6819 | HasRecMap.clear(); | ||||||
6820 | MinTrailingZerosCache.clear(); | ||||||
6821 | PredicatedSCEVRewrites.clear(); | ||||||
6822 | } | ||||||
6823 | |||||||
6824 | void ScalarEvolution::forgetLoop(const Loop *L) { | ||||||
6825 | // Drop any stored trip count value. | ||||||
6826 | auto RemoveLoopFromBackedgeMap = | ||||||
6827 | [](DenseMap<const Loop *, BackedgeTakenInfo> &Map, const Loop *L) { | ||||||
6828 | auto BTCPos = Map.find(L); | ||||||
6829 | if (BTCPos != Map.end()) { | ||||||
6830 | BTCPos->second.clear(); | ||||||
6831 | Map.erase(BTCPos); | ||||||
6832 | } | ||||||
6833 | }; | ||||||
6834 | |||||||
6835 | SmallVector<const Loop *, 16> LoopWorklist(1, L); | ||||||
6836 | SmallVector<Instruction *, 32> Worklist; | ||||||
6837 | SmallPtrSet<Instruction *, 16> Visited; | ||||||
6838 | |||||||
6839 | // Iterate over all the loops and sub-loops to drop SCEV information. | ||||||
6840 | while (!LoopWorklist.empty()) { | ||||||
6841 | auto *CurrL = LoopWorklist.pop_back_val(); | ||||||
6842 | |||||||
6843 | RemoveLoopFromBackedgeMap(BackedgeTakenCounts, CurrL); | ||||||
6844 | RemoveLoopFromBackedgeMap(PredicatedBackedgeTakenCounts, CurrL); | ||||||
6845 | |||||||
6846 | // Drop information about predicated SCEV rewrites for this loop. | ||||||
6847 | for (auto I = PredicatedSCEVRewrites.begin(); | ||||||
6848 | I != PredicatedSCEVRewrites.end();) { | ||||||
6849 | std::pair<const SCEV *, const Loop *> Entry = I->first; | ||||||
6850 | if (Entry.second == CurrL) | ||||||
6851 | PredicatedSCEVRewrites.erase(I++); | ||||||
6852 | else | ||||||
6853 | ++I; | ||||||
6854 | } | ||||||
6855 | |||||||
6856 | auto LoopUsersItr = LoopUsers.find(CurrL); | ||||||
6857 | if (LoopUsersItr != LoopUsers.end()) { | ||||||
6858 | for (auto *S : LoopUsersItr->second) | ||||||
6859 | forgetMemoizedResults(S); | ||||||
6860 | LoopUsers.erase(LoopUsersItr); | ||||||
6861 | } | ||||||
6862 | |||||||
6863 | // Drop information about expressions based on loop-header PHIs. | ||||||
6864 | PushLoopPHIs(CurrL, Worklist); | ||||||
6865 | |||||||
6866 | while (!Worklist.empty()) { | ||||||
6867 | Instruction *I = Worklist.pop_back_val(); | ||||||
6868 | if (!Visited.insert(I).second) | ||||||
6869 | continue; | ||||||
6870 | |||||||
6871 | ValueExprMapType::iterator It = | ||||||
6872 | ValueExprMap.find_as(static_cast<Value *>(I)); | ||||||
6873 | if (It != ValueExprMap.end()) { | ||||||
6874 | eraseValueFromMap(It->first); | ||||||
6875 | forgetMemoizedResults(It->second); | ||||||
6876 | if (PHINode *PN = dyn_cast<PHINode>(I)) | ||||||
6877 | ConstantEvolutionLoopExitValue.erase(PN); | ||||||
6878 | } | ||||||
6879 | |||||||
6880 | PushDefUseChildren(I, Worklist); | ||||||
6881 | } | ||||||
6882 | |||||||
6883 | LoopPropertiesCache.erase(CurrL); | ||||||
6884 | // Forget all contained loops too, to avoid dangling entries in the | ||||||
6885 | // ValuesAtScopes map. | ||||||
6886 | LoopWorklist.append(CurrL->begin(), CurrL->end()); | ||||||
6887 | } | ||||||
6888 | } | ||||||
6889 | |||||||
6890 | void ScalarEvolution::forgetTopmostLoop(const Loop *L) { | ||||||
6891 | while (Loop *Parent = L->getParentLoop()) | ||||||
6892 | L = Parent; | ||||||
6893 | forgetLoop(L); | ||||||
6894 | } | ||||||
6895 | |||||||
6896 | void ScalarEvolution::forgetValue(Value *V) { | ||||||
6897 | Instruction *I = dyn_cast<Instruction>(V); | ||||||
6898 | if (!I) return; | ||||||
6899 | |||||||
6900 | // Drop information about expressions based on loop-header PHIs. | ||||||
6901 | SmallVector<Instruction *, 16> Worklist; | ||||||
6902 | Worklist.push_back(I); | ||||||
6903 | |||||||
6904 | SmallPtrSet<Instruction *, 8> Visited; | ||||||
6905 | while (!Worklist.empty()) { | ||||||
6906 | I = Worklist.pop_back_val(); | ||||||
6907 | if (!Visited.insert(I).second) | ||||||
6908 | continue; | ||||||
6909 | |||||||
6910 | ValueExprMapType::iterator It = | ||||||
6911 | ValueExprMap.find_as(static_cast<Value *>(I)); | ||||||
6912 | if (It != ValueExprMap.end()) { | ||||||
6913 | eraseValueFromMap(It->first); | ||||||
6914 | forgetMemoizedResults(It->second); | ||||||
6915 | if (PHINode *PN = dyn_cast<PHINode>(I)) | ||||||
6916 | ConstantEvolutionLoopExitValue.erase(PN); | ||||||
6917 | } | ||||||
6918 | |||||||
6919 | PushDefUseChildren(I, Worklist); | ||||||
6920 | } | ||||||
6921 | } | ||||||
6922 | |||||||
6923 | /// Get the exact loop backedge taken count considering all loop exits. A | ||||||
6924 | /// computable result can only be returned for loops with all exiting blocks | ||||||
6925 | /// dominating the latch. howFarToZero assumes that the limit of each loop test | ||||||
6926 | /// is never skipped. This is a valid assumption as long as the loop exits via | ||||||
6927 | /// that test. For precise results, it is the caller's responsibility to specify | ||||||
6928 | /// the relevant loop exiting block using getExact(ExitingBlock, SE). | ||||||
6929 | const SCEV * | ||||||
6930 | ScalarEvolution::BackedgeTakenInfo::getExact(const Loop *L, ScalarEvolution *SE, | ||||||
6931 | SCEVUnionPredicate *Preds) const { | ||||||
6932 | // If any exits were not computable, the loop is not computable. | ||||||
6933 | if (!isComplete() || ExitNotTaken.empty()) | ||||||
6934 | return SE->getCouldNotCompute(); | ||||||
6935 | |||||||
6936 | const BasicBlock *Latch = L->getLoopLatch(); | ||||||
6937 | // All exiting blocks we have collected must dominate the only backedge. | ||||||
6938 | if (!Latch) | ||||||
6939 | return SE->getCouldNotCompute(); | ||||||
6940 | |||||||
6941 | // All exiting blocks we have gathered dominate loop's latch, so exact trip | ||||||
6942 | // count is simply a minimum out of all these calculated exit counts. | ||||||
6943 | SmallVector<const SCEV *, 2> Ops; | ||||||
6944 | for (auto &ENT : ExitNotTaken) { | ||||||
6945 | const SCEV *BECount = ENT.ExactNotTaken; | ||||||
6946 | assert(BECount != SE->getCouldNotCompute() && "Bad exit SCEV!")((BECount != SE->getCouldNotCompute() && "Bad exit SCEV!" ) ? static_cast<void> (0) : __assert_fail ("BECount != SE->getCouldNotCompute() && \"Bad exit SCEV!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6946, __PRETTY_FUNCTION__)); | ||||||
6947 | assert(SE->DT.dominates(ENT.ExitingBlock, Latch) &&((SE->DT.dominates(ENT.ExitingBlock, Latch) && "We should only have known counts for exiting blocks that dominate " "latch!") ? static_cast<void> (0) : __assert_fail ("SE->DT.dominates(ENT.ExitingBlock, Latch) && \"We should only have known counts for exiting blocks that dominate \" \"latch!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6949, __PRETTY_FUNCTION__)) | ||||||
6948 | "We should only have known counts for exiting blocks that dominate "((SE->DT.dominates(ENT.ExitingBlock, Latch) && "We should only have known counts for exiting blocks that dominate " "latch!") ? static_cast<void> (0) : __assert_fail ("SE->DT.dominates(ENT.ExitingBlock, Latch) && \"We should only have known counts for exiting blocks that dominate \" \"latch!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6949, __PRETTY_FUNCTION__)) | ||||||
6949 | "latch!")((SE->DT.dominates(ENT.ExitingBlock, Latch) && "We should only have known counts for exiting blocks that dominate " "latch!") ? static_cast<void> (0) : __assert_fail ("SE->DT.dominates(ENT.ExitingBlock, Latch) && \"We should only have known counts for exiting blocks that dominate \" \"latch!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6949, __PRETTY_FUNCTION__)); | ||||||
6950 | |||||||
6951 | Ops.push_back(BECount); | ||||||
6952 | |||||||
6953 | if (Preds && !ENT.hasAlwaysTruePredicate()) | ||||||
6954 | Preds->add(ENT.Predicate.get()); | ||||||
6955 | |||||||
6956 | assert((Preds || ENT.hasAlwaysTruePredicate()) &&(((Preds || ENT.hasAlwaysTruePredicate()) && "Predicate should be always true!" ) ? static_cast<void> (0) : __assert_fail ("(Preds || ENT.hasAlwaysTruePredicate()) && \"Predicate should be always true!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6957, __PRETTY_FUNCTION__)) | ||||||
6957 | "Predicate should be always true!")(((Preds || ENT.hasAlwaysTruePredicate()) && "Predicate should be always true!" ) ? static_cast<void> (0) : __assert_fail ("(Preds || ENT.hasAlwaysTruePredicate()) && \"Predicate should be always true!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6957, __PRETTY_FUNCTION__)); | ||||||
6958 | } | ||||||
6959 | |||||||
6960 | return SE->getUMinFromMismatchedTypes(Ops); | ||||||
6961 | } | ||||||
6962 | |||||||
6963 | /// Get the exact not taken count for this loop exit. | ||||||
6964 | const SCEV * | ||||||
6965 | ScalarEvolution::BackedgeTakenInfo::getExact(BasicBlock *ExitingBlock, | ||||||
6966 | ScalarEvolution *SE) const { | ||||||
6967 | for (auto &ENT : ExitNotTaken) | ||||||
6968 | if (ENT.ExitingBlock == ExitingBlock && ENT.hasAlwaysTruePredicate()) | ||||||
6969 | return ENT.ExactNotTaken; | ||||||
6970 | |||||||
6971 | return SE->getCouldNotCompute(); | ||||||
6972 | } | ||||||
6973 | |||||||
6974 | const SCEV * | ||||||
6975 | ScalarEvolution::BackedgeTakenInfo::getMax(BasicBlock *ExitingBlock, | ||||||
6976 | ScalarEvolution *SE) const { | ||||||
6977 | for (auto &ENT : ExitNotTaken) | ||||||
6978 | if (ENT.ExitingBlock == ExitingBlock && ENT.hasAlwaysTruePredicate()) | ||||||
6979 | return ENT.MaxNotTaken; | ||||||
6980 | |||||||
6981 | return SE->getCouldNotCompute(); | ||||||
6982 | } | ||||||
6983 | |||||||
6984 | /// getMax - Get the max backedge taken count for the loop. | ||||||
6985 | const SCEV * | ||||||
6986 | ScalarEvolution::BackedgeTakenInfo::getMax(ScalarEvolution *SE) const { | ||||||
6987 | auto PredicateNotAlwaysTrue = [](const ExitNotTakenInfo &ENT) { | ||||||
6988 | return !ENT.hasAlwaysTruePredicate(); | ||||||
6989 | }; | ||||||
6990 | |||||||
6991 | if (any_of(ExitNotTaken, PredicateNotAlwaysTrue) || !getMax()) | ||||||
6992 | return SE->getCouldNotCompute(); | ||||||
6993 | |||||||
6994 | assert((isa<SCEVCouldNotCompute>(getMax()) || isa<SCEVConstant>(getMax())) &&(((isa<SCEVCouldNotCompute>(getMax()) || isa<SCEVConstant >(getMax())) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(getMax()) || isa<SCEVConstant>(getMax())) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6995, __PRETTY_FUNCTION__)) | ||||||
6995 | "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(getMax()) || isa<SCEVConstant >(getMax())) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(getMax()) || isa<SCEVConstant>(getMax())) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 6995, __PRETTY_FUNCTION__)); | ||||||
6996 | return getMax(); | ||||||
6997 | } | ||||||
6998 | |||||||
6999 | bool ScalarEvolution::BackedgeTakenInfo::isMaxOrZero(ScalarEvolution *SE) const { | ||||||
7000 | auto PredicateNotAlwaysTrue = [](const ExitNotTakenInfo &ENT) { | ||||||
7001 | return !ENT.hasAlwaysTruePredicate(); | ||||||
7002 | }; | ||||||
7003 | return MaxOrZero && !any_of(ExitNotTaken, PredicateNotAlwaysTrue); | ||||||
7004 | } | ||||||
7005 | |||||||
7006 | bool ScalarEvolution::BackedgeTakenInfo::hasOperand(const SCEV *S, | ||||||
7007 | ScalarEvolution *SE) const { | ||||||
7008 | if (getMax() && getMax() != SE->getCouldNotCompute() && | ||||||
7009 | SE->hasOperand(getMax(), S)) | ||||||
7010 | return true; | ||||||
7011 | |||||||
7012 | for (auto &ENT : ExitNotTaken) | ||||||
7013 | if (ENT.ExactNotTaken != SE->getCouldNotCompute() && | ||||||
7014 | SE->hasOperand(ENT.ExactNotTaken, S)) | ||||||
7015 | return true; | ||||||
7016 | |||||||
7017 | return false; | ||||||
7018 | } | ||||||
7019 | |||||||
7020 | ScalarEvolution::ExitLimit::ExitLimit(const SCEV *E) | ||||||
7021 | : ExactNotTaken(E), MaxNotTaken(E) { | ||||||
7022 | assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7024, __PRETTY_FUNCTION__)) | ||||||
7023 | isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7024, __PRETTY_FUNCTION__)) | ||||||
7024 | "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7024, __PRETTY_FUNCTION__)); | ||||||
7025 | } | ||||||
7026 | |||||||
7027 | ScalarEvolution::ExitLimit::ExitLimit( | ||||||
7028 | const SCEV *E, const SCEV *M, bool MaxOrZero, | ||||||
7029 | ArrayRef<const SmallPtrSetImpl<const SCEVPredicate *> *> PredSetList) | ||||||
7030 | : ExactNotTaken(E), MaxNotTaken(M), MaxOrZero(MaxOrZero) { | ||||||
7031 | assert((isa<SCEVCouldNotCompute>(ExactNotTaken) ||(((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute >(MaxNotTaken)) && "Exact is not allowed to be less precise than Max" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken)) && \"Exact is not allowed to be less precise than Max\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7033, __PRETTY_FUNCTION__)) | ||||||
7032 | !isa<SCEVCouldNotCompute>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute >(MaxNotTaken)) && "Exact is not allowed to be less precise than Max" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken)) && \"Exact is not allowed to be less precise than Max\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7033, __PRETTY_FUNCTION__)) | ||||||
7033 | "Exact is not allowed to be less precise than Max")(((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute >(MaxNotTaken)) && "Exact is not allowed to be less precise than Max" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken)) && \"Exact is not allowed to be less precise than Max\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7033, __PRETTY_FUNCTION__)); | ||||||
7034 | assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7036, __PRETTY_FUNCTION__)) | ||||||
7035 | isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7036, __PRETTY_FUNCTION__)) | ||||||
7036 | "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7036, __PRETTY_FUNCTION__)); | ||||||
7037 | for (auto *PredSet : PredSetList) | ||||||
7038 | for (auto *P : *PredSet) | ||||||
7039 | addPredicate(P); | ||||||
7040 | } | ||||||
7041 | |||||||
7042 | ScalarEvolution::ExitLimit::ExitLimit( | ||||||
7043 | const SCEV *E, const SCEV *M, bool MaxOrZero, | ||||||
7044 | const SmallPtrSetImpl<const SCEVPredicate *> &PredSet) | ||||||
7045 | : ExitLimit(E, M, MaxOrZero, {&PredSet}) { | ||||||
7046 | assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7048, __PRETTY_FUNCTION__)) | ||||||
7047 | isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7048, __PRETTY_FUNCTION__)) | ||||||
7048 | "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7048, __PRETTY_FUNCTION__)); | ||||||
7049 | } | ||||||
7050 | |||||||
7051 | ScalarEvolution::ExitLimit::ExitLimit(const SCEV *E, const SCEV *M, | ||||||
7052 | bool MaxOrZero) | ||||||
7053 | : ExitLimit(E, M, MaxOrZero, None) { | ||||||
7054 | assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7056, __PRETTY_FUNCTION__)) | ||||||
7055 | isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7056, __PRETTY_FUNCTION__)) | ||||||
7056 | "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant >(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7056, __PRETTY_FUNCTION__)); | ||||||
7057 | } | ||||||
7058 | |||||||
7059 | /// Allocate memory for BackedgeTakenInfo and copy the not-taken count of each | ||||||
7060 | /// computable exit into a persistent ExitNotTakenInfo array. | ||||||
7061 | ScalarEvolution::BackedgeTakenInfo::BackedgeTakenInfo( | ||||||
7062 | ArrayRef<ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo> | ||||||
7063 | ExitCounts, | ||||||
7064 | bool Complete, const SCEV *MaxCount, bool MaxOrZero) | ||||||
7065 | : MaxAndComplete(MaxCount, Complete), MaxOrZero(MaxOrZero) { | ||||||
7066 | using EdgeExitInfo = ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo; | ||||||
7067 | |||||||
7068 | ExitNotTaken.reserve(ExitCounts.size()); | ||||||
7069 | std::transform( | ||||||
7070 | ExitCounts.begin(), ExitCounts.end(), std::back_inserter(ExitNotTaken), | ||||||
7071 | [&](const EdgeExitInfo &EEI) { | ||||||
7072 | BasicBlock *ExitBB = EEI.first; | ||||||
7073 | const ExitLimit &EL = EEI.second; | ||||||
7074 | if (EL.Predicates.empty()) | ||||||
7075 | return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, EL.MaxNotTaken, | ||||||
7076 | nullptr); | ||||||
7077 | |||||||
7078 | std::unique_ptr<SCEVUnionPredicate> Predicate(new SCEVUnionPredicate); | ||||||
7079 | for (auto *Pred : EL.Predicates) | ||||||
7080 | Predicate->add(Pred); | ||||||
7081 | |||||||
7082 | return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, EL.MaxNotTaken, | ||||||
7083 | std::move(Predicate)); | ||||||
7084 | }); | ||||||
7085 | assert((isa<SCEVCouldNotCompute>(MaxCount) || isa<SCEVConstant>(MaxCount)) &&(((isa<SCEVCouldNotCompute>(MaxCount) || isa<SCEVConstant >(MaxCount)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxCount) || isa<SCEVConstant>(MaxCount)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7086, __PRETTY_FUNCTION__)) | ||||||
7086 | "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxCount) || isa<SCEVConstant >(MaxCount)) && "No point in having a non-constant max backedge taken count!" ) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxCount) || isa<SCEVConstant>(MaxCount)) && \"No point in having a non-constant max backedge taken count!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7086, __PRETTY_FUNCTION__)); | ||||||
7087 | } | ||||||
7088 | |||||||
7089 | /// Invalidate this result and free the ExitNotTakenInfo array. | ||||||
7090 | void ScalarEvolution::BackedgeTakenInfo::clear() { | ||||||
7091 | ExitNotTaken.clear(); | ||||||
7092 | } | ||||||
7093 | |||||||
7094 | /// Compute the number of times the backedge of the specified loop will execute. | ||||||
7095 | ScalarEvolution::BackedgeTakenInfo | ||||||
7096 | ScalarEvolution::computeBackedgeTakenCount(const Loop *L, | ||||||
7097 | bool AllowPredicates) { | ||||||
7098 | SmallVector<BasicBlock *, 8> ExitingBlocks; | ||||||
7099 | L->getExitingBlocks(ExitingBlocks); | ||||||
7100 | |||||||
7101 | using EdgeExitInfo = ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo; | ||||||
7102 | |||||||
7103 | SmallVector<EdgeExitInfo, 4> ExitCounts; | ||||||
7104 | bool CouldComputeBECount = true; | ||||||
7105 | BasicBlock *Latch = L->getLoopLatch(); // may be NULL. | ||||||
7106 | const SCEV *MustExitMaxBECount = nullptr; | ||||||
7107 | const SCEV *MayExitMaxBECount = nullptr; | ||||||
7108 | bool MustExitMaxOrZero = false; | ||||||
7109 | |||||||
7110 | // Compute the ExitLimit for each loop exit. Use this to populate ExitCounts | ||||||
7111 | // and compute maxBECount. | ||||||
7112 | // Do a union of all the predicates here. | ||||||
7113 | for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) { | ||||||
7114 | BasicBlock *ExitBB = ExitingBlocks[i]; | ||||||
7115 | |||||||
7116 | // We canonicalize untaken exits to br (constant), ignore them so that | ||||||
7117 | // proving an exit untaken doesn't negatively impact our ability to reason | ||||||
7118 | // about the loop as whole. | ||||||
7119 | if (auto *BI = dyn_cast<BranchInst>(ExitBB->getTerminator())) | ||||||
7120 | if (auto *CI = dyn_cast<ConstantInt>(BI->getCondition())) { | ||||||
7121 | bool ExitIfTrue = !L->contains(BI->getSuccessor(0)); | ||||||
7122 | if ((ExitIfTrue && CI->isZero()) || (!ExitIfTrue && CI->isOne())) | ||||||
7123 | continue; | ||||||
7124 | } | ||||||
7125 | |||||||
7126 | ExitLimit EL = computeExitLimit(L, ExitBB, AllowPredicates); | ||||||
7127 | |||||||
7128 | assert((AllowPredicates || EL.Predicates.empty()) &&(((AllowPredicates || EL.Predicates.empty()) && "Predicated exit limit when predicates are not allowed!" ) ? static_cast<void> (0) : __assert_fail ("(AllowPredicates || EL.Predicates.empty()) && \"Predicated exit limit when predicates are not allowed!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7129, __PRETTY_FUNCTION__)) | ||||||
7129 | "Predicated exit limit when predicates are not allowed!")(((AllowPredicates || EL.Predicates.empty()) && "Predicated exit limit when predicates are not allowed!" ) ? static_cast<void> (0) : __assert_fail ("(AllowPredicates || EL.Predicates.empty()) && \"Predicated exit limit when predicates are not allowed!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7129, __PRETTY_FUNCTION__)); | ||||||
7130 | |||||||
7131 | // 1. For each exit that can be computed, add an entry to ExitCounts. | ||||||
7132 | // CouldComputeBECount is true only if all exits can be computed. | ||||||
7133 | if (EL.ExactNotTaken == getCouldNotCompute()) | ||||||
7134 | // We couldn't compute an exact value for this exit, so | ||||||
7135 | // we won't be able to compute an exact value for the loop. | ||||||
7136 | CouldComputeBECount = false; | ||||||
7137 | else | ||||||
7138 | ExitCounts.emplace_back(ExitBB, EL); | ||||||
7139 | |||||||
7140 | // 2. Derive the loop's MaxBECount from each exit's max number of | ||||||
7141 | // non-exiting iterations. Partition the loop exits into two kinds: | ||||||
7142 | // LoopMustExits and LoopMayExits. | ||||||
7143 | // | ||||||
7144 | // If the exit dominates the loop latch, it is a LoopMustExit otherwise it | ||||||
7145 | // is a LoopMayExit. If any computable LoopMustExit is found, then | ||||||
7146 | // MaxBECount is the minimum EL.MaxNotTaken of computable | ||||||
7147 | // LoopMustExits. Otherwise, MaxBECount is conservatively the maximum | ||||||
7148 | // EL.MaxNotTaken, where CouldNotCompute is considered greater than any | ||||||
7149 | // computable EL.MaxNotTaken. | ||||||
7150 | if (EL.MaxNotTaken != getCouldNotCompute() && Latch && | ||||||
7151 | DT.dominates(ExitBB, Latch)) { | ||||||
7152 | if (!MustExitMaxBECount) { | ||||||
7153 | MustExitMaxBECount = EL.MaxNotTaken; | ||||||
7154 | MustExitMaxOrZero = EL.MaxOrZero; | ||||||
7155 | } else { | ||||||
7156 | MustExitMaxBECount = | ||||||
7157 | getUMinFromMismatchedTypes(MustExitMaxBECount, EL.MaxNotTaken); | ||||||
7158 | } | ||||||
7159 | } else if (MayExitMaxBECount != getCouldNotCompute()) { | ||||||
7160 | if (!MayExitMaxBECount || EL.MaxNotTaken == getCouldNotCompute()) | ||||||
7161 | MayExitMaxBECount = EL.MaxNotTaken; | ||||||
7162 | else { | ||||||
7163 | MayExitMaxBECount = | ||||||
7164 | getUMaxFromMismatchedTypes(MayExitMaxBECount, EL.MaxNotTaken); | ||||||
7165 | } | ||||||
7166 | } | ||||||
7167 | } | ||||||
7168 | const SCEV *MaxBECount = MustExitMaxBECount ? MustExitMaxBECount : | ||||||
7169 | (MayExitMaxBECount ? MayExitMaxBECount : getCouldNotCompute()); | ||||||
7170 | // The loop backedge will be taken the maximum or zero times if there's | ||||||
7171 | // a single exit that must be taken the maximum or zero times. | ||||||
7172 | bool MaxOrZero = (MustExitMaxOrZero && ExitingBlocks.size() == 1); | ||||||
7173 | return BackedgeTakenInfo(std::move(ExitCounts), CouldComputeBECount, | ||||||
7174 | MaxBECount, MaxOrZero); | ||||||
7175 | } | ||||||
7176 | |||||||
7177 | ScalarEvolution::ExitLimit | ||||||
7178 | ScalarEvolution::computeExitLimit(const Loop *L, BasicBlock *ExitingBlock, | ||||||
7179 | bool AllowPredicates) { | ||||||
7180 | assert(L->contains(ExitingBlock) && "Exit count for non-loop block?")((L->contains(ExitingBlock) && "Exit count for non-loop block?" ) ? static_cast<void> (0) : __assert_fail ("L->contains(ExitingBlock) && \"Exit count for non-loop block?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7180, __PRETTY_FUNCTION__)); | ||||||
7181 | // If our exiting block does not dominate the latch, then its connection with | ||||||
7182 | // loop's exit limit may be far from trivial. | ||||||
7183 | const BasicBlock *Latch = L->getLoopLatch(); | ||||||
7184 | if (!Latch || !DT.dominates(ExitingBlock, Latch)) | ||||||
7185 | return getCouldNotCompute(); | ||||||
7186 | |||||||
7187 | bool IsOnlyExit = (L->getExitingBlock() != nullptr); | ||||||
7188 | Instruction *Term = ExitingBlock->getTerminator(); | ||||||
7189 | if (BranchInst *BI = dyn_cast<BranchInst>(Term)) { | ||||||
7190 | assert(BI->isConditional() && "If unconditional, it can't be in loop!")((BI->isConditional() && "If unconditional, it can't be in loop!" ) ? static_cast<void> (0) : __assert_fail ("BI->isConditional() && \"If unconditional, it can't be in loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7190, __PRETTY_FUNCTION__)); | ||||||
7191 | bool ExitIfTrue = !L->contains(BI->getSuccessor(0)); | ||||||
7192 | assert(ExitIfTrue == L->contains(BI->getSuccessor(1)) &&((ExitIfTrue == L->contains(BI->getSuccessor(1)) && "It should have one successor in loop and one exit block!") ? static_cast<void> (0) : __assert_fail ("ExitIfTrue == L->contains(BI->getSuccessor(1)) && \"It should have one successor in loop and one exit block!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7193, __PRETTY_FUNCTION__)) | ||||||
7193 | "It should have one successor in loop and one exit block!")((ExitIfTrue == L->contains(BI->getSuccessor(1)) && "It should have one successor in loop and one exit block!") ? static_cast<void> (0) : __assert_fail ("ExitIfTrue == L->contains(BI->getSuccessor(1)) && \"It should have one successor in loop and one exit block!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7193, __PRETTY_FUNCTION__)); | ||||||
7194 | // Proceed to the next level to examine the exit condition expression. | ||||||
7195 | return computeExitLimitFromCond( | ||||||
7196 | L, BI->getCondition(), ExitIfTrue, | ||||||
7197 | /*ControlsExit=*/IsOnlyExit, AllowPredicates); | ||||||
7198 | } | ||||||
7199 | |||||||
7200 | if (SwitchInst *SI = dyn_cast<SwitchInst>(Term)) { | ||||||
7201 | // For switch, make sure that there is a single exit from the loop. | ||||||
7202 | BasicBlock *Exit = nullptr; | ||||||
7203 | for (auto *SBB : successors(ExitingBlock)) | ||||||
7204 | if (!L->contains(SBB)) { | ||||||
7205 | if (Exit) // Multiple exit successors. | ||||||
7206 | return getCouldNotCompute(); | ||||||
7207 | Exit = SBB; | ||||||
7208 | } | ||||||
7209 | assert(Exit && "Exiting block must have at least one exit")((Exit && "Exiting block must have at least one exit" ) ? static_cast<void> (0) : __assert_fail ("Exit && \"Exiting block must have at least one exit\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7209, __PRETTY_FUNCTION__)); | ||||||
7210 | return computeExitLimitFromSingleExitSwitch(L, SI, Exit, | ||||||
7211 | /*ControlsExit=*/IsOnlyExit); | ||||||
7212 | } | ||||||
7213 | |||||||
7214 | return getCouldNotCompute(); | ||||||
7215 | } | ||||||
7216 | |||||||
7217 | ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCond( | ||||||
7218 | const Loop *L, Value *ExitCond, bool ExitIfTrue, | ||||||
7219 | bool ControlsExit, bool AllowPredicates) { | ||||||
7220 | ScalarEvolution::ExitLimitCacheTy Cache(L, ExitIfTrue, AllowPredicates); | ||||||
7221 | return computeExitLimitFromCondCached(Cache, L, ExitCond, ExitIfTrue, | ||||||
7222 | ControlsExit, AllowPredicates); | ||||||
7223 | } | ||||||
7224 | |||||||
7225 | Optional<ScalarEvolution::ExitLimit> | ||||||
7226 | ScalarEvolution::ExitLimitCache::find(const Loop *L, Value *ExitCond, | ||||||
7227 | bool ExitIfTrue, bool ControlsExit, | ||||||
7228 | bool AllowPredicates) { | ||||||
7229 | (void)this->L; | ||||||
7230 | (void)this->ExitIfTrue; | ||||||
7231 | (void)this->AllowPredicates; | ||||||
7232 | |||||||
7233 | assert(this->L == L && this->ExitIfTrue == ExitIfTrue &&((this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && "Variance in assumed invariant key components!") ? static_cast <void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7235, __PRETTY_FUNCTION__)) | ||||||
7234 | this->AllowPredicates == AllowPredicates &&((this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && "Variance in assumed invariant key components!") ? static_cast <void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7235, __PRETTY_FUNCTION__)) | ||||||
7235 | "Variance in assumed invariant key components!")((this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && "Variance in assumed invariant key components!") ? static_cast <void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7235, __PRETTY_FUNCTION__)); | ||||||
7236 | auto Itr = TripCountMap.find({ExitCond, ControlsExit}); | ||||||
7237 | if (Itr == TripCountMap.end()) | ||||||
7238 | return None; | ||||||
7239 | return Itr->second; | ||||||
7240 | } | ||||||
7241 | |||||||
7242 | void ScalarEvolution::ExitLimitCache::insert(const Loop *L, Value *ExitCond, | ||||||
7243 | bool ExitIfTrue, | ||||||
7244 | bool ControlsExit, | ||||||
7245 | bool AllowPredicates, | ||||||
7246 | const ExitLimit &EL) { | ||||||
7247 | assert(this->L == L && this->ExitIfTrue == ExitIfTrue &&((this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && "Variance in assumed invariant key components!") ? static_cast <void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7249, __PRETTY_FUNCTION__)) | ||||||
7248 | this->AllowPredicates == AllowPredicates &&((this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && "Variance in assumed invariant key components!") ? static_cast <void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7249, __PRETTY_FUNCTION__)) | ||||||
7249 | "Variance in assumed invariant key components!")((this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && "Variance in assumed invariant key components!") ? static_cast <void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7249, __PRETTY_FUNCTION__)); | ||||||
7250 | |||||||
7251 | auto InsertResult = TripCountMap.insert({{ExitCond, ControlsExit}, EL}); | ||||||
7252 | assert(InsertResult.second && "Expected successful insertion!")((InsertResult.second && "Expected successful insertion!" ) ? static_cast<void> (0) : __assert_fail ("InsertResult.second && \"Expected successful insertion!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7252, __PRETTY_FUNCTION__)); | ||||||
7253 | (void)InsertResult; | ||||||
7254 | (void)ExitIfTrue; | ||||||
7255 | } | ||||||
7256 | |||||||
7257 | ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCondCached( | ||||||
7258 | ExitLimitCacheTy &Cache, const Loop *L, Value *ExitCond, bool ExitIfTrue, | ||||||
7259 | bool ControlsExit, bool AllowPredicates) { | ||||||
7260 | |||||||
7261 | if (auto MaybeEL = | ||||||
7262 | Cache.find(L, ExitCond, ExitIfTrue, ControlsExit, AllowPredicates)) | ||||||
7263 | return *MaybeEL; | ||||||
7264 | |||||||
7265 | ExitLimit EL = computeExitLimitFromCondImpl(Cache, L, ExitCond, ExitIfTrue, | ||||||
7266 | ControlsExit, AllowPredicates); | ||||||
7267 | Cache.insert(L, ExitCond, ExitIfTrue, ControlsExit, AllowPredicates, EL); | ||||||
7268 | return EL; | ||||||
7269 | } | ||||||
7270 | |||||||
7271 | ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCondImpl( | ||||||
7272 | ExitLimitCacheTy &Cache, const Loop *L, Value *ExitCond, bool ExitIfTrue, | ||||||
7273 | bool ControlsExit, bool AllowPredicates) { | ||||||
7274 | // Check if the controlling expression for this loop is an And or Or. | ||||||
7275 | if (BinaryOperator *BO = dyn_cast<BinaryOperator>(ExitCond)) { | ||||||
7276 | if (BO->getOpcode() == Instruction::And) { | ||||||
7277 | // Recurse on the operands of the and. | ||||||
7278 | bool EitherMayExit = !ExitIfTrue; | ||||||
7279 | ExitLimit EL0 = computeExitLimitFromCondCached( | ||||||
7280 | Cache, L, BO->getOperand(0), ExitIfTrue, | ||||||
7281 | ControlsExit && !EitherMayExit, AllowPredicates); | ||||||
7282 | ExitLimit EL1 = computeExitLimitFromCondCached( | ||||||
7283 | Cache, L, BO->getOperand(1), ExitIfTrue, | ||||||
7284 | ControlsExit && !EitherMayExit, AllowPredicates); | ||||||
7285 | // Be robust against unsimplified IR for the form "and i1 X, true" | ||||||
7286 | if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1))) | ||||||
7287 | return CI->isOne() ? EL0 : EL1; | ||||||
7288 | if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(0))) | ||||||
7289 | return CI->isOne() ? EL1 : EL0; | ||||||
7290 | const SCEV *BECount = getCouldNotCompute(); | ||||||
7291 | const SCEV *MaxBECount = getCouldNotCompute(); | ||||||
7292 | if (EitherMayExit) { | ||||||
7293 | // Both conditions must be true for the loop to continue executing. | ||||||
7294 | // Choose the less conservative count. | ||||||
7295 | if (EL0.ExactNotTaken == getCouldNotCompute() || | ||||||
7296 | EL1.ExactNotTaken == getCouldNotCompute()) | ||||||
7297 | BECount = getCouldNotCompute(); | ||||||
7298 | else | ||||||
7299 | BECount = | ||||||
7300 | getUMinFromMismatchedTypes(EL0.ExactNotTaken, EL1.ExactNotTaken); | ||||||
7301 | if (EL0.MaxNotTaken == getCouldNotCompute()) | ||||||
7302 | MaxBECount = EL1.MaxNotTaken; | ||||||
7303 | else if (EL1.MaxNotTaken == getCouldNotCompute()) | ||||||
7304 | MaxBECount = EL0.MaxNotTaken; | ||||||
7305 | else | ||||||
7306 | MaxBECount = | ||||||
7307 | getUMinFromMismatchedTypes(EL0.MaxNotTaken, EL1.MaxNotTaken); | ||||||
7308 | } else { | ||||||
7309 | // Both conditions must be true at the same time for the loop to exit. | ||||||
7310 | // For now, be conservative. | ||||||
7311 | if (EL0.MaxNotTaken == EL1.MaxNotTaken) | ||||||
7312 | MaxBECount = EL0.MaxNotTaken; | ||||||
7313 | if (EL0.ExactNotTaken == EL1.ExactNotTaken) | ||||||
7314 | BECount = EL0.ExactNotTaken; | ||||||
7315 | } | ||||||
7316 | |||||||
7317 | // There are cases (e.g. PR26207) where computeExitLimitFromCond is able | ||||||
7318 | // to be more aggressive when computing BECount than when computing | ||||||
7319 | // MaxBECount. In these cases it is possible for EL0.ExactNotTaken and | ||||||
7320 | // EL1.ExactNotTaken to match, but for EL0.MaxNotTaken and EL1.MaxNotTaken | ||||||
7321 | // to not. | ||||||
7322 | if (isa<SCEVCouldNotCompute>(MaxBECount) && | ||||||
7323 | !isa<SCEVCouldNotCompute>(BECount)) | ||||||
7324 | MaxBECount = getConstant(getUnsignedRangeMax(BECount)); | ||||||
7325 | |||||||
7326 | return ExitLimit(BECount, MaxBECount, false, | ||||||
7327 | {&EL0.Predicates, &EL1.Predicates}); | ||||||
7328 | } | ||||||
7329 | if (BO->getOpcode() == Instruction::Or) { | ||||||
7330 | // Recurse on the operands of the or. | ||||||
7331 | bool EitherMayExit = ExitIfTrue; | ||||||
7332 | ExitLimit EL0 = computeExitLimitFromCondCached( | ||||||
7333 | Cache, L, BO->getOperand(0), ExitIfTrue, | ||||||
7334 | ControlsExit && !EitherMayExit, AllowPredicates); | ||||||
7335 | ExitLimit EL1 = computeExitLimitFromCondCached( | ||||||
7336 | Cache, L, BO->getOperand(1), ExitIfTrue, | ||||||
7337 | ControlsExit && !EitherMayExit, AllowPredicates); | ||||||
7338 | // Be robust against unsimplified IR for the form "or i1 X, true" | ||||||
7339 | if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1))) | ||||||
7340 | return CI->isZero() ? EL0 : EL1; | ||||||
7341 | if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(0))) | ||||||
7342 | return CI->isZero() ? EL1 : EL0; | ||||||
7343 | const SCEV *BECount = getCouldNotCompute(); | ||||||
7344 | const SCEV *MaxBECount = getCouldNotCompute(); | ||||||
7345 | if (EitherMayExit) { | ||||||
7346 | // Both conditions must be false for the loop to continue executing. | ||||||
7347 | // Choose the less conservative count. | ||||||
7348 | if (EL0.ExactNotTaken == getCouldNotCompute() || | ||||||
7349 | EL1.ExactNotTaken == getCouldNotCompute()) | ||||||
7350 | BECount = getCouldNotCompute(); | ||||||
7351 | else | ||||||
7352 | BECount = | ||||||
7353 | getUMinFromMismatchedTypes(EL0.ExactNotTaken, EL1.ExactNotTaken); | ||||||
7354 | if (EL0.MaxNotTaken == getCouldNotCompute()) | ||||||
7355 | MaxBECount = EL1.MaxNotTaken; | ||||||
7356 | else if (EL1.MaxNotTaken == getCouldNotCompute()) | ||||||
7357 | MaxBECount = EL0.MaxNotTaken; | ||||||
7358 | else | ||||||
7359 | MaxBECount = | ||||||
7360 | getUMinFromMismatchedTypes(EL0.MaxNotTaken, EL1.MaxNotTaken); | ||||||
7361 | } else { | ||||||
7362 | // Both conditions must be false at the same time for the loop to exit. | ||||||
7363 | // For now, be conservative. | ||||||
7364 | if (EL0.MaxNotTaken == EL1.MaxNotTaken) | ||||||
7365 | MaxBECount = EL0.MaxNotTaken; | ||||||
7366 | if (EL0.ExactNotTaken == EL1.ExactNotTaken) | ||||||
7367 | BECount = EL0.ExactNotTaken; | ||||||
7368 | } | ||||||
7369 | // There are cases (e.g. PR26207) where computeExitLimitFromCond is able | ||||||
7370 | // to be more aggressive when computing BECount than when computing | ||||||
7371 | // MaxBECount. In these cases it is possible for EL0.ExactNotTaken and | ||||||
7372 | // EL1.ExactNotTaken to match, but for EL0.MaxNotTaken and EL1.MaxNotTaken | ||||||
7373 | // to not. | ||||||
7374 | if (isa<SCEVCouldNotCompute>(MaxBECount) && | ||||||
7375 | !isa<SCEVCouldNotCompute>(BECount)) | ||||||
7376 | MaxBECount = getConstant(getUnsignedRangeMax(BECount)); | ||||||
7377 | |||||||
7378 | return ExitLimit(BECount, MaxBECount, false, | ||||||
7379 | {&EL0.Predicates, &EL1.Predicates}); | ||||||
7380 | } | ||||||
7381 | } | ||||||
7382 | |||||||
7383 | // With an icmp, it may be feasible to compute an exact backedge-taken count. | ||||||
7384 | // Proceed to the next level to examine the icmp. | ||||||
7385 | if (ICmpInst *ExitCondICmp = dyn_cast<ICmpInst>(ExitCond)) { | ||||||
7386 | ExitLimit EL = | ||||||
7387 | computeExitLimitFromICmp(L, ExitCondICmp, ExitIfTrue, ControlsExit); | ||||||
7388 | if (EL.hasFullInfo() || !AllowPredicates) | ||||||
7389 | return EL; | ||||||
7390 | |||||||
7391 | // Try again, but use SCEV predicates this time. | ||||||
7392 | return computeExitLimitFromICmp(L, ExitCondICmp, ExitIfTrue, ControlsExit, | ||||||
7393 | /*AllowPredicates=*/true); | ||||||
7394 | } | ||||||
7395 | |||||||
7396 | // Check for a constant condition. These are normally stripped out by | ||||||
7397 | // SimplifyCFG, but ScalarEvolution may be used by a pass which wishes to | ||||||
7398 | // preserve the CFG and is temporarily leaving constant conditions | ||||||
7399 | // in place. | ||||||
7400 | if (ConstantInt *CI = dyn_cast<ConstantInt>(ExitCond)) { | ||||||
7401 | if (ExitIfTrue == !CI->getZExtValue()) | ||||||
7402 | // The backedge is always taken. | ||||||
7403 | return getCouldNotCompute(); | ||||||
7404 | else | ||||||
7405 | // The backedge is never taken. | ||||||
7406 | return getZero(CI->getType()); | ||||||
7407 | } | ||||||
7408 | |||||||
7409 | // If it's not an integer or pointer comparison then compute it the hard way. | ||||||
7410 | return computeExitCountExhaustively(L, ExitCond, ExitIfTrue); | ||||||
7411 | } | ||||||
7412 | |||||||
7413 | ScalarEvolution::ExitLimit | ||||||
7414 | ScalarEvolution::computeExitLimitFromICmp(const Loop *L, | ||||||
7415 | ICmpInst *ExitCond, | ||||||
7416 | bool ExitIfTrue, | ||||||
7417 | bool ControlsExit, | ||||||
7418 | bool AllowPredicates) { | ||||||
7419 | // If the condition was exit on true, convert the condition to exit on false | ||||||
7420 | ICmpInst::Predicate Pred; | ||||||
7421 | if (!ExitIfTrue) | ||||||
7422 | Pred = ExitCond->getPredicate(); | ||||||
7423 | else | ||||||
7424 | Pred = ExitCond->getInversePredicate(); | ||||||
7425 | const ICmpInst::Predicate OriginalPred = Pred; | ||||||
7426 | |||||||
7427 | // Handle common loops like: for (X = "string"; *X; ++X) | ||||||
7428 | if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0))) | ||||||
7429 | if (Constant *RHS = dyn_cast<Constant>(ExitCond->getOperand(1))) { | ||||||
7430 | ExitLimit ItCnt = | ||||||
7431 | computeLoadConstantCompareExitLimit(LI, RHS, L, Pred); | ||||||
7432 | if (ItCnt.hasAnyInfo()) | ||||||
7433 | return ItCnt; | ||||||
7434 | } | ||||||
7435 | |||||||
7436 | const SCEV *LHS = getSCEV(ExitCond->getOperand(0)); | ||||||
7437 | const SCEV *RHS = getSCEV(ExitCond->getOperand(1)); | ||||||
7438 | |||||||
7439 | // Try to evaluate any dependencies out of the loop. | ||||||
7440 | LHS = getSCEVAtScope(LHS, L); | ||||||
7441 | RHS = getSCEVAtScope(RHS, L); | ||||||
7442 | |||||||
7443 | // At this point, we would like to compute how many iterations of the | ||||||
7444 | // loop the predicate will return true for these inputs. | ||||||
7445 | if (isLoopInvariant(LHS, L) && !isLoopInvariant(RHS, L)) { | ||||||
7446 | // If there is a loop-invariant, force it into the RHS. | ||||||
7447 | std::swap(LHS, RHS); | ||||||
7448 | Pred = ICmpInst::getSwappedPredicate(Pred); | ||||||
7449 | } | ||||||
7450 | |||||||
7451 | // Simplify the operands before analyzing them. | ||||||
7452 | (void)SimplifyICmpOperands(Pred, LHS, RHS); | ||||||
7453 | |||||||
7454 | // If we have a comparison of a chrec against a constant, try to use value | ||||||
7455 | // ranges to answer this query. | ||||||
7456 | if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) | ||||||
7457 | if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS)) | ||||||
7458 | if (AddRec->getLoop() == L) { | ||||||
7459 | // Form the constant range. | ||||||
7460 | ConstantRange CompRange = | ||||||
7461 | ConstantRange::makeExactICmpRegion(Pred, RHSC->getAPInt()); | ||||||
7462 | |||||||
7463 | const SCEV *Ret = AddRec->getNumIterationsInRange(CompRange, *this); | ||||||
7464 | if (!isa<SCEVCouldNotCompute>(Ret)) return Ret; | ||||||
7465 | } | ||||||
7466 | |||||||
7467 | switch (Pred) { | ||||||
7468 | case ICmpInst::ICMP_NE: { // while (X != Y) | ||||||
7469 | // Convert to: while (X-Y != 0) | ||||||
7470 | ExitLimit EL = howFarToZero(getMinusSCEV(LHS, RHS), L, ControlsExit, | ||||||
7471 | AllowPredicates); | ||||||
7472 | if (EL.hasAnyInfo()) return EL; | ||||||
7473 | break; | ||||||
7474 | } | ||||||
7475 | case ICmpInst::ICMP_EQ: { // while (X == Y) | ||||||
7476 | // Convert to: while (X-Y == 0) | ||||||
7477 | ExitLimit EL = howFarToNonZero(getMinusSCEV(LHS, RHS), L); | ||||||
7478 | if (EL.hasAnyInfo()) return EL; | ||||||
7479 | break; | ||||||
7480 | } | ||||||
7481 | case ICmpInst::ICMP_SLT: | ||||||
7482 | case ICmpInst::ICMP_ULT: { // while (X < Y) | ||||||
7483 | bool IsSigned = Pred == ICmpInst::ICMP_SLT; | ||||||
7484 | ExitLimit EL = howManyLessThans(LHS, RHS, L, IsSigned, ControlsExit, | ||||||
7485 | AllowPredicates); | ||||||
7486 | if (EL.hasAnyInfo()) return EL; | ||||||
7487 | break; | ||||||
7488 | } | ||||||
7489 | case ICmpInst::ICMP_SGT: | ||||||
7490 | case ICmpInst::ICMP_UGT: { // while (X > Y) | ||||||
7491 | bool IsSigned = Pred == ICmpInst::ICMP_SGT; | ||||||
7492 | ExitLimit EL = | ||||||
7493 | howManyGreaterThans(LHS, RHS, L, IsSigned, ControlsExit, | ||||||
7494 | AllowPredicates); | ||||||
7495 | if (EL.hasAnyInfo()) return EL; | ||||||
7496 | break; | ||||||
7497 | } | ||||||
7498 | default: | ||||||
7499 | break; | ||||||
7500 | } | ||||||
7501 | |||||||
7502 | auto *ExhaustiveCount = | ||||||
7503 | computeExitCountExhaustively(L, ExitCond, ExitIfTrue); | ||||||
7504 | |||||||
7505 | if (!isa<SCEVCouldNotCompute>(ExhaustiveCount)) | ||||||
7506 | return ExhaustiveCount; | ||||||
7507 | |||||||
7508 | return computeShiftCompareExitLimit(ExitCond->getOperand(0), | ||||||
7509 | ExitCond->getOperand(1), L, OriginalPred); | ||||||
7510 | } | ||||||
7511 | |||||||
7512 | ScalarEvolution::ExitLimit | ||||||
7513 | ScalarEvolution::computeExitLimitFromSingleExitSwitch(const Loop *L, | ||||||
7514 | SwitchInst *Switch, | ||||||
7515 | BasicBlock *ExitingBlock, | ||||||
7516 | bool ControlsExit) { | ||||||
7517 | assert(!L->contains(ExitingBlock) && "Not an exiting block!")((!L->contains(ExitingBlock) && "Not an exiting block!" ) ? static_cast<void> (0) : __assert_fail ("!L->contains(ExitingBlock) && \"Not an exiting block!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7517, __PRETTY_FUNCTION__)); | ||||||
7518 | |||||||
7519 | // Give up if the exit is the default dest of a switch. | ||||||
7520 | if (Switch->getDefaultDest() == ExitingBlock) | ||||||
7521 | return getCouldNotCompute(); | ||||||
7522 | |||||||
7523 | assert(L->contains(Switch->getDefaultDest()) &&((L->contains(Switch->getDefaultDest()) && "Default case must not exit the loop!" ) ? static_cast<void> (0) : __assert_fail ("L->contains(Switch->getDefaultDest()) && \"Default case must not exit the loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7524, __PRETTY_FUNCTION__)) | ||||||
7524 | "Default case must not exit the loop!")((L->contains(Switch->getDefaultDest()) && "Default case must not exit the loop!" ) ? static_cast<void> (0) : __assert_fail ("L->contains(Switch->getDefaultDest()) && \"Default case must not exit the loop!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7524, __PRETTY_FUNCTION__)); | ||||||
7525 | const SCEV *LHS = getSCEVAtScope(Switch->getCondition(), L); | ||||||
7526 | const SCEV *RHS = getConstant(Switch->findCaseDest(ExitingBlock)); | ||||||
7527 | |||||||
7528 | // while (X != Y) --> while (X-Y != 0) | ||||||
7529 | ExitLimit EL = howFarToZero(getMinusSCEV(LHS, RHS), L, ControlsExit); | ||||||
7530 | if (EL.hasAnyInfo()) | ||||||
7531 | return EL; | ||||||
7532 | |||||||
7533 | return getCouldNotCompute(); | ||||||
7534 | } | ||||||
7535 | |||||||
7536 | static ConstantInt * | ||||||
7537 | EvaluateConstantChrecAtConstant(const SCEVAddRecExpr *AddRec, ConstantInt *C, | ||||||
7538 | ScalarEvolution &SE) { | ||||||
7539 | const SCEV *InVal = SE.getConstant(C); | ||||||
7540 | const SCEV *Val = AddRec->evaluateAtIteration(InVal, SE); | ||||||
7541 | assert(isa<SCEVConstant>(Val) &&((isa<SCEVConstant>(Val) && "Evaluation of SCEV at constant didn't fold correctly?" ) ? static_cast<void> (0) : __assert_fail ("isa<SCEVConstant>(Val) && \"Evaluation of SCEV at constant didn't fold correctly?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7542, __PRETTY_FUNCTION__)) | ||||||
7542 | "Evaluation of SCEV at constant didn't fold correctly?")((isa<SCEVConstant>(Val) && "Evaluation of SCEV at constant didn't fold correctly?" ) ? static_cast<void> (0) : __assert_fail ("isa<SCEVConstant>(Val) && \"Evaluation of SCEV at constant didn't fold correctly?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7542, __PRETTY_FUNCTION__)); | ||||||
7543 | return cast<SCEVConstant>(Val)->getValue(); | ||||||
7544 | } | ||||||
7545 | |||||||
7546 | /// Given an exit condition of 'icmp op load X, cst', try to see if we can | ||||||
7547 | /// compute the backedge execution count. | ||||||
7548 | ScalarEvolution::ExitLimit | ||||||
7549 | ScalarEvolution::computeLoadConstantCompareExitLimit( | ||||||
7550 | LoadInst *LI, | ||||||
7551 | Constant *RHS, | ||||||
7552 | const Loop *L, | ||||||
7553 | ICmpInst::Predicate predicate) { | ||||||
7554 | if (LI->isVolatile()) return getCouldNotCompute(); | ||||||
7555 | |||||||
7556 | // Check to see if the loaded pointer is a getelementptr of a global. | ||||||
7557 | // TODO: Use SCEV instead of manually grubbing with GEPs. | ||||||
7558 | GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0)); | ||||||
7559 | if (!GEP) return getCouldNotCompute(); | ||||||
7560 | |||||||
7561 | // Make sure that it is really a constant global we are gepping, with an | ||||||
7562 | // initializer, and make sure the first IDX is really 0. | ||||||
7563 | GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0)); | ||||||
7564 | if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer() || | ||||||
7565 | GEP->getNumOperands() < 3 || !isa<Constant>(GEP->getOperand(1)) || | ||||||
7566 | !cast<Constant>(GEP->getOperand(1))->isNullValue()) | ||||||
7567 | return getCouldNotCompute(); | ||||||
7568 | |||||||
7569 | // Okay, we allow one non-constant index into the GEP instruction. | ||||||
7570 | Value *VarIdx = nullptr; | ||||||
7571 | std::vector<Constant*> Indexes; | ||||||
7572 | unsigned VarIdxNum = 0; | ||||||
7573 | for (unsigned i = 2, e = GEP->getNumOperands(); i != e; ++i) | ||||||
7574 | if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i))) { | ||||||
7575 | Indexes.push_back(CI); | ||||||
7576 | } else if (!isa<ConstantInt>(GEP->getOperand(i))) { | ||||||
7577 | if (VarIdx) return getCouldNotCompute(); // Multiple non-constant idx's. | ||||||
7578 | VarIdx = GEP->getOperand(i); | ||||||
7579 | VarIdxNum = i-2; | ||||||
7580 | Indexes.push_back(nullptr); | ||||||
7581 | } | ||||||
7582 | |||||||
7583 | // Loop-invariant loads may be a byproduct of loop optimization. Skip them. | ||||||
7584 | if (!VarIdx) | ||||||
7585 | return getCouldNotCompute(); | ||||||
7586 | |||||||
7587 | // Okay, we know we have a (load (gep GV, 0, X)) comparison with a constant. | ||||||
7588 | // Check to see if X is a loop variant variable value now. | ||||||
7589 | const SCEV *Idx = getSCEV(VarIdx); | ||||||
7590 | Idx = getSCEVAtScope(Idx, L); | ||||||
7591 | |||||||
7592 | // We can only recognize very limited forms of loop index expressions, in | ||||||
7593 | // particular, only affine AddRec's like {C1,+,C2}. | ||||||
7594 | const SCEVAddRecExpr *IdxExpr = dyn_cast<SCEVAddRecExpr>(Idx); | ||||||
7595 | if (!IdxExpr || !IdxExpr->isAffine() || isLoopInvariant(IdxExpr, L) || | ||||||
7596 | !isa<SCEVConstant>(IdxExpr->getOperand(0)) || | ||||||
7597 | !isa<SCEVConstant>(IdxExpr->getOperand(1))) | ||||||
7598 | return getCouldNotCompute(); | ||||||
7599 | |||||||
7600 | unsigned MaxSteps = MaxBruteForceIterations; | ||||||
7601 | for (unsigned IterationNum = 0; IterationNum != MaxSteps; ++IterationNum) { | ||||||
7602 | ConstantInt *ItCst = ConstantInt::get( | ||||||
7603 | cast<IntegerType>(IdxExpr->getType()), IterationNum); | ||||||
7604 | ConstantInt *Val = EvaluateConstantChrecAtConstant(IdxExpr, ItCst, *this); | ||||||
7605 | |||||||
7606 | // Form the GEP offset. | ||||||
7607 | Indexes[VarIdxNum] = Val; | ||||||
7608 | |||||||
7609 | Constant *Result = ConstantFoldLoadThroughGEPIndices(GV->getInitializer(), | ||||||
7610 | Indexes); | ||||||
7611 | if (!Result) break; // Cannot compute! | ||||||
7612 | |||||||
7613 | // Evaluate the condition for this iteration. | ||||||
7614 | Result = ConstantExpr::getICmp(predicate, Result, RHS); | ||||||
7615 | if (!isa<ConstantInt>(Result)) break; // Couldn't decide for sure | ||||||
7616 | if (cast<ConstantInt>(Result)->getValue().isMinValue()) { | ||||||
7617 | ++NumArrayLenItCounts; | ||||||
7618 | return getConstant(ItCst); // Found terminating iteration! | ||||||
7619 | } | ||||||
7620 | } | ||||||
7621 | return getCouldNotCompute(); | ||||||
7622 | } | ||||||
7623 | |||||||
7624 | ScalarEvolution::ExitLimit ScalarEvolution::computeShiftCompareExitLimit( | ||||||
7625 | Value *LHS, Value *RHSV, const Loop *L, ICmpInst::Predicate Pred) { | ||||||
7626 | ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV); | ||||||
7627 | if (!RHS) | ||||||
7628 | return getCouldNotCompute(); | ||||||
7629 | |||||||
7630 | const BasicBlock *Latch = L->getLoopLatch(); | ||||||
7631 | if (!Latch) | ||||||
7632 | return getCouldNotCompute(); | ||||||
7633 | |||||||
7634 | const BasicBlock *Predecessor = L->getLoopPredecessor(); | ||||||
7635 | if (!Predecessor) | ||||||
7636 | return getCouldNotCompute(); | ||||||
7637 | |||||||
7638 | // Return true if V is of the form "LHS `shift_op` <positive constant>". | ||||||
7639 | // Return LHS in OutLHS and shift_opt in OutOpCode. | ||||||
7640 | auto MatchPositiveShift = | ||||||
7641 | [](Value *V, Value *&OutLHS, Instruction::BinaryOps &OutOpCode) { | ||||||
7642 | |||||||
7643 | using namespace PatternMatch; | ||||||
7644 | |||||||
7645 | ConstantInt *ShiftAmt; | ||||||
7646 | if (match(V, m_LShr(m_Value(OutLHS), m_ConstantInt(ShiftAmt)))) | ||||||
7647 | OutOpCode = Instruction::LShr; | ||||||
7648 | else if (match(V, m_AShr(m_Value(OutLHS), m_ConstantInt(ShiftAmt)))) | ||||||
7649 | OutOpCode = Instruction::AShr; | ||||||
7650 | else if (match(V, m_Shl(m_Value(OutLHS), m_ConstantInt(ShiftAmt)))) | ||||||
7651 | OutOpCode = Instruction::Shl; | ||||||
7652 | else | ||||||
7653 | return false; | ||||||
7654 | |||||||
7655 | return ShiftAmt->getValue().isStrictlyPositive(); | ||||||
7656 | }; | ||||||
7657 | |||||||
7658 | // Recognize a "shift recurrence" either of the form %iv or of %iv.shifted in | ||||||
7659 | // | ||||||
7660 | // loop: | ||||||
7661 | // %iv = phi i32 [ %iv.shifted, %loop ], [ %val, %preheader ] | ||||||
7662 | // %iv.shifted = lshr i32 %iv, <positive constant> | ||||||
7663 | // | ||||||
7664 | // Return true on a successful match. Return the corresponding PHI node (%iv | ||||||
7665 | // above) in PNOut and the opcode of the shift operation in OpCodeOut. | ||||||
7666 | auto MatchShiftRecurrence = | ||||||
7667 | [&](Value *V, PHINode *&PNOut, Instruction::BinaryOps &OpCodeOut) { | ||||||
7668 | Optional<Instruction::BinaryOps> PostShiftOpCode; | ||||||
7669 | |||||||
7670 | { | ||||||
7671 | Instruction::BinaryOps OpC; | ||||||
7672 | Value *V; | ||||||
7673 | |||||||
7674 | // If we encounter a shift instruction, "peel off" the shift operation, | ||||||
7675 | // and remember that we did so. Later when we inspect %iv's backedge | ||||||
7676 | // value, we will make sure that the backedge value uses the same | ||||||
7677 | // operation. | ||||||
7678 | // | ||||||
7679 | // Note: the peeled shift operation does not have to be the same | ||||||
7680 | // instruction as the one feeding into the PHI's backedge value. We only | ||||||
7681 | // really care about it being the same *kind* of shift instruction -- | ||||||
7682 | // that's all that is required for our later inferences to hold. | ||||||
7683 | if (MatchPositiveShift(LHS, V, OpC)) { | ||||||
7684 | PostShiftOpCode = OpC; | ||||||
7685 | LHS = V; | ||||||
7686 | } | ||||||
7687 | } | ||||||
7688 | |||||||
7689 | PNOut = dyn_cast<PHINode>(LHS); | ||||||
7690 | if (!PNOut || PNOut->getParent() != L->getHeader()) | ||||||
7691 | return false; | ||||||
7692 | |||||||
7693 | Value *BEValue = PNOut->getIncomingValueForBlock(Latch); | ||||||
7694 | Value *OpLHS; | ||||||
7695 | |||||||
7696 | return | ||||||
7697 | // The backedge value for the PHI node must be a shift by a positive | ||||||
7698 | // amount | ||||||
7699 | MatchPositiveShift(BEValue, OpLHS, OpCodeOut) && | ||||||
7700 | |||||||
7701 | // of the PHI node itself | ||||||
7702 | OpLHS == PNOut && | ||||||
7703 | |||||||
7704 | // and the kind of shift should be match the kind of shift we peeled | ||||||
7705 | // off, if any. | ||||||
7706 | (!PostShiftOpCode.hasValue() || *PostShiftOpCode == OpCodeOut); | ||||||
7707 | }; | ||||||
7708 | |||||||
7709 | PHINode *PN; | ||||||
7710 | Instruction::BinaryOps OpCode; | ||||||
7711 | if (!MatchShiftRecurrence(LHS, PN, OpCode)) | ||||||
7712 | return getCouldNotCompute(); | ||||||
7713 | |||||||
7714 | const DataLayout &DL = getDataLayout(); | ||||||
7715 | |||||||
7716 | // The key rationale for this optimization is that for some kinds of shift | ||||||
7717 | // recurrences, the value of the recurrence "stabilizes" to either 0 or -1 | ||||||
7718 | // within a finite number of iterations. If the condition guarding the | ||||||
7719 | // backedge (in the sense that the backedge is taken if the condition is true) | ||||||
7720 | // is false for the value the shift recurrence stabilizes to, then we know | ||||||
7721 | // that the backedge is taken only a finite number of times. | ||||||
7722 | |||||||
7723 | ConstantInt *StableValue = nullptr; | ||||||
7724 | switch (OpCode) { | ||||||
7725 | default: | ||||||
7726 | llvm_unreachable("Impossible case!")::llvm::llvm_unreachable_internal("Impossible case!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7726); | ||||||
7727 | |||||||
7728 | case Instruction::AShr: { | ||||||
7729 | // {K,ashr,<positive-constant>} stabilizes to signum(K) in at most | ||||||
7730 | // bitwidth(K) iterations. | ||||||
7731 | Value *FirstValue = PN->getIncomingValueForBlock(Predecessor); | ||||||
7732 | KnownBits Known = computeKnownBits(FirstValue, DL, 0, nullptr, | ||||||
7733 | Predecessor->getTerminator(), &DT); | ||||||
7734 | auto *Ty = cast<IntegerType>(RHS->getType()); | ||||||
7735 | if (Known.isNonNegative()) | ||||||
7736 | StableValue = ConstantInt::get(Ty, 0); | ||||||
7737 | else if (Known.isNegative()) | ||||||
7738 | StableValue = ConstantInt::get(Ty, -1, true); | ||||||
7739 | else | ||||||
7740 | return getCouldNotCompute(); | ||||||
7741 | |||||||
7742 | break; | ||||||
7743 | } | ||||||
7744 | case Instruction::LShr: | ||||||
7745 | case Instruction::Shl: | ||||||
7746 | // Both {K,lshr,<positive-constant>} and {K,shl,<positive-constant>} | ||||||
7747 | // stabilize to 0 in at most bitwidth(K) iterations. | ||||||
7748 | StableValue = ConstantInt::get(cast<IntegerType>(RHS->getType()), 0); | ||||||
7749 | break; | ||||||
7750 | } | ||||||
7751 | |||||||
7752 | auto *Result = | ||||||
7753 | ConstantFoldCompareInstOperands(Pred, StableValue, RHS, DL, &TLI); | ||||||
7754 | assert(Result->getType()->isIntegerTy(1) &&((Result->getType()->isIntegerTy(1) && "Otherwise cannot be an operand to a branch instruction" ) ? static_cast<void> (0) : __assert_fail ("Result->getType()->isIntegerTy(1) && \"Otherwise cannot be an operand to a branch instruction\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7755, __PRETTY_FUNCTION__)) | ||||||
7755 | "Otherwise cannot be an operand to a branch instruction")((Result->getType()->isIntegerTy(1) && "Otherwise cannot be an operand to a branch instruction" ) ? static_cast<void> (0) : __assert_fail ("Result->getType()->isIntegerTy(1) && \"Otherwise cannot be an operand to a branch instruction\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7755, __PRETTY_FUNCTION__)); | ||||||
7756 | |||||||
7757 | if (Result->isZeroValue()) { | ||||||
7758 | unsigned BitWidth = getTypeSizeInBits(RHS->getType()); | ||||||
7759 | const SCEV *UpperBound = | ||||||
7760 | getConstant(getEffectiveSCEVType(RHS->getType()), BitWidth); | ||||||
7761 | return ExitLimit(getCouldNotCompute(), UpperBound, false); | ||||||
7762 | } | ||||||
7763 | |||||||
7764 | return getCouldNotCompute(); | ||||||
7765 | } | ||||||
7766 | |||||||
7767 | /// Return true if we can constant fold an instruction of the specified type, | ||||||
7768 | /// assuming that all operands were constants. | ||||||
7769 | static bool CanConstantFold(const Instruction *I) { | ||||||
7770 | if (isa<BinaryOperator>(I) || isa<CmpInst>(I) || | ||||||
7771 | isa<SelectInst>(I) || isa<CastInst>(I) || isa<GetElementPtrInst>(I) || | ||||||
7772 | isa<LoadInst>(I) || isa<ExtractValueInst>(I)) | ||||||
7773 | return true; | ||||||
7774 | |||||||
7775 | if (const CallInst *CI = dyn_cast<CallInst>(I)) | ||||||
7776 | if (const Function *F = CI->getCalledFunction()) | ||||||
7777 | return canConstantFoldCallTo(CI, F); | ||||||
7778 | return false; | ||||||
7779 | } | ||||||
7780 | |||||||
7781 | /// Determine whether this instruction can constant evolve within this loop | ||||||
7782 | /// assuming its operands can all constant evolve. | ||||||
7783 | static bool canConstantEvolve(Instruction *I, const Loop *L) { | ||||||
7784 | // An instruction outside of the loop can't be derived from a loop PHI. | ||||||
7785 | if (!L->contains(I)) return false; | ||||||
7786 | |||||||
7787 | if (isa<PHINode>(I)) { | ||||||
7788 | // We don't currently keep track of the control flow needed to evaluate | ||||||
7789 | // PHIs, so we cannot handle PHIs inside of loops. | ||||||
7790 | return L->getHeader() == I->getParent(); | ||||||
7791 | } | ||||||
7792 | |||||||
7793 | // If we won't be able to constant fold this expression even if the operands | ||||||
7794 | // are constants, bail early. | ||||||
7795 | return CanConstantFold(I); | ||||||
7796 | } | ||||||
7797 | |||||||
7798 | /// getConstantEvolvingPHIOperands - Implement getConstantEvolvingPHI by | ||||||
7799 | /// recursing through each instruction operand until reaching a loop header phi. | ||||||
7800 | static PHINode * | ||||||
7801 | getConstantEvolvingPHIOperands(Instruction *UseInst, const Loop *L, | ||||||
7802 | DenseMap<Instruction *, PHINode *> &PHIMap, | ||||||
7803 | unsigned Depth) { | ||||||
7804 | if (Depth > MaxConstantEvolvingDepth) | ||||||
7805 | return nullptr; | ||||||
7806 | |||||||
7807 | // Otherwise, we can evaluate this instruction if all of its operands are | ||||||
7808 | // constant or derived from a PHI node themselves. | ||||||
7809 | PHINode *PHI = nullptr; | ||||||
7810 | for (Value *Op : UseInst->operands()) { | ||||||
7811 | if (isa<Constant>(Op)) continue; | ||||||
7812 | |||||||
7813 | Instruction *OpInst = dyn_cast<Instruction>(Op); | ||||||
7814 | if (!OpInst || !canConstantEvolve(OpInst, L)) return nullptr; | ||||||
7815 | |||||||
7816 | PHINode *P = dyn_cast<PHINode>(OpInst); | ||||||
7817 | if (!P) | ||||||
7818 | // If this operand is already visited, reuse the prior result. | ||||||
7819 | // We may have P != PHI if this is the deepest point at which the | ||||||
7820 | // inconsistent paths meet. | ||||||
7821 | P = PHIMap.lookup(OpInst); | ||||||
7822 | if (!P) { | ||||||
7823 | // Recurse and memoize the results, whether a phi is found or not. | ||||||
7824 | // This recursive call invalidates pointers into PHIMap. | ||||||
7825 | P = getConstantEvolvingPHIOperands(OpInst, L, PHIMap, Depth + 1); | ||||||
7826 | PHIMap[OpInst] = P; | ||||||
7827 | } | ||||||
7828 | if (!P) | ||||||
7829 | return nullptr; // Not evolving from PHI | ||||||
7830 | if (PHI && PHI != P) | ||||||
7831 | return nullptr; // Evolving from multiple different PHIs. | ||||||
7832 | PHI = P; | ||||||
7833 | } | ||||||
7834 | // This is a expression evolving from a constant PHI! | ||||||
7835 | return PHI; | ||||||
7836 | } | ||||||
7837 | |||||||
7838 | /// getConstantEvolvingPHI - Given an LLVM value and a loop, return a PHI node | ||||||
7839 | /// in the loop that V is derived from. We allow arbitrary operations along the | ||||||
7840 | /// way, but the operands of an operation must either be constants or a value | ||||||
7841 | /// derived from a constant PHI. If this expression does not fit with these | ||||||
7842 | /// constraints, return null. | ||||||
7843 | static PHINode *getConstantEvolvingPHI(Value *V, const Loop *L) { | ||||||
7844 | Instruction *I = dyn_cast<Instruction>(V); | ||||||
7845 | if (!I || !canConstantEvolve(I, L)) return nullptr; | ||||||
7846 | |||||||
7847 | if (PHINode *PN = dyn_cast<PHINode>(I)) | ||||||
7848 | return PN; | ||||||
7849 | |||||||
7850 | // Record non-constant instructions contained by the loop. | ||||||
7851 | DenseMap<Instruction *, PHINode *> PHIMap; | ||||||
7852 | return getConstantEvolvingPHIOperands(I, L, PHIMap, 0); | ||||||
7853 | } | ||||||
7854 | |||||||
7855 | /// EvaluateExpression - Given an expression that passes the | ||||||
7856 | /// getConstantEvolvingPHI predicate, evaluate its value assuming the PHI node | ||||||
7857 | /// in the loop has the value PHIVal. If we can't fold this expression for some | ||||||
7858 | /// reason, return null. | ||||||
7859 | static Constant *EvaluateExpression(Value *V, const Loop *L, | ||||||
7860 | DenseMap<Instruction *, Constant *> &Vals, | ||||||
7861 | const DataLayout &DL, | ||||||
7862 | const TargetLibraryInfo *TLI) { | ||||||
7863 | // Convenient constant check, but redundant for recursive calls. | ||||||
7864 | if (Constant *C = dyn_cast<Constant>(V)) return C; | ||||||
7865 | Instruction *I = dyn_cast<Instruction>(V); | ||||||
7866 | if (!I) return nullptr; | ||||||
7867 | |||||||
7868 | if (Constant *C = Vals.lookup(I)) return C; | ||||||
7869 | |||||||
7870 | // An instruction inside the loop depends on a value outside the loop that we | ||||||
7871 | // weren't given a mapping for, or a value such as a call inside the loop. | ||||||
7872 | if (!canConstantEvolve(I, L)) return nullptr; | ||||||
7873 | |||||||
7874 | // An unmapped PHI can be due to a branch or another loop inside this loop, | ||||||
7875 | // or due to this not being the initial iteration through a loop where we | ||||||
7876 | // couldn't compute the evolution of this particular PHI last time. | ||||||
7877 | if (isa<PHINode>(I)) return nullptr; | ||||||
7878 | |||||||
7879 | std::vector<Constant*> Operands(I->getNumOperands()); | ||||||
7880 | |||||||
7881 | for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { | ||||||
7882 | Instruction *Operand = dyn_cast<Instruction>(I->getOperand(i)); | ||||||
7883 | if (!Operand) { | ||||||
7884 | Operands[i] = dyn_cast<Constant>(I->getOperand(i)); | ||||||
7885 | if (!Operands[i]) return nullptr; | ||||||
7886 | continue; | ||||||
7887 | } | ||||||
7888 | Constant *C = EvaluateExpression(Operand, L, Vals, DL, TLI); | ||||||
7889 | Vals[Operand] = C; | ||||||
7890 | if (!C) return nullptr; | ||||||
7891 | Operands[i] = C; | ||||||
7892 | } | ||||||
7893 | |||||||
7894 | if (CmpInst *CI = dyn_cast<CmpInst>(I)) | ||||||
7895 | return ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0], | ||||||
7896 | Operands[1], DL, TLI); | ||||||
7897 | if (LoadInst *LI = dyn_cast<LoadInst>(I)) { | ||||||
7898 | if (!LI->isVolatile()) | ||||||
7899 | return ConstantFoldLoadFromConstPtr(Operands[0], LI->getType(), DL); | ||||||
7900 | } | ||||||
7901 | return ConstantFoldInstOperands(I, Operands, DL, TLI); | ||||||
7902 | } | ||||||
7903 | |||||||
7904 | |||||||
7905 | // If every incoming value to PN except the one for BB is a specific Constant, | ||||||
7906 | // return that, else return nullptr. | ||||||
7907 | static Constant *getOtherIncomingValue(PHINode *PN, BasicBlock *BB) { | ||||||
7908 | Constant *IncomingVal = nullptr; | ||||||
7909 | |||||||
7910 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { | ||||||
7911 | if (PN->getIncomingBlock(i) == BB) | ||||||
7912 | continue; | ||||||
7913 | |||||||
7914 | auto *CurrentVal = dyn_cast<Constant>(PN->getIncomingValue(i)); | ||||||
7915 | if (!CurrentVal) | ||||||
7916 | return nullptr; | ||||||
7917 | |||||||
7918 | if (IncomingVal != CurrentVal) { | ||||||
7919 | if (IncomingVal) | ||||||
7920 | return nullptr; | ||||||
7921 | IncomingVal = CurrentVal; | ||||||
7922 | } | ||||||
7923 | } | ||||||
7924 | |||||||
7925 | return IncomingVal; | ||||||
7926 | } | ||||||
7927 | |||||||
7928 | /// getConstantEvolutionLoopExitValue - If we know that the specified Phi is | ||||||
7929 | /// in the header of its containing loop, we know the loop executes a | ||||||
7930 | /// constant number of times, and the PHI node is just a recurrence | ||||||
7931 | /// involving constants, fold it. | ||||||
7932 | Constant * | ||||||
7933 | ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN, | ||||||
7934 | const APInt &BEs, | ||||||
7935 | const Loop *L) { | ||||||
7936 | auto I = ConstantEvolutionLoopExitValue.find(PN); | ||||||
7937 | if (I != ConstantEvolutionLoopExitValue.end()) | ||||||
7938 | return I->second; | ||||||
7939 | |||||||
7940 | if (BEs.ugt(MaxBruteForceIterations)) | ||||||
7941 | return ConstantEvolutionLoopExitValue[PN] = nullptr; // Not going to evaluate it. | ||||||
7942 | |||||||
7943 | Constant *&RetVal = ConstantEvolutionLoopExitValue[PN]; | ||||||
7944 | |||||||
7945 | DenseMap<Instruction *, Constant *> CurrentIterVals; | ||||||
7946 | BasicBlock *Header = L->getHeader(); | ||||||
7947 | assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!")((PN->getParent() == Header && "Can't evaluate PHI not in loop header!" ) ? static_cast<void> (0) : __assert_fail ("PN->getParent() == Header && \"Can't evaluate PHI not in loop header!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7947, __PRETTY_FUNCTION__)); | ||||||
7948 | |||||||
7949 | BasicBlock *Latch = L->getLoopLatch(); | ||||||
7950 | if (!Latch) | ||||||
7951 | return nullptr; | ||||||
7952 | |||||||
7953 | for (PHINode &PHI : Header->phis()) { | ||||||
7954 | if (auto *StartCST = getOtherIncomingValue(&PHI, Latch)) | ||||||
7955 | CurrentIterVals[&PHI] = StartCST; | ||||||
7956 | } | ||||||
7957 | if (!CurrentIterVals.count(PN)) | ||||||
7958 | return RetVal = nullptr; | ||||||
7959 | |||||||
7960 | Value *BEValue = PN->getIncomingValueForBlock(Latch); | ||||||
7961 | |||||||
7962 | // Execute the loop symbolically to determine the exit value. | ||||||
7963 | assert(BEs.getActiveBits() < CHAR_BIT * sizeof(unsigned) &&((BEs.getActiveBits() < 8 * sizeof(unsigned) && "BEs is <= MaxBruteForceIterations which is an 'unsigned'!" ) ? static_cast<void> (0) : __assert_fail ("BEs.getActiveBits() < CHAR_BIT * sizeof(unsigned) && \"BEs is <= MaxBruteForceIterations which is an 'unsigned'!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7964, __PRETTY_FUNCTION__)) | ||||||
7964 | "BEs is <= MaxBruteForceIterations which is an 'unsigned'!")((BEs.getActiveBits() < 8 * sizeof(unsigned) && "BEs is <= MaxBruteForceIterations which is an 'unsigned'!" ) ? static_cast<void> (0) : __assert_fail ("BEs.getActiveBits() < CHAR_BIT * sizeof(unsigned) && \"BEs is <= MaxBruteForceIterations which is an 'unsigned'!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 7964, __PRETTY_FUNCTION__)); | ||||||
7965 | |||||||
7966 | unsigned NumIterations = BEs.getZExtValue(); // must be in range | ||||||
7967 | unsigned IterationNum = 0; | ||||||
7968 | const DataLayout &DL = getDataLayout(); | ||||||
7969 | for (; ; ++IterationNum) { | ||||||
7970 | if (IterationNum == NumIterations) | ||||||
7971 | return RetVal = CurrentIterVals[PN]; // Got exit value! | ||||||
7972 | |||||||
7973 | // Compute the value of the PHIs for the next iteration. | ||||||
7974 | // EvaluateExpression adds non-phi values to the CurrentIterVals map. | ||||||
7975 | DenseMap<Instruction *, Constant *> NextIterVals; | ||||||
7976 | Constant *NextPHI = | ||||||
7977 | EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI); | ||||||
7978 | if (!NextPHI) | ||||||
7979 | return nullptr; // Couldn't evaluate! | ||||||
7980 | NextIterVals[PN] = NextPHI; | ||||||
7981 | |||||||
7982 | bool StoppedEvolving = NextPHI == CurrentIterVals[PN]; | ||||||
7983 | |||||||
7984 | // Also evaluate the other PHI nodes. However, we don't get to stop if we | ||||||
7985 | // cease to be able to evaluate one of them or if they stop evolving, | ||||||
7986 | // because that doesn't necessarily prevent us from computing PN. | ||||||
7987 | SmallVector<std::pair<PHINode *, Constant *>, 8> PHIsToCompute; | ||||||
7988 | for (const auto &I : CurrentIterVals) { | ||||||
7989 | PHINode *PHI = dyn_cast<PHINode>(I.first); | ||||||
7990 | if (!PHI || PHI == PN || PHI->getParent() != Header) continue; | ||||||
7991 | PHIsToCompute.emplace_back(PHI, I.second); | ||||||
7992 | } | ||||||
7993 | // We use two distinct loops because EvaluateExpression may invalidate any | ||||||
7994 | // iterators into CurrentIterVals. | ||||||
7995 | for (const auto &I : PHIsToCompute) { | ||||||
7996 | PHINode *PHI = I.first; | ||||||
7997 | Constant *&NextPHI = NextIterVals[PHI]; | ||||||
7998 | if (!NextPHI) { // Not already computed. | ||||||
7999 | Value *BEValue = PHI->getIncomingValueForBlock(Latch); | ||||||
8000 | NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI); | ||||||
8001 | } | ||||||
8002 | if (NextPHI != I.second) | ||||||
8003 | StoppedEvolving = false; | ||||||
8004 | } | ||||||
8005 | |||||||
8006 | // If all entries in CurrentIterVals == NextIterVals then we can stop | ||||||
8007 | // iterating, the loop can't continue to change. | ||||||
8008 | if (StoppedEvolving) | ||||||
8009 | return RetVal = CurrentIterVals[PN]; | ||||||
8010 | |||||||
8011 | CurrentIterVals.swap(NextIterVals); | ||||||
8012 | } | ||||||
8013 | } | ||||||
8014 | |||||||
8015 | const SCEV *ScalarEvolution::computeExitCountExhaustively(const Loop *L, | ||||||
8016 | Value *Cond, | ||||||
8017 | bool ExitWhen) { | ||||||
8018 | PHINode *PN = getConstantEvolvingPHI(Cond, L); | ||||||
8019 | if (!PN) return getCouldNotCompute(); | ||||||
8020 | |||||||
8021 | // If the loop is canonicalized, the PHI will have exactly two entries. | ||||||
8022 | // That's the only form we support here. | ||||||
8023 | if (PN->getNumIncomingValues() != 2) return getCouldNotCompute(); | ||||||
8024 | |||||||
8025 | DenseMap<Instruction *, Constant *> CurrentIterVals; | ||||||
8026 | BasicBlock *Header = L->getHeader(); | ||||||
8027 | assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!")((PN->getParent() == Header && "Can't evaluate PHI not in loop header!" ) ? static_cast<void> (0) : __assert_fail ("PN->getParent() == Header && \"Can't evaluate PHI not in loop header!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8027, __PRETTY_FUNCTION__)); | ||||||
8028 | |||||||
8029 | BasicBlock *Latch = L->getLoopLatch(); | ||||||
8030 | assert(Latch && "Should follow from NumIncomingValues == 2!")((Latch && "Should follow from NumIncomingValues == 2!" ) ? static_cast<void> (0) : __assert_fail ("Latch && \"Should follow from NumIncomingValues == 2!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8030, __PRETTY_FUNCTION__)); | ||||||
8031 | |||||||
8032 | for (PHINode &PHI : Header->phis()) { | ||||||
8033 | if (auto *StartCST = getOtherIncomingValue(&PHI, Latch)) | ||||||
8034 | CurrentIterVals[&PHI] = StartCST; | ||||||
8035 | } | ||||||
8036 | if (!CurrentIterVals.count(PN)) | ||||||
8037 | return getCouldNotCompute(); | ||||||
8038 | |||||||
8039 | // Okay, we find a PHI node that defines the trip count of this loop. Execute | ||||||
8040 | // the loop symbolically to determine when the condition gets a value of | ||||||
8041 | // "ExitWhen". | ||||||
8042 | unsigned MaxIterations = MaxBruteForceIterations; // Limit analysis. | ||||||
8043 | const DataLayout &DL = getDataLayout(); | ||||||
8044 | for (unsigned IterationNum = 0; IterationNum != MaxIterations;++IterationNum){ | ||||||
8045 | auto *CondVal = dyn_cast_or_null<ConstantInt>( | ||||||
8046 | EvaluateExpression(Cond, L, CurrentIterVals, DL, &TLI)); | ||||||
8047 | |||||||
8048 | // Couldn't symbolically evaluate. | ||||||
8049 | if (!CondVal) return getCouldNotCompute(); | ||||||
8050 | |||||||
8051 | if (CondVal->getValue() == uint64_t(ExitWhen)) { | ||||||
8052 | ++NumBruteForceTripCountsComputed; | ||||||
8053 | return getConstant(Type::getInt32Ty(getContext()), IterationNum); | ||||||
8054 | } | ||||||
8055 | |||||||
8056 | // Update all the PHI nodes for the next iteration. | ||||||
8057 | DenseMap<Instruction *, Constant *> NextIterVals; | ||||||
8058 | |||||||
8059 | // Create a list of which PHIs we need to compute. We want to do this before | ||||||
8060 | // calling EvaluateExpression on them because that may invalidate iterators | ||||||
8061 | // into CurrentIterVals. | ||||||
8062 | SmallVector<PHINode *, 8> PHIsToCompute; | ||||||
8063 | for (const auto &I : CurrentIterVals) { | ||||||
8064 | PHINode *PHI = dyn_cast<PHINode>(I.first); | ||||||
8065 | if (!PHI || PHI->getParent() != Header) continue; | ||||||
8066 | PHIsToCompute.push_back(PHI); | ||||||
8067 | } | ||||||
8068 | for (PHINode *PHI : PHIsToCompute) { | ||||||
8069 | Constant *&NextPHI = NextIterVals[PHI]; | ||||||
8070 | if (NextPHI) continue; // Already computed! | ||||||
8071 | |||||||
8072 | Value *BEValue = PHI->getIncomingValueForBlock(Latch); | ||||||
8073 | NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI); | ||||||
8074 | } | ||||||
8075 | CurrentIterVals.swap(NextIterVals); | ||||||
8076 | } | ||||||
8077 | |||||||
8078 | // Too many iterations were needed to evaluate. | ||||||
8079 | return getCouldNotCompute(); | ||||||
8080 | } | ||||||
8081 | |||||||
8082 | const SCEV *ScalarEvolution::getSCEVAtScope(const SCEV *V, const Loop *L) { | ||||||
8083 | SmallVector<std::pair<const Loop *, const SCEV *>, 2> &Values = | ||||||
8084 | ValuesAtScopes[V]; | ||||||
8085 | // Check to see if we've folded this expression at this loop before. | ||||||
8086 | for (auto &LS : Values) | ||||||
8087 | if (LS.first == L) | ||||||
8088 | return LS.second ? LS.second : V; | ||||||
8089 | |||||||
8090 | Values.emplace_back(L, nullptr); | ||||||
8091 | |||||||
8092 | // Otherwise compute it. | ||||||
8093 | const SCEV *C = computeSCEVAtScope(V, L); | ||||||
8094 | for (auto &LS : reverse(ValuesAtScopes[V])) | ||||||
8095 | if (LS.first == L) { | ||||||
8096 | LS.second = C; | ||||||
8097 | break; | ||||||
8098 | } | ||||||
8099 | return C; | ||||||
8100 | } | ||||||
8101 | |||||||
8102 | /// This builds up a Constant using the ConstantExpr interface. That way, we | ||||||
8103 | /// will return Constants for objects which aren't represented by a | ||||||
8104 | /// SCEVConstant, because SCEVConstant is restricted to ConstantInt. | ||||||
8105 | /// Returns NULL if the SCEV isn't representable as a Constant. | ||||||
8106 | static Constant *BuildConstantFromSCEV(const SCEV *V) { | ||||||
8107 | switch (static_cast<SCEVTypes>(V->getSCEVType())) { | ||||||
8108 | case scCouldNotCompute: | ||||||
8109 | case scAddRecExpr: | ||||||
8110 | break; | ||||||
8111 | case scConstant: | ||||||
8112 | return cast<SCEVConstant>(V)->getValue(); | ||||||
8113 | case scUnknown: | ||||||
8114 | return dyn_cast<Constant>(cast<SCEVUnknown>(V)->getValue()); | ||||||
8115 | case scSignExtend: { | ||||||
8116 | const SCEVSignExtendExpr *SS = cast<SCEVSignExtendExpr>(V); | ||||||
8117 | if (Constant *CastOp = BuildConstantFromSCEV(SS->getOperand())) | ||||||
8118 | return ConstantExpr::getSExt(CastOp, SS->getType()); | ||||||
8119 | break; | ||||||
8120 | } | ||||||
8121 | case scZeroExtend: { | ||||||
8122 | const SCEVZeroExtendExpr *SZ = cast<SCEVZeroExtendExpr>(V); | ||||||
8123 | if (Constant *CastOp = BuildConstantFromSCEV(SZ->getOperand())) | ||||||
8124 | return ConstantExpr::getZExt(CastOp, SZ->getType()); | ||||||
8125 | break; | ||||||
8126 | } | ||||||
8127 | case scTruncate: { | ||||||
8128 | const SCEVTruncateExpr *ST = cast<SCEVTruncateExpr>(V); | ||||||
8129 | if (Constant *CastOp = BuildConstantFromSCEV(ST->getOperand())) | ||||||
8130 | return ConstantExpr::getTrunc(CastOp, ST->getType()); | ||||||
8131 | break; | ||||||
8132 | } | ||||||
8133 | case scAddExpr: { | ||||||
8134 | const SCEVAddExpr *SA = cast<SCEVAddExpr>(V); | ||||||
8135 | if (Constant *C = BuildConstantFromSCEV(SA->getOperand(0))) { | ||||||
8136 | if (PointerType *PTy = dyn_cast<PointerType>(C->getType())) { | ||||||
8137 | unsigned AS = PTy->getAddressSpace(); | ||||||
8138 | Type *DestPtrTy = Type::getInt8PtrTy(C->getContext(), AS); | ||||||
8139 | C = ConstantExpr::getBitCast(C, DestPtrTy); | ||||||
8140 | } | ||||||
8141 | for (unsigned i = 1, e = SA->getNumOperands(); i != e; ++i) { | ||||||
8142 | Constant *C2 = BuildConstantFromSCEV(SA->getOperand(i)); | ||||||
8143 | if (!C2) return nullptr; | ||||||
8144 | |||||||
8145 | // First pointer! | ||||||
8146 | if (!C->getType()->isPointerTy() && C2->getType()->isPointerTy()) { | ||||||
8147 | unsigned AS = C2->getType()->getPointerAddressSpace(); | ||||||
8148 | std::swap(C, C2); | ||||||
8149 | Type *DestPtrTy = Type::getInt8PtrTy(C->getContext(), AS); | ||||||
8150 | // The offsets have been converted to bytes. We can add bytes to an | ||||||
8151 | // i8* by GEP with the byte count in the first index. | ||||||
8152 | C = ConstantExpr::getBitCast(C, DestPtrTy); | ||||||
8153 | } | ||||||
8154 | |||||||
8155 | // Don't bother trying to sum two pointers. We probably can't | ||||||
8156 | // statically compute a load that results from it anyway. | ||||||
8157 | if (C2->getType()->isPointerTy()) | ||||||
8158 | return nullptr; | ||||||
8159 | |||||||
8160 | if (PointerType *PTy = dyn_cast<PointerType>(C->getType())) { | ||||||
8161 | if (PTy->getElementType()->isStructTy()) | ||||||
8162 | C2 = ConstantExpr::getIntegerCast( | ||||||
8163 | C2, Type::getInt32Ty(C->getContext()), true); | ||||||
8164 | C = ConstantExpr::getGetElementPtr(PTy->getElementType(), C, C2); | ||||||
8165 | } else | ||||||
8166 | C = ConstantExpr::getAdd(C, C2); | ||||||
8167 | } | ||||||
8168 | return C; | ||||||
8169 | } | ||||||
8170 | break; | ||||||
8171 | } | ||||||
8172 | case scMulExpr: { | ||||||
8173 | const SCEVMulExpr *SM = cast<SCEVMulExpr>(V); | ||||||
8174 | if (Constant *C = BuildConstantFromSCEV(SM->getOperand(0))) { | ||||||
8175 | // Don't bother with pointers at all. | ||||||
8176 | if (C->getType()->isPointerTy()) return nullptr; | ||||||
8177 | for (unsigned i = 1, e = SM->getNumOperands(); i != e; ++i) { | ||||||
8178 | Constant *C2 = BuildConstantFromSCEV(SM->getOperand(i)); | ||||||
8179 | if (!C2 || C2->getType()->isPointerTy()) return nullptr; | ||||||
8180 | C = ConstantExpr::getMul(C, C2); | ||||||
8181 | } | ||||||
8182 | return C; | ||||||
8183 | } | ||||||
8184 | break; | ||||||
8185 | } | ||||||
8186 | case scUDivExpr: { | ||||||
8187 | const SCEVUDivExpr *SU = cast<SCEVUDivExpr>(V); | ||||||
8188 | if (Constant *LHS = BuildConstantFromSCEV(SU->getLHS())) | ||||||
8189 | if (Constant *RHS = BuildConstantFromSCEV(SU->getRHS())) | ||||||
8190 | if (LHS->getType() == RHS->getType()) | ||||||
8191 | return ConstantExpr::getUDiv(LHS, RHS); | ||||||
8192 | break; | ||||||
8193 | } | ||||||
8194 | case scSMaxExpr: | ||||||
8195 | case scUMaxExpr: | ||||||
8196 | case scSMinExpr: | ||||||
8197 | case scUMinExpr: | ||||||
8198 | break; // TODO: smax, umax, smin, umax. | ||||||
8199 | } | ||||||
8200 | return nullptr; | ||||||
8201 | } | ||||||
8202 | |||||||
8203 | const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) { | ||||||
8204 | if (isa<SCEVConstant>(V)) return V; | ||||||
8205 | |||||||
8206 | // If this instruction is evolved from a constant-evolving PHI, compute the | ||||||
8207 | // exit value from the loop without using SCEVs. | ||||||
8208 | if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(V)) { | ||||||
8209 | if (Instruction *I = dyn_cast<Instruction>(SU->getValue())) { | ||||||
8210 | if (PHINode *PN = dyn_cast<PHINode>(I)) { | ||||||
8211 | const Loop *LI = this->LI[I->getParent()]; | ||||||
8212 | // Looking for loop exit value. | ||||||
8213 | if (LI && LI->getParentLoop() == L && | ||||||
8214 | PN->getParent() == LI->getHeader()) { | ||||||
8215 | // Okay, there is no closed form solution for the PHI node. Check | ||||||
8216 | // to see if the loop that contains it has a known backedge-taken | ||||||
8217 | // count. If so, we may be able to force computation of the exit | ||||||
8218 | // value. | ||||||
8219 | const SCEV *BackedgeTakenCount = getBackedgeTakenCount(LI); | ||||||
8220 | // This trivial case can show up in some degenerate cases where | ||||||
8221 | // the incoming IR has not yet been fully simplified. | ||||||
8222 | if (BackedgeTakenCount->isZero()) { | ||||||
8223 | Value *InitValue = nullptr; | ||||||
8224 | bool MultipleInitValues = false; | ||||||
8225 | for (unsigned i = 0; i < PN->getNumIncomingValues(); i++) { | ||||||
8226 | if (!LI->contains(PN->getIncomingBlock(i))) { | ||||||
8227 | if (!InitValue) | ||||||
8228 | InitValue = PN->getIncomingValue(i); | ||||||
8229 | else if (InitValue != PN->getIncomingValue(i)) { | ||||||
8230 | MultipleInitValues = true; | ||||||
8231 | break; | ||||||
8232 | } | ||||||
8233 | } | ||||||
8234 | } | ||||||
8235 | if (!MultipleInitValues && InitValue) | ||||||
8236 | return getSCEV(InitValue); | ||||||
8237 | } | ||||||
8238 | // Do we have a loop invariant value flowing around the backedge | ||||||
8239 | // for a loop which must execute the backedge? | ||||||
8240 | if (!isa<SCEVCouldNotCompute>(BackedgeTakenCount) && | ||||||
8241 | isKnownPositive(BackedgeTakenCount) && | ||||||
8242 | PN->getNumIncomingValues() == 2) { | ||||||
8243 | unsigned InLoopPred = LI->contains(PN->getIncomingBlock(0)) ? 0 : 1; | ||||||
8244 | const SCEV *OnBackedge = getSCEV(PN->getIncomingValue(InLoopPred)); | ||||||
8245 | if (IsAvailableOnEntry(LI, DT, OnBackedge, PN->getParent())) | ||||||
8246 | return OnBackedge; | ||||||
8247 | } | ||||||
8248 | if (auto *BTCC = dyn_cast<SCEVConstant>(BackedgeTakenCount)) { | ||||||
8249 | // Okay, we know how many times the containing loop executes. If | ||||||
8250 | // this is a constant evolving PHI node, get the final value at | ||||||
8251 | // the specified iteration number. | ||||||
8252 | Constant *RV = | ||||||
8253 | getConstantEvolutionLoopExitValue(PN, BTCC->getAPInt(), LI); | ||||||
8254 | if (RV) return getSCEV(RV); | ||||||
8255 | } | ||||||
8256 | } | ||||||
8257 | |||||||
8258 | // If there is a single-input Phi, evaluate it at our scope. If we can | ||||||
8259 | // prove that this replacement does not break LCSSA form, use new value. | ||||||
8260 | if (PN->getNumOperands() == 1) { | ||||||
8261 | const SCEV *Input = getSCEV(PN->getOperand(0)); | ||||||
8262 | const SCEV *InputAtScope = getSCEVAtScope(Input, L); | ||||||
8263 | // TODO: We can generalize it using LI.replacementPreservesLCSSAForm, | ||||||
8264 | // for the simplest case just support constants. | ||||||
8265 | if (isa<SCEVConstant>(InputAtScope)) return InputAtScope; | ||||||
8266 | } | ||||||
8267 | } | ||||||
8268 | |||||||
8269 | // Okay, this is an expression that we cannot symbolically evaluate | ||||||
8270 | // into a SCEV. Check to see if it's possible to symbolically evaluate | ||||||
8271 | // the arguments into constants, and if so, try to constant propagate the | ||||||
8272 | // result. This is particularly useful for computing loop exit values. | ||||||
8273 | if (CanConstantFold(I)) { | ||||||
8274 | SmallVector<Constant *, 4> Operands; | ||||||
8275 | bool MadeImprovement = false; | ||||||
8276 | for (Value *Op : I->operands()) { | ||||||
8277 | if (Constant *C = dyn_cast<Constant>(Op)) { | ||||||
8278 | Operands.push_back(C); | ||||||
8279 | continue; | ||||||
8280 | } | ||||||
8281 | |||||||
8282 | // If any of the operands is non-constant and if they are | ||||||
8283 | // non-integer and non-pointer, don't even try to analyze them | ||||||
8284 | // with scev techniques. | ||||||
8285 | if (!isSCEVable(Op->getType())) | ||||||
8286 | return V; | ||||||
8287 | |||||||
8288 | const SCEV *OrigV = getSCEV(Op); | ||||||
8289 | const SCEV *OpV = getSCEVAtScope(OrigV, L); | ||||||
8290 | MadeImprovement |= OrigV != OpV; | ||||||
8291 | |||||||
8292 | Constant *C = BuildConstantFromSCEV(OpV); | ||||||
8293 | if (!C) return V; | ||||||
8294 | if (C->getType() != Op->getType()) | ||||||
8295 | C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false, | ||||||
8296 | Op->getType(), | ||||||
8297 | false), | ||||||
8298 | C, Op->getType()); | ||||||
8299 | Operands.push_back(C); | ||||||
8300 | } | ||||||
8301 | |||||||
8302 | // Check to see if getSCEVAtScope actually made an improvement. | ||||||
8303 | if (MadeImprovement) { | ||||||
8304 | Constant *C = nullptr; | ||||||
8305 | const DataLayout &DL = getDataLayout(); | ||||||
8306 | if (const CmpInst *CI = dyn_cast<CmpInst>(I)) | ||||||
8307 | C = ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0], | ||||||
8308 | Operands[1], DL, &TLI); | ||||||
8309 | else if (const LoadInst *LI = dyn_cast<LoadInst>(I)) { | ||||||
8310 | if (!LI->isVolatile()) | ||||||
8311 | C = ConstantFoldLoadFromConstPtr(Operands[0], LI->getType(), DL); | ||||||
8312 | } else | ||||||
8313 | C = ConstantFoldInstOperands(I, Operands, DL, &TLI); | ||||||
8314 | if (!C) return V; | ||||||
8315 | return getSCEV(C); | ||||||
8316 | } | ||||||
8317 | } | ||||||
8318 | } | ||||||
8319 | |||||||
8320 | // This is some other type of SCEVUnknown, just return it. | ||||||
8321 | return V; | ||||||
8322 | } | ||||||
8323 | |||||||
8324 | if (const SCEVCommutativeExpr *Comm = dyn_cast<SCEVCommutativeExpr>(V)) { | ||||||
8325 | // Avoid performing the look-up in the common case where the specified | ||||||
8326 | // expression has no loop-variant portions. | ||||||
8327 | for (unsigned i = 0, e = Comm->getNumOperands(); i != e; ++i) { | ||||||
8328 | const SCEV *OpAtScope = getSCEVAtScope(Comm->getOperand(i), L); | ||||||
8329 | if (OpAtScope != Comm->getOperand(i)) { | ||||||
8330 | // Okay, at least one of these operands is loop variant but might be | ||||||
8331 | // foldable. Build a new instance of the folded commutative expression. | ||||||
8332 | SmallVector<const SCEV *, 8> NewOps(Comm->op_begin(), | ||||||
8333 | Comm->op_begin()+i); | ||||||
8334 | NewOps.push_back(OpAtScope); | ||||||
8335 | |||||||
8336 | for (++i; i != e; ++i) { | ||||||
8337 | OpAtScope = getSCEVAtScope(Comm->getOperand(i), L); | ||||||
8338 | NewOps.push_back(OpAtScope); | ||||||
8339 | } | ||||||
8340 | if (isa<SCEVAddExpr>(Comm)) | ||||||
8341 | return getAddExpr(NewOps, Comm->getNoWrapFlags()); | ||||||
8342 | if (isa<SCEVMulExpr>(Comm)) | ||||||
8343 | return getMulExpr(NewOps, Comm->getNoWrapFlags()); | ||||||
8344 | if (isa<SCEVMinMaxExpr>(Comm)) | ||||||
8345 | return getMinMaxExpr(Comm->getSCEVType(), NewOps); | ||||||
8346 | llvm_unreachable("Unknown commutative SCEV type!")::llvm::llvm_unreachable_internal("Unknown commutative SCEV type!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8346); | ||||||
8347 | } | ||||||
8348 | } | ||||||
8349 | // If we got here, all operands are loop invariant. | ||||||
8350 | return Comm; | ||||||
8351 | } | ||||||
8352 | |||||||
8353 | if (const SCEVUDivExpr *Div = dyn_cast<SCEVUDivExpr>(V)) { | ||||||
8354 | const SCEV *LHS = getSCEVAtScope(Div->getLHS(), L); | ||||||
8355 | const SCEV *RHS = getSCEVAtScope(Div->getRHS(), L); | ||||||
8356 | if (LHS == Div->getLHS() && RHS == Div->getRHS()) | ||||||
8357 | return Div; // must be loop invariant | ||||||
8358 | return getUDivExpr(LHS, RHS); | ||||||
8359 | } | ||||||
8360 | |||||||
8361 | // If this is a loop recurrence for a loop that does not contain L, then we | ||||||
8362 | // are dealing with the final value computed by the loop. | ||||||
8363 | if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) { | ||||||
8364 | // First, attempt to evaluate each operand. | ||||||
8365 | // Avoid performing the look-up in the common case where the specified | ||||||
8366 | // expression has no loop-variant portions. | ||||||
8367 | for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) { | ||||||
8368 | const SCEV *OpAtScope = getSCEVAtScope(AddRec->getOperand(i), L); | ||||||
8369 | if (OpAtScope == AddRec->getOperand(i)) | ||||||
8370 | continue; | ||||||
8371 | |||||||
8372 | // Okay, at least one of these operands is loop variant but might be | ||||||
8373 | // foldable. Build a new instance of the folded commutative expression. | ||||||
8374 | SmallVector<const SCEV *, 8> NewOps(AddRec->op_begin(), | ||||||
8375 | AddRec->op_begin()+i); | ||||||
8376 | NewOps.push_back(OpAtScope); | ||||||
8377 | for (++i; i != e; ++i) | ||||||
8378 | NewOps.push_back(getSCEVAtScope(AddRec->getOperand(i), L)); | ||||||
8379 | |||||||
8380 | const SCEV *FoldedRec = | ||||||
8381 | getAddRecExpr(NewOps, AddRec->getLoop(), | ||||||
8382 | AddRec->getNoWrapFlags(SCEV::FlagNW)); | ||||||
8383 | AddRec = dyn_cast<SCEVAddRecExpr>(FoldedRec); | ||||||
8384 | // The addrec may be folded to a nonrecurrence, for example, if the | ||||||
8385 | // induction variable is multiplied by zero after constant folding. Go | ||||||
8386 | // ahead and return the folded value. | ||||||
8387 | if (!AddRec) | ||||||
8388 | return FoldedRec; | ||||||
8389 | break; | ||||||
8390 | } | ||||||
8391 | |||||||
8392 | // If the scope is outside the addrec's loop, evaluate it by using the | ||||||
8393 | // loop exit value of the addrec. | ||||||
8394 | if (!AddRec->getLoop()->contains(L)) { | ||||||
8395 | // To evaluate this recurrence, we need to know how many times the AddRec | ||||||
8396 | // loop iterates. Compute this now. | ||||||
8397 | const SCEV *BackedgeTakenCount = getBackedgeTakenCount(AddRec->getLoop()); | ||||||
8398 | if (BackedgeTakenCount == getCouldNotCompute()) return AddRec; | ||||||
8399 | |||||||
8400 | // Then, evaluate the AddRec. | ||||||
8401 | return AddRec->evaluateAtIteration(BackedgeTakenCount, *this); | ||||||
8402 | } | ||||||
8403 | |||||||
8404 | return AddRec; | ||||||
8405 | } | ||||||
8406 | |||||||
8407 | if (const SCEVZeroExtendExpr *Cast = dyn_cast<SCEVZeroExtendExpr>(V)) { | ||||||
8408 | const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L); | ||||||
8409 | if (Op == Cast->getOperand()) | ||||||
8410 | return Cast; // must be loop invariant | ||||||
8411 | return getZeroExtendExpr(Op, Cast->getType()); | ||||||
8412 | } | ||||||
8413 | |||||||
8414 | if (const SCEVSignExtendExpr *Cast = dyn_cast<SCEVSignExtendExpr>(V)) { | ||||||
8415 | const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L); | ||||||
8416 | if (Op == Cast->getOperand()) | ||||||
8417 | return Cast; // must be loop invariant | ||||||
8418 | return getSignExtendExpr(Op, Cast->getType()); | ||||||
8419 | } | ||||||
8420 | |||||||
8421 | if (const SCEVTruncateExpr *Cast = dyn_cast<SCEVTruncateExpr>(V)) { | ||||||
8422 | const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L); | ||||||
8423 | if (Op == Cast->getOperand()) | ||||||
8424 | return Cast; // must be loop invariant | ||||||
8425 | return getTruncateExpr(Op, Cast->getType()); | ||||||
8426 | } | ||||||
8427 | |||||||
8428 | llvm_unreachable("Unknown SCEV type!")::llvm::llvm_unreachable_internal("Unknown SCEV type!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8428); | ||||||
8429 | } | ||||||
8430 | |||||||
8431 | const SCEV *ScalarEvolution::getSCEVAtScope(Value *V, const Loop *L) { | ||||||
8432 | return getSCEVAtScope(getSCEV(V), L); | ||||||
8433 | } | ||||||
8434 | |||||||
8435 | const SCEV *ScalarEvolution::stripInjectiveFunctions(const SCEV *S) const { | ||||||
8436 | if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) | ||||||
8437 | return stripInjectiveFunctions(ZExt->getOperand()); | ||||||
8438 | if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) | ||||||
8439 | return stripInjectiveFunctions(SExt->getOperand()); | ||||||
8440 | return S; | ||||||
8441 | } | ||||||
8442 | |||||||
8443 | /// Finds the minimum unsigned root of the following equation: | ||||||
8444 | /// | ||||||
8445 | /// A * X = B (mod N) | ||||||
8446 | /// | ||||||
8447 | /// where N = 2^BW and BW is the common bit width of A and B. The signedness of | ||||||
8448 | /// A and B isn't important. | ||||||
8449 | /// | ||||||
8450 | /// If the equation does not have a solution, SCEVCouldNotCompute is returned. | ||||||
8451 | static const SCEV *SolveLinEquationWithOverflow(const APInt &A, const SCEV *B, | ||||||
8452 | ScalarEvolution &SE) { | ||||||
8453 | uint32_t BW = A.getBitWidth(); | ||||||
8454 | assert(BW == SE.getTypeSizeInBits(B->getType()))((BW == SE.getTypeSizeInBits(B->getType())) ? static_cast< void> (0) : __assert_fail ("BW == SE.getTypeSizeInBits(B->getType())" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8454, __PRETTY_FUNCTION__)); | ||||||
8455 | assert(A != 0 && "A must be non-zero.")((A != 0 && "A must be non-zero.") ? static_cast<void > (0) : __assert_fail ("A != 0 && \"A must be non-zero.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8455, __PRETTY_FUNCTION__)); | ||||||
8456 | |||||||
8457 | // 1. D = gcd(A, N) | ||||||
8458 | // | ||||||
8459 | // The gcd of A and N may have only one prime factor: 2. The number of | ||||||
8460 | // trailing zeros in A is its multiplicity | ||||||
8461 | uint32_t Mult2 = A.countTrailingZeros(); | ||||||
8462 | // D = 2^Mult2 | ||||||
8463 | |||||||
8464 | // 2. Check if B is divisible by D. | ||||||
8465 | // | ||||||
8466 | // B is divisible by D if and only if the multiplicity of prime factor 2 for B | ||||||
8467 | // is not less than multiplicity of this prime factor for D. | ||||||
8468 | if (SE.GetMinTrailingZeros(B) < Mult2) | ||||||
8469 | return SE.getCouldNotCompute(); | ||||||
8470 | |||||||
8471 | // 3. Compute I: the multiplicative inverse of (A / D) in arithmetic | ||||||
8472 | // modulo (N / D). | ||||||
8473 | // | ||||||
8474 | // If D == 1, (N / D) == N == 2^BW, so we need one extra bit to represent | ||||||
8475 | // (N / D) in general. The inverse itself always fits into BW bits, though, | ||||||
8476 | // so we immediately truncate it. | ||||||
8477 | APInt AD = A.lshr(Mult2).zext(BW + 1); // AD = A / D | ||||||
8478 | APInt Mod(BW + 1, 0); | ||||||
8479 | Mod.setBit(BW - Mult2); // Mod = N / D | ||||||
8480 | APInt I = AD.multiplicativeInverse(Mod).trunc(BW); | ||||||
8481 | |||||||
8482 | // 4. Compute the minimum unsigned root of the equation: | ||||||
8483 | // I * (B / D) mod (N / D) | ||||||
8484 | // To simplify the computation, we factor out the divide by D: | ||||||
8485 | // (I * B mod N) / D | ||||||
8486 | const SCEV *D = SE.getConstant(APInt::getOneBitSet(BW, Mult2)); | ||||||
8487 | return SE.getUDivExactExpr(SE.getMulExpr(B, SE.getConstant(I)), D); | ||||||
8488 | } | ||||||
8489 | |||||||
8490 | /// For a given quadratic addrec, generate coefficients of the corresponding | ||||||
8491 | /// quadratic equation, multiplied by a common value to ensure that they are | ||||||
8492 | /// integers. | ||||||
8493 | /// The returned value is a tuple { A, B, C, M, BitWidth }, where | ||||||
8494 | /// Ax^2 + Bx + C is the quadratic function, M is the value that A, B and C | ||||||
8495 | /// were multiplied by, and BitWidth is the bit width of the original addrec | ||||||
8496 | /// coefficients. | ||||||
8497 | /// This function returns None if the addrec coefficients are not compile- | ||||||
8498 | /// time constants. | ||||||
8499 | static Optional<std::tuple<APInt, APInt, APInt, APInt, unsigned>> | ||||||
8500 | GetQuadraticEquation(const SCEVAddRecExpr *AddRec) { | ||||||
8501 | assert(AddRec->getNumOperands() == 3 && "This is not a quadratic chrec!")((AddRec->getNumOperands() == 3 && "This is not a quadratic chrec!" ) ? static_cast<void> (0) : __assert_fail ("AddRec->getNumOperands() == 3 && \"This is not a quadratic chrec!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8501, __PRETTY_FUNCTION__)); | ||||||
8502 | const SCEVConstant *LC = dyn_cast<SCEVConstant>(AddRec->getOperand(0)); | ||||||
8503 | const SCEVConstant *MC = dyn_cast<SCEVConstant>(AddRec->getOperand(1)); | ||||||
8504 | const SCEVConstant *NC = dyn_cast<SCEVConstant>(AddRec->getOperand(2)); | ||||||
8505 | LLVM_DEBUG(dbgs() << __func__ << ": analyzing quadratic addrec: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": analyzing quadratic addrec: " << *AddRec << '\n'; } } while (false) | ||||||
8506 | << *AddRec << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": analyzing quadratic addrec: " << *AddRec << '\n'; } } while (false); | ||||||
8507 | |||||||
8508 | // We currently can only solve this if the coefficients are constants. | ||||||
8509 | if (!LC || !MC || !NC) { | ||||||
8510 | LLVM_DEBUG(dbgs() << __func__ << ": coefficients are not constant\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": coefficients are not constant\n" ; } } while (false); | ||||||
8511 | return None; | ||||||
8512 | } | ||||||
8513 | |||||||
8514 | APInt L = LC->getAPInt(); | ||||||
8515 | APInt M = MC->getAPInt(); | ||||||
8516 | APInt N = NC->getAPInt(); | ||||||
8517 | assert(!N.isNullValue() && "This is not a quadratic addrec")((!N.isNullValue() && "This is not a quadratic addrec" ) ? static_cast<void> (0) : __assert_fail ("!N.isNullValue() && \"This is not a quadratic addrec\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8517, __PRETTY_FUNCTION__)); | ||||||
8518 | |||||||
8519 | unsigned BitWidth = LC->getAPInt().getBitWidth(); | ||||||
8520 | unsigned NewWidth = BitWidth + 1; | ||||||
8521 | LLVM_DEBUG(dbgs() << __func__ << ": addrec coeff bw: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": addrec coeff bw: " << BitWidth << '\n'; } } while (false) | ||||||
8522 | << BitWidth << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": addrec coeff bw: " << BitWidth << '\n'; } } while (false); | ||||||
8523 | // The sign-extension (as opposed to a zero-extension) here matches the | ||||||
8524 | // extension used in SolveQuadraticEquationWrap (with the same motivation). | ||||||
8525 | N = N.sext(NewWidth); | ||||||
8526 | M = M.sext(NewWidth); | ||||||
8527 | L = L.sext(NewWidth); | ||||||
8528 | |||||||
8529 | // The increments are M, M+N, M+2N, ..., so the accumulated values are | ||||||
8530 | // L+M, (L+M)+(M+N), (L+M)+(M+N)+(M+2N), ..., that is, | ||||||
8531 | // L+M, L+2M+N, L+3M+3N, ... | ||||||
8532 | // After n iterations the accumulated value Acc is L + nM + n(n-1)/2 N. | ||||||
8533 | // | ||||||
8534 | // The equation Acc = 0 is then | ||||||
8535 | // L + nM + n(n-1)/2 N = 0, or 2L + 2M n + n(n-1) N = 0. | ||||||
8536 | // In a quadratic form it becomes: | ||||||
8537 | // N n^2 + (2M-N) n + 2L = 0. | ||||||
8538 | |||||||
8539 | APInt A = N; | ||||||
8540 | APInt B = 2 * M - A; | ||||||
8541 | APInt C = 2 * L; | ||||||
8542 | APInt T = APInt(NewWidth, 2); | ||||||
8543 | LLVM_DEBUG(dbgs() << __func__ << ": equation " << A << "x^2 + " << Bdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": equation " << A << "x^2 + " << B << "x + " << C << ", coeff bw: " << NewWidth << ", multiplied by " << T << '\n'; } } while (false) | ||||||
8544 | << "x + " << C << ", coeff bw: " << NewWidthdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": equation " << A << "x^2 + " << B << "x + " << C << ", coeff bw: " << NewWidth << ", multiplied by " << T << '\n'; } } while (false) | ||||||
8545 | << ", multiplied by " << T << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": equation " << A << "x^2 + " << B << "x + " << C << ", coeff bw: " << NewWidth << ", multiplied by " << T << '\n'; } } while (false); | ||||||
8546 | return std::make_tuple(A, B, C, T, BitWidth); | ||||||
8547 | } | ||||||
8548 | |||||||
8549 | /// Helper function to compare optional APInts: | ||||||
8550 | /// (a) if X and Y both exist, return min(X, Y), | ||||||
8551 | /// (b) if neither X nor Y exist, return None, | ||||||
8552 | /// (c) if exactly one of X and Y exists, return that value. | ||||||
8553 | static Optional<APInt> MinOptional(Optional<APInt> X, Optional<APInt> Y) { | ||||||
8554 | if (X.hasValue() && Y.hasValue()) { | ||||||
8555 | unsigned W = std::max(X->getBitWidth(), Y->getBitWidth()); | ||||||
8556 | APInt XW = X->sextOrSelf(W); | ||||||
8557 | APInt YW = Y->sextOrSelf(W); | ||||||
8558 | return XW.slt(YW) ? *X : *Y; | ||||||
8559 | } | ||||||
8560 | if (!X.hasValue() && !Y.hasValue()) | ||||||
8561 | return None; | ||||||
8562 | return X.hasValue() ? *X : *Y; | ||||||
8563 | } | ||||||
8564 | |||||||
8565 | /// Helper function to truncate an optional APInt to a given BitWidth. | ||||||
8566 | /// When solving addrec-related equations, it is preferable to return a value | ||||||
8567 | /// that has the same bit width as the original addrec's coefficients. If the | ||||||
8568 | /// solution fits in the original bit width, truncate it (except for i1). | ||||||
8569 | /// Returning a value of a different bit width may inhibit some optimizations. | ||||||
8570 | /// | ||||||
8571 | /// In general, a solution to a quadratic equation generated from an addrec | ||||||
8572 | /// may require BW+1 bits, where BW is the bit width of the addrec's | ||||||
8573 | /// coefficients. The reason is that the coefficients of the quadratic | ||||||
8574 | /// equation are BW+1 bits wide (to avoid truncation when converting from | ||||||
8575 | /// the addrec to the equation). | ||||||
8576 | static Optional<APInt> TruncIfPossible(Optional<APInt> X, unsigned BitWidth) { | ||||||
8577 | if (!X.hasValue()) | ||||||
8578 | return None; | ||||||
8579 | unsigned W = X->getBitWidth(); | ||||||
8580 | if (BitWidth > 1 && BitWidth < W && X->isIntN(BitWidth)) | ||||||
8581 | return X->trunc(BitWidth); | ||||||
8582 | return X; | ||||||
8583 | } | ||||||
8584 | |||||||
8585 | /// Let c(n) be the value of the quadratic chrec {L,+,M,+,N} after n | ||||||
8586 | /// iterations. The values L, M, N are assumed to be signed, and they | ||||||
8587 | /// should all have the same bit widths. | ||||||
8588 | /// Find the least n >= 0 such that c(n) = 0 in the arithmetic modulo 2^BW, | ||||||
8589 | /// where BW is the bit width of the addrec's coefficients. | ||||||
8590 | /// If the calculated value is a BW-bit integer (for BW > 1), it will be | ||||||
8591 | /// returned as such, otherwise the bit width of the returned value may | ||||||
8592 | /// be greater than BW. | ||||||
8593 | /// | ||||||
8594 | /// This function returns None if | ||||||
8595 | /// (a) the addrec coefficients are not constant, or | ||||||
8596 | /// (b) SolveQuadraticEquationWrap was unable to find a solution. For cases | ||||||
8597 | /// like x^2 = 5, no integer solutions exist, in other cases an integer | ||||||
8598 | /// solution may exist, but SolveQuadraticEquationWrap may fail to find it. | ||||||
8599 | static Optional<APInt> | ||||||
8600 | SolveQuadraticAddRecExact(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) { | ||||||
8601 | APInt A, B, C, M; | ||||||
8602 | unsigned BitWidth; | ||||||
8603 | auto T = GetQuadraticEquation(AddRec); | ||||||
8604 | if (!T.hasValue()) | ||||||
8605 | return None; | ||||||
8606 | |||||||
8607 | std::tie(A, B, C, M, BitWidth) = *T; | ||||||
8608 | LLVM_DEBUG(dbgs() << __func__ << ": solving for unsigned overflow\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": solving for unsigned overflow\n" ; } } while (false); | ||||||
8609 | Optional<APInt> X = APIntOps::SolveQuadraticEquationWrap(A, B, C, BitWidth+1); | ||||||
8610 | if (!X.hasValue()) | ||||||
8611 | return None; | ||||||
8612 | |||||||
8613 | ConstantInt *CX = ConstantInt::get(SE.getContext(), *X); | ||||||
8614 | ConstantInt *V = EvaluateConstantChrecAtConstant(AddRec, CX, SE); | ||||||
8615 | if (!V->isZero()) | ||||||
8616 | return None; | ||||||
8617 | |||||||
8618 | return TruncIfPossible(X, BitWidth); | ||||||
8619 | } | ||||||
8620 | |||||||
8621 | /// Let c(n) be the value of the quadratic chrec {0,+,M,+,N} after n | ||||||
8622 | /// iterations. The values M, N are assumed to be signed, and they | ||||||
8623 | /// should all have the same bit widths. | ||||||
8624 | /// Find the least n such that c(n) does not belong to the given range, | ||||||
8625 | /// while c(n-1) does. | ||||||
8626 | /// | ||||||
8627 | /// This function returns None if | ||||||
8628 | /// (a) the addrec coefficients are not constant, or | ||||||
8629 | /// (b) SolveQuadraticEquationWrap was unable to find a solution for the | ||||||
8630 | /// bounds of the range. | ||||||
8631 | static Optional<APInt> | ||||||
8632 | SolveQuadraticAddRecRange(const SCEVAddRecExpr *AddRec, | ||||||
8633 | const ConstantRange &Range, ScalarEvolution &SE) { | ||||||
8634 | assert(AddRec->getOperand(0)->isZero() &&((AddRec->getOperand(0)->isZero() && "Starting value of addrec should be 0" ) ? static_cast<void> (0) : __assert_fail ("AddRec->getOperand(0)->isZero() && \"Starting value of addrec should be 0\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8635, __PRETTY_FUNCTION__)) | ||||||
8635 | "Starting value of addrec should be 0")((AddRec->getOperand(0)->isZero() && "Starting value of addrec should be 0" ) ? static_cast<void> (0) : __assert_fail ("AddRec->getOperand(0)->isZero() && \"Starting value of addrec should be 0\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8635, __PRETTY_FUNCTION__)); | ||||||
8636 | LLVM_DEBUG(dbgs() << __func__ << ": solving boundary crossing for range "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": solving boundary crossing for range " << Range << ", addrec " << *AddRec << '\n'; } } while (false) | ||||||
8637 | << Range << ", addrec " << *AddRec << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << __func__ << ": solving boundary crossing for range " << Range << ", addrec " << *AddRec << '\n'; } } while (false); | ||||||
8638 | // This case is handled in getNumIterationsInRange. Here we can assume that | ||||||
8639 | // we start in the range. | ||||||
8640 | assert(Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType()), 0)) &&((Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType ()), 0)) && "Addrec's initial value should be in range" ) ? static_cast<void> (0) : __assert_fail ("Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType()), 0)) && \"Addrec's initial value should be in range\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8641, __PRETTY_FUNCTION__)) | ||||||
8641 | "Addrec's initial value should be in range")((Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType ()), 0)) && "Addrec's initial value should be in range" ) ? static_cast<void> (0) : __assert_fail ("Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType()), 0)) && \"Addrec's initial value should be in range\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 8641, __PRETTY_FUNCTION__)); | ||||||
8642 | |||||||
8643 | APInt A, B, C, M; | ||||||
8644 | unsigned BitWidth; | ||||||
8645 | auto T = GetQuadraticEquation(AddRec); | ||||||
8646 | if (!T.hasValue()) | ||||||
8647 | return None; | ||||||
8648 | |||||||
8649 | // Be careful about the return value: there can be two reasons for not | ||||||
8650 | // returning an actual number. First, if no solutions to the equations | ||||||
8651 | // were found, and second, if the solutions don't leave the given range. | ||||||
8652 | // The first case means that the actual solution is "unknown", the second | ||||||
8653 | // means that it's known, but not valid. If the solution is unknown, we | ||||||
8654 | // cannot make any conclusions. | ||||||
8655 | // Return a pair: the optional solution and a flag indicating if the | ||||||
8656 | // solution was found. | ||||||
8657 | auto SolveForBoundary = [&](APInt Bound) -> std::pair<Optional<APInt>,bool> { | ||||||
8658 | // Solve for signed overflow and unsigned overflow, pick the lower | ||||||
8659 | // solution. | ||||||
8660 | LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: checking boundary "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: checking boundary " << Bound << " (before multiplying by " << M << ")\n"; } } while (false) | ||||||
8661 | << Bound << " (before multiplying by " << M << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: checking boundary " << Bound << " (before multiplying by " << M << ")\n"; } } while (false); | ||||||
8662 | Bound *= M; // The quadratic equation multiplier. | ||||||
8663 | |||||||
8664 | Optional<APInt> SO = None; | ||||||
8665 | if (BitWidth > 1) { | ||||||
8666 | LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: solving for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for " "signed overflow\n"; } } while (false) | ||||||
8667 | "signed overflow\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for " "signed overflow\n"; } } while (false); | ||||||
8668 | SO = APIntOps::SolveQuadraticEquationWrap(A, B, -Bound, BitWidth); | ||||||
8669 | } | ||||||
8670 | LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: solving for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for " "unsigned overflow\n"; } } while (false) | ||||||
8671 | "unsigned overflow\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for " "unsigned overflow\n"; } } while (false); | ||||||
8672 | Optional<APInt> UO = APIntOps::SolveQuadraticEquationWrap(A, B, -Bound, | ||||||
8673 | BitWidth+1); | ||||||
8674 | |||||||
8675 | auto LeavesRange = [&] (const APInt &X) { | ||||||
8676 | ConstantInt *C0 = ConstantInt::get(SE.getContext(), X); | ||||||
8677 | ConstantInt *V0 = EvaluateConstantChrecAtConstant(AddRec, C0, SE); | ||||||
8678 | if (Range.contains(V0->getValue())) | ||||||
8679 | return false; | ||||||
8680 | // X should be at least 1, so X-1 is non-negative. | ||||||
8681 | ConstantInt *C1 = ConstantInt::get(SE.getContext(), X-1); | ||||||
8682 | ConstantInt *V1 = EvaluateConstantChrecAtConstant(AddRec, C1, SE); | ||||||
8683 | if (Range.contains(V1->getValue())) | ||||||
8684 | return true; | ||||||
8685 | return false; | ||||||
8686 | }; | ||||||
8687 | |||||||
8688 | // If SolveQuadraticEquationWrap returns None, it means that there can | ||||||
8689 | // be a solution, but the function failed to find it. We cannot treat it | ||||||
8690 | // as "no solution". | ||||||
8691 | if (!SO.hasValue() || !UO.hasValue()) | ||||||
8692 | return { None, false }; | ||||||
8693 | |||||||
8694 | // Check the smaller value first to see if it leaves the range. | ||||||
8695 | // At this point, both SO and UO must have values. | ||||||
8696 | Optional<APInt> Min = MinOptional(SO, UO); | ||||||
8697 | if (LeavesRange(*Min)) | ||||||
8698 | return { Min, true }; | ||||||
8699 | Optional<APInt> Max = Min == SO ? UO : SO; | ||||||
8700 | if (LeavesRange(*Max)) | ||||||
8701 | return { Max, true }; | ||||||
8702 | |||||||
8703 | // Solutions were found, but were eliminated, hence the "true". | ||||||
8704 | return { None, true }; | ||||||
8705 | }; | ||||||
8706 | |||||||
8707 | std::tie(A, B, C, M, BitWidth) = *T; | ||||||
8708 | // Lower bound is inclusive, subtract 1 to represent the exiting value. | ||||||
8709 | APInt Lower = Range.getLower().sextOrSelf(A.getBitWidth()) - 1; | ||||||
8710 | APInt Upper = Range.getUpper().sextOrSelf(A.getBitWidth()); | ||||||
8711 | auto SL = SolveForBoundary(Lower); | ||||||
8712 | auto SU = SolveForBoundary(Upper); | ||||||
8713 | // If any of the solutions was unknown, no meaninigful conclusions can | ||||||
8714 | // be made. | ||||||
8715 | if (!SL.second || !SU.second) | ||||||
8716 | return None; | ||||||
8717 | |||||||
8718 | // Claim: The correct solution is not some value between Min and Max. | ||||||
8719 | // | ||||||
8720 | // Justification: Assuming that Min and Max are different values, one of | ||||||
8721 | // them is when the first signed overflow happens, the other is when the | ||||||
8722 | // first unsigned overflow happens. Crossing the range boundary is only | ||||||
8723 | // possible via an overflow (treating 0 as a special case of it, modeling | ||||||
8724 | // an overflow as crossing k*2^W for some k). | ||||||
8725 | // | ||||||
8726 | // The interesting case here is when Min was eliminated as an invalid | ||||||
8727 | // solution, but Max was not. The argument is that if there was another | ||||||
8728 | // overflow between Min and Max, it would also have been eliminated if | ||||||
8729 | // it was considered. | ||||||
8730 | // | ||||||
8731 | // For a given boundary, it is possible to have two overflows of the same | ||||||
8732 | // type (signed/unsigned) without having the other type in between: this | ||||||
8733 | // can happen when the vertex of the parabola is between the iterations | ||||||
8734 | // corresponding to the overflows. This is only possible when the two | ||||||
8735 | // overflows cross k*2^W for the same k. In such case, if the second one | ||||||
8736 | // left the range (and was the first one to do so), the first overflow | ||||||
8737 | // would have to enter the range, which would mean that either we had left | ||||||
8738 | // the range before or that we started outside of it. Both of these cases | ||||||
8739 | // are contradictions. | ||||||
8740 | // | ||||||
8741 | // Claim: In the case where SolveForBoundary returns None, the correct | ||||||
8742 | // solution is not some value between the Max for this boundary and the | ||||||
8743 | // Min of the other boundary. | ||||||
8744 | // | ||||||
8745 | // Justification: Assume that we had such Max_A and Min_B corresponding | ||||||
8746 | // to range boundaries A and B and such that Max_A < Min_B. If there was | ||||||
8747 | // a solution between Max_A and Min_B, it would have to be caused by an | ||||||
8748 | // overflow corresponding to either A or B. It cannot correspond to B, | ||||||
8749 | // since Min_B is the first occurrence of such an overflow. If it | ||||||
8750 | // corresponded to A, it would have to be either a signed or an unsigned | ||||||
8751 | // overflow that is larger than both eliminated overflows for A. But | ||||||
8752 | // between the eliminated overflows and this overflow, the values would | ||||||
8753 | // cover the entire value space, thus crossing the other boundary, which | ||||||
8754 | // is a contradiction. | ||||||
8755 | |||||||
8756 | return TruncIfPossible(MinOptional(SL.first, SU.first), BitWidth); | ||||||
8757 | } | ||||||
8758 | |||||||
8759 | ScalarEvolution::ExitLimit | ||||||
8760 | ScalarEvolution::howFarToZero(const SCEV *V, const Loop *L, bool ControlsExit, | ||||||
8761 | bool AllowPredicates) { | ||||||
8762 | |||||||
8763 | // This is only used for loops with a "x != y" exit test. The exit condition | ||||||
8764 | // is now expressed as a single expression, V = x-y. So the exit test is | ||||||
8765 | // effectively V != 0. We know and take advantage of the fact that this | ||||||
8766 | // expression only being used in a comparison by zero context. | ||||||
8767 | |||||||
8768 | SmallPtrSet<const SCEVPredicate *, 4> Predicates; | ||||||
8769 | // If the value is a constant | ||||||
8770 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) { | ||||||
8771 | // If the value is already zero, the branch will execute zero times. | ||||||
8772 | if (C->getValue()->isZero()) return C; | ||||||
8773 | return getCouldNotCompute(); // Otherwise it will loop infinitely. | ||||||
8774 | } | ||||||
8775 | |||||||
8776 | const SCEVAddRecExpr *AddRec = | ||||||
8777 | dyn_cast<SCEVAddRecExpr>(stripInjectiveFunctions(V)); | ||||||
8778 | |||||||
8779 | if (!AddRec && AllowPredicates) | ||||||
8780 | // Try to make this an AddRec using runtime tests, in the first X | ||||||
8781 | // iterations of this loop, where X is the SCEV expression found by the | ||||||
8782 | // algorithm below. | ||||||
8783 | AddRec = convertSCEVToAddRecWithPredicates(V, L, Predicates); | ||||||
8784 | |||||||
8785 | if (!AddRec || AddRec->getLoop() != L) | ||||||
8786 | return getCouldNotCompute(); | ||||||
8787 | |||||||
8788 | // If this is a quadratic (3-term) AddRec {L,+,M,+,N}, find the roots of | ||||||
8789 | // the quadratic equation to solve it. | ||||||
8790 | if (AddRec->isQuadratic() && AddRec->getType()->isIntegerTy()) { | ||||||
8791 | // We can only use this value if the chrec ends up with an exact zero | ||||||
8792 | // value at this index. When solving for "X*X != 5", for example, we | ||||||
8793 | // should not accept a root of 2. | ||||||
8794 | if (auto S = SolveQuadraticAddRecExact(AddRec, *this)) { | ||||||
8795 | const auto *R = cast<SCEVConstant>(getConstant(S.getValue())); | ||||||
8796 | return ExitLimit(R, R, false, Predicates); | ||||||
8797 | } | ||||||
8798 | return getCouldNotCompute(); | ||||||
8799 | } | ||||||
8800 | |||||||
8801 | // Otherwise we can only handle this if it is affine. | ||||||
8802 | if (!AddRec->isAffine()) | ||||||
8803 | return getCouldNotCompute(); | ||||||
8804 | |||||||
8805 | // If this is an affine expression, the execution count of this branch is | ||||||
8806 | // the minimum unsigned root of the following equation: | ||||||
8807 | // | ||||||
8808 | // Start + Step*N = 0 (mod 2^BW) | ||||||
8809 | // | ||||||
8810 | // equivalent to: | ||||||
8811 | // | ||||||
8812 | // Step*N = -Start (mod 2^BW) | ||||||
8813 | // | ||||||
8814 | // where BW is the common bit width of Start and Step. | ||||||
8815 | |||||||
8816 | // Get the initial value for the loop. | ||||||
8817 | const SCEV *Start = getSCEVAtScope(AddRec->getStart(), L->getParentLoop()); | ||||||
8818 | const SCEV *Step = getSCEVAtScope(AddRec->getOperand(1), L->getParentLoop()); | ||||||
8819 | |||||||
8820 | // For now we handle only constant steps. | ||||||
8821 | // | ||||||
8822 | // TODO: Handle a nonconstant Step given AddRec<NUW>. If the | ||||||
8823 | // AddRec is NUW, then (in an unsigned sense) it cannot be counting up to wrap | ||||||
8824 | // to 0, it must be counting down to equal 0. Consequently, N = Start / -Step. | ||||||
8825 | // We have not yet seen any such cases. | ||||||
8826 | const SCEVConstant *StepC = dyn_cast<SCEVConstant>(Step); | ||||||
8827 | if (!StepC || StepC->getValue()->isZero()) | ||||||
8828 | return getCouldNotCompute(); | ||||||
8829 | |||||||
8830 | // For positive steps (counting up until unsigned overflow): | ||||||
8831 | // N = -Start/Step (as unsigned) | ||||||
8832 | // For negative steps (counting down to zero): | ||||||
8833 | // N = Start/-Step | ||||||
8834 | // First compute the unsigned distance from zero in the direction of Step. | ||||||
8835 | bool CountDown = StepC->getAPInt().isNegative(); | ||||||
8836 | const SCEV *Distance = CountDown ? Start : getNegativeSCEV(Start); | ||||||
8837 | |||||||
8838 | // Handle unitary steps, which cannot wraparound. | ||||||
8839 | // 1*N = -Start; -1*N = Start (mod 2^BW), so: | ||||||
8840 | // N = Distance (as unsigned) | ||||||
8841 | if (StepC->getValue()->isOne() || StepC->getValue()->isMinusOne()) { | ||||||
8842 | APInt MaxBECount = getUnsignedRangeMax(Distance); | ||||||
8843 | |||||||
8844 | // When a loop like "for (int i = 0; i != n; ++i) { /* body */ }" is rotated, | ||||||
8845 | // we end up with a loop whose backedge-taken count is n - 1. Detect this | ||||||
8846 | // case, and see if we can improve the bound. | ||||||
8847 | // | ||||||
8848 | // Explicitly handling this here is necessary because getUnsignedRange | ||||||
8849 | // isn't context-sensitive; it doesn't know that we only care about the | ||||||
8850 | // range inside the loop. | ||||||
8851 | const SCEV *Zero = getZero(Distance->getType()); | ||||||
8852 | const SCEV *One = getOne(Distance->getType()); | ||||||
8853 | const SCEV *DistancePlusOne = getAddExpr(Distance, One); | ||||||
8854 | if (isLoopEntryGuardedByCond(L, ICmpInst::ICMP_NE, DistancePlusOne, Zero)) { | ||||||
8855 | // If Distance + 1 doesn't overflow, we can compute the maximum distance | ||||||
8856 | // as "unsigned_max(Distance + 1) - 1". | ||||||
8857 | ConstantRange CR = getUnsignedRange(DistancePlusOne); | ||||||
8858 | MaxBECount = APIntOps::umin(MaxBECount, CR.getUnsignedMax() - 1); | ||||||
8859 | } | ||||||
8860 | return ExitLimit(Distance, getConstant(MaxBECount), false, Predicates); | ||||||
8861 | } | ||||||
8862 | |||||||
8863 | // If the condition controls loop exit (the loop exits only if the expression | ||||||
8864 | // is true) and the addition is no-wrap we can use unsigned divide to | ||||||
8865 | // compute the backedge count. In this case, the step may not divide the | ||||||
8866 | // distance, but we don't care because if the condition is "missed" the loop | ||||||
8867 | // will have undefined behavior due to wrapping. | ||||||
8868 | if (ControlsExit && AddRec->hasNoSelfWrap() && | ||||||
8869 | loopHasNoAbnormalExits(AddRec->getLoop())) { | ||||||
8870 | const SCEV *Exact = | ||||||
8871 | getUDivExpr(Distance, CountDown ? getNegativeSCEV(Step) : Step); | ||||||
8872 | const SCEV *Max = | ||||||
8873 | Exact == getCouldNotCompute() | ||||||
8874 | ? Exact | ||||||
8875 | : getConstant(getUnsignedRangeMax(Exact)); | ||||||
8876 | return ExitLimit(Exact, Max, false, Predicates); | ||||||
8877 | } | ||||||
8878 | |||||||
8879 | // Solve the general equation. | ||||||
8880 | const SCEV *E = SolveLinEquationWithOverflow(StepC->getAPInt(), | ||||||
8881 | getNegativeSCEV(Start), *this); | ||||||
8882 | const SCEV *M = E == getCouldNotCompute() | ||||||
8883 | ? E | ||||||
8884 | : getConstant(getUnsignedRangeMax(E)); | ||||||
8885 | return ExitLimit(E, M, false, Predicates); | ||||||
8886 | } | ||||||
8887 | |||||||
8888 | ScalarEvolution::ExitLimit | ||||||
8889 | ScalarEvolution::howFarToNonZero(const SCEV *V, const Loop *L) { | ||||||
8890 | // Loops that look like: while (X == 0) are very strange indeed. We don't | ||||||
8891 | // handle them yet except for the trivial case. This could be expanded in the | ||||||
8892 | // future as needed. | ||||||
8893 | |||||||
8894 | // If the value is a constant, check to see if it is known to be non-zero | ||||||
8895 | // already. If so, the backedge will execute zero times. | ||||||
8896 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) { | ||||||
8897 | if (!C->getValue()->isZero()) | ||||||
8898 | return getZero(C->getType()); | ||||||
8899 | return getCouldNotCompute(); // Otherwise it will loop infinitely. | ||||||
8900 | } | ||||||
8901 | |||||||
8902 | // We could implement others, but I really doubt anyone writes loops like | ||||||
8903 | // this, and if they did, they would already be constant folded. | ||||||
8904 | return getCouldNotCompute(); | ||||||
8905 | } | ||||||
8906 | |||||||
8907 | std::pair<BasicBlock *, BasicBlock *> | ||||||
8908 | ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB) { | ||||||
8909 | // If the block has a unique predecessor, then there is no path from the | ||||||
8910 | // predecessor to the block that does not go through the direct edge | ||||||
8911 | // from the predecessor to the block. | ||||||
8912 | if (BasicBlock *Pred = BB->getSinglePredecessor()) | ||||||
8913 | return {Pred, BB}; | ||||||
8914 | |||||||
8915 | // A loop's header is defined to be a block that dominates the loop. | ||||||
8916 | // If the header has a unique predecessor outside the loop, it must be | ||||||
8917 | // a block that has exactly one successor that can reach the loop. | ||||||
8918 | if (Loop *L = LI.getLoopFor(BB)) | ||||||
8919 | return {L->getLoopPredecessor(), L->getHeader()}; | ||||||
8920 | |||||||
8921 | return {nullptr, nullptr}; | ||||||
8922 | } | ||||||
8923 | |||||||
8924 | /// SCEV structural equivalence is usually sufficient for testing whether two | ||||||
8925 | /// expressions are equal, however for the purposes of looking for a condition | ||||||
8926 | /// guarding a loop, it can be useful to be a little more general, since a | ||||||
8927 | /// front-end may have replicated the controlling expression. | ||||||
8928 | static bool HasSameValue(const SCEV *A, const SCEV *B) { | ||||||
8929 | // Quick check to see if they are the same SCEV. | ||||||
8930 | if (A == B) return true; | ||||||
8931 | |||||||
8932 | auto ComputesEqualValues = [](const Instruction *A, const Instruction *B) { | ||||||
8933 | // Not all instructions that are "identical" compute the same value. For | ||||||
8934 | // instance, two distinct alloca instructions allocating the same type are | ||||||
8935 | // identical and do not read memory; but compute distinct values. | ||||||
8936 | return A->isIdenticalTo(B) && (isa<BinaryOperator>(A) || isa<GetElementPtrInst>(A)); | ||||||
8937 | }; | ||||||
8938 | |||||||
8939 | // Otherwise, if they're both SCEVUnknown, it's possible that they hold | ||||||
8940 | // two different instructions with the same value. Check for this case. | ||||||
8941 | if (const SCEVUnknown *AU = dyn_cast<SCEVUnknown>(A)) | ||||||
8942 | if (const SCEVUnknown *BU = dyn_cast<SCEVUnknown>(B)) | ||||||
8943 | if (const Instruction *AI = dyn_cast<Instruction>(AU->getValue())) | ||||||
8944 | if (const Instruction *BI = dyn_cast<Instruction>(BU->getValue())) | ||||||
8945 | if (ComputesEqualValues(AI, BI)) | ||||||
8946 | return true; | ||||||
8947 | |||||||
8948 | // Otherwise assume they may have a different value. | ||||||
8949 | return false; | ||||||
8950 | } | ||||||
8951 | |||||||
8952 | bool ScalarEvolution::SimplifyICmpOperands(ICmpInst::Predicate &Pred, | ||||||
8953 | const SCEV *&LHS, const SCEV *&RHS, | ||||||
8954 | unsigned Depth) { | ||||||
8955 | bool Changed = false; | ||||||
8956 | // Simplifies ICMP to trivial true or false by turning it into '0 == 0' or | ||||||
8957 | // '0 != 0'. | ||||||
8958 | auto TrivialCase = [&](bool TriviallyTrue) { | ||||||
8959 | LHS = RHS = getConstant(ConstantInt::getFalse(getContext())); | ||||||
8960 | Pred = TriviallyTrue ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE; | ||||||
8961 | return true; | ||||||
8962 | }; | ||||||
8963 | // If we hit the max recursion limit bail out. | ||||||
8964 | if (Depth >= 3) | ||||||
8965 | return false; | ||||||
8966 | |||||||
8967 | // Canonicalize a constant to the right side. | ||||||
8968 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) { | ||||||
8969 | // Check for both operands constant. | ||||||
8970 | if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) { | ||||||
8971 | if (ConstantExpr::getICmp(Pred, | ||||||
8972 | LHSC->getValue(), | ||||||
8973 | RHSC->getValue())->isNullValue()) | ||||||
8974 | return TrivialCase(false); | ||||||
8975 | else | ||||||
8976 | return TrivialCase(true); | ||||||
8977 | } | ||||||
8978 | // Otherwise swap the operands to put the constant on the right. | ||||||
8979 | std::swap(LHS, RHS); | ||||||
8980 | Pred = ICmpInst::getSwappedPredicate(Pred); | ||||||
8981 | Changed = true; | ||||||
8982 | } | ||||||
8983 | |||||||
8984 | // If we're comparing an addrec with a value which is loop-invariant in the | ||||||
8985 | // addrec's loop, put the addrec on the left. Also make a dominance check, | ||||||
8986 | // as both operands could be addrecs loop-invariant in each other's loop. | ||||||
8987 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS)) { | ||||||
8988 | const Loop *L = AR->getLoop(); | ||||||
8989 | if (isLoopInvariant(LHS, L) && properlyDominates(LHS, L->getHeader())) { | ||||||
8990 | std::swap(LHS, RHS); | ||||||
8991 | Pred = ICmpInst::getSwappedPredicate(Pred); | ||||||
8992 | Changed = true; | ||||||
8993 | } | ||||||
8994 | } | ||||||
8995 | |||||||
8996 | // If there's a constant operand, canonicalize comparisons with boundary | ||||||
8997 | // cases, and canonicalize *-or-equal comparisons to regular comparisons. | ||||||
8998 | if (const SCEVConstant *RC = dyn_cast<SCEVConstant>(RHS)) { | ||||||
8999 | const APInt &RA = RC->getAPInt(); | ||||||
9000 | |||||||
9001 | bool SimplifiedByConstantRange = false; | ||||||
9002 | |||||||
9003 | if (!ICmpInst::isEquality(Pred)) { | ||||||
9004 | ConstantRange ExactCR = ConstantRange::makeExactICmpRegion(Pred, RA); | ||||||
9005 | if (ExactCR.isFullSet()) | ||||||
9006 | return TrivialCase(true); | ||||||
9007 | else if (ExactCR.isEmptySet()) | ||||||
9008 | return TrivialCase(false); | ||||||
9009 | |||||||
9010 | APInt NewRHS; | ||||||
9011 | CmpInst::Predicate NewPred; | ||||||
9012 | if (ExactCR.getEquivalentICmp(NewPred, NewRHS) && | ||||||
9013 | ICmpInst::isEquality(NewPred)) { | ||||||
9014 | // We were able to convert an inequality to an equality. | ||||||
9015 | Pred = NewPred; | ||||||
9016 | RHS = getConstant(NewRHS); | ||||||
9017 | Changed = SimplifiedByConstantRange = true; | ||||||
9018 | } | ||||||
9019 | } | ||||||
9020 | |||||||
9021 | if (!SimplifiedByConstantRange) { | ||||||
9022 | switch (Pred) { | ||||||
9023 | default: | ||||||
9024 | break; | ||||||
9025 | case ICmpInst::ICMP_EQ: | ||||||
9026 | case ICmpInst::ICMP_NE: | ||||||
9027 | // Fold ((-1) * %a) + %b == 0 (equivalent to %b-%a == 0) into %a == %b. | ||||||
9028 | if (!RA) | ||||||
9029 | if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(LHS)) | ||||||
9030 | if (const SCEVMulExpr *ME = | ||||||
9031 | dyn_cast<SCEVMulExpr>(AE->getOperand(0))) | ||||||
9032 | if (AE->getNumOperands() == 2 && ME->getNumOperands() == 2 && | ||||||
9033 | ME->getOperand(0)->isAllOnesValue()) { | ||||||
9034 | RHS = AE->getOperand(1); | ||||||
9035 | LHS = ME->getOperand(1); | ||||||
9036 | Changed = true; | ||||||
9037 | } | ||||||
9038 | break; | ||||||
9039 | |||||||
9040 | |||||||
9041 | // The "Should have been caught earlier!" messages refer to the fact | ||||||
9042 | // that the ExactCR.isFullSet() or ExactCR.isEmptySet() check above | ||||||
9043 | // should have fired on the corresponding cases, and canonicalized the | ||||||
9044 | // check to trivial case. | ||||||
9045 | |||||||
9046 | case ICmpInst::ICMP_UGE: | ||||||
9047 | assert(!RA.isMinValue() && "Should have been caught earlier!")((!RA.isMinValue() && "Should have been caught earlier!" ) ? static_cast<void> (0) : __assert_fail ("!RA.isMinValue() && \"Should have been caught earlier!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9047, __PRETTY_FUNCTION__)); | ||||||
9048 | Pred = ICmpInst::ICMP_UGT; | ||||||
9049 | RHS = getConstant(RA - 1); | ||||||
9050 | Changed = true; | ||||||
9051 | break; | ||||||
9052 | case ICmpInst::ICMP_ULE: | ||||||
9053 | assert(!RA.isMaxValue() && "Should have been caught earlier!")((!RA.isMaxValue() && "Should have been caught earlier!" ) ? static_cast<void> (0) : __assert_fail ("!RA.isMaxValue() && \"Should have been caught earlier!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9053, __PRETTY_FUNCTION__)); | ||||||
9054 | Pred = ICmpInst::ICMP_ULT; | ||||||
9055 | RHS = getConstant(RA + 1); | ||||||
9056 | Changed = true; | ||||||
9057 | break; | ||||||
9058 | case ICmpInst::ICMP_SGE: | ||||||
9059 | assert(!RA.isMinSignedValue() && "Should have been caught earlier!")((!RA.isMinSignedValue() && "Should have been caught earlier!" ) ? static_cast<void> (0) : __assert_fail ("!RA.isMinSignedValue() && \"Should have been caught earlier!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9059, __PRETTY_FUNCTION__)); | ||||||
9060 | Pred = ICmpInst::ICMP_SGT; | ||||||
9061 | RHS = getConstant(RA - 1); | ||||||
9062 | Changed = true; | ||||||
9063 | break; | ||||||
9064 | case ICmpInst::ICMP_SLE: | ||||||
9065 | assert(!RA.isMaxSignedValue() && "Should have been caught earlier!")((!RA.isMaxSignedValue() && "Should have been caught earlier!" ) ? static_cast<void> (0) : __assert_fail ("!RA.isMaxSignedValue() && \"Should have been caught earlier!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9065, __PRETTY_FUNCTION__)); | ||||||
9066 | Pred = ICmpInst::ICMP_SLT; | ||||||
9067 | RHS = getConstant(RA + 1); | ||||||
9068 | Changed = true; | ||||||
9069 | break; | ||||||
9070 | } | ||||||
9071 | } | ||||||
9072 | } | ||||||
9073 | |||||||
9074 | // Check for obvious equality. | ||||||
9075 | if (HasSameValue(LHS, RHS)) { | ||||||
9076 | if (ICmpInst::isTrueWhenEqual(Pred)) | ||||||
9077 | return TrivialCase(true); | ||||||
9078 | if (ICmpInst::isFalseWhenEqual(Pred)) | ||||||
9079 | return TrivialCase(false); | ||||||
9080 | } | ||||||
9081 | |||||||
9082 | // If possible, canonicalize GE/LE comparisons to GT/LT comparisons, by | ||||||
9083 | // adding or subtracting 1 from one of the operands. | ||||||
9084 | switch (Pred) { | ||||||
9085 | case ICmpInst::ICMP_SLE: | ||||||
9086 | if (!getSignedRangeMax(RHS).isMaxSignedValue()) { | ||||||
9087 | RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS, | ||||||
9088 | SCEV::FlagNSW); | ||||||
9089 | Pred = ICmpInst::ICMP_SLT; | ||||||
9090 | Changed = true; | ||||||
9091 | } else if (!getSignedRangeMin(LHS).isMinSignedValue()) { | ||||||
9092 | LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS, | ||||||
9093 | SCEV::FlagNSW); | ||||||
9094 | Pred = ICmpInst::ICMP_SLT; | ||||||
9095 | Changed = true; | ||||||
9096 | } | ||||||
9097 | break; | ||||||
9098 | case ICmpInst::ICMP_SGE: | ||||||
9099 | if (!getSignedRangeMin(RHS).isMinSignedValue()) { | ||||||
9100 | RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS, | ||||||
9101 | SCEV::FlagNSW); | ||||||
9102 | Pred = ICmpInst::ICMP_SGT; | ||||||
9103 | Changed = true; | ||||||
9104 | } else if (!getSignedRangeMax(LHS).isMaxSignedValue()) { | ||||||
9105 | LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS, | ||||||
9106 | SCEV::FlagNSW); | ||||||
9107 | Pred = ICmpInst::ICMP_SGT; | ||||||
9108 | Changed = true; | ||||||
9109 | } | ||||||
9110 | break; | ||||||
9111 | case ICmpInst::ICMP_ULE: | ||||||
9112 | if (!getUnsignedRangeMax(RHS).isMaxValue()) { | ||||||
9113 | RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS, | ||||||
9114 | SCEV::FlagNUW); | ||||||
9115 | Pred = ICmpInst::ICMP_ULT; | ||||||
9116 | Changed = true; | ||||||
9117 | } else if (!getUnsignedRangeMin(LHS).isMinValue()) { | ||||||
9118 | LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS); | ||||||
9119 | Pred = ICmpInst::ICMP_ULT; | ||||||
9120 | Changed = true; | ||||||
9121 | } | ||||||
9122 | break; | ||||||
9123 | case ICmpInst::ICMP_UGE: | ||||||
9124 | if (!getUnsignedRangeMin(RHS).isMinValue()) { | ||||||
9125 | RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS); | ||||||
9126 | Pred = ICmpInst::ICMP_UGT; | ||||||
9127 | Changed = true; | ||||||
9128 | } else if (!getUnsignedRangeMax(LHS).isMaxValue()) { | ||||||
9129 | LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS, | ||||||
9130 | SCEV::FlagNUW); | ||||||
9131 | Pred = ICmpInst::ICMP_UGT; | ||||||
9132 | Changed = true; | ||||||
9133 | } | ||||||
9134 | break; | ||||||
9135 | default: | ||||||
9136 | break; | ||||||
9137 | } | ||||||
9138 | |||||||
9139 | // TODO: More simplifications are possible here. | ||||||
9140 | |||||||
9141 | // Recursively simplify until we either hit a recursion limit or nothing | ||||||
9142 | // changes. | ||||||
9143 | if (Changed) | ||||||
9144 | return SimplifyICmpOperands(Pred, LHS, RHS, Depth+1); | ||||||
9145 | |||||||
9146 | return Changed; | ||||||
9147 | } | ||||||
9148 | |||||||
9149 | bool ScalarEvolution::isKnownNegative(const SCEV *S) { | ||||||
9150 | return getSignedRangeMax(S).isNegative(); | ||||||
9151 | } | ||||||
9152 | |||||||
9153 | bool ScalarEvolution::isKnownPositive(const SCEV *S) { | ||||||
9154 | return getSignedRangeMin(S).isStrictlyPositive(); | ||||||
9155 | } | ||||||
9156 | |||||||
9157 | bool ScalarEvolution::isKnownNonNegative(const SCEV *S) { | ||||||
9158 | return !getSignedRangeMin(S).isNegative(); | ||||||
9159 | } | ||||||
9160 | |||||||
9161 | bool ScalarEvolution::isKnownNonPositive(const SCEV *S) { | ||||||
9162 | return !getSignedRangeMax(S).isStrictlyPositive(); | ||||||
9163 | } | ||||||
9164 | |||||||
9165 | bool ScalarEvolution::isKnownNonZero(const SCEV *S) { | ||||||
9166 | return isKnownNegative(S) || isKnownPositive(S); | ||||||
9167 | } | ||||||
9168 | |||||||
9169 | std::pair<const SCEV *, const SCEV *> | ||||||
9170 | ScalarEvolution::SplitIntoInitAndPostInc(const Loop *L, const SCEV *S) { | ||||||
9171 | // Compute SCEV on entry of loop L. | ||||||
9172 | const SCEV *Start = SCEVInitRewriter::rewrite(S, L, *this); | ||||||
9173 | if (Start == getCouldNotCompute()) | ||||||
9174 | return { Start, Start }; | ||||||
9175 | // Compute post increment SCEV for loop L. | ||||||
9176 | const SCEV *PostInc = SCEVPostIncRewriter::rewrite(S, L, *this); | ||||||
9177 | assert(PostInc != getCouldNotCompute() && "Unexpected could not compute")((PostInc != getCouldNotCompute() && "Unexpected could not compute" ) ? static_cast<void> (0) : __assert_fail ("PostInc != getCouldNotCompute() && \"Unexpected could not compute\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9177, __PRETTY_FUNCTION__)); | ||||||
9178 | return { Start, PostInc }; | ||||||
9179 | } | ||||||
9180 | |||||||
9181 | bool ScalarEvolution::isKnownViaInduction(ICmpInst::Predicate Pred, | ||||||
9182 | const SCEV *LHS, const SCEV *RHS) { | ||||||
9183 | // First collect all loops. | ||||||
9184 | SmallPtrSet<const Loop *, 8> LoopsUsed; | ||||||
9185 | getUsedLoops(LHS, LoopsUsed); | ||||||
9186 | getUsedLoops(RHS, LoopsUsed); | ||||||
9187 | |||||||
9188 | if (LoopsUsed.empty()) | ||||||
9189 | return false; | ||||||
9190 | |||||||
9191 | // Domination relationship must be a linear order on collected loops. | ||||||
9192 | #ifndef NDEBUG | ||||||
9193 | for (auto *L1 : LoopsUsed) | ||||||
9194 | for (auto *L2 : LoopsUsed) | ||||||
9195 | assert((DT.dominates(L1->getHeader(), L2->getHeader()) ||(((DT.dominates(L1->getHeader(), L2->getHeader()) || DT .dominates(L2->getHeader(), L1->getHeader())) && "Domination relationship is not a linear order") ? static_cast <void> (0) : __assert_fail ("(DT.dominates(L1->getHeader(), L2->getHeader()) || DT.dominates(L2->getHeader(), L1->getHeader())) && \"Domination relationship is not a linear order\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9197, __PRETTY_FUNCTION__)) | ||||||
9196 | DT.dominates(L2->getHeader(), L1->getHeader())) &&(((DT.dominates(L1->getHeader(), L2->getHeader()) || DT .dominates(L2->getHeader(), L1->getHeader())) && "Domination relationship is not a linear order") ? static_cast <void> (0) : __assert_fail ("(DT.dominates(L1->getHeader(), L2->getHeader()) || DT.dominates(L2->getHeader(), L1->getHeader())) && \"Domination relationship is not a linear order\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9197, __PRETTY_FUNCTION__)) | ||||||
9197 | "Domination relationship is not a linear order")(((DT.dominates(L1->getHeader(), L2->getHeader()) || DT .dominates(L2->getHeader(), L1->getHeader())) && "Domination relationship is not a linear order") ? static_cast <void> (0) : __assert_fail ("(DT.dominates(L1->getHeader(), L2->getHeader()) || DT.dominates(L2->getHeader(), L1->getHeader())) && \"Domination relationship is not a linear order\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9197, __PRETTY_FUNCTION__)); | ||||||
9198 | #endif | ||||||
9199 | |||||||
9200 | const Loop *MDL = | ||||||
9201 | *std::max_element(LoopsUsed.begin(), LoopsUsed.end(), | ||||||
9202 | [&](const Loop *L1, const Loop *L2) { | ||||||
9203 | return DT.properlyDominates(L1->getHeader(), L2->getHeader()); | ||||||
9204 | }); | ||||||
9205 | |||||||
9206 | // Get init and post increment value for LHS. | ||||||
9207 | auto SplitLHS = SplitIntoInitAndPostInc(MDL, LHS); | ||||||
9208 | // if LHS contains unknown non-invariant SCEV then bail out. | ||||||
9209 | if (SplitLHS.first == getCouldNotCompute()) | ||||||
9210 | return false; | ||||||
9211 | assert (SplitLHS.second != getCouldNotCompute() && "Unexpected CNC")((SplitLHS.second != getCouldNotCompute() && "Unexpected CNC" ) ? static_cast<void> (0) : __assert_fail ("SplitLHS.second != getCouldNotCompute() && \"Unexpected CNC\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9211, __PRETTY_FUNCTION__)); | ||||||
9212 | // Get init and post increment value for RHS. | ||||||
9213 | auto SplitRHS = SplitIntoInitAndPostInc(MDL, RHS); | ||||||
9214 | // if RHS contains unknown non-invariant SCEV then bail out. | ||||||
9215 | if (SplitRHS.first == getCouldNotCompute()) | ||||||
9216 | return false; | ||||||
9217 | assert (SplitRHS.second != getCouldNotCompute() && "Unexpected CNC")((SplitRHS.second != getCouldNotCompute() && "Unexpected CNC" ) ? static_cast<void> (0) : __assert_fail ("SplitRHS.second != getCouldNotCompute() && \"Unexpected CNC\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9217, __PRETTY_FUNCTION__)); | ||||||
9218 | // It is possible that init SCEV contains an invariant load but it does | ||||||
9219 | // not dominate MDL and is not available at MDL loop entry, so we should | ||||||
9220 | // check it here. | ||||||
9221 | if (!isAvailableAtLoopEntry(SplitLHS.first, MDL) || | ||||||
9222 | !isAvailableAtLoopEntry(SplitRHS.first, MDL)) | ||||||
9223 | return false; | ||||||
9224 | |||||||
9225 | // It seems backedge guard check is faster than entry one so in some cases | ||||||
9226 | // it can speed up whole estimation by short circuit | ||||||
9227 | return isLoopBackedgeGuardedByCond(MDL, Pred, SplitLHS.second, | ||||||
9228 | SplitRHS.second) && | ||||||
9229 | isLoopEntryGuardedByCond(MDL, Pred, SplitLHS.first, SplitRHS.first); | ||||||
9230 | } | ||||||
9231 | |||||||
9232 | bool ScalarEvolution::isKnownPredicate(ICmpInst::Predicate Pred, | ||||||
9233 | const SCEV *LHS, const SCEV *RHS) { | ||||||
9234 | // Canonicalize the inputs first. | ||||||
9235 | (void)SimplifyICmpOperands(Pred, LHS, RHS); | ||||||
9236 | |||||||
9237 | if (isKnownViaInduction(Pred, LHS, RHS)) | ||||||
9238 | return true; | ||||||
9239 | |||||||
9240 | if (isKnownPredicateViaSplitting(Pred, LHS, RHS)) | ||||||
9241 | return true; | ||||||
9242 | |||||||
9243 | // Otherwise see what can be done with some simple reasoning. | ||||||
9244 | return isKnownViaNonRecursiveReasoning(Pred, LHS, RHS); | ||||||
9245 | } | ||||||
9246 | |||||||
9247 | bool ScalarEvolution::isKnownOnEveryIteration(ICmpInst::Predicate Pred, | ||||||
9248 | const SCEVAddRecExpr *LHS, | ||||||
9249 | const SCEV *RHS) { | ||||||
9250 | const Loop *L = LHS->getLoop(); | ||||||
9251 | return isLoopEntryGuardedByCond(L, Pred, LHS->getStart(), RHS) && | ||||||
9252 | isLoopBackedgeGuardedByCond(L, Pred, LHS->getPostIncExpr(*this), RHS); | ||||||
9253 | } | ||||||
9254 | |||||||
9255 | bool ScalarEvolution::isMonotonicPredicate(const SCEVAddRecExpr *LHS, | ||||||
9256 | ICmpInst::Predicate Pred, | ||||||
9257 | bool &Increasing) { | ||||||
9258 | bool Result = isMonotonicPredicateImpl(LHS, Pred, Increasing); | ||||||
9259 | |||||||
9260 | #ifndef NDEBUG | ||||||
9261 | // Verify an invariant: inverting the predicate should turn a monotonically | ||||||
9262 | // increasing change to a monotonically decreasing one, and vice versa. | ||||||
9263 | bool IncreasingSwapped; | ||||||
9264 | bool ResultSwapped = isMonotonicPredicateImpl( | ||||||
9265 | LHS, ICmpInst::getSwappedPredicate(Pred), IncreasingSwapped); | ||||||
9266 | |||||||
9267 | assert(Result == ResultSwapped && "should be able to analyze both!")((Result == ResultSwapped && "should be able to analyze both!" ) ? static_cast<void> (0) : __assert_fail ("Result == ResultSwapped && \"should be able to analyze both!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9267, __PRETTY_FUNCTION__)); | ||||||
9268 | if (ResultSwapped) | ||||||
9269 | assert(Increasing == !IncreasingSwapped &&((Increasing == !IncreasingSwapped && "monotonicity should flip as we flip the predicate" ) ? static_cast<void> (0) : __assert_fail ("Increasing == !IncreasingSwapped && \"monotonicity should flip as we flip the predicate\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9270, __PRETTY_FUNCTION__)) | ||||||
9270 | "monotonicity should flip as we flip the predicate")((Increasing == !IncreasingSwapped && "monotonicity should flip as we flip the predicate" ) ? static_cast<void> (0) : __assert_fail ("Increasing == !IncreasingSwapped && \"monotonicity should flip as we flip the predicate\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9270, __PRETTY_FUNCTION__)); | ||||||
9271 | #endif | ||||||
9272 | |||||||
9273 | return Result; | ||||||
9274 | } | ||||||
9275 | |||||||
9276 | bool ScalarEvolution::isMonotonicPredicateImpl(const SCEVAddRecExpr *LHS, | ||||||
9277 | ICmpInst::Predicate Pred, | ||||||
9278 | bool &Increasing) { | ||||||
9279 | |||||||
9280 | // A zero step value for LHS means the induction variable is essentially a | ||||||
9281 | // loop invariant value. We don't really depend on the predicate actually | ||||||
9282 | // flipping from false to true (for increasing predicates, and the other way | ||||||
9283 | // around for decreasing predicates), all we care about is that *if* the | ||||||
9284 | // predicate changes then it only changes from false to true. | ||||||
9285 | // | ||||||
9286 | // A zero step value in itself is not very useful, but there may be places | ||||||
9287 | // where SCEV can prove X >= 0 but not prove X > 0, so it is helpful to be | ||||||
9288 | // as general as possible. | ||||||
9289 | |||||||
9290 | switch (Pred) { | ||||||
9291 | default: | ||||||
9292 | return false; // Conservative answer | ||||||
9293 | |||||||
9294 | case ICmpInst::ICMP_UGT: | ||||||
9295 | case ICmpInst::ICMP_UGE: | ||||||
9296 | case ICmpInst::ICMP_ULT: | ||||||
9297 | case ICmpInst::ICMP_ULE: | ||||||
9298 | if (!LHS->hasNoUnsignedWrap()) | ||||||
9299 | return false; | ||||||
9300 | |||||||
9301 | Increasing = Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE; | ||||||
9302 | return true; | ||||||
9303 | |||||||
9304 | case ICmpInst::ICMP_SGT: | ||||||
9305 | case ICmpInst::ICMP_SGE: | ||||||
9306 | case ICmpInst::ICMP_SLT: | ||||||
9307 | case ICmpInst::ICMP_SLE: { | ||||||
9308 | if (!LHS->hasNoSignedWrap()) | ||||||
9309 | return false; | ||||||
9310 | |||||||
9311 | const SCEV *Step = LHS->getStepRecurrence(*this); | ||||||
9312 | |||||||
9313 | if (isKnownNonNegative(Step)) { | ||||||
9314 | Increasing = Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE; | ||||||
9315 | return true; | ||||||
9316 | } | ||||||
9317 | |||||||
9318 | if (isKnownNonPositive(Step)) { | ||||||
9319 | Increasing = Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE; | ||||||
9320 | return true; | ||||||
9321 | } | ||||||
9322 | |||||||
9323 | return false; | ||||||
9324 | } | ||||||
9325 | |||||||
9326 | } | ||||||
9327 | |||||||
9328 | llvm_unreachable("switch has default clause!")::llvm::llvm_unreachable_internal("switch has default clause!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9328); | ||||||
9329 | } | ||||||
9330 | |||||||
9331 | bool ScalarEvolution::isLoopInvariantPredicate( | ||||||
9332 | ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, const Loop *L, | ||||||
9333 | ICmpInst::Predicate &InvariantPred, const SCEV *&InvariantLHS, | ||||||
9334 | const SCEV *&InvariantRHS) { | ||||||
9335 | |||||||
9336 | // If there is a loop-invariant, force it into the RHS, otherwise bail out. | ||||||
9337 | if (!isLoopInvariant(RHS, L)) { | ||||||
9338 | if (!isLoopInvariant(LHS, L)) | ||||||
9339 | return false; | ||||||
9340 | |||||||
9341 | std::swap(LHS, RHS); | ||||||
9342 | Pred = ICmpInst::getSwappedPredicate(Pred); | ||||||
9343 | } | ||||||
9344 | |||||||
9345 | const SCEVAddRecExpr *ArLHS = dyn_cast<SCEVAddRecExpr>(LHS); | ||||||
9346 | if (!ArLHS || ArLHS->getLoop() != L) | ||||||
9347 | return false; | ||||||
9348 | |||||||
9349 | bool Increasing; | ||||||
9350 | if (!isMonotonicPredicate(ArLHS, Pred, Increasing)) | ||||||
9351 | return false; | ||||||
9352 | |||||||
9353 | // If the predicate "ArLHS `Pred` RHS" monotonically increases from false to | ||||||
9354 | // true as the loop iterates, and the backedge is control dependent on | ||||||
9355 | // "ArLHS `Pred` RHS" == true then we can reason as follows: | ||||||
9356 | // | ||||||
9357 | // * if the predicate was false in the first iteration then the predicate | ||||||
9358 | // is never evaluated again, since the loop exits without taking the | ||||||
9359 | // backedge. | ||||||
9360 | // * if the predicate was true in the first iteration then it will | ||||||
9361 | // continue to be true for all future iterations since it is | ||||||
9362 | // monotonically increasing. | ||||||
9363 | // | ||||||
9364 | // For both the above possibilities, we can replace the loop varying | ||||||
9365 | // predicate with its value on the first iteration of the loop (which is | ||||||
9366 | // loop invariant). | ||||||
9367 | // | ||||||
9368 | // A similar reasoning applies for a monotonically decreasing predicate, by | ||||||
9369 | // replacing true with false and false with true in the above two bullets. | ||||||
9370 | |||||||
9371 | auto P = Increasing ? Pred : ICmpInst::getInversePredicate(Pred); | ||||||
9372 | |||||||
9373 | if (!isLoopBackedgeGuardedByCond(L, P, LHS, RHS)) | ||||||
9374 | return false; | ||||||
9375 | |||||||
9376 | InvariantPred = Pred; | ||||||
9377 | InvariantLHS = ArLHS->getStart(); | ||||||
9378 | InvariantRHS = RHS; | ||||||
9379 | return true; | ||||||
9380 | } | ||||||
9381 | |||||||
9382 | bool ScalarEvolution::isKnownPredicateViaConstantRanges( | ||||||
9383 | ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS) { | ||||||
9384 | if (HasSameValue(LHS, RHS)) | ||||||
9385 | return ICmpInst::isTrueWhenEqual(Pred); | ||||||
9386 | |||||||
9387 | // This code is split out from isKnownPredicate because it is called from | ||||||
9388 | // within isLoopEntryGuardedByCond. | ||||||
9389 | |||||||
9390 | auto CheckRanges = | ||||||
9391 | [&](const ConstantRange &RangeLHS, const ConstantRange &RangeRHS) { | ||||||
9392 | return ConstantRange::makeSatisfyingICmpRegion(Pred, RangeRHS) | ||||||
9393 | .contains(RangeLHS); | ||||||
9394 | }; | ||||||
9395 | |||||||
9396 | // The check at the top of the function catches the case where the values are | ||||||
9397 | // known to be equal. | ||||||
9398 | if (Pred == CmpInst::ICMP_EQ) | ||||||
9399 | return false; | ||||||
9400 | |||||||
9401 | if (Pred == CmpInst::ICMP_NE) | ||||||
9402 | return CheckRanges(getSignedRange(LHS), getSignedRange(RHS)) || | ||||||
9403 | CheckRanges(getUnsignedRange(LHS), getUnsignedRange(RHS)) || | ||||||
9404 | isKnownNonZero(getMinusSCEV(LHS, RHS)); | ||||||
9405 | |||||||
9406 | if (CmpInst::isSigned(Pred)) | ||||||
9407 | return CheckRanges(getSignedRange(LHS), getSignedRange(RHS)); | ||||||
9408 | |||||||
9409 | return CheckRanges(getUnsignedRange(LHS), getUnsignedRange(RHS)); | ||||||
9410 | } | ||||||
9411 | |||||||
9412 | bool ScalarEvolution::isKnownPredicateViaNoOverflow(ICmpInst::Predicate Pred, | ||||||
9413 | const SCEV *LHS, | ||||||
9414 | const SCEV *RHS) { | ||||||
9415 | // Match Result to (X + Y)<ExpectedFlags> where Y is a constant integer. | ||||||
9416 | // Return Y via OutY. | ||||||
9417 | auto MatchBinaryAddToConst = | ||||||
9418 | [this](const SCEV *Result, const SCEV *X, APInt &OutY, | ||||||
9419 | SCEV::NoWrapFlags ExpectedFlags) { | ||||||
9420 | const SCEV *NonConstOp, *ConstOp; | ||||||
9421 | SCEV::NoWrapFlags FlagsPresent; | ||||||
9422 | |||||||
9423 | if (!splitBinaryAdd(Result, ConstOp, NonConstOp, FlagsPresent) || | ||||||
9424 | !isa<SCEVConstant>(ConstOp) || NonConstOp != X) | ||||||
9425 | return false; | ||||||
9426 | |||||||
9427 | OutY = cast<SCEVConstant>(ConstOp)->getAPInt(); | ||||||
9428 | return (FlagsPresent & ExpectedFlags) == ExpectedFlags; | ||||||
9429 | }; | ||||||
9430 | |||||||
9431 | APInt C; | ||||||
9432 | |||||||
9433 | switch (Pred) { | ||||||
9434 | default: | ||||||
9435 | break; | ||||||
9436 | |||||||
9437 | case ICmpInst::ICMP_SGE: | ||||||
9438 | std::swap(LHS, RHS); | ||||||
9439 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
9440 | case ICmpInst::ICMP_SLE: | ||||||
9441 | // X s<= (X + C)<nsw> if C >= 0 | ||||||
9442 | if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) && C.isNonNegative()) | ||||||
9443 | return true; | ||||||
9444 | |||||||
9445 | // (X + C)<nsw> s<= X if C <= 0 | ||||||
9446 | if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) && | ||||||
9447 | !C.isStrictlyPositive()) | ||||||
9448 | return true; | ||||||
9449 | break; | ||||||
9450 | |||||||
9451 | case ICmpInst::ICMP_SGT: | ||||||
9452 | std::swap(LHS, RHS); | ||||||
9453 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
9454 | case ICmpInst::ICMP_SLT: | ||||||
9455 | // X s< (X + C)<nsw> if C > 0 | ||||||
9456 | if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) && | ||||||
9457 | C.isStrictlyPositive()) | ||||||
9458 | return true; | ||||||
9459 | |||||||
9460 | // (X + C)<nsw> s< X if C < 0 | ||||||
9461 | if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) && C.isNegative()) | ||||||
9462 | return true; | ||||||
9463 | break; | ||||||
9464 | } | ||||||
9465 | |||||||
9466 | return false; | ||||||
9467 | } | ||||||
9468 | |||||||
9469 | bool ScalarEvolution::isKnownPredicateViaSplitting(ICmpInst::Predicate Pred, | ||||||
9470 | const SCEV *LHS, | ||||||
9471 | const SCEV *RHS) { | ||||||
9472 | if (Pred != ICmpInst::ICMP_ULT || ProvingSplitPredicate) | ||||||
9473 | return false; | ||||||
9474 | |||||||
9475 | // Allowing arbitrary number of activations of isKnownPredicateViaSplitting on | ||||||
9476 | // the stack can result in exponential time complexity. | ||||||
9477 | SaveAndRestore<bool> Restore(ProvingSplitPredicate, true); | ||||||
9478 | |||||||
9479 | // If L >= 0 then I `ult` L <=> I >= 0 && I `slt` L | ||||||
9480 | // | ||||||
9481 | // To prove L >= 0 we use isKnownNonNegative whereas to prove I >= 0 we use | ||||||
9482 | // isKnownPredicate. isKnownPredicate is more powerful, but also more | ||||||
9483 | // expensive; and using isKnownNonNegative(RHS) is sufficient for most of the | ||||||
9484 | // interesting cases seen in practice. We can consider "upgrading" L >= 0 to | ||||||
9485 | // use isKnownPredicate later if needed. | ||||||
9486 | return isKnownNonNegative(RHS) && | ||||||
9487 | isKnownPredicate(CmpInst::ICMP_SGE, LHS, getZero(LHS->getType())) && | ||||||
9488 | isKnownPredicate(CmpInst::ICMP_SLT, LHS, RHS); | ||||||
9489 | } | ||||||
9490 | |||||||
9491 | bool ScalarEvolution::isImpliedViaGuard(BasicBlock *BB, | ||||||
9492 | ICmpInst::Predicate Pred, | ||||||
9493 | const SCEV *LHS, const SCEV *RHS) { | ||||||
9494 | // No need to even try if we know the module has no guards. | ||||||
9495 | if (!HasGuards) | ||||||
9496 | return false; | ||||||
9497 | |||||||
9498 | return any_of(*BB, [&](Instruction &I) { | ||||||
9499 | using namespace llvm::PatternMatch; | ||||||
9500 | |||||||
9501 | Value *Condition; | ||||||
9502 | return match(&I, m_Intrinsic<Intrinsic::experimental_guard>( | ||||||
9503 | m_Value(Condition))) && | ||||||
9504 | isImpliedCond(Pred, LHS, RHS, Condition, false); | ||||||
9505 | }); | ||||||
9506 | } | ||||||
9507 | |||||||
9508 | /// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is | ||||||
9509 | /// protected by a conditional between LHS and RHS. This is used to | ||||||
9510 | /// to eliminate casts. | ||||||
9511 | bool | ||||||
9512 | ScalarEvolution::isLoopBackedgeGuardedByCond(const Loop *L, | ||||||
9513 | ICmpInst::Predicate Pred, | ||||||
9514 | const SCEV *LHS, const SCEV *RHS) { | ||||||
9515 | // Interpret a null as meaning no loop, where there is obviously no guard | ||||||
9516 | // (interprocedural conditions notwithstanding). | ||||||
9517 | if (!L) return true; | ||||||
9518 | |||||||
9519 | if (VerifyIR) | ||||||
9520 | assert(!verifyFunction(*L->getHeader()->getParent(), &dbgs()) &&((!verifyFunction(*L->getHeader()->getParent(), &dbgs ()) && "This cannot be done on broken IR!") ? static_cast <void> (0) : __assert_fail ("!verifyFunction(*L->getHeader()->getParent(), &dbgs()) && \"This cannot be done on broken IR!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9521, __PRETTY_FUNCTION__)) | ||||||
9521 | "This cannot be done on broken IR!")((!verifyFunction(*L->getHeader()->getParent(), &dbgs ()) && "This cannot be done on broken IR!") ? static_cast <void> (0) : __assert_fail ("!verifyFunction(*L->getHeader()->getParent(), &dbgs()) && \"This cannot be done on broken IR!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9521, __PRETTY_FUNCTION__)); | ||||||
9522 | |||||||
9523 | |||||||
9524 | if (isKnownViaNonRecursiveReasoning(Pred, LHS, RHS)) | ||||||
9525 | return true; | ||||||
9526 | |||||||
9527 | BasicBlock *Latch = L->getLoopLatch(); | ||||||
9528 | if (!Latch) | ||||||
9529 | return false; | ||||||
9530 | |||||||
9531 | BranchInst *LoopContinuePredicate = | ||||||
9532 | dyn_cast<BranchInst>(Latch->getTerminator()); | ||||||
9533 | if (LoopContinuePredicate && LoopContinuePredicate->isConditional() && | ||||||
9534 | isImpliedCond(Pred, LHS, RHS, | ||||||
9535 | LoopContinuePredicate->getCondition(), | ||||||
9536 | LoopContinuePredicate->getSuccessor(0) != L->getHeader())) | ||||||
9537 | return true; | ||||||
9538 | |||||||
9539 | // We don't want more than one activation of the following loops on the stack | ||||||
9540 | // -- that can lead to O(n!) time complexity. | ||||||
9541 | if (WalkingBEDominatingConds) | ||||||
9542 | return false; | ||||||
9543 | |||||||
9544 | SaveAndRestore<bool> ClearOnExit(WalkingBEDominatingConds, true); | ||||||
9545 | |||||||
9546 | // See if we can exploit a trip count to prove the predicate. | ||||||
9547 | const auto &BETakenInfo = getBackedgeTakenInfo(L); | ||||||
9548 | const SCEV *LatchBECount = BETakenInfo.getExact(Latch, this); | ||||||
9549 | if (LatchBECount != getCouldNotCompute()) { | ||||||
9550 | // We know that Latch branches back to the loop header exactly | ||||||
9551 | // LatchBECount times. This means the backdege condition at Latch is | ||||||
9552 | // equivalent to "{0,+,1} u< LatchBECount". | ||||||
9553 | Type *Ty = LatchBECount->getType(); | ||||||
9554 | auto NoWrapFlags = SCEV::NoWrapFlags(SCEV::FlagNUW | SCEV::FlagNW); | ||||||
9555 | const SCEV *LoopCounter = | ||||||
9556 | getAddRecExpr(getZero(Ty), getOne(Ty), L, NoWrapFlags); | ||||||
9557 | if (isImpliedCond(Pred, LHS, RHS, ICmpInst::ICMP_ULT, LoopCounter, | ||||||
9558 | LatchBECount)) | ||||||
9559 | return true; | ||||||
9560 | } | ||||||
9561 | |||||||
9562 | // Check conditions due to any @llvm.assume intrinsics. | ||||||
9563 | for (auto &AssumeVH : AC.assumptions()) { | ||||||
9564 | if (!AssumeVH) | ||||||
9565 | continue; | ||||||
9566 | auto *CI = cast<CallInst>(AssumeVH); | ||||||
9567 | if (!DT.dominates(CI, Latch->getTerminator())) | ||||||
9568 | continue; | ||||||
9569 | |||||||
9570 | if (isImpliedCond(Pred, LHS, RHS, CI->getArgOperand(0), false)) | ||||||
9571 | return true; | ||||||
9572 | } | ||||||
9573 | |||||||
9574 | // If the loop is not reachable from the entry block, we risk running into an | ||||||
9575 | // infinite loop as we walk up into the dom tree. These loops do not matter | ||||||
9576 | // anyway, so we just return a conservative answer when we see them. | ||||||
9577 | if (!DT.isReachableFromEntry(L->getHeader())) | ||||||
9578 | return false; | ||||||
9579 | |||||||
9580 | if (isImpliedViaGuard(Latch, Pred, LHS, RHS)) | ||||||
9581 | return true; | ||||||
9582 | |||||||
9583 | for (DomTreeNode *DTN = DT[Latch], *HeaderDTN = DT[L->getHeader()]; | ||||||
9584 | DTN != HeaderDTN; DTN = DTN->getIDom()) { | ||||||
9585 | assert(DTN && "should reach the loop header before reaching the root!")((DTN && "should reach the loop header before reaching the root!" ) ? static_cast<void> (0) : __assert_fail ("DTN && \"should reach the loop header before reaching the root!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9585, __PRETTY_FUNCTION__)); | ||||||
9586 | |||||||
9587 | BasicBlock *BB = DTN->getBlock(); | ||||||
9588 | if (isImpliedViaGuard(BB, Pred, LHS, RHS)) | ||||||
9589 | return true; | ||||||
9590 | |||||||
9591 | BasicBlock *PBB = BB->getSinglePredecessor(); | ||||||
9592 | if (!PBB) | ||||||
9593 | continue; | ||||||
9594 | |||||||
9595 | BranchInst *ContinuePredicate = dyn_cast<BranchInst>(PBB->getTerminator()); | ||||||
9596 | if (!ContinuePredicate || !ContinuePredicate->isConditional()) | ||||||
9597 | continue; | ||||||
9598 | |||||||
9599 | Value *Condition = ContinuePredicate->getCondition(); | ||||||
9600 | |||||||
9601 | // If we have an edge `E` within the loop body that dominates the only | ||||||
9602 | // latch, the condition guarding `E` also guards the backedge. This | ||||||
9603 | // reasoning works only for loops with a single latch. | ||||||
9604 | |||||||
9605 | BasicBlockEdge DominatingEdge(PBB, BB); | ||||||
9606 | if (DominatingEdge.isSingleEdge()) { | ||||||
9607 | // We're constructively (and conservatively) enumerating edges within the | ||||||
9608 | // loop body that dominate the latch. The dominator tree better agree | ||||||
9609 | // with us on this: | ||||||
9610 | assert(DT.dominates(DominatingEdge, Latch) && "should be!")((DT.dominates(DominatingEdge, Latch) && "should be!" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(DominatingEdge, Latch) && \"should be!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9610, __PRETTY_FUNCTION__)); | ||||||
9611 | |||||||
9612 | if (isImpliedCond(Pred, LHS, RHS, Condition, | ||||||
9613 | BB != ContinuePredicate->getSuccessor(0))) | ||||||
9614 | return true; | ||||||
9615 | } | ||||||
9616 | } | ||||||
9617 | |||||||
9618 | return false; | ||||||
9619 | } | ||||||
9620 | |||||||
9621 | bool | ||||||
9622 | ScalarEvolution::isLoopEntryGuardedByCond(const Loop *L, | ||||||
9623 | ICmpInst::Predicate Pred, | ||||||
9624 | const SCEV *LHS, const SCEV *RHS) { | ||||||
9625 | // Interpret a null as meaning no loop, where there is obviously no guard | ||||||
9626 | // (interprocedural conditions notwithstanding). | ||||||
9627 | if (!L) return false; | ||||||
9628 | |||||||
9629 | if (VerifyIR) | ||||||
9630 | assert(!verifyFunction(*L->getHeader()->getParent(), &dbgs()) &&((!verifyFunction(*L->getHeader()->getParent(), &dbgs ()) && "This cannot be done on broken IR!") ? static_cast <void> (0) : __assert_fail ("!verifyFunction(*L->getHeader()->getParent(), &dbgs()) && \"This cannot be done on broken IR!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9631, __PRETTY_FUNCTION__)) | ||||||
9631 | "This cannot be done on broken IR!")((!verifyFunction(*L->getHeader()->getParent(), &dbgs ()) && "This cannot be done on broken IR!") ? static_cast <void> (0) : __assert_fail ("!verifyFunction(*L->getHeader()->getParent(), &dbgs()) && \"This cannot be done on broken IR!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9631, __PRETTY_FUNCTION__)); | ||||||
9632 | |||||||
9633 | // Both LHS and RHS must be available at loop entry. | ||||||
9634 | assert(isAvailableAtLoopEntry(LHS, L) &&((isAvailableAtLoopEntry(LHS, L) && "LHS is not available at Loop Entry" ) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(LHS, L) && \"LHS is not available at Loop Entry\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9635, __PRETTY_FUNCTION__)) | ||||||
9635 | "LHS is not available at Loop Entry")((isAvailableAtLoopEntry(LHS, L) && "LHS is not available at Loop Entry" ) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(LHS, L) && \"LHS is not available at Loop Entry\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9635, __PRETTY_FUNCTION__)); | ||||||
9636 | assert(isAvailableAtLoopEntry(RHS, L) &&((isAvailableAtLoopEntry(RHS, L) && "RHS is not available at Loop Entry" ) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(RHS, L) && \"RHS is not available at Loop Entry\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9637, __PRETTY_FUNCTION__)) | ||||||
9637 | "RHS is not available at Loop Entry")((isAvailableAtLoopEntry(RHS, L) && "RHS is not available at Loop Entry" ) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(RHS, L) && \"RHS is not available at Loop Entry\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 9637, __PRETTY_FUNCTION__)); | ||||||
9638 | |||||||
9639 | if (isKnownViaNonRecursiveReasoning(Pred, LHS, RHS)) | ||||||
9640 | return true; | ||||||
9641 | |||||||
9642 | // If we cannot prove strict comparison (e.g. a > b), maybe we can prove | ||||||
9643 | // the facts (a >= b && a != b) separately. A typical situation is when the | ||||||
9644 | // non-strict comparison is known from ranges and non-equality is known from | ||||||
9645 | // dominating predicates. If we are proving strict comparison, we always try | ||||||
9646 | // to prove non-equality and non-strict comparison separately. | ||||||
9647 | auto NonStrictPredicate = ICmpInst::getNonStrictPredicate(Pred); | ||||||
9648 | const bool ProvingStrictComparison = (Pred != NonStrictPredicate); | ||||||
9649 | bool ProvedNonStrictComparison = false; | ||||||
9650 | bool ProvedNonEquality = false; | ||||||
9651 | |||||||
9652 | if (ProvingStrictComparison) { | ||||||
9653 | ProvedNonStrictComparison = | ||||||
9654 | isKnownViaNonRecursiveReasoning(NonStrictPredicate, LHS, RHS); | ||||||
9655 | ProvedNonEquality = | ||||||
9656 | isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_NE, LHS, RHS); | ||||||
9657 | if (ProvedNonStrictComparison && ProvedNonEquality) | ||||||
9658 | return true; | ||||||
9659 | } | ||||||
9660 | |||||||
9661 | // Try to prove (Pred, LHS, RHS) using isImpliedViaGuard. | ||||||
9662 | auto ProveViaGuard = [&](BasicBlock *Block) { | ||||||
9663 | if (isImpliedViaGuard(Block, Pred, LHS, RHS)) | ||||||
9664 | return true; | ||||||
9665 | if (ProvingStrictComparison) { | ||||||
9666 | if (!ProvedNonStrictComparison) | ||||||
9667 | ProvedNonStrictComparison = | ||||||
9668 | isImpliedViaGuard(Block, NonStrictPredicate, LHS, RHS); | ||||||
9669 | if (!ProvedNonEquality) | ||||||
9670 | ProvedNonEquality = | ||||||
9671 | isImpliedViaGuard(Block, ICmpInst::ICMP_NE, LHS, RHS); | ||||||
9672 | if (ProvedNonStrictComparison && ProvedNonEquality) | ||||||
9673 | return true; | ||||||
9674 | } | ||||||
9675 | return false; | ||||||
9676 | }; | ||||||
9677 | |||||||
9678 | // Try to prove (Pred, LHS, RHS) using isImpliedCond. | ||||||
9679 | auto ProveViaCond = [&](Value *Condition, bool Inverse) { | ||||||
9680 | if (isImpliedCond(Pred, LHS, RHS, Condition, Inverse)) | ||||||
9681 | return true; | ||||||
9682 | if (ProvingStrictComparison) { | ||||||
9683 | if (!ProvedNonStrictComparison) | ||||||
9684 | ProvedNonStrictComparison = | ||||||
9685 | isImpliedCond(NonStrictPredicate, LHS, RHS, Condition, Inverse); | ||||||
9686 | if (!ProvedNonEquality) | ||||||
9687 | ProvedNonEquality = | ||||||
9688 | isImpliedCond(ICmpInst::ICMP_NE, LHS, RHS, Condition, Inverse); | ||||||
9689 | if (ProvedNonStrictComparison && ProvedNonEquality) | ||||||
9690 | return true; | ||||||
9691 | } | ||||||
9692 | return false; | ||||||
9693 | }; | ||||||
9694 | |||||||
9695 | // Starting at the loop predecessor, climb up the predecessor chain, as long | ||||||
9696 | // as there are predecessors that can be found that have unique successors | ||||||
9697 | // leading to the original header. | ||||||
9698 | for (std::pair<BasicBlock *, BasicBlock *> | ||||||
9699 | Pair(L->getLoopPredecessor(), L->getHeader()); | ||||||
9700 | Pair.first; | ||||||
9701 | Pair = getPredecessorWithUniqueSuccessorForBB(Pair.first)) { | ||||||
9702 | |||||||
9703 | if (ProveViaGuard(Pair.first)) | ||||||
9704 | return true; | ||||||
9705 | |||||||
9706 | BranchInst *LoopEntryPredicate = | ||||||
9707 | dyn_cast<BranchInst>(Pair.first->getTerminator()); | ||||||
9708 | if (!LoopEntryPredicate || | ||||||
9709 | LoopEntryPredicate->isUnconditional()) | ||||||
9710 | continue; | ||||||
9711 | |||||||
9712 | if (ProveViaCond(LoopEntryPredicate->getCondition(), | ||||||
9713 | LoopEntryPredicate->getSuccessor(0) != Pair.second)) | ||||||
9714 | return true; | ||||||
9715 | } | ||||||
9716 | |||||||
9717 | // Check conditions due to any @llvm.assume intrinsics. | ||||||
9718 | for (auto &AssumeVH : AC.assumptions()) { | ||||||
9719 | if (!AssumeVH) | ||||||
9720 | continue; | ||||||
9721 | auto *CI = cast<CallInst>(AssumeVH); | ||||||
9722 | if (!DT.dominates(CI, L->getHeader())) | ||||||
9723 | continue; | ||||||
9724 | |||||||
9725 | if (ProveViaCond(CI->getArgOperand(0), false)) | ||||||
9726 | return true; | ||||||
9727 | } | ||||||
9728 | |||||||
9729 | return false; | ||||||
9730 | } | ||||||
9731 | |||||||
9732 | bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred, | ||||||
9733 | const SCEV *LHS, const SCEV *RHS, | ||||||
9734 | Value *FoundCondValue, | ||||||
9735 | bool Inverse) { | ||||||
9736 | if (!PendingLoopPredicates.insert(FoundCondValue).second) | ||||||
9737 | return false; | ||||||
9738 | |||||||
9739 | auto ClearOnExit = | ||||||
9740 | make_scope_exit([&]() { PendingLoopPredicates.erase(FoundCondValue); }); | ||||||
9741 | |||||||
9742 | // Recursively handle And and Or conditions. | ||||||
9743 | if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FoundCondValue)) { | ||||||
9744 | if (BO->getOpcode() == Instruction::And) { | ||||||
9745 | if (!Inverse) | ||||||
9746 | return isImpliedCond(Pred, LHS, RHS, BO->getOperand(0), Inverse) || | ||||||
9747 | isImpliedCond(Pred, LHS, RHS, BO->getOperand(1), Inverse); | ||||||
9748 | } else if (BO->getOpcode() == Instruction::Or) { | ||||||
9749 | if (Inverse) | ||||||
9750 | return isImpliedCond(Pred, LHS, RHS, BO->getOperand(0), Inverse) || | ||||||
9751 | isImpliedCond(Pred, LHS, RHS, BO->getOperand(1), Inverse); | ||||||
9752 | } | ||||||
9753 | } | ||||||
9754 | |||||||
9755 | ICmpInst *ICI = dyn_cast<ICmpInst>(FoundCondValue); | ||||||
9756 | if (!ICI) return false; | ||||||
9757 | |||||||
9758 | // Now that we found a conditional branch that dominates the loop or controls | ||||||
9759 | // the loop latch. Check to see if it is the comparison we are looking for. | ||||||
9760 | ICmpInst::Predicate FoundPred; | ||||||
9761 | if (Inverse) | ||||||
9762 | FoundPred = ICI->getInversePredicate(); | ||||||
9763 | else | ||||||
9764 | FoundPred = ICI->getPredicate(); | ||||||
9765 | |||||||
9766 | const SCEV *FoundLHS = getSCEV(ICI->getOperand(0)); | ||||||
9767 | const SCEV *FoundRHS = getSCEV(ICI->getOperand(1)); | ||||||
9768 | |||||||
9769 | return isImpliedCond(Pred, LHS, RHS, FoundPred, FoundLHS, FoundRHS); | ||||||
9770 | } | ||||||
9771 | |||||||
9772 | bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred, const SCEV *LHS, | ||||||
9773 | const SCEV *RHS, | ||||||
9774 | ICmpInst::Predicate FoundPred, | ||||||
9775 | const SCEV *FoundLHS, | ||||||
9776 | const SCEV *FoundRHS) { | ||||||
9777 | // Balance the types. | ||||||
9778 | if (getTypeSizeInBits(LHS->getType()) < | ||||||
9779 | getTypeSizeInBits(FoundLHS->getType())) { | ||||||
9780 | if (CmpInst::isSigned(Pred)) { | ||||||
9781 | LHS = getSignExtendExpr(LHS, FoundLHS->getType()); | ||||||
9782 | RHS = getSignExtendExpr(RHS, FoundLHS->getType()); | ||||||
9783 | } else { | ||||||
9784 | LHS = getZeroExtendExpr(LHS, FoundLHS->getType()); | ||||||
9785 | RHS = getZeroExtendExpr(RHS, FoundLHS->getType()); | ||||||
9786 | } | ||||||
9787 | } else if (getTypeSizeInBits(LHS->getType()) > | ||||||
9788 | getTypeSizeInBits(FoundLHS->getType())) { | ||||||
9789 | if (CmpInst::isSigned(FoundPred)) { | ||||||
9790 | FoundLHS = getSignExtendExpr(FoundLHS, LHS->getType()); | ||||||
9791 | FoundRHS = getSignExtendExpr(FoundRHS, LHS->getType()); | ||||||
9792 | } else { | ||||||
9793 | FoundLHS = getZeroExtendExpr(FoundLHS, LHS->getType()); | ||||||
9794 | FoundRHS = getZeroExtendExpr(FoundRHS, LHS->getType()); | ||||||
9795 | } | ||||||
9796 | } | ||||||
9797 | |||||||
9798 | // Canonicalize the query to match the way instcombine will have | ||||||
9799 | // canonicalized the comparison. | ||||||
9800 | if (SimplifyICmpOperands(Pred, LHS, RHS)) | ||||||
9801 | if (LHS == RHS) | ||||||
9802 | return CmpInst::isTrueWhenEqual(Pred); | ||||||
9803 | if (SimplifyICmpOperands(FoundPred, FoundLHS, FoundRHS)) | ||||||
9804 | if (FoundLHS == FoundRHS) | ||||||
9805 | return CmpInst::isFalseWhenEqual(FoundPred); | ||||||
9806 | |||||||
9807 | // Check to see if we can make the LHS or RHS match. | ||||||
9808 | if (LHS == FoundRHS || RHS == FoundLHS) { | ||||||
9809 | if (isa<SCEVConstant>(RHS)) { | ||||||
9810 | std::swap(FoundLHS, FoundRHS); | ||||||
9811 | FoundPred = ICmpInst::getSwappedPredicate(FoundPred); | ||||||
9812 | } else { | ||||||
9813 | std::swap(LHS, RHS); | ||||||
9814 | Pred = ICmpInst::getSwappedPredicate(Pred); | ||||||
9815 | } | ||||||
9816 | } | ||||||
9817 | |||||||
9818 | // Check whether the found predicate is the same as the desired predicate. | ||||||
9819 | if (FoundPred == Pred) | ||||||
9820 | return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS); | ||||||
9821 | |||||||
9822 | // Check whether swapping the found predicate makes it the same as the | ||||||
9823 | // desired predicate. | ||||||
9824 | if (ICmpInst::getSwappedPredicate(FoundPred) == Pred) { | ||||||
9825 | if (isa<SCEVConstant>(RHS)) | ||||||
9826 | return isImpliedCondOperands(Pred, LHS, RHS, FoundRHS, FoundLHS); | ||||||
9827 | else | ||||||
9828 | return isImpliedCondOperands(ICmpInst::getSwappedPredicate(Pred), | ||||||
9829 | RHS, LHS, FoundLHS, FoundRHS); | ||||||
9830 | } | ||||||
9831 | |||||||
9832 | // Unsigned comparison is the same as signed comparison when both the operands | ||||||
9833 | // are non-negative. | ||||||
9834 | if (CmpInst::isUnsigned(FoundPred) && | ||||||
9835 | CmpInst::getSignedPredicate(FoundPred) == Pred && | ||||||
9836 | isKnownNonNegative(FoundLHS) && isKnownNonNegative(FoundRHS)) | ||||||
9837 | return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS); | ||||||
9838 | |||||||
9839 | // Check if we can make progress by sharpening ranges. | ||||||
9840 | if (FoundPred == ICmpInst::ICMP_NE && | ||||||
9841 | (isa<SCEVConstant>(FoundLHS) || isa<SCEVConstant>(FoundRHS))) { | ||||||
9842 | |||||||
9843 | const SCEVConstant *C = nullptr; | ||||||
9844 | const SCEV *V = nullptr; | ||||||
9845 | |||||||
9846 | if (isa<SCEVConstant>(FoundLHS)) { | ||||||
9847 | C = cast<SCEVConstant>(FoundLHS); | ||||||
9848 | V = FoundRHS; | ||||||
9849 | } else { | ||||||
9850 | C = cast<SCEVConstant>(FoundRHS); | ||||||
9851 | V = FoundLHS; | ||||||
9852 | } | ||||||
9853 | |||||||
9854 | // The guarding predicate tells us that C != V. If the known range | ||||||
9855 | // of V is [C, t), we can sharpen the range to [C + 1, t). The | ||||||
9856 | // range we consider has to correspond to same signedness as the | ||||||
9857 | // predicate we're interested in folding. | ||||||
9858 | |||||||
9859 | APInt Min = ICmpInst::isSigned(Pred) ? | ||||||
9860 | getSignedRangeMin(V) : getUnsignedRangeMin(V); | ||||||
9861 | |||||||
9862 | if (Min == C->getAPInt()) { | ||||||
9863 | // Given (V >= Min && V != Min) we conclude V >= (Min + 1). | ||||||
9864 | // This is true even if (Min + 1) wraps around -- in case of | ||||||
9865 | // wraparound, (Min + 1) < Min, so (V >= Min => V >= (Min + 1)). | ||||||
9866 | |||||||
9867 | APInt SharperMin = Min + 1; | ||||||
9868 | |||||||
9869 | switch (Pred) { | ||||||
9870 | case ICmpInst::ICMP_SGE: | ||||||
9871 | case ICmpInst::ICMP_UGE: | ||||||
9872 | // We know V `Pred` SharperMin. If this implies LHS `Pred` | ||||||
9873 | // RHS, we're done. | ||||||
9874 | if (isImpliedCondOperands(Pred, LHS, RHS, V, | ||||||
9875 | getConstant(SharperMin))) | ||||||
9876 | return true; | ||||||
9877 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
9878 | |||||||
9879 | case ICmpInst::ICMP_SGT: | ||||||
9880 | case ICmpInst::ICMP_UGT: | ||||||
9881 | // We know from the range information that (V `Pred` Min || | ||||||
9882 | // V == Min). We know from the guarding condition that !(V | ||||||
9883 | // == Min). This gives us | ||||||
9884 | // | ||||||
9885 | // V `Pred` Min || V == Min && !(V == Min) | ||||||
9886 | // => V `Pred` Min | ||||||
9887 | // | ||||||
9888 | // If V `Pred` Min implies LHS `Pred` RHS, we're done. | ||||||
9889 | |||||||
9890 | if (isImpliedCondOperands(Pred, LHS, RHS, V, getConstant(Min))) | ||||||
9891 | return true; | ||||||
9892 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
9893 | |||||||
9894 | default: | ||||||
9895 | // No change | ||||||
9896 | break; | ||||||
9897 | } | ||||||
9898 | } | ||||||
9899 | } | ||||||
9900 | |||||||
9901 | // Check whether the actual condition is beyond sufficient. | ||||||
9902 | if (FoundPred == ICmpInst::ICMP_EQ) | ||||||
9903 | if (ICmpInst::isTrueWhenEqual(Pred)) | ||||||
9904 | if (isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS)) | ||||||
9905 | return true; | ||||||
9906 | if (Pred == ICmpInst::ICMP_NE) | ||||||
9907 | if (!ICmpInst::isTrueWhenEqual(FoundPred)) | ||||||
9908 | if (isImpliedCondOperands(FoundPred, LHS, RHS, FoundLHS, FoundRHS)) | ||||||
9909 | return true; | ||||||
9910 | |||||||
9911 | // Otherwise assume the worst. | ||||||
9912 | return false; | ||||||
9913 | } | ||||||
9914 | |||||||
9915 | bool ScalarEvolution::splitBinaryAdd(const SCEV *Expr, | ||||||
9916 | const SCEV *&L, const SCEV *&R, | ||||||
9917 | SCEV::NoWrapFlags &Flags) { | ||||||
9918 | const auto *AE = dyn_cast<SCEVAddExpr>(Expr); | ||||||
9919 | if (!AE || AE->getNumOperands() != 2) | ||||||
9920 | return false; | ||||||
9921 | |||||||
9922 | L = AE->getOperand(0); | ||||||
9923 | R = AE->getOperand(1); | ||||||
9924 | Flags = AE->getNoWrapFlags(); | ||||||
9925 | return true; | ||||||
9926 | } | ||||||
9927 | |||||||
9928 | Optional<APInt> ScalarEvolution::computeConstantDifference(const SCEV *More, | ||||||
9929 | const SCEV *Less) { | ||||||
9930 | // We avoid subtracting expressions here because this function is usually | ||||||
9931 | // fairly deep in the call stack (i.e. is called many times). | ||||||
9932 | |||||||
9933 | // X - X = 0. | ||||||
9934 | if (More == Less) | ||||||
9935 | return APInt(getTypeSizeInBits(More->getType()), 0); | ||||||
9936 | |||||||
9937 | if (isa<SCEVAddRecExpr>(Less) && isa<SCEVAddRecExpr>(More)) { | ||||||
9938 | const auto *LAR = cast<SCEVAddRecExpr>(Less); | ||||||
9939 | const auto *MAR = cast<SCEVAddRecExpr>(More); | ||||||
9940 | |||||||
9941 | if (LAR->getLoop() != MAR->getLoop()) | ||||||
9942 | return None; | ||||||
9943 | |||||||
9944 | // We look at affine expressions only; not for correctness but to keep | ||||||
9945 | // getStepRecurrence cheap. | ||||||
9946 | if (!LAR->isAffine() || !MAR->isAffine()) | ||||||
9947 | return None; | ||||||
9948 | |||||||
9949 | if (LAR->getStepRecurrence(*this) != MAR->getStepRecurrence(*this)) | ||||||
9950 | return None; | ||||||
9951 | |||||||
9952 | Less = LAR->getStart(); | ||||||
9953 | More = MAR->getStart(); | ||||||
9954 | |||||||
9955 | // fall through | ||||||
9956 | } | ||||||
9957 | |||||||
9958 | if (isa<SCEVConstant>(Less) && isa<SCEVConstant>(More)) { | ||||||
9959 | const auto &M = cast<SCEVConstant>(More)->getAPInt(); | ||||||
9960 | const auto &L = cast<SCEVConstant>(Less)->getAPInt(); | ||||||
9961 | return M - L; | ||||||
9962 | } | ||||||
9963 | |||||||
9964 | SCEV::NoWrapFlags Flags; | ||||||
9965 | const SCEV *LLess = nullptr, *RLess = nullptr; | ||||||
9966 | const SCEV *LMore = nullptr, *RMore = nullptr; | ||||||
9967 | const SCEVConstant *C1 = nullptr, *C2 = nullptr; | ||||||
9968 | // Compare (X + C1) vs X. | ||||||
9969 | if (splitBinaryAdd(Less, LLess, RLess, Flags)) | ||||||
9970 | if ((C1 = dyn_cast<SCEVConstant>(LLess))) | ||||||
9971 | if (RLess == More) | ||||||
9972 | return -(C1->getAPInt()); | ||||||
9973 | |||||||
9974 | // Compare X vs (X + C2). | ||||||
9975 | if (splitBinaryAdd(More, LMore, RMore, Flags)) | ||||||
9976 | if ((C2 = dyn_cast<SCEVConstant>(LMore))) | ||||||
9977 | if (RMore == Less) | ||||||
9978 | return C2->getAPInt(); | ||||||
9979 | |||||||
9980 | // Compare (X + C1) vs (X + C2). | ||||||
9981 | if (C1 && C2 && RLess == RMore) | ||||||
9982 | return C2->getAPInt() - C1->getAPInt(); | ||||||
9983 | |||||||
9984 | return None; | ||||||
9985 | } | ||||||
9986 | |||||||
9987 | bool ScalarEvolution::isImpliedCondOperandsViaNoOverflow( | ||||||
9988 | ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, | ||||||
9989 | const SCEV *FoundLHS, const SCEV *FoundRHS) { | ||||||
9990 | if (Pred != CmpInst::ICMP_SLT && Pred != CmpInst::ICMP_ULT) | ||||||
9991 | return false; | ||||||
9992 | |||||||
9993 | const auto *AddRecLHS = dyn_cast<SCEVAddRecExpr>(LHS); | ||||||
9994 | if (!AddRecLHS) | ||||||
9995 | return false; | ||||||
9996 | |||||||
9997 | const auto *AddRecFoundLHS = dyn_cast<SCEVAddRecExpr>(FoundLHS); | ||||||
9998 | if (!AddRecFoundLHS) | ||||||
9999 | return false; | ||||||
10000 | |||||||
10001 | // We'd like to let SCEV reason about control dependencies, so we constrain | ||||||
10002 | // both the inequalities to be about add recurrences on the same loop. This | ||||||
10003 | // way we can use isLoopEntryGuardedByCond later. | ||||||
10004 | |||||||
10005 | const Loop *L = AddRecFoundLHS->getLoop(); | ||||||
10006 | if (L != AddRecLHS->getLoop()) | ||||||
10007 | return false; | ||||||
10008 | |||||||
10009 | // FoundLHS u< FoundRHS u< -C => (FoundLHS + C) u< (FoundRHS + C) ... (1) | ||||||
10010 | // | ||||||
10011 | // FoundLHS s< FoundRHS s< INT_MIN - C => (FoundLHS + C) s< (FoundRHS + C) | ||||||
10012 | // ... (2) | ||||||
10013 | // | ||||||
10014 | // Informal proof for (2), assuming (1) [*]: | ||||||
10015 | // | ||||||
10016 | // We'll also assume (A s< B) <=> ((A + INT_MIN) u< (B + INT_MIN)) ... (3)[**] | ||||||
10017 | // | ||||||
10018 | // Then | ||||||
10019 | // | ||||||
10020 | // FoundLHS s< FoundRHS s< INT_MIN - C | ||||||
10021 | // <=> (FoundLHS + INT_MIN) u< (FoundRHS + INT_MIN) u< -C [ using (3) ] | ||||||
10022 | // <=> (FoundLHS + INT_MIN + C) u< (FoundRHS + INT_MIN + C) [ using (1) ] | ||||||
10023 | // <=> (FoundLHS + INT_MIN + C + INT_MIN) s< | ||||||
10024 | // (FoundRHS + INT_MIN + C + INT_MIN) [ using (3) ] | ||||||
10025 | // <=> FoundLHS + C s< FoundRHS + C | ||||||
10026 | // | ||||||
10027 | // [*]: (1) can be proved by ruling out overflow. | ||||||
10028 | // | ||||||
10029 | // [**]: This can be proved by analyzing all the four possibilities: | ||||||
10030 | // (A s< 0, B s< 0), (A s< 0, B s>= 0), (A s>= 0, B s< 0) and | ||||||
10031 | // (A s>= 0, B s>= 0). | ||||||
10032 | // | ||||||
10033 | // Note: | ||||||
10034 | // Despite (2), "FoundRHS s< INT_MIN - C" does not mean that "FoundRHS + C" | ||||||
10035 | // will not sign underflow. For instance, say FoundLHS = (i8 -128), FoundRHS | ||||||
10036 | // = (i8 -127) and C = (i8 -100). Then INT_MIN - C = (i8 -28), and FoundRHS | ||||||
10037 | // s< (INT_MIN - C). Lack of sign overflow / underflow in "FoundRHS + C" is | ||||||
10038 | // neither necessary nor sufficient to prove "(FoundLHS + C) s< (FoundRHS + | ||||||
10039 | // C)". | ||||||
10040 | |||||||
10041 | Optional<APInt> LDiff = computeConstantDifference(LHS, FoundLHS); | ||||||
10042 | Optional<APInt> RDiff = computeConstantDifference(RHS, FoundRHS); | ||||||
10043 | if (!LDiff || !RDiff || *LDiff != *RDiff) | ||||||
10044 | return false; | ||||||
10045 | |||||||
10046 | if (LDiff->isMinValue()) | ||||||
10047 | return true; | ||||||
10048 | |||||||
10049 | APInt FoundRHSLimit; | ||||||
10050 | |||||||
10051 | if (Pred == CmpInst::ICMP_ULT) { | ||||||
10052 | FoundRHSLimit = -(*RDiff); | ||||||
10053 | } else { | ||||||
10054 | assert(Pred == CmpInst::ICMP_SLT && "Checked above!")((Pred == CmpInst::ICMP_SLT && "Checked above!") ? static_cast <void> (0) : __assert_fail ("Pred == CmpInst::ICMP_SLT && \"Checked above!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10054, __PRETTY_FUNCTION__)); | ||||||
10055 | FoundRHSLimit = APInt::getSignedMinValue(getTypeSizeInBits(RHS->getType())) - *RDiff; | ||||||
10056 | } | ||||||
10057 | |||||||
10058 | // Try to prove (1) or (2), as needed. | ||||||
10059 | return isAvailableAtLoopEntry(FoundRHS, L) && | ||||||
10060 | isLoopEntryGuardedByCond(L, Pred, FoundRHS, | ||||||
10061 | getConstant(FoundRHSLimit)); | ||||||
10062 | } | ||||||
10063 | |||||||
10064 | bool ScalarEvolution::isImpliedViaMerge(ICmpInst::Predicate Pred, | ||||||
10065 | const SCEV *LHS, const SCEV *RHS, | ||||||
10066 | const SCEV *FoundLHS, | ||||||
10067 | const SCEV *FoundRHS, unsigned Depth) { | ||||||
10068 | const PHINode *LPhi = nullptr, *RPhi = nullptr; | ||||||
10069 | |||||||
10070 | auto ClearOnExit = make_scope_exit([&]() { | ||||||
10071 | if (LPhi) { | ||||||
10072 | bool Erased = PendingMerges.erase(LPhi); | ||||||
10073 | assert(Erased && "Failed to erase LPhi!")((Erased && "Failed to erase LPhi!") ? static_cast< void> (0) : __assert_fail ("Erased && \"Failed to erase LPhi!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10073, __PRETTY_FUNCTION__)); | ||||||
10074 | (void)Erased; | ||||||
10075 | } | ||||||
10076 | if (RPhi) { | ||||||
10077 | bool Erased = PendingMerges.erase(RPhi); | ||||||
10078 | assert(Erased && "Failed to erase RPhi!")((Erased && "Failed to erase RPhi!") ? static_cast< void> (0) : __assert_fail ("Erased && \"Failed to erase RPhi!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10078, __PRETTY_FUNCTION__)); | ||||||
10079 | (void)Erased; | ||||||
10080 | } | ||||||
10081 | }); | ||||||
10082 | |||||||
10083 | // Find respective Phis and check that they are not being pending. | ||||||
10084 | if (const SCEVUnknown *LU = dyn_cast<SCEVUnknown>(LHS)) | ||||||
10085 | if (auto *Phi = dyn_cast<PHINode>(LU->getValue())) { | ||||||
10086 | if (!PendingMerges.insert(Phi).second) | ||||||
10087 | return false; | ||||||
10088 | LPhi = Phi; | ||||||
10089 | } | ||||||
10090 | if (const SCEVUnknown *RU = dyn_cast<SCEVUnknown>(RHS)) | ||||||
10091 | if (auto *Phi = dyn_cast<PHINode>(RU->getValue())) { | ||||||
10092 | // If we detect a loop of Phi nodes being processed by this method, for | ||||||
10093 | // example: | ||||||
10094 | // | ||||||
10095 | // %a = phi i32 [ %some1, %preheader ], [ %b, %latch ] | ||||||
10096 | // %b = phi i32 [ %some2, %preheader ], [ %a, %latch ] | ||||||
10097 | // | ||||||
10098 | // we don't want to deal with a case that complex, so return conservative | ||||||
10099 | // answer false. | ||||||
10100 | if (!PendingMerges.insert(Phi).second) | ||||||
10101 | return false; | ||||||
10102 | RPhi = Phi; | ||||||
10103 | } | ||||||
10104 | |||||||
10105 | // If none of LHS, RHS is a Phi, nothing to do here. | ||||||
10106 | if (!LPhi && !RPhi) | ||||||
10107 | return false; | ||||||
10108 | |||||||
10109 | // If there is a SCEVUnknown Phi we are interested in, make it left. | ||||||
10110 | if (!LPhi) { | ||||||
10111 | std::swap(LHS, RHS); | ||||||
10112 | std::swap(FoundLHS, FoundRHS); | ||||||
10113 | std::swap(LPhi, RPhi); | ||||||
10114 | Pred = ICmpInst::getSwappedPredicate(Pred); | ||||||
10115 | } | ||||||
10116 | |||||||
10117 | assert(LPhi && "LPhi should definitely be a SCEVUnknown Phi!")((LPhi && "LPhi should definitely be a SCEVUnknown Phi!" ) ? static_cast<void> (0) : __assert_fail ("LPhi && \"LPhi should definitely be a SCEVUnknown Phi!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10117, __PRETTY_FUNCTION__)); | ||||||
10118 | const BasicBlock *LBB = LPhi->getParent(); | ||||||
10119 | const SCEVAddRecExpr *RAR = dyn_cast<SCEVAddRecExpr>(RHS); | ||||||
10120 | |||||||
10121 | auto ProvedEasily = [&](const SCEV *S1, const SCEV *S2) { | ||||||
10122 | return isKnownViaNonRecursiveReasoning(Pred, S1, S2) || | ||||||
10123 | isImpliedCondOperandsViaRanges(Pred, S1, S2, FoundLHS, FoundRHS) || | ||||||
10124 | isImpliedViaOperations(Pred, S1, S2, FoundLHS, FoundRHS, Depth); | ||||||
10125 | }; | ||||||
10126 | |||||||
10127 | if (RPhi && RPhi->getParent() == LBB) { | ||||||
10128 | // Case one: RHS is also a SCEVUnknown Phi from the same basic block. | ||||||
10129 | // If we compare two Phis from the same block, and for each entry block | ||||||
10130 | // the predicate is true for incoming values from this block, then the | ||||||
10131 | // predicate is also true for the Phis. | ||||||
10132 | for (const BasicBlock *IncBB : predecessors(LBB)) { | ||||||
10133 | const SCEV *L = getSCEV(LPhi->getIncomingValueForBlock(IncBB)); | ||||||
10134 | const SCEV *R = getSCEV(RPhi->getIncomingValueForBlock(IncBB)); | ||||||
10135 | if (!ProvedEasily(L, R)) | ||||||
10136 | return false; | ||||||
10137 | } | ||||||
10138 | } else if (RAR && RAR->getLoop()->getHeader() == LBB) { | ||||||
10139 | // Case two: RHS is also a Phi from the same basic block, and it is an | ||||||
10140 | // AddRec. It means that there is a loop which has both AddRec and Unknown | ||||||
10141 | // PHIs, for it we can compare incoming values of AddRec from above the loop | ||||||
10142 | // and latch with their respective incoming values of LPhi. | ||||||
10143 | // TODO: Generalize to handle loops with many inputs in a header. | ||||||
10144 | if (LPhi->getNumIncomingValues() != 2) return false; | ||||||
10145 | |||||||
10146 | auto *RLoop = RAR->getLoop(); | ||||||
10147 | auto *Predecessor = RLoop->getLoopPredecessor(); | ||||||
10148 | assert(Predecessor && "Loop with AddRec with no predecessor?")((Predecessor && "Loop with AddRec with no predecessor?" ) ? static_cast<void> (0) : __assert_fail ("Predecessor && \"Loop with AddRec with no predecessor?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10148, __PRETTY_FUNCTION__)); | ||||||
10149 | const SCEV *L1 = getSCEV(LPhi->getIncomingValueForBlock(Predecessor)); | ||||||
10150 | if (!ProvedEasily(L1, RAR->getStart())) | ||||||
10151 | return false; | ||||||
10152 | auto *Latch = RLoop->getLoopLatch(); | ||||||
10153 | assert(Latch && "Loop with AddRec with no latch?")((Latch && "Loop with AddRec with no latch?") ? static_cast <void> (0) : __assert_fail ("Latch && \"Loop with AddRec with no latch?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10153, __PRETTY_FUNCTION__)); | ||||||
10154 | const SCEV *L2 = getSCEV(LPhi->getIncomingValueForBlock(Latch)); | ||||||
10155 | if (!ProvedEasily(L2, RAR->getPostIncExpr(*this))) | ||||||
10156 | return false; | ||||||
10157 | } else { | ||||||
10158 | // In all other cases go over inputs of LHS and compare each of them to RHS, | ||||||
10159 | // the predicate is true for (LHS, RHS) if it is true for all such pairs. | ||||||
10160 | // At this point RHS is either a non-Phi, or it is a Phi from some block | ||||||
10161 | // different from LBB. | ||||||
10162 | for (const BasicBlock *IncBB : predecessors(LBB)) { | ||||||
10163 | // Check that RHS is available in this block. | ||||||
10164 | if (!dominates(RHS, IncBB)) | ||||||
10165 | return false; | ||||||
10166 | const SCEV *L = getSCEV(LPhi->getIncomingValueForBlock(IncBB)); | ||||||
10167 | if (!ProvedEasily(L, RHS)) | ||||||
10168 | return false; | ||||||
10169 | } | ||||||
10170 | } | ||||||
10171 | return true; | ||||||
10172 | } | ||||||
10173 | |||||||
10174 | bool ScalarEvolution::isImpliedCondOperands(ICmpInst::Predicate Pred, | ||||||
10175 | const SCEV *LHS, const SCEV *RHS, | ||||||
10176 | const SCEV *FoundLHS, | ||||||
10177 | const SCEV *FoundRHS) { | ||||||
10178 | if (isImpliedCondOperandsViaRanges(Pred, LHS, RHS, FoundLHS, FoundRHS)) | ||||||
10179 | return true; | ||||||
10180 | |||||||
10181 | if (isImpliedCondOperandsViaNoOverflow(Pred, LHS, RHS, FoundLHS, FoundRHS)) | ||||||
10182 | return true; | ||||||
10183 | |||||||
10184 | return isImpliedCondOperandsHelper(Pred, LHS, RHS, | ||||||
10185 | FoundLHS, FoundRHS) || | ||||||
10186 | // ~x < ~y --> x > y | ||||||
10187 | isImpliedCondOperandsHelper(Pred, LHS, RHS, | ||||||
10188 | getNotSCEV(FoundRHS), | ||||||
10189 | getNotSCEV(FoundLHS)); | ||||||
10190 | } | ||||||
10191 | |||||||
10192 | /// Is MaybeMinMaxExpr an (U|S)(Min|Max) of Candidate and some other values? | ||||||
10193 | template <typename MinMaxExprType> | ||||||
10194 | static bool IsMinMaxConsistingOf(const SCEV *MaybeMinMaxExpr, | ||||||
10195 | const SCEV *Candidate) { | ||||||
10196 | const MinMaxExprType *MinMaxExpr = dyn_cast<MinMaxExprType>(MaybeMinMaxExpr); | ||||||
10197 | if (!MinMaxExpr) | ||||||
10198 | return false; | ||||||
10199 | |||||||
10200 | return find(MinMaxExpr->operands(), Candidate) != MinMaxExpr->op_end(); | ||||||
10201 | } | ||||||
10202 | |||||||
10203 | static bool IsKnownPredicateViaAddRecStart(ScalarEvolution &SE, | ||||||
10204 | ICmpInst::Predicate Pred, | ||||||
10205 | const SCEV *LHS, const SCEV *RHS) { | ||||||
10206 | // If both sides are affine addrecs for the same loop, with equal | ||||||
10207 | // steps, and we know the recurrences don't wrap, then we only | ||||||
10208 | // need to check the predicate on the starting values. | ||||||
10209 | |||||||
10210 | if (!ICmpInst::isRelational(Pred)) | ||||||
10211 | return false; | ||||||
10212 | |||||||
10213 | const SCEVAddRecExpr *LAR = dyn_cast<SCEVAddRecExpr>(LHS); | ||||||
10214 | if (!LAR) | ||||||
10215 | return false; | ||||||
10216 | const SCEVAddRecExpr *RAR = dyn_cast<SCEVAddRecExpr>(RHS); | ||||||
10217 | if (!RAR) | ||||||
10218 | return false; | ||||||
10219 | if (LAR->getLoop() != RAR->getLoop()) | ||||||
10220 | return false; | ||||||
10221 | if (!LAR->isAffine() || !RAR->isAffine()) | ||||||
10222 | return false; | ||||||
10223 | |||||||
10224 | if (LAR->getStepRecurrence(SE) != RAR->getStepRecurrence(SE)) | ||||||
10225 | return false; | ||||||
10226 | |||||||
10227 | SCEV::NoWrapFlags NW = ICmpInst::isSigned(Pred) ? | ||||||
10228 | SCEV::FlagNSW : SCEV::FlagNUW; | ||||||
10229 | if (!LAR->getNoWrapFlags(NW) || !RAR->getNoWrapFlags(NW)) | ||||||
10230 | return false; | ||||||
10231 | |||||||
10232 | return SE.isKnownPredicate(Pred, LAR->getStart(), RAR->getStart()); | ||||||
10233 | } | ||||||
10234 | |||||||
10235 | /// Is LHS `Pred` RHS true on the virtue of LHS or RHS being a Min or Max | ||||||
10236 | /// expression? | ||||||
10237 | static bool IsKnownPredicateViaMinOrMax(ScalarEvolution &SE, | ||||||
10238 | ICmpInst::Predicate Pred, | ||||||
10239 | const SCEV *LHS, const SCEV *RHS) { | ||||||
10240 | switch (Pred) { | ||||||
10241 | default: | ||||||
10242 | return false; | ||||||
10243 | |||||||
10244 | case ICmpInst::ICMP_SGE: | ||||||
10245 | std::swap(LHS, RHS); | ||||||
10246 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
10247 | case ICmpInst::ICMP_SLE: | ||||||
10248 | return | ||||||
10249 | // min(A, ...) <= A | ||||||
10250 | IsMinMaxConsistingOf<SCEVSMinExpr>(LHS, RHS) || | ||||||
10251 | // A <= max(A, ...) | ||||||
10252 | IsMinMaxConsistingOf<SCEVSMaxExpr>(RHS, LHS); | ||||||
10253 | |||||||
10254 | case ICmpInst::ICMP_UGE: | ||||||
10255 | std::swap(LHS, RHS); | ||||||
10256 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
10257 | case ICmpInst::ICMP_ULE: | ||||||
10258 | return | ||||||
10259 | // min(A, ...) <= A | ||||||
10260 | IsMinMaxConsistingOf<SCEVUMinExpr>(LHS, RHS) || | ||||||
10261 | // A <= max(A, ...) | ||||||
10262 | IsMinMaxConsistingOf<SCEVUMaxExpr>(RHS, LHS); | ||||||
10263 | } | ||||||
10264 | |||||||
10265 | llvm_unreachable("covered switch fell through?!")::llvm::llvm_unreachable_internal("covered switch fell through?!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10265); | ||||||
10266 | } | ||||||
10267 | |||||||
10268 | bool ScalarEvolution::isImpliedViaOperations(ICmpInst::Predicate Pred, | ||||||
10269 | const SCEV *LHS, const SCEV *RHS, | ||||||
10270 | const SCEV *FoundLHS, | ||||||
10271 | const SCEV *FoundRHS, | ||||||
10272 | unsigned Depth) { | ||||||
10273 | assert(getTypeSizeInBits(LHS->getType()) ==((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS ->getType()) && "LHS and RHS have different sizes?" ) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS->getType()) && \"LHS and RHS have different sizes?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10275, __PRETTY_FUNCTION__)) | ||||||
10274 | getTypeSizeInBits(RHS->getType()) &&((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS ->getType()) && "LHS and RHS have different sizes?" ) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS->getType()) && \"LHS and RHS have different sizes?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10275, __PRETTY_FUNCTION__)) | ||||||
10275 | "LHS and RHS have different sizes?")((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS ->getType()) && "LHS and RHS have different sizes?" ) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS->getType()) && \"LHS and RHS have different sizes?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10275, __PRETTY_FUNCTION__)); | ||||||
10276 | assert(getTypeSizeInBits(FoundLHS->getType()) ==((getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits (FoundRHS->getType()) && "FoundLHS and FoundRHS have different sizes?" ) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits(FoundRHS->getType()) && \"FoundLHS and FoundRHS have different sizes?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10278, __PRETTY_FUNCTION__)) | ||||||
10277 | getTypeSizeInBits(FoundRHS->getType()) &&((getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits (FoundRHS->getType()) && "FoundLHS and FoundRHS have different sizes?" ) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits(FoundRHS->getType()) && \"FoundLHS and FoundRHS have different sizes?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10278, __PRETTY_FUNCTION__)) | ||||||
10278 | "FoundLHS and FoundRHS have different sizes?")((getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits (FoundRHS->getType()) && "FoundLHS and FoundRHS have different sizes?" ) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits(FoundRHS->getType()) && \"FoundLHS and FoundRHS have different sizes?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10278, __PRETTY_FUNCTION__)); | ||||||
10279 | // We want to avoid hurting the compile time with analysis of too big trees. | ||||||
10280 | if (Depth > MaxSCEVOperationsImplicationDepth) | ||||||
10281 | return false; | ||||||
10282 | // We only want to work with ICMP_SGT comparison so far. | ||||||
10283 | // TODO: Extend to ICMP_UGT? | ||||||
10284 | if (Pred == ICmpInst::ICMP_SLT) { | ||||||
10285 | Pred = ICmpInst::ICMP_SGT; | ||||||
10286 | std::swap(LHS, RHS); | ||||||
10287 | std::swap(FoundLHS, FoundRHS); | ||||||
10288 | } | ||||||
10289 | if (Pred != ICmpInst::ICMP_SGT) | ||||||
10290 | return false; | ||||||
10291 | |||||||
10292 | auto GetOpFromSExt = [&](const SCEV *S) { | ||||||
10293 | if (auto *Ext = dyn_cast<SCEVSignExtendExpr>(S)) | ||||||
10294 | return Ext->getOperand(); | ||||||
10295 | // TODO: If S is a SCEVConstant then you can cheaply "strip" the sext off | ||||||
10296 | // the constant in some cases. | ||||||
10297 | return S; | ||||||
10298 | }; | ||||||
10299 | |||||||
10300 | // Acquire values from extensions. | ||||||
10301 | auto *OrigLHS = LHS; | ||||||
10302 | auto *OrigFoundLHS = FoundLHS; | ||||||
10303 | LHS = GetOpFromSExt(LHS); | ||||||
10304 | FoundLHS = GetOpFromSExt(FoundLHS); | ||||||
10305 | |||||||
10306 | // Is the SGT predicate can be proved trivially or using the found context. | ||||||
10307 | auto IsSGTViaContext = [&](const SCEV *S1, const SCEV *S2) { | ||||||
10308 | return isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGT, S1, S2) || | ||||||
10309 | isImpliedViaOperations(ICmpInst::ICMP_SGT, S1, S2, OrigFoundLHS, | ||||||
10310 | FoundRHS, Depth + 1); | ||||||
10311 | }; | ||||||
10312 | |||||||
10313 | if (auto *LHSAddExpr = dyn_cast<SCEVAddExpr>(LHS)) { | ||||||
10314 | // We want to avoid creation of any new non-constant SCEV. Since we are | ||||||
10315 | // going to compare the operands to RHS, we should be certain that we don't | ||||||
10316 | // need any size extensions for this. So let's decline all cases when the | ||||||
10317 | // sizes of types of LHS and RHS do not match. | ||||||
10318 | // TODO: Maybe try to get RHS from sext to catch more cases? | ||||||
10319 | if (getTypeSizeInBits(LHS->getType()) != getTypeSizeInBits(RHS->getType())) | ||||||
10320 | return false; | ||||||
10321 | |||||||
10322 | // Should not overflow. | ||||||
10323 | if (!LHSAddExpr->hasNoSignedWrap()) | ||||||
10324 | return false; | ||||||
10325 | |||||||
10326 | auto *LL = LHSAddExpr->getOperand(0); | ||||||
10327 | auto *LR = LHSAddExpr->getOperand(1); | ||||||
10328 | auto *MinusOne = getNegativeSCEV(getOne(RHS->getType())); | ||||||
10329 | |||||||
10330 | // Checks that S1 >= 0 && S2 > RHS, trivially or using the found context. | ||||||
10331 | auto IsSumGreaterThanRHS = [&](const SCEV *S1, const SCEV *S2) { | ||||||
10332 | return IsSGTViaContext(S1, MinusOne) && IsSGTViaContext(S2, RHS); | ||||||
10333 | }; | ||||||
10334 | // Try to prove the following rule: | ||||||
10335 | // (LHS = LL + LR) && (LL >= 0) && (LR > RHS) => (LHS > RHS). | ||||||
10336 | // (LHS = LL + LR) && (LR >= 0) && (LL > RHS) => (LHS > RHS). | ||||||
10337 | if (IsSumGreaterThanRHS(LL, LR) || IsSumGreaterThanRHS(LR, LL)) | ||||||
10338 | return true; | ||||||
10339 | } else if (auto *LHSUnknownExpr = dyn_cast<SCEVUnknown>(LHS)) { | ||||||
10340 | Value *LL, *LR; | ||||||
10341 | // FIXME: Once we have SDiv implemented, we can get rid of this matching. | ||||||
10342 | |||||||
10343 | using namespace llvm::PatternMatch; | ||||||
10344 | |||||||
10345 | if (match(LHSUnknownExpr->getValue(), m_SDiv(m_Value(LL), m_Value(LR)))) { | ||||||
10346 | // Rules for division. | ||||||
10347 | // We are going to perform some comparisons with Denominator and its | ||||||
10348 | // derivative expressions. In general case, creating a SCEV for it may | ||||||
10349 | // lead to a complex analysis of the entire graph, and in particular it | ||||||
10350 | // can request trip count recalculation for the same loop. This would | ||||||
10351 | // cache as SCEVCouldNotCompute to avoid the infinite recursion. To avoid | ||||||
10352 | // this, we only want to create SCEVs that are constants in this section. | ||||||
10353 | // So we bail if Denominator is not a constant. | ||||||
10354 | if (!isa<ConstantInt>(LR)) | ||||||
10355 | return false; | ||||||
10356 | |||||||
10357 | auto *Denominator = cast<SCEVConstant>(getSCEV(LR)); | ||||||
10358 | |||||||
10359 | // We want to make sure that LHS = FoundLHS / Denominator. If it is so, | ||||||
10360 | // then a SCEV for the numerator already exists and matches with FoundLHS. | ||||||
10361 | auto *Numerator = getExistingSCEV(LL); | ||||||
10362 | if (!Numerator || Numerator->getType() != FoundLHS->getType()) | ||||||
10363 | return false; | ||||||
10364 | |||||||
10365 | // Make sure that the numerator matches with FoundLHS and the denominator | ||||||
10366 | // is positive. | ||||||
10367 | if (!HasSameValue(Numerator, FoundLHS) || !isKnownPositive(Denominator)) | ||||||
10368 | return false; | ||||||
10369 | |||||||
10370 | auto *DTy = Denominator->getType(); | ||||||
10371 | auto *FRHSTy = FoundRHS->getType(); | ||||||
10372 | if (DTy->isPointerTy() != FRHSTy->isPointerTy()) | ||||||
10373 | // One of types is a pointer and another one is not. We cannot extend | ||||||
10374 | // them properly to a wider type, so let us just reject this case. | ||||||
10375 | // TODO: Usage of getEffectiveSCEVType for DTy, FRHSTy etc should help | ||||||
10376 | // to avoid this check. | ||||||
10377 | return false; | ||||||
10378 | |||||||
10379 | // Given that: | ||||||
10380 | // FoundLHS > FoundRHS, LHS = FoundLHS / Denominator, Denominator > 0. | ||||||
10381 | auto *WTy = getWiderType(DTy, FRHSTy); | ||||||
10382 | auto *DenominatorExt = getNoopOrSignExtend(Denominator, WTy); | ||||||
10383 | auto *FoundRHSExt = getNoopOrSignExtend(FoundRHS, WTy); | ||||||
10384 | |||||||
10385 | // Try to prove the following rule: | ||||||
10386 | // (FoundRHS > Denominator - 2) && (RHS <= 0) => (LHS > RHS). | ||||||
10387 | // For example, given that FoundLHS > 2. It means that FoundLHS is at | ||||||
10388 | // least 3. If we divide it by Denominator < 4, we will have at least 1. | ||||||
10389 | auto *DenomMinusTwo = getMinusSCEV(DenominatorExt, getConstant(WTy, 2)); | ||||||
10390 | if (isKnownNonPositive(RHS) && | ||||||
10391 | IsSGTViaContext(FoundRHSExt, DenomMinusTwo)) | ||||||
10392 | return true; | ||||||
10393 | |||||||
10394 | // Try to prove the following rule: | ||||||
10395 | // (FoundRHS > -1 - Denominator) && (RHS < 0) => (LHS > RHS). | ||||||
10396 | // For example, given that FoundLHS > -3. Then FoundLHS is at least -2. | ||||||
10397 | // If we divide it by Denominator > 2, then: | ||||||
10398 | // 1. If FoundLHS is negative, then the result is 0. | ||||||
10399 | // 2. If FoundLHS is non-negative, then the result is non-negative. | ||||||
10400 | // Anyways, the result is non-negative. | ||||||
10401 | auto *MinusOne = getNegativeSCEV(getOne(WTy)); | ||||||
10402 | auto *NegDenomMinusOne = getMinusSCEV(MinusOne, DenominatorExt); | ||||||
10403 | if (isKnownNegative(RHS) && | ||||||
10404 | IsSGTViaContext(FoundRHSExt, NegDenomMinusOne)) | ||||||
10405 | return true; | ||||||
10406 | } | ||||||
10407 | } | ||||||
10408 | |||||||
10409 | // If our expression contained SCEVUnknown Phis, and we split it down and now | ||||||
10410 | // need to prove something for them, try to prove the predicate for every | ||||||
10411 | // possible incoming values of those Phis. | ||||||
10412 | if (isImpliedViaMerge(Pred, OrigLHS, RHS, OrigFoundLHS, FoundRHS, Depth + 1)) | ||||||
10413 | return true; | ||||||
10414 | |||||||
10415 | return false; | ||||||
10416 | } | ||||||
10417 | |||||||
10418 | static bool isKnownPredicateExtendIdiom(ICmpInst::Predicate Pred, | ||||||
10419 | const SCEV *LHS, const SCEV *RHS) { | ||||||
10420 | // zext x u<= sext x, sext x s<= zext x | ||||||
10421 | switch (Pred) { | ||||||
10422 | case ICmpInst::ICMP_SGE: | ||||||
10423 | std::swap(LHS, RHS); | ||||||
10424 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
10425 | case ICmpInst::ICMP_SLE: { | ||||||
10426 | // If operand >=s 0 then ZExt == SExt. If operand <s 0 then SExt <s ZExt. | ||||||
10427 | const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(LHS); | ||||||
10428 | const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(RHS); | ||||||
10429 | if (SExt && ZExt && SExt->getOperand() == ZExt->getOperand()) | ||||||
10430 | return true; | ||||||
10431 | break; | ||||||
10432 | } | ||||||
10433 | case ICmpInst::ICMP_UGE: | ||||||
10434 | std::swap(LHS, RHS); | ||||||
10435 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
10436 | case ICmpInst::ICMP_ULE: { | ||||||
10437 | // If operand >=s 0 then ZExt == SExt. If operand <s 0 then ZExt <u SExt. | ||||||
10438 | const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(LHS); | ||||||
10439 | const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(RHS); | ||||||
10440 | if (SExt && ZExt && SExt->getOperand() == ZExt->getOperand()) | ||||||
10441 | return true; | ||||||
10442 | break; | ||||||
10443 | } | ||||||
10444 | default: | ||||||
10445 | break; | ||||||
10446 | }; | ||||||
10447 | return false; | ||||||
10448 | } | ||||||
10449 | |||||||
10450 | bool | ||||||
10451 | ScalarEvolution::isKnownViaNonRecursiveReasoning(ICmpInst::Predicate Pred, | ||||||
10452 | const SCEV *LHS, const SCEV *RHS) { | ||||||
10453 | return isKnownPredicateExtendIdiom(Pred, LHS, RHS) || | ||||||
10454 | isKnownPredicateViaConstantRanges(Pred, LHS, RHS) || | ||||||
10455 | IsKnownPredicateViaMinOrMax(*this, Pred, LHS, RHS) || | ||||||
10456 | IsKnownPredicateViaAddRecStart(*this, Pred, LHS, RHS) || | ||||||
10457 | isKnownPredicateViaNoOverflow(Pred, LHS, RHS); | ||||||
10458 | } | ||||||
10459 | |||||||
10460 | bool | ||||||
10461 | ScalarEvolution::isImpliedCondOperandsHelper(ICmpInst::Predicate Pred, | ||||||
10462 | const SCEV *LHS, const SCEV *RHS, | ||||||
10463 | const SCEV *FoundLHS, | ||||||
10464 | const SCEV *FoundRHS) { | ||||||
10465 | switch (Pred) { | ||||||
10466 | default: llvm_unreachable("Unexpected ICmpInst::Predicate value!")::llvm::llvm_unreachable_internal("Unexpected ICmpInst::Predicate value!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10466); | ||||||
10467 | case ICmpInst::ICMP_EQ: | ||||||
10468 | case ICmpInst::ICMP_NE: | ||||||
10469 | if (HasSameValue(LHS, FoundLHS) && HasSameValue(RHS, FoundRHS)) | ||||||
10470 | return true; | ||||||
10471 | break; | ||||||
10472 | case ICmpInst::ICMP_SLT: | ||||||
10473 | case ICmpInst::ICMP_SLE: | ||||||
10474 | if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SLE, LHS, FoundLHS) && | ||||||
10475 | isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGE, RHS, FoundRHS)) | ||||||
10476 | return true; | ||||||
10477 | break; | ||||||
10478 | case ICmpInst::ICMP_SGT: | ||||||
10479 | case ICmpInst::ICMP_SGE: | ||||||
10480 | if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGE, LHS, FoundLHS) && | ||||||
10481 | isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SLE, RHS, FoundRHS)) | ||||||
10482 | return true; | ||||||
10483 | break; | ||||||
10484 | case ICmpInst::ICMP_ULT: | ||||||
10485 | case ICmpInst::ICMP_ULE: | ||||||
10486 | if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_ULE, LHS, FoundLHS) && | ||||||
10487 | isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_UGE, RHS, FoundRHS)) | ||||||
10488 | return true; | ||||||
10489 | break; | ||||||
10490 | case ICmpInst::ICMP_UGT: | ||||||
10491 | case ICmpInst::ICMP_UGE: | ||||||
10492 | if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_UGE, LHS, FoundLHS) && | ||||||
10493 | isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_ULE, RHS, FoundRHS)) | ||||||
10494 | return true; | ||||||
10495 | break; | ||||||
10496 | } | ||||||
10497 | |||||||
10498 | // Maybe it can be proved via operations? | ||||||
10499 | if (isImpliedViaOperations(Pred, LHS, RHS, FoundLHS, FoundRHS)) | ||||||
10500 | return true; | ||||||
10501 | |||||||
10502 | return false; | ||||||
10503 | } | ||||||
10504 | |||||||
10505 | bool ScalarEvolution::isImpliedCondOperandsViaRanges(ICmpInst::Predicate Pred, | ||||||
10506 | const SCEV *LHS, | ||||||
10507 | const SCEV *RHS, | ||||||
10508 | const SCEV *FoundLHS, | ||||||
10509 | const SCEV *FoundRHS) { | ||||||
10510 | if (!isa<SCEVConstant>(RHS) || !isa<SCEVConstant>(FoundRHS)) | ||||||
10511 | // The restriction on `FoundRHS` be lifted easily -- it exists only to | ||||||
10512 | // reduce the compile time impact of this optimization. | ||||||
10513 | return false; | ||||||
10514 | |||||||
10515 | Optional<APInt> Addend = computeConstantDifference(LHS, FoundLHS); | ||||||
10516 | if (!Addend) | ||||||
10517 | return false; | ||||||
10518 | |||||||
10519 | const APInt &ConstFoundRHS = cast<SCEVConstant>(FoundRHS)->getAPInt(); | ||||||
10520 | |||||||
10521 | // `FoundLHSRange` is the range we know `FoundLHS` to be in by virtue of the | ||||||
10522 | // antecedent "`FoundLHS` `Pred` `FoundRHS`". | ||||||
10523 | ConstantRange FoundLHSRange = | ||||||
10524 | ConstantRange::makeAllowedICmpRegion(Pred, ConstFoundRHS); | ||||||
10525 | |||||||
10526 | // Since `LHS` is `FoundLHS` + `Addend`, we can compute a range for `LHS`: | ||||||
10527 | ConstantRange LHSRange = FoundLHSRange.add(ConstantRange(*Addend)); | ||||||
10528 | |||||||
10529 | // We can also compute the range of values for `LHS` that satisfy the | ||||||
10530 | // consequent, "`LHS` `Pred` `RHS`": | ||||||
10531 | const APInt &ConstRHS = cast<SCEVConstant>(RHS)->getAPInt(); | ||||||
10532 | ConstantRange SatisfyingLHSRange = | ||||||
10533 | ConstantRange::makeSatisfyingICmpRegion(Pred, ConstRHS); | ||||||
10534 | |||||||
10535 | // The antecedent implies the consequent if every value of `LHS` that | ||||||
10536 | // satisfies the antecedent also satisfies the consequent. | ||||||
10537 | return SatisfyingLHSRange.contains(LHSRange); | ||||||
10538 | } | ||||||
10539 | |||||||
10540 | bool ScalarEvolution::doesIVOverflowOnLT(const SCEV *RHS, const SCEV *Stride, | ||||||
10541 | bool IsSigned, bool NoWrap) { | ||||||
10542 | assert(isKnownPositive(Stride) && "Positive stride expected!")((isKnownPositive(Stride) && "Positive stride expected!" ) ? static_cast<void> (0) : __assert_fail ("isKnownPositive(Stride) && \"Positive stride expected!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10542, __PRETTY_FUNCTION__)); | ||||||
10543 | |||||||
10544 | if (NoWrap) return false; | ||||||
10545 | |||||||
10546 | unsigned BitWidth = getTypeSizeInBits(RHS->getType()); | ||||||
10547 | const SCEV *One = getOne(Stride->getType()); | ||||||
10548 | |||||||
10549 | if (IsSigned) { | ||||||
10550 | APInt MaxRHS = getSignedRangeMax(RHS); | ||||||
10551 | APInt MaxValue = APInt::getSignedMaxValue(BitWidth); | ||||||
10552 | APInt MaxStrideMinusOne = getSignedRangeMax(getMinusSCEV(Stride, One)); | ||||||
10553 | |||||||
10554 | // SMaxRHS + SMaxStrideMinusOne > SMaxValue => overflow! | ||||||
10555 | return (std::move(MaxValue) - MaxStrideMinusOne).slt(MaxRHS); | ||||||
10556 | } | ||||||
10557 | |||||||
10558 | APInt MaxRHS = getUnsignedRangeMax(RHS); | ||||||
10559 | APInt MaxValue = APInt::getMaxValue(BitWidth); | ||||||
10560 | APInt MaxStrideMinusOne = getUnsignedRangeMax(getMinusSCEV(Stride, One)); | ||||||
10561 | |||||||
10562 | // UMaxRHS + UMaxStrideMinusOne > UMaxValue => overflow! | ||||||
10563 | return (std::move(MaxValue) - MaxStrideMinusOne).ult(MaxRHS); | ||||||
10564 | } | ||||||
10565 | |||||||
10566 | bool ScalarEvolution::doesIVOverflowOnGT(const SCEV *RHS, const SCEV *Stride, | ||||||
10567 | bool IsSigned, bool NoWrap) { | ||||||
10568 | if (NoWrap) return false; | ||||||
10569 | |||||||
10570 | unsigned BitWidth = getTypeSizeInBits(RHS->getType()); | ||||||
10571 | const SCEV *One = getOne(Stride->getType()); | ||||||
10572 | |||||||
10573 | if (IsSigned) { | ||||||
10574 | APInt MinRHS = getSignedRangeMin(RHS); | ||||||
10575 | APInt MinValue = APInt::getSignedMinValue(BitWidth); | ||||||
10576 | APInt MaxStrideMinusOne = getSignedRangeMax(getMinusSCEV(Stride, One)); | ||||||
10577 | |||||||
10578 | // SMinRHS - SMaxStrideMinusOne < SMinValue => overflow! | ||||||
10579 | return (std::move(MinValue) + MaxStrideMinusOne).sgt(MinRHS); | ||||||
10580 | } | ||||||
10581 | |||||||
10582 | APInt MinRHS = getUnsignedRangeMin(RHS); | ||||||
10583 | APInt MinValue = APInt::getMinValue(BitWidth); | ||||||
10584 | APInt MaxStrideMinusOne = getUnsignedRangeMax(getMinusSCEV(Stride, One)); | ||||||
10585 | |||||||
10586 | // UMinRHS - UMaxStrideMinusOne < UMinValue => overflow! | ||||||
10587 | return (std::move(MinValue) + MaxStrideMinusOne).ugt(MinRHS); | ||||||
10588 | } | ||||||
10589 | |||||||
10590 | const SCEV *ScalarEvolution::computeBECount(const SCEV *Delta, const SCEV *Step, | ||||||
10591 | bool Equality) { | ||||||
10592 | const SCEV *One = getOne(Step->getType()); | ||||||
10593 | Delta = Equality ? getAddExpr(Delta, Step) | ||||||
10594 | : getAddExpr(Delta, getMinusSCEV(Step, One)); | ||||||
10595 | return getUDivExpr(Delta, Step); | ||||||
10596 | } | ||||||
10597 | |||||||
10598 | const SCEV *ScalarEvolution::computeMaxBECountForLT(const SCEV *Start, | ||||||
10599 | const SCEV *Stride, | ||||||
10600 | const SCEV *End, | ||||||
10601 | unsigned BitWidth, | ||||||
10602 | bool IsSigned) { | ||||||
10603 | |||||||
10604 | assert(!isKnownNonPositive(Stride) &&((!isKnownNonPositive(Stride) && "Stride is expected strictly positive!" ) ? static_cast<void> (0) : __assert_fail ("!isKnownNonPositive(Stride) && \"Stride is expected strictly positive!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10605, __PRETTY_FUNCTION__)) | ||||||
10605 | "Stride is expected strictly positive!")((!isKnownNonPositive(Stride) && "Stride is expected strictly positive!" ) ? static_cast<void> (0) : __assert_fail ("!isKnownNonPositive(Stride) && \"Stride is expected strictly positive!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10605, __PRETTY_FUNCTION__)); | ||||||
10606 | // Calculate the maximum backedge count based on the range of values | ||||||
10607 | // permitted by Start, End, and Stride. | ||||||
10608 | const SCEV *MaxBECount; | ||||||
10609 | APInt MinStart = | ||||||
10610 | IsSigned ? getSignedRangeMin(Start) : getUnsignedRangeMin(Start); | ||||||
10611 | |||||||
10612 | APInt StrideForMaxBECount = | ||||||
10613 | IsSigned ? getSignedRangeMin(Stride) : getUnsignedRangeMin(Stride); | ||||||
10614 | |||||||
10615 | // We already know that the stride is positive, so we paper over conservatism | ||||||
10616 | // in our range computation by forcing StrideForMaxBECount to be at least one. | ||||||
10617 | // In theory this is unnecessary, but we expect MaxBECount to be a | ||||||
10618 | // SCEVConstant, and (udiv <constant> 0) is not constant folded by SCEV (there | ||||||
10619 | // is nothing to constant fold it to). | ||||||
10620 | APInt One(BitWidth, 1, IsSigned); | ||||||
10621 | StrideForMaxBECount = APIntOps::smax(One, StrideForMaxBECount); | ||||||
10622 | |||||||
10623 | APInt MaxValue = IsSigned ? APInt::getSignedMaxValue(BitWidth) | ||||||
10624 | : APInt::getMaxValue(BitWidth); | ||||||
10625 | APInt Limit = MaxValue - (StrideForMaxBECount - 1); | ||||||
10626 | |||||||
10627 | // Although End can be a MAX expression we estimate MaxEnd considering only | ||||||
10628 | // the case End = RHS of the loop termination condition. This is safe because | ||||||
10629 | // in the other case (End - Start) is zero, leading to a zero maximum backedge | ||||||
10630 | // taken count. | ||||||
10631 | APInt MaxEnd = IsSigned ? APIntOps::smin(getSignedRangeMax(End), Limit) | ||||||
10632 | : APIntOps::umin(getUnsignedRangeMax(End), Limit); | ||||||
10633 | |||||||
10634 | MaxBECount = computeBECount(getConstant(MaxEnd - MinStart) /* Delta */, | ||||||
10635 | getConstant(StrideForMaxBECount) /* Step */, | ||||||
10636 | false /* Equality */); | ||||||
10637 | |||||||
10638 | return MaxBECount; | ||||||
10639 | } | ||||||
10640 | |||||||
10641 | ScalarEvolution::ExitLimit | ||||||
10642 | ScalarEvolution::howManyLessThans(const SCEV *LHS, const SCEV *RHS, | ||||||
10643 | const Loop *L, bool IsSigned, | ||||||
10644 | bool ControlsExit, bool AllowPredicates) { | ||||||
10645 | SmallPtrSet<const SCEVPredicate *, 4> Predicates; | ||||||
10646 | |||||||
10647 | const SCEVAddRecExpr *IV = dyn_cast<SCEVAddRecExpr>(LHS); | ||||||
10648 | bool PredicatedIV = false; | ||||||
10649 | |||||||
10650 | if (!IV && AllowPredicates) { | ||||||
10651 | // Try to make this an AddRec using runtime tests, in the first X | ||||||
10652 | // iterations of this loop, where X is the SCEV expression found by the | ||||||
10653 | // algorithm below. | ||||||
10654 | IV = convertSCEVToAddRecWithPredicates(LHS, L, Predicates); | ||||||
10655 | PredicatedIV = true; | ||||||
10656 | } | ||||||
10657 | |||||||
10658 | // Avoid weird loops | ||||||
10659 | if (!IV || IV->getLoop() != L || !IV->isAffine()) | ||||||
10660 | return getCouldNotCompute(); | ||||||
10661 | |||||||
10662 | bool NoWrap = ControlsExit && | ||||||
10663 | IV->getNoWrapFlags(IsSigned ? SCEV::FlagNSW : SCEV::FlagNUW); | ||||||
10664 | |||||||
10665 | const SCEV *Stride = IV->getStepRecurrence(*this); | ||||||
10666 | |||||||
10667 | bool PositiveStride = isKnownPositive(Stride); | ||||||
10668 | |||||||
10669 | // Avoid negative or zero stride values. | ||||||
10670 | if (!PositiveStride) { | ||||||
10671 | // We can compute the correct backedge taken count for loops with unknown | ||||||
10672 | // strides if we can prove that the loop is not an infinite loop with side | ||||||
10673 | // effects. Here's the loop structure we are trying to handle - | ||||||
10674 | // | ||||||
10675 | // i = start | ||||||
10676 | // do { | ||||||
10677 | // A[i] = i; | ||||||
10678 | // i += s; | ||||||
10679 | // } while (i < end); | ||||||
10680 | // | ||||||
10681 | // The backedge taken count for such loops is evaluated as - | ||||||
10682 | // (max(end, start + stride) - start - 1) /u stride | ||||||
10683 | // | ||||||
10684 | // The additional preconditions that we need to check to prove correctness | ||||||
10685 | // of the above formula is as follows - | ||||||
10686 | // | ||||||
10687 | // a) IV is either nuw or nsw depending upon signedness (indicated by the | ||||||
10688 | // NoWrap flag). | ||||||
10689 | // b) loop is single exit with no side effects. | ||||||
10690 | // | ||||||
10691 | // | ||||||
10692 | // Precondition a) implies that if the stride is negative, this is a single | ||||||
10693 | // trip loop. The backedge taken count formula reduces to zero in this case. | ||||||
10694 | // | ||||||
10695 | // Precondition b) implies that the unknown stride cannot be zero otherwise | ||||||
10696 | // we have UB. | ||||||
10697 | // | ||||||
10698 | // The positive stride case is the same as isKnownPositive(Stride) returning | ||||||
10699 | // true (original behavior of the function). | ||||||
10700 | // | ||||||
10701 | // We want to make sure that the stride is truly unknown as there are edge | ||||||
10702 | // cases where ScalarEvolution propagates no wrap flags to the | ||||||
10703 | // post-increment/decrement IV even though the increment/decrement operation | ||||||
10704 | // itself is wrapping. The computed backedge taken count may be wrong in | ||||||
10705 | // such cases. This is prevented by checking that the stride is not known to | ||||||
10706 | // be either positive or non-positive. For example, no wrap flags are | ||||||
10707 | // propagated to the post-increment IV of this loop with a trip count of 2 - | ||||||
10708 | // | ||||||
10709 | // unsigned char i; | ||||||
10710 | // for(i=127; i<128; i+=129) | ||||||
10711 | // A[i] = i; | ||||||
10712 | // | ||||||
10713 | if (PredicatedIV || !NoWrap || isKnownNonPositive(Stride) || | ||||||
10714 | !loopHasNoSideEffects(L)) | ||||||
10715 | return getCouldNotCompute(); | ||||||
10716 | } else if (!Stride->isOne() && | ||||||
10717 | doesIVOverflowOnLT(RHS, Stride, IsSigned, NoWrap)) | ||||||
10718 | // Avoid proven overflow cases: this will ensure that the backedge taken | ||||||
10719 | // count will not generate any unsigned overflow. Relaxed no-overflow | ||||||
10720 | // conditions exploit NoWrapFlags, allowing to optimize in presence of | ||||||
10721 | // undefined behaviors like the case of C language. | ||||||
10722 | return getCouldNotCompute(); | ||||||
10723 | |||||||
10724 | ICmpInst::Predicate Cond = IsSigned ? ICmpInst::ICMP_SLT | ||||||
10725 | : ICmpInst::ICMP_ULT; | ||||||
10726 | const SCEV *Start = IV->getStart(); | ||||||
10727 | const SCEV *End = RHS; | ||||||
10728 | // When the RHS is not invariant, we do not know the end bound of the loop and | ||||||
10729 | // cannot calculate the ExactBECount needed by ExitLimit. However, we can | ||||||
10730 | // calculate the MaxBECount, given the start, stride and max value for the end | ||||||
10731 | // bound of the loop (RHS), and the fact that IV does not overflow (which is | ||||||
10732 | // checked above). | ||||||
10733 | if (!isLoopInvariant(RHS, L)) { | ||||||
10734 | const SCEV *MaxBECount = computeMaxBECountForLT( | ||||||
10735 | Start, Stride, RHS, getTypeSizeInBits(LHS->getType()), IsSigned); | ||||||
10736 | return ExitLimit(getCouldNotCompute() /* ExactNotTaken */, MaxBECount, | ||||||
10737 | false /*MaxOrZero*/, Predicates); | ||||||
10738 | } | ||||||
10739 | // If the backedge is taken at least once, then it will be taken | ||||||
10740 | // (End-Start)/Stride times (rounded up to a multiple of Stride), where Start | ||||||
10741 | // is the LHS value of the less-than comparison the first time it is evaluated | ||||||
10742 | // and End is the RHS. | ||||||
10743 | const SCEV *BECountIfBackedgeTaken = | ||||||
10744 | computeBECount(getMinusSCEV(End, Start), Stride, false); | ||||||
10745 | // If the loop entry is guarded by the result of the backedge test of the | ||||||
10746 | // first loop iteration, then we know the backedge will be taken at least | ||||||
10747 | // once and so the backedge taken count is as above. If not then we use the | ||||||
10748 | // expression (max(End,Start)-Start)/Stride to describe the backedge count, | ||||||
10749 | // as if the backedge is taken at least once max(End,Start) is End and so the | ||||||
10750 | // result is as above, and if not max(End,Start) is Start so we get a backedge | ||||||
10751 | // count of zero. | ||||||
10752 | const SCEV *BECount; | ||||||
10753 | if (isLoopEntryGuardedByCond(L, Cond, getMinusSCEV(Start, Stride), RHS)) | ||||||
10754 | BECount = BECountIfBackedgeTaken; | ||||||
10755 | else { | ||||||
10756 | End = IsSigned ? getSMaxExpr(RHS, Start) : getUMaxExpr(RHS, Start); | ||||||
10757 | BECount = computeBECount(getMinusSCEV(End, Start), Stride, false); | ||||||
10758 | } | ||||||
10759 | |||||||
10760 | const SCEV *MaxBECount; | ||||||
10761 | bool MaxOrZero = false; | ||||||
10762 | if (isa<SCEVConstant>(BECount)) | ||||||
10763 | MaxBECount = BECount; | ||||||
10764 | else if (isa<SCEVConstant>(BECountIfBackedgeTaken)) { | ||||||
10765 | // If we know exactly how many times the backedge will be taken if it's | ||||||
10766 | // taken at least once, then the backedge count will either be that or | ||||||
10767 | // zero. | ||||||
10768 | MaxBECount = BECountIfBackedgeTaken; | ||||||
10769 | MaxOrZero = true; | ||||||
10770 | } else { | ||||||
10771 | MaxBECount = computeMaxBECountForLT( | ||||||
10772 | Start, Stride, RHS, getTypeSizeInBits(LHS->getType()), IsSigned); | ||||||
10773 | } | ||||||
10774 | |||||||
10775 | if (isa<SCEVCouldNotCompute>(MaxBECount) && | ||||||
10776 | !isa<SCEVCouldNotCompute>(BECount)) | ||||||
10777 | MaxBECount = getConstant(getUnsignedRangeMax(BECount)); | ||||||
10778 | |||||||
10779 | return ExitLimit(BECount, MaxBECount, MaxOrZero, Predicates); | ||||||
10780 | } | ||||||
10781 | |||||||
10782 | ScalarEvolution::ExitLimit | ||||||
10783 | ScalarEvolution::howManyGreaterThans(const SCEV *LHS, const SCEV *RHS, | ||||||
10784 | const Loop *L, bool IsSigned, | ||||||
10785 | bool ControlsExit, bool AllowPredicates) { | ||||||
10786 | SmallPtrSet<const SCEVPredicate *, 4> Predicates; | ||||||
10787 | // We handle only IV > Invariant | ||||||
10788 | if (!isLoopInvariant(RHS, L)) | ||||||
10789 | return getCouldNotCompute(); | ||||||
10790 | |||||||
10791 | const SCEVAddRecExpr *IV = dyn_cast<SCEVAddRecExpr>(LHS); | ||||||
10792 | if (!IV && AllowPredicates) | ||||||
10793 | // Try to make this an AddRec using runtime tests, in the first X | ||||||
10794 | // iterations of this loop, where X is the SCEV expression found by the | ||||||
10795 | // algorithm below. | ||||||
10796 | IV = convertSCEVToAddRecWithPredicates(LHS, L, Predicates); | ||||||
10797 | |||||||
10798 | // Avoid weird loops | ||||||
10799 | if (!IV || IV->getLoop() != L || !IV->isAffine()) | ||||||
10800 | return getCouldNotCompute(); | ||||||
10801 | |||||||
10802 | bool NoWrap = ControlsExit && | ||||||
10803 | IV->getNoWrapFlags(IsSigned ? SCEV::FlagNSW : SCEV::FlagNUW); | ||||||
10804 | |||||||
10805 | const SCEV *Stride = getNegativeSCEV(IV->getStepRecurrence(*this)); | ||||||
10806 | |||||||
10807 | // Avoid negative or zero stride values | ||||||
10808 | if (!isKnownPositive(Stride)) | ||||||
10809 | return getCouldNotCompute(); | ||||||
10810 | |||||||
10811 | // Avoid proven overflow cases: this will ensure that the backedge taken count | ||||||
10812 | // will not generate any unsigned overflow. Relaxed no-overflow conditions | ||||||
10813 | // exploit NoWrapFlags, allowing to optimize in presence of undefined | ||||||
10814 | // behaviors like the case of C language. | ||||||
10815 | if (!Stride->isOne() && doesIVOverflowOnGT(RHS, Stride, IsSigned, NoWrap)) | ||||||
10816 | return getCouldNotCompute(); | ||||||
10817 | |||||||
10818 | ICmpInst::Predicate Cond = IsSigned ? ICmpInst::ICMP_SGT | ||||||
10819 | : ICmpInst::ICMP_UGT; | ||||||
10820 | |||||||
10821 | const SCEV *Start = IV->getStart(); | ||||||
10822 | const SCEV *End = RHS; | ||||||
10823 | if (!isLoopEntryGuardedByCond(L, Cond, getAddExpr(Start, Stride), RHS)) | ||||||
10824 | End = IsSigned ? getSMinExpr(RHS, Start) : getUMinExpr(RHS, Start); | ||||||
10825 | |||||||
10826 | const SCEV *BECount = computeBECount(getMinusSCEV(Start, End), Stride, false); | ||||||
10827 | |||||||
10828 | APInt MaxStart = IsSigned ? getSignedRangeMax(Start) | ||||||
10829 | : getUnsignedRangeMax(Start); | ||||||
10830 | |||||||
10831 | APInt MinStride = IsSigned ? getSignedRangeMin(Stride) | ||||||
10832 | : getUnsignedRangeMin(Stride); | ||||||
10833 | |||||||
10834 | unsigned BitWidth = getTypeSizeInBits(LHS->getType()); | ||||||
10835 | APInt Limit = IsSigned ? APInt::getSignedMinValue(BitWidth) + (MinStride - 1) | ||||||
10836 | : APInt::getMinValue(BitWidth) + (MinStride - 1); | ||||||
10837 | |||||||
10838 | // Although End can be a MIN expression we estimate MinEnd considering only | ||||||
10839 | // the case End = RHS. This is safe because in the other case (Start - End) | ||||||
10840 | // is zero, leading to a zero maximum backedge taken count. | ||||||
10841 | APInt MinEnd = | ||||||
10842 | IsSigned ? APIntOps::smax(getSignedRangeMin(RHS), Limit) | ||||||
10843 | : APIntOps::umax(getUnsignedRangeMin(RHS), Limit); | ||||||
10844 | |||||||
10845 | const SCEV *MaxBECount = isa<SCEVConstant>(BECount) | ||||||
10846 | ? BECount | ||||||
10847 | : computeBECount(getConstant(MaxStart - MinEnd), | ||||||
10848 | getConstant(MinStride), false); | ||||||
10849 | |||||||
10850 | if (isa<SCEVCouldNotCompute>(MaxBECount)) | ||||||
10851 | MaxBECount = BECount; | ||||||
10852 | |||||||
10853 | return ExitLimit(BECount, MaxBECount, false, Predicates); | ||||||
10854 | } | ||||||
10855 | |||||||
10856 | const SCEV *SCEVAddRecExpr::getNumIterationsInRange(const ConstantRange &Range, | ||||||
10857 | ScalarEvolution &SE) const { | ||||||
10858 | if (Range.isFullSet()) // Infinite loop. | ||||||
10859 | return SE.getCouldNotCompute(); | ||||||
10860 | |||||||
10861 | // If the start is a non-zero constant, shift the range to simplify things. | ||||||
10862 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(getStart())) | ||||||
10863 | if (!SC->getValue()->isZero()) { | ||||||
10864 | SmallVector<const SCEV *, 4> Operands(op_begin(), op_end()); | ||||||
10865 | Operands[0] = SE.getZero(SC->getType()); | ||||||
10866 | const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop(), | ||||||
10867 | getNoWrapFlags(FlagNW)); | ||||||
10868 | if (const auto *ShiftedAddRec = dyn_cast<SCEVAddRecExpr>(Shifted)) | ||||||
10869 | return ShiftedAddRec->getNumIterationsInRange( | ||||||
10870 | Range.subtract(SC->getAPInt()), SE); | ||||||
10871 | // This is strange and shouldn't happen. | ||||||
10872 | return SE.getCouldNotCompute(); | ||||||
10873 | } | ||||||
10874 | |||||||
10875 | // The only time we can solve this is when we have all constant indices. | ||||||
10876 | // Otherwise, we cannot determine the overflow conditions. | ||||||
10877 | if (any_of(operands(), [](const SCEV *Op) { return !isa<SCEVConstant>(Op); })) | ||||||
10878 | return SE.getCouldNotCompute(); | ||||||
10879 | |||||||
10880 | // Okay at this point we know that all elements of the chrec are constants and | ||||||
10881 | // that the start element is zero. | ||||||
10882 | |||||||
10883 | // First check to see if the range contains zero. If not, the first | ||||||
10884 | // iteration exits. | ||||||
10885 | unsigned BitWidth = SE.getTypeSizeInBits(getType()); | ||||||
10886 | if (!Range.contains(APInt(BitWidth, 0))) | ||||||
10887 | return SE.getZero(getType()); | ||||||
10888 | |||||||
10889 | if (isAffine()) { | ||||||
10890 | // If this is an affine expression then we have this situation: | ||||||
10891 | // Solve {0,+,A} in Range === Ax in Range | ||||||
10892 | |||||||
10893 | // We know that zero is in the range. If A is positive then we know that | ||||||
10894 | // the upper value of the range must be the first possible exit value. | ||||||
10895 | // If A is negative then the lower of the range is the last possible loop | ||||||
10896 | // value. Also note that we already checked for a full range. | ||||||
10897 | APInt A = cast<SCEVConstant>(getOperand(1))->getAPInt(); | ||||||
10898 | APInt End = A.sge(1) ? (Range.getUpper() - 1) : Range.getLower(); | ||||||
10899 | |||||||
10900 | // The exit value should be (End+A)/A. | ||||||
10901 | APInt ExitVal = (End + A).udiv(A); | ||||||
10902 | ConstantInt *ExitValue = ConstantInt::get(SE.getContext(), ExitVal); | ||||||
10903 | |||||||
10904 | // Evaluate at the exit value. If we really did fall out of the valid | ||||||
10905 | // range, then we computed our trip count, otherwise wrap around or other | ||||||
10906 | // things must have happened. | ||||||
10907 | ConstantInt *Val = EvaluateConstantChrecAtConstant(this, ExitValue, SE); | ||||||
10908 | if (Range.contains(Val->getValue())) | ||||||
10909 | return SE.getCouldNotCompute(); // Something strange happened | ||||||
10910 | |||||||
10911 | // Ensure that the previous value is in the range. This is a sanity check. | ||||||
10912 | assert(Range.contains(((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt ::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && "Linear scev computation is off in a bad way!") ? static_cast <void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10915, __PRETTY_FUNCTION__)) | ||||||
10913 | EvaluateConstantChrecAtConstant(this,((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt ::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && "Linear scev computation is off in a bad way!") ? static_cast <void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10915, __PRETTY_FUNCTION__)) | ||||||
10914 | ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) &&((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt ::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && "Linear scev computation is off in a bad way!") ? static_cast <void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10915, __PRETTY_FUNCTION__)) | ||||||
10915 | "Linear scev computation is off in a bad way!")((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt ::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && "Linear scev computation is off in a bad way!") ? static_cast <void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10915, __PRETTY_FUNCTION__)); | ||||||
10916 | return SE.getConstant(ExitValue); | ||||||
10917 | } | ||||||
10918 | |||||||
10919 | if (isQuadratic()) { | ||||||
10920 | if (auto S = SolveQuadraticAddRecRange(this, Range, SE)) | ||||||
10921 | return SE.getConstant(S.getValue()); | ||||||
10922 | } | ||||||
10923 | |||||||
10924 | return SE.getCouldNotCompute(); | ||||||
10925 | } | ||||||
10926 | |||||||
10927 | const SCEVAddRecExpr * | ||||||
10928 | SCEVAddRecExpr::getPostIncExpr(ScalarEvolution &SE) const { | ||||||
10929 | assert(getNumOperands() > 1 && "AddRec with zero step?")((getNumOperands() > 1 && "AddRec with zero step?" ) ? static_cast<void> (0) : __assert_fail ("getNumOperands() > 1 && \"AddRec with zero step?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10929, __PRETTY_FUNCTION__)); | ||||||
10930 | // There is a temptation to just call getAddExpr(this, getStepRecurrence(SE)), | ||||||
10931 | // but in this case we cannot guarantee that the value returned will be an | ||||||
10932 | // AddRec because SCEV does not have a fixed point where it stops | ||||||
10933 | // simplification: it is legal to return ({rec1} + {rec2}). For example, it | ||||||
10934 | // may happen if we reach arithmetic depth limit while simplifying. So we | ||||||
10935 | // construct the returned value explicitly. | ||||||
10936 | SmallVector<const SCEV *, 3> Ops; | ||||||
10937 | // If this is {A,+,B,+,C,...,+,N}, then its step is {B,+,C,+,...,+,N}, and | ||||||
10938 | // (this + Step) is {A+B,+,B+C,+...,+,N}. | ||||||
10939 | for (unsigned i = 0, e = getNumOperands() - 1; i < e; ++i) | ||||||
10940 | Ops.push_back(SE.getAddExpr(getOperand(i), getOperand(i + 1))); | ||||||
10941 | // We know that the last operand is not a constant zero (otherwise it would | ||||||
10942 | // have been popped out earlier). This guarantees us that if the result has | ||||||
10943 | // the same last operand, then it will also not be popped out, meaning that | ||||||
10944 | // the returned value will be an AddRec. | ||||||
10945 | const SCEV *Last = getOperand(getNumOperands() - 1); | ||||||
10946 | assert(!Last->isZero() && "Recurrency with zero step?")((!Last->isZero() && "Recurrency with zero step?") ? static_cast<void> (0) : __assert_fail ("!Last->isZero() && \"Recurrency with zero step?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 10946, __PRETTY_FUNCTION__)); | ||||||
10947 | Ops.push_back(Last); | ||||||
10948 | return cast<SCEVAddRecExpr>(SE.getAddRecExpr(Ops, getLoop(), | ||||||
10949 | SCEV::FlagAnyWrap)); | ||||||
10950 | } | ||||||
10951 | |||||||
10952 | // Return true when S contains at least an undef value. | ||||||
10953 | static inline bool containsUndefs(const SCEV *S) { | ||||||
10954 | return SCEVExprContains(S, [](const SCEV *S) { | ||||||
10955 | if (const auto *SU = dyn_cast<SCEVUnknown>(S)) | ||||||
10956 | return isa<UndefValue>(SU->getValue()); | ||||||
10957 | return false; | ||||||
10958 | }); | ||||||
10959 | } | ||||||
10960 | |||||||
10961 | namespace { | ||||||
10962 | |||||||
10963 | // Collect all steps of SCEV expressions. | ||||||
10964 | struct SCEVCollectStrides { | ||||||
10965 | ScalarEvolution &SE; | ||||||
10966 | SmallVectorImpl<const SCEV *> &Strides; | ||||||
10967 | |||||||
10968 | SCEVCollectStrides(ScalarEvolution &SE, SmallVectorImpl<const SCEV *> &S) | ||||||
10969 | : SE(SE), Strides(S) {} | ||||||
10970 | |||||||
10971 | bool follow(const SCEV *S) { | ||||||
10972 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) | ||||||
10973 | Strides.push_back(AR->getStepRecurrence(SE)); | ||||||
10974 | return true; | ||||||
10975 | } | ||||||
10976 | |||||||
10977 | bool isDone() const { return false; } | ||||||
10978 | }; | ||||||
10979 | |||||||
10980 | // Collect all SCEVUnknown and SCEVMulExpr expressions. | ||||||
10981 | struct SCEVCollectTerms { | ||||||
10982 | SmallVectorImpl<const SCEV *> &Terms; | ||||||
10983 | |||||||
10984 | SCEVCollectTerms(SmallVectorImpl<const SCEV *> &T) : Terms(T) {} | ||||||
10985 | |||||||
10986 | bool follow(const SCEV *S) { | ||||||
10987 | if (isa<SCEVUnknown>(S) || isa<SCEVMulExpr>(S) || | ||||||
10988 | isa<SCEVSignExtendExpr>(S)) { | ||||||
10989 | if (!containsUndefs(S)) | ||||||
10990 | Terms.push_back(S); | ||||||
10991 | |||||||
10992 | // Stop recursion: once we collected a term, do not walk its operands. | ||||||
10993 | return false; | ||||||
10994 | } | ||||||
10995 | |||||||
10996 | // Keep looking. | ||||||
10997 | return true; | ||||||
10998 | } | ||||||
10999 | |||||||
11000 | bool isDone() const { return false; } | ||||||
11001 | }; | ||||||
11002 | |||||||
11003 | // Check if a SCEV contains an AddRecExpr. | ||||||
11004 | struct SCEVHasAddRec { | ||||||
11005 | bool &ContainsAddRec; | ||||||
11006 | |||||||
11007 | SCEVHasAddRec(bool &ContainsAddRec) : ContainsAddRec(ContainsAddRec) { | ||||||
11008 | ContainsAddRec = false; | ||||||
11009 | } | ||||||
11010 | |||||||
11011 | bool follow(const SCEV *S) { | ||||||
11012 | if (isa<SCEVAddRecExpr>(S)) { | ||||||
11013 | ContainsAddRec = true; | ||||||
11014 | |||||||
11015 | // Stop recursion: once we collected a term, do not walk its operands. | ||||||
11016 | return false; | ||||||
11017 | } | ||||||
11018 | |||||||
11019 | // Keep looking. | ||||||
11020 | return true; | ||||||
11021 | } | ||||||
11022 | |||||||
11023 | bool isDone() const { return false; } | ||||||
11024 | }; | ||||||
11025 | |||||||
11026 | // Find factors that are multiplied with an expression that (possibly as a | ||||||
11027 | // subexpression) contains an AddRecExpr. In the expression: | ||||||
11028 | // | ||||||
11029 | // 8 * (100 + %p * %q * (%a + {0, +, 1}_loop)) | ||||||
11030 | // | ||||||
11031 | // "%p * %q" are factors multiplied by the expression "(%a + {0, +, 1}_loop)" | ||||||
11032 | // that contains the AddRec {0, +, 1}_loop. %p * %q are likely to be array size | ||||||
11033 | // parameters as they form a product with an induction variable. | ||||||
11034 | // | ||||||
11035 | // This collector expects all array size parameters to be in the same MulExpr. | ||||||
11036 | // It might be necessary to later add support for collecting parameters that are | ||||||
11037 | // spread over different nested MulExpr. | ||||||
11038 | struct SCEVCollectAddRecMultiplies { | ||||||
11039 | SmallVectorImpl<const SCEV *> &Terms; | ||||||
11040 | ScalarEvolution &SE; | ||||||
11041 | |||||||
11042 | SCEVCollectAddRecMultiplies(SmallVectorImpl<const SCEV *> &T, ScalarEvolution &SE) | ||||||
11043 | : Terms(T), SE(SE) {} | ||||||
11044 | |||||||
11045 | bool follow(const SCEV *S) { | ||||||
11046 | if (auto *Mul = dyn_cast<SCEVMulExpr>(S)) { | ||||||
11047 | bool HasAddRec = false; | ||||||
11048 | SmallVector<const SCEV *, 0> Operands; | ||||||
11049 | for (auto Op : Mul->operands()) { | ||||||
11050 | const SCEVUnknown *Unknown = dyn_cast<SCEVUnknown>(Op); | ||||||
11051 | if (Unknown && !isa<CallInst>(Unknown->getValue())) { | ||||||
11052 | Operands.push_back(Op); | ||||||
11053 | } else if (Unknown) { | ||||||
11054 | HasAddRec = true; | ||||||
11055 | } else { | ||||||
11056 | bool ContainsAddRec = false; | ||||||
11057 | SCEVHasAddRec ContiansAddRec(ContainsAddRec); | ||||||
11058 | visitAll(Op, ContiansAddRec); | ||||||
11059 | HasAddRec |= ContainsAddRec; | ||||||
11060 | } | ||||||
11061 | } | ||||||
11062 | if (Operands.size() == 0) | ||||||
11063 | return true; | ||||||
11064 | |||||||
11065 | if (!HasAddRec) | ||||||
11066 | return false; | ||||||
11067 | |||||||
11068 | Terms.push_back(SE.getMulExpr(Operands)); | ||||||
11069 | // Stop recursion: once we collected a term, do not walk its operands. | ||||||
11070 | return false; | ||||||
11071 | } | ||||||
11072 | |||||||
11073 | // Keep looking. | ||||||
11074 | return true; | ||||||
11075 | } | ||||||
11076 | |||||||
11077 | bool isDone() const { return false; } | ||||||
11078 | }; | ||||||
11079 | |||||||
11080 | } // end anonymous namespace | ||||||
11081 | |||||||
11082 | /// Find parametric terms in this SCEVAddRecExpr. We first for parameters in | ||||||
11083 | /// two places: | ||||||
11084 | /// 1) The strides of AddRec expressions. | ||||||
11085 | /// 2) Unknowns that are multiplied with AddRec expressions. | ||||||
11086 | void ScalarEvolution::collectParametricTerms(const SCEV *Expr, | ||||||
11087 | SmallVectorImpl<const SCEV *> &Terms) { | ||||||
11088 | SmallVector<const SCEV *, 4> Strides; | ||||||
11089 | SCEVCollectStrides StrideCollector(*this, Strides); | ||||||
11090 | visitAll(Expr, StrideCollector); | ||||||
11091 | |||||||
11092 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Strides:\n"; for ( const SCEV *S : Strides) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11093 | dbgs() << "Strides:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Strides:\n"; for ( const SCEV *S : Strides) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11094 | for (const SCEV *S : Strides)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Strides:\n"; for ( const SCEV *S : Strides) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11095 | dbgs() << *S << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Strides:\n"; for ( const SCEV *S : Strides) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11096 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Strides:\n"; for ( const SCEV *S : Strides) dbgs() << *S << "\n"; }; } } while (false); | ||||||
11097 | |||||||
11098 | for (const SCEV *S : Strides) { | ||||||
11099 | SCEVCollectTerms TermCollector(Terms); | ||||||
11100 | visitAll(S, TermCollector); | ||||||
11101 | } | ||||||
11102 | |||||||
11103 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11104 | dbgs() << "Terms:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11105 | for (const SCEV *T : Terms)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11106 | dbgs() << *T << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11107 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false); | ||||||
11108 | |||||||
11109 | SCEVCollectAddRecMultiplies MulCollector(Terms, *this); | ||||||
11110 | visitAll(Expr, MulCollector); | ||||||
11111 | } | ||||||
11112 | |||||||
11113 | static bool findArrayDimensionsRec(ScalarEvolution &SE, | ||||||
11114 | SmallVectorImpl<const SCEV *> &Terms, | ||||||
11115 | SmallVectorImpl<const SCEV *> &Sizes) { | ||||||
11116 | int Last = Terms.size() - 1; | ||||||
11117 | const SCEV *Step = Terms[Last]; | ||||||
11118 | |||||||
11119 | // End of recursion. | ||||||
11120 | if (Last == 0) { | ||||||
11121 | if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Step)) { | ||||||
11122 | SmallVector<const SCEV *, 2> Qs; | ||||||
11123 | for (const SCEV *Op : M->operands()) | ||||||
11124 | if (!isa<SCEVConstant>(Op)) | ||||||
11125 | Qs.push_back(Op); | ||||||
11126 | |||||||
11127 | Step = SE.getMulExpr(Qs); | ||||||
11128 | } | ||||||
11129 | |||||||
11130 | Sizes.push_back(Step); | ||||||
11131 | return true; | ||||||
11132 | } | ||||||
11133 | |||||||
11134 | for (const SCEV *&Term : Terms) { | ||||||
11135 | // Normalize the terms before the next call to findArrayDimensionsRec. | ||||||
11136 | const SCEV *Q, *R; | ||||||
11137 | SCEVDivision::divide(SE, Term, Step, &Q, &R); | ||||||
11138 | |||||||
11139 | // Bail out when GCD does not evenly divide one of the terms. | ||||||
11140 | if (!R->isZero()) | ||||||
11141 | return false; | ||||||
11142 | |||||||
11143 | Term = Q; | ||||||
11144 | } | ||||||
11145 | |||||||
11146 | // Remove all SCEVConstants. | ||||||
11147 | Terms.erase( | ||||||
11148 | remove_if(Terms, [](const SCEV *E) { return isa<SCEVConstant>(E); }), | ||||||
11149 | Terms.end()); | ||||||
11150 | |||||||
11151 | if (Terms.size() > 0) | ||||||
11152 | if (!findArrayDimensionsRec(SE, Terms, Sizes)) | ||||||
11153 | return false; | ||||||
11154 | |||||||
11155 | Sizes.push_back(Step); | ||||||
11156 | return true; | ||||||
11157 | } | ||||||
11158 | |||||||
11159 | // Returns true when one of the SCEVs of Terms contains a SCEVUnknown parameter. | ||||||
11160 | static inline bool containsParameters(SmallVectorImpl<const SCEV *> &Terms) { | ||||||
11161 | for (const SCEV *T : Terms) | ||||||
11162 | if (SCEVExprContains(T, isa<SCEVUnknown, const SCEV *>)) | ||||||
11163 | return true; | ||||||
11164 | return false; | ||||||
11165 | } | ||||||
11166 | |||||||
11167 | // Return the number of product terms in S. | ||||||
11168 | static inline int numberOfTerms(const SCEV *S) { | ||||||
11169 | if (const SCEVMulExpr *Expr = dyn_cast<SCEVMulExpr>(S)) | ||||||
11170 | return Expr->getNumOperands(); | ||||||
11171 | return 1; | ||||||
11172 | } | ||||||
11173 | |||||||
11174 | static const SCEV *removeConstantFactors(ScalarEvolution &SE, const SCEV *T) { | ||||||
11175 | if (isa<SCEVConstant>(T)) | ||||||
11176 | return nullptr; | ||||||
11177 | |||||||
11178 | if (isa<SCEVUnknown>(T)) | ||||||
11179 | return T; | ||||||
11180 | |||||||
11181 | if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(T)) { | ||||||
11182 | SmallVector<const SCEV *, 2> Factors; | ||||||
11183 | for (const SCEV *Op : M->operands()) | ||||||
11184 | if (!isa<SCEVConstant>(Op)) | ||||||
11185 | Factors.push_back(Op); | ||||||
11186 | |||||||
11187 | return SE.getMulExpr(Factors); | ||||||
11188 | } | ||||||
11189 | |||||||
11190 | return T; | ||||||
11191 | } | ||||||
11192 | |||||||
11193 | /// Return the size of an element read or written by Inst. | ||||||
11194 | const SCEV *ScalarEvolution::getElementSize(Instruction *Inst) { | ||||||
11195 | Type *Ty; | ||||||
11196 | if (StoreInst *Store = dyn_cast<StoreInst>(Inst)) | ||||||
11197 | Ty = Store->getValueOperand()->getType(); | ||||||
11198 | else if (LoadInst *Load = dyn_cast<LoadInst>(Inst)) | ||||||
11199 | Ty = Load->getType(); | ||||||
11200 | else | ||||||
11201 | return nullptr; | ||||||
11202 | |||||||
11203 | Type *ETy = getEffectiveSCEVType(PointerType::getUnqual(Ty)); | ||||||
11204 | return getSizeOfExpr(ETy, Ty); | ||||||
11205 | } | ||||||
11206 | |||||||
11207 | void ScalarEvolution::findArrayDimensions(SmallVectorImpl<const SCEV *> &Terms, | ||||||
11208 | SmallVectorImpl<const SCEV *> &Sizes, | ||||||
11209 | const SCEV *ElementSize) { | ||||||
11210 | if (Terms.size() < 1 || !ElementSize) | ||||||
11211 | return; | ||||||
11212 | |||||||
11213 | // Early return when Terms do not contain parameters: we do not delinearize | ||||||
11214 | // non parametric SCEVs. | ||||||
11215 | if (!containsParameters(Terms)) | ||||||
11216 | return; | ||||||
11217 | |||||||
11218 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11219 | dbgs() << "Terms:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11220 | for (const SCEV *T : Terms)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11221 | dbgs() << *T << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false) | ||||||
11222 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while (false); | ||||||
11223 | |||||||
11224 | // Remove duplicates. | ||||||
11225 | array_pod_sort(Terms.begin(), Terms.end()); | ||||||
11226 | Terms.erase(std::unique(Terms.begin(), Terms.end()), Terms.end()); | ||||||
11227 | |||||||
11228 | // Put larger terms first. | ||||||
11229 | llvm::sort(Terms, [](const SCEV *LHS, const SCEV *RHS) { | ||||||
11230 | return numberOfTerms(LHS) > numberOfTerms(RHS); | ||||||
11231 | }); | ||||||
11232 | |||||||
11233 | // Try to divide all terms by the element size. If term is not divisible by | ||||||
11234 | // element size, proceed with the original term. | ||||||
11235 | for (const SCEV *&Term : Terms) { | ||||||
11236 | const SCEV *Q, *R; | ||||||
11237 | SCEVDivision::divide(*this, Term, ElementSize, &Q, &R); | ||||||
11238 | if (!Q->isZero()) | ||||||
11239 | Term = Q; | ||||||
11240 | } | ||||||
11241 | |||||||
11242 | SmallVector<const SCEV *, 4> NewTerms; | ||||||
11243 | |||||||
11244 | // Remove constant factors. | ||||||
11245 | for (const SCEV *T : Terms) | ||||||
11246 | if (const SCEV *NewT = removeConstantFactors(*this, T)) | ||||||
11247 | NewTerms.push_back(NewT); | ||||||
11248 | |||||||
11249 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms after sorting:\n" ; for (const SCEV *T : NewTerms) dbgs() << *T << "\n" ; }; } } while (false) | ||||||
11250 | dbgs() << "Terms after sorting:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms after sorting:\n" ; for (const SCEV *T : NewTerms) dbgs() << *T << "\n" ; }; } } while (false) | ||||||
11251 | for (const SCEV *T : NewTerms)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms after sorting:\n" ; for (const SCEV *T : NewTerms) dbgs() << *T << "\n" ; }; } } while (false) | ||||||
11252 | dbgs() << *T << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms after sorting:\n" ; for (const SCEV *T : NewTerms) dbgs() << *T << "\n" ; }; } } while (false) | ||||||
11253 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Terms after sorting:\n" ; for (const SCEV *T : NewTerms) dbgs() << *T << "\n" ; }; } } while (false); | ||||||
11254 | |||||||
11255 | if (NewTerms.empty() || !findArrayDimensionsRec(*this, NewTerms, Sizes)) { | ||||||
11256 | Sizes.clear(); | ||||||
11257 | return; | ||||||
11258 | } | ||||||
11259 | |||||||
11260 | // The last element to be pushed into Sizes is the size of an element. | ||||||
11261 | Sizes.push_back(ElementSize); | ||||||
11262 | |||||||
11263 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11264 | dbgs() << "Sizes:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11265 | for (const SCEV *S : Sizes)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11266 | dbgs() << *S << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while (false) | ||||||
11267 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while (false); | ||||||
11268 | } | ||||||
11269 | |||||||
11270 | void ScalarEvolution::computeAccessFunctions( | ||||||
11271 | const SCEV *Expr, SmallVectorImpl<const SCEV *> &Subscripts, | ||||||
11272 | SmallVectorImpl<const SCEV *> &Sizes) { | ||||||
11273 | // Early exit in case this SCEV is not an affine multivariate function. | ||||||
11274 | if (Sizes.empty()) | ||||||
11275 | return; | ||||||
11276 | |||||||
11277 | if (auto *AR = dyn_cast<SCEVAddRecExpr>(Expr)) | ||||||
11278 | if (!AR->isAffine()) | ||||||
11279 | return; | ||||||
11280 | |||||||
11281 | const SCEV *Res = Expr; | ||||||
11282 | int Last = Sizes.size() - 1; | ||||||
11283 | for (int i = Last; i >= 0; i--) { | ||||||
11284 | const SCEV *Q, *R; | ||||||
11285 | SCEVDivision::divide(*this, Res, Sizes[i], &Q, &R); | ||||||
11286 | |||||||
11287 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Res: " << *Res << "\n"; dbgs() << "Sizes[i]: " << *Sizes[ i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n" ; dbgs() << "Quotient: " << *Q << "\n"; dbgs () << "Remainder: " << *R << "\n"; }; } } while (false) | ||||||
11288 | dbgs() << "Res: " << *Res << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Res: " << *Res << "\n"; dbgs() << "Sizes[i]: " << *Sizes[ i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n" ; dbgs() << "Quotient: " << *Q << "\n"; dbgs () << "Remainder: " << *R << "\n"; }; } } while (false) | ||||||
11289 | dbgs() << "Sizes[i]: " << *Sizes[i] << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Res: " << *Res << "\n"; dbgs() << "Sizes[i]: " << *Sizes[ i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n" ; dbgs() << "Quotient: " << *Q << "\n"; dbgs () << "Remainder: " << *R << "\n"; }; } } while (false) | ||||||
11290 | dbgs() << "Res divided by Sizes[i]:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Res: " << *Res << "\n"; dbgs() << "Sizes[i]: " << *Sizes[ i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n" ; dbgs() << "Quotient: " << *Q << "\n"; dbgs () << "Remainder: " << *R << "\n"; }; } } while (false) | ||||||
11291 | dbgs() << "Quotient: " << *Q << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Res: " << *Res << "\n"; dbgs() << "Sizes[i]: " << *Sizes[ i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n" ; dbgs() << "Quotient: " << *Q << "\n"; dbgs () << "Remainder: " << *R << "\n"; }; } } while (false) | ||||||
11292 | dbgs() << "Remainder: " << *R << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Res: " << *Res << "\n"; dbgs() << "Sizes[i]: " << *Sizes[ i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n" ; dbgs() << "Quotient: " << *Q << "\n"; dbgs () << "Remainder: " << *R << "\n"; }; } } while (false) | ||||||
11293 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Res: " << *Res << "\n"; dbgs() << "Sizes[i]: " << *Sizes[ i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n" ; dbgs() << "Quotient: " << *Q << "\n"; dbgs () << "Remainder: " << *R << "\n"; }; } } while (false); | ||||||
11294 | |||||||
11295 | Res = Q; | ||||||
11296 | |||||||
11297 | // Do not record the last subscript corresponding to the size of elements in | ||||||
11298 | // the array. | ||||||
11299 | if (i == Last) { | ||||||
11300 | |||||||
11301 | // Bail out if the remainder is too complex. | ||||||
11302 | if (isa<SCEVAddRecExpr>(R)) { | ||||||
11303 | Subscripts.clear(); | ||||||
11304 | Sizes.clear(); | ||||||
11305 | return; | ||||||
11306 | } | ||||||
11307 | |||||||
11308 | continue; | ||||||
11309 | } | ||||||
11310 | |||||||
11311 | // Record the access function for the current subscript. | ||||||
11312 | Subscripts.push_back(R); | ||||||
11313 | } | ||||||
11314 | |||||||
11315 | // Also push in last position the remainder of the last division: it will be | ||||||
11316 | // the access function of the innermost dimension. | ||||||
11317 | Subscripts.push_back(Res); | ||||||
11318 | |||||||
11319 | std::reverse(Subscripts.begin(), Subscripts.end()); | ||||||
11320 | |||||||
11321 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for (const SCEV *S : Subscripts) dbgs() << *S << "\n" ; }; } } while (false) | ||||||
11322 | dbgs() << "Subscripts:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for (const SCEV *S : Subscripts) dbgs() << *S << "\n" ; }; } } while (false) | ||||||
11323 | for (const SCEV *S : Subscripts)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for (const SCEV *S : Subscripts) dbgs() << *S << "\n" ; }; } } while (false) | ||||||
11324 | dbgs() << *S << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for (const SCEV *S : Subscripts) dbgs() << *S << "\n" ; }; } } while (false) | ||||||
11325 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for (const SCEV *S : Subscripts) dbgs() << *S << "\n" ; }; } } while (false); | ||||||
11326 | } | ||||||
11327 | |||||||
11328 | /// Splits the SCEV into two vectors of SCEVs representing the subscripts and | ||||||
11329 | /// sizes of an array access. Returns the remainder of the delinearization that | ||||||
11330 | /// is the offset start of the array. The SCEV->delinearize algorithm computes | ||||||
11331 | /// the multiples of SCEV coefficients: that is a pattern matching of sub | ||||||
11332 | /// expressions in the stride and base of a SCEV corresponding to the | ||||||
11333 | /// computation of a GCD (greatest common divisor) of base and stride. When | ||||||
11334 | /// SCEV->delinearize fails, it returns the SCEV unchanged. | ||||||
11335 | /// | ||||||
11336 | /// For example: when analyzing the memory access A[i][j][k] in this loop nest | ||||||
11337 | /// | ||||||
11338 | /// void foo(long n, long m, long o, double A[n][m][o]) { | ||||||
11339 | /// | ||||||
11340 | /// for (long i = 0; i < n; i++) | ||||||
11341 | /// for (long j = 0; j < m; j++) | ||||||
11342 | /// for (long k = 0; k < o; k++) | ||||||
11343 | /// A[i][j][k] = 1.0; | ||||||
11344 | /// } | ||||||
11345 | /// | ||||||
11346 | /// the delinearization input is the following AddRec SCEV: | ||||||
11347 | /// | ||||||
11348 | /// AddRec: {{{%A,+,(8 * %m * %o)}<%for.i>,+,(8 * %o)}<%for.j>,+,8}<%for.k> | ||||||
11349 | /// | ||||||
11350 | /// From this SCEV, we are able to say that the base offset of the access is %A | ||||||
11351 | /// because it appears as an offset that does not divide any of the strides in | ||||||
11352 | /// the loops: | ||||||
11353 | /// | ||||||
11354 | /// CHECK: Base offset: %A | ||||||
11355 | /// | ||||||
11356 | /// and then SCEV->delinearize determines the size of some of the dimensions of | ||||||
11357 | /// the array as these are the multiples by which the strides are happening: | ||||||
11358 | /// | ||||||
11359 | /// CHECK: ArrayDecl[UnknownSize][%m][%o] with elements of sizeof(double) bytes. | ||||||
11360 | /// | ||||||
11361 | /// Note that the outermost dimension remains of UnknownSize because there are | ||||||
11362 | /// no strides that would help identifying the size of the last dimension: when | ||||||
11363 | /// the array has been statically allocated, one could compute the size of that | ||||||
11364 | /// dimension by dividing the overall size of the array by the size of the known | ||||||
11365 | /// dimensions: %m * %o * 8. | ||||||
11366 | /// | ||||||
11367 | /// Finally delinearize provides the access functions for the array reference | ||||||
11368 | /// that does correspond to A[i][j][k] of the above C testcase: | ||||||
11369 | /// | ||||||
11370 | /// CHECK: ArrayRef[{0,+,1}<%for.i>][{0,+,1}<%for.j>][{0,+,1}<%for.k>] | ||||||
11371 | /// | ||||||
11372 | /// The testcases are checking the output of a function pass: | ||||||
11373 | /// DelinearizationPass that walks through all loads and stores of a function | ||||||
11374 | /// asking for the SCEV of the memory access with respect to all enclosing | ||||||
11375 | /// loops, calling SCEV->delinearize on that and printing the results. | ||||||
11376 | void ScalarEvolution::delinearize(const SCEV *Expr, | ||||||
11377 | SmallVectorImpl<const SCEV *> &Subscripts, | ||||||
11378 | SmallVectorImpl<const SCEV *> &Sizes, | ||||||
11379 | const SCEV *ElementSize) { | ||||||
11380 | // First step: collect parametric terms. | ||||||
11381 | SmallVector<const SCEV *, 4> Terms; | ||||||
11382 | collectParametricTerms(Expr, Terms); | ||||||
11383 | |||||||
11384 | if (Terms.empty()) | ||||||
11385 | return; | ||||||
11386 | |||||||
11387 | // Second step: find subscript sizes. | ||||||
11388 | findArrayDimensions(Terms, Sizes, ElementSize); | ||||||
11389 | |||||||
11390 | if (Sizes.empty()) | ||||||
11391 | return; | ||||||
11392 | |||||||
11393 | // Third step: compute the access functions for each subscript. | ||||||
11394 | computeAccessFunctions(Expr, Subscripts, Sizes); | ||||||
11395 | |||||||
11396 | if (Subscripts.empty()) | ||||||
11397 | return; | ||||||
11398 | |||||||
11399 | LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11400 | dbgs() << "succeeded to delinearize " << *Expr << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11401 | dbgs() << "ArrayDecl[UnknownSize]";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11402 | for (const SCEV *S : Sizes)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11403 | dbgs() << "[" << *S << "]";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11404 | |||||||
11405 | dbgs() << "\nArrayRef";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11406 | for (const SCEV *S : Subscripts)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11407 | dbgs() << "[" << *S << "]";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11408 | dbgs() << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false) | ||||||
11409 | })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { { dbgs() << "succeeded to delinearize " << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]" ; for (const SCEV *S : Sizes) dbgs() << "[" << *S << "]"; dbgs() << "\nArrayRef"; for (const SCEV * S : Subscripts) dbgs() << "[" << *S << "]"; dbgs() << "\n"; }; } } while (false); | ||||||
11410 | } | ||||||
11411 | |||||||
11412 | bool ScalarEvolution::getIndexExpressionsFromGEP( | ||||||
11413 | const GetElementPtrInst *GEP, SmallVectorImpl<const SCEV *> &Subscripts, | ||||||
11414 | SmallVectorImpl<int> &Sizes) { | ||||||
11415 | assert(Subscripts.empty() && Sizes.empty() &&((Subscripts.empty() && Sizes.empty() && "Expected output lists to be empty on entry to this function." ) ? static_cast<void> (0) : __assert_fail ("Subscripts.empty() && Sizes.empty() && \"Expected output lists to be empty on entry to this function.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11416, __PRETTY_FUNCTION__)) | ||||||
11416 | "Expected output lists to be empty on entry to this function.")((Subscripts.empty() && Sizes.empty() && "Expected output lists to be empty on entry to this function." ) ? static_cast<void> (0) : __assert_fail ("Subscripts.empty() && Sizes.empty() && \"Expected output lists to be empty on entry to this function.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11416, __PRETTY_FUNCTION__)); | ||||||
11417 | assert(GEP && "getIndexExpressionsFromGEP called with a null GEP")((GEP && "getIndexExpressionsFromGEP called with a null GEP" ) ? static_cast<void> (0) : __assert_fail ("GEP && \"getIndexExpressionsFromGEP called with a null GEP\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11417, __PRETTY_FUNCTION__)); | ||||||
11418 | Type *Ty = GEP->getPointerOperandType(); | ||||||
11419 | bool DroppedFirstDim = false; | ||||||
11420 | for (unsigned i = 1; i < GEP->getNumOperands(); i++) { | ||||||
11421 | const SCEV *Expr = getSCEV(GEP->getOperand(i)); | ||||||
11422 | if (i == 1) { | ||||||
11423 | if (auto *PtrTy = dyn_cast<PointerType>(Ty)) { | ||||||
11424 | Ty = PtrTy->getElementType(); | ||||||
11425 | } else if (auto *ArrayTy = dyn_cast<ArrayType>(Ty)) { | ||||||
11426 | Ty = ArrayTy->getElementType(); | ||||||
11427 | } else { | ||||||
11428 | Subscripts.clear(); | ||||||
11429 | Sizes.clear(); | ||||||
11430 | return false; | ||||||
11431 | } | ||||||
11432 | if (auto *Const = dyn_cast<SCEVConstant>(Expr)) | ||||||
11433 | if (Const->getValue()->isZero()) { | ||||||
11434 | DroppedFirstDim = true; | ||||||
11435 | continue; | ||||||
11436 | } | ||||||
11437 | Subscripts.push_back(Expr); | ||||||
11438 | continue; | ||||||
11439 | } | ||||||
11440 | |||||||
11441 | auto *ArrayTy = dyn_cast<ArrayType>(Ty); | ||||||
11442 | if (!ArrayTy) { | ||||||
11443 | Subscripts.clear(); | ||||||
11444 | Sizes.clear(); | ||||||
11445 | return false; | ||||||
11446 | } | ||||||
11447 | |||||||
11448 | Subscripts.push_back(Expr); | ||||||
11449 | if (!(DroppedFirstDim && i == 2)) | ||||||
11450 | Sizes.push_back(ArrayTy->getNumElements()); | ||||||
11451 | |||||||
11452 | Ty = ArrayTy->getElementType(); | ||||||
11453 | } | ||||||
11454 | return !Subscripts.empty(); | ||||||
11455 | } | ||||||
11456 | |||||||
11457 | //===----------------------------------------------------------------------===// | ||||||
11458 | // SCEVCallbackVH Class Implementation | ||||||
11459 | //===----------------------------------------------------------------------===// | ||||||
11460 | |||||||
11461 | void ScalarEvolution::SCEVCallbackVH::deleted() { | ||||||
11462 | assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!")((SE && "SCEVCallbackVH called with a null ScalarEvolution!" ) ? static_cast<void> (0) : __assert_fail ("SE && \"SCEVCallbackVH called with a null ScalarEvolution!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11462, __PRETTY_FUNCTION__)); | ||||||
11463 | if (PHINode *PN = dyn_cast<PHINode>(getValPtr())) | ||||||
11464 | SE->ConstantEvolutionLoopExitValue.erase(PN); | ||||||
11465 | SE->eraseValueFromMap(getValPtr()); | ||||||
11466 | // this now dangles! | ||||||
11467 | } | ||||||
11468 | |||||||
11469 | void ScalarEvolution::SCEVCallbackVH::allUsesReplacedWith(Value *V) { | ||||||
11470 | assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!")((SE && "SCEVCallbackVH called with a null ScalarEvolution!" ) ? static_cast<void> (0) : __assert_fail ("SE && \"SCEVCallbackVH called with a null ScalarEvolution!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11470, __PRETTY_FUNCTION__)); | ||||||
11471 | |||||||
11472 | // Forget all the expressions associated with users of the old value, | ||||||
11473 | // so that future queries will recompute the expressions using the new | ||||||
11474 | // value. | ||||||
11475 | Value *Old = getValPtr(); | ||||||
11476 | SmallVector<User *, 16> Worklist(Old->user_begin(), Old->user_end()); | ||||||
11477 | SmallPtrSet<User *, 8> Visited; | ||||||
11478 | while (!Worklist.empty()) { | ||||||
11479 | User *U = Worklist.pop_back_val(); | ||||||
11480 | // Deleting the Old value will cause this to dangle. Postpone | ||||||
11481 | // that until everything else is done. | ||||||
11482 | if (U == Old) | ||||||
11483 | continue; | ||||||
11484 | if (!Visited.insert(U).second) | ||||||
11485 | continue; | ||||||
11486 | if (PHINode *PN = dyn_cast<PHINode>(U)) | ||||||
11487 | SE->ConstantEvolutionLoopExitValue.erase(PN); | ||||||
11488 | SE->eraseValueFromMap(U); | ||||||
11489 | Worklist.insert(Worklist.end(), U->user_begin(), U->user_end()); | ||||||
11490 | } | ||||||
11491 | // Delete the Old value. | ||||||
11492 | if (PHINode *PN = dyn_cast<PHINode>(Old)) | ||||||
11493 | SE->ConstantEvolutionLoopExitValue.erase(PN); | ||||||
11494 | SE->eraseValueFromMap(Old); | ||||||
11495 | // this now dangles! | ||||||
11496 | } | ||||||
11497 | |||||||
11498 | ScalarEvolution::SCEVCallbackVH::SCEVCallbackVH(Value *V, ScalarEvolution *se) | ||||||
11499 | : CallbackVH(V), SE(se) {} | ||||||
11500 | |||||||
11501 | //===----------------------------------------------------------------------===// | ||||||
11502 | // ScalarEvolution Class Implementation | ||||||
11503 | //===----------------------------------------------------------------------===// | ||||||
11504 | |||||||
11505 | ScalarEvolution::ScalarEvolution(Function &F, TargetLibraryInfo &TLI, | ||||||
11506 | AssumptionCache &AC, DominatorTree &DT, | ||||||
11507 | LoopInfo &LI) | ||||||
11508 | : F(F), TLI(TLI), AC(AC), DT(DT), LI(LI), | ||||||
11509 | CouldNotCompute(new SCEVCouldNotCompute()), ValuesAtScopes(64), | ||||||
11510 | LoopDispositions(64), BlockDispositions(64) { | ||||||
11511 | // To use guards for proving predicates, we need to scan every instruction in | ||||||
11512 | // relevant basic blocks, and not just terminators. Doing this is a waste of | ||||||
11513 | // time if the IR does not actually contain any calls to | ||||||
11514 | // @llvm.experimental.guard, so do a quick check and remember this beforehand. | ||||||
11515 | // | ||||||
11516 | // This pessimizes the case where a pass that preserves ScalarEvolution wants | ||||||
11517 | // to _add_ guards to the module when there weren't any before, and wants | ||||||
11518 | // ScalarEvolution to optimize based on those guards. For now we prefer to be | ||||||
11519 | // efficient in lieu of being smart in that rather obscure case. | ||||||
11520 | |||||||
11521 | auto *GuardDecl = F.getParent()->getFunction( | ||||||
11522 | Intrinsic::getName(Intrinsic::experimental_guard)); | ||||||
11523 | HasGuards = GuardDecl && !GuardDecl->use_empty(); | ||||||
11524 | } | ||||||
11525 | |||||||
11526 | ScalarEvolution::ScalarEvolution(ScalarEvolution &&Arg) | ||||||
11527 | : F(Arg.F), HasGuards(Arg.HasGuards), TLI(Arg.TLI), AC(Arg.AC), DT(Arg.DT), | ||||||
11528 | LI(Arg.LI), CouldNotCompute(std::move(Arg.CouldNotCompute)), | ||||||
11529 | ValueExprMap(std::move(Arg.ValueExprMap)), | ||||||
11530 | PendingLoopPredicates(std::move(Arg.PendingLoopPredicates)), | ||||||
11531 | PendingPhiRanges(std::move(Arg.PendingPhiRanges)), | ||||||
11532 | PendingMerges(std::move(Arg.PendingMerges)), | ||||||
11533 | MinTrailingZerosCache(std::move(Arg.MinTrailingZerosCache)), | ||||||
11534 | BackedgeTakenCounts(std::move(Arg.BackedgeTakenCounts)), | ||||||
11535 | PredicatedBackedgeTakenCounts( | ||||||
11536 | std::move(Arg.PredicatedBackedgeTakenCounts)), | ||||||
11537 | ConstantEvolutionLoopExitValue( | ||||||
11538 | std::move(Arg.ConstantEvolutionLoopExitValue)), | ||||||
11539 | ValuesAtScopes(std::move(Arg.ValuesAtScopes)), | ||||||
11540 | LoopDispositions(std::move(Arg.LoopDispositions)), | ||||||
11541 | LoopPropertiesCache(std::move(Arg.LoopPropertiesCache)), | ||||||
11542 | BlockDispositions(std::move(Arg.BlockDispositions)), | ||||||
11543 | UnsignedRanges(std::move(Arg.UnsignedRanges)), | ||||||
11544 | SignedRanges(std::move(Arg.SignedRanges)), | ||||||
11545 | UniqueSCEVs(std::move(Arg.UniqueSCEVs)), | ||||||
11546 | UniquePreds(std::move(Arg.UniquePreds)), | ||||||
11547 | SCEVAllocator(std::move(Arg.SCEVAllocator)), | ||||||
11548 | LoopUsers(std::move(Arg.LoopUsers)), | ||||||
11549 | PredicatedSCEVRewrites(std::move(Arg.PredicatedSCEVRewrites)), | ||||||
11550 | FirstUnknown(Arg.FirstUnknown) { | ||||||
11551 | Arg.FirstUnknown = nullptr; | ||||||
11552 | } | ||||||
11553 | |||||||
11554 | ScalarEvolution::~ScalarEvolution() { | ||||||
11555 | // Iterate through all the SCEVUnknown instances and call their | ||||||
11556 | // destructors, so that they release their references to their values. | ||||||
11557 | for (SCEVUnknown *U = FirstUnknown; U;) { | ||||||
11558 | SCEVUnknown *Tmp = U; | ||||||
11559 | U = U->Next; | ||||||
11560 | Tmp->~SCEVUnknown(); | ||||||
11561 | } | ||||||
11562 | FirstUnknown = nullptr; | ||||||
11563 | |||||||
11564 | ExprValueMap.clear(); | ||||||
11565 | ValueExprMap.clear(); | ||||||
11566 | HasRecMap.clear(); | ||||||
11567 | |||||||
11568 | // Free any extra memory created for ExitNotTakenInfo in the unlikely event | ||||||
11569 | // that a loop had multiple computable exits. | ||||||
11570 | for (auto &BTCI : BackedgeTakenCounts) | ||||||
11571 | BTCI.second.clear(); | ||||||
11572 | for (auto &BTCI : PredicatedBackedgeTakenCounts) | ||||||
11573 | BTCI.second.clear(); | ||||||
11574 | |||||||
11575 | assert(PendingLoopPredicates.empty() && "isImpliedCond garbage")((PendingLoopPredicates.empty() && "isImpliedCond garbage" ) ? static_cast<void> (0) : __assert_fail ("PendingLoopPredicates.empty() && \"isImpliedCond garbage\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11575, __PRETTY_FUNCTION__)); | ||||||
11576 | assert(PendingPhiRanges.empty() && "getRangeRef garbage")((PendingPhiRanges.empty() && "getRangeRef garbage") ? static_cast<void> (0) : __assert_fail ("PendingPhiRanges.empty() && \"getRangeRef garbage\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11576, __PRETTY_FUNCTION__)); | ||||||
11577 | assert(PendingMerges.empty() && "isImpliedViaMerge garbage")((PendingMerges.empty() && "isImpliedViaMerge garbage" ) ? static_cast<void> (0) : __assert_fail ("PendingMerges.empty() && \"isImpliedViaMerge garbage\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11577, __PRETTY_FUNCTION__)); | ||||||
11578 | assert(!WalkingBEDominatingConds && "isLoopBackedgeGuardedByCond garbage!")((!WalkingBEDominatingConds && "isLoopBackedgeGuardedByCond garbage!" ) ? static_cast<void> (0) : __assert_fail ("!WalkingBEDominatingConds && \"isLoopBackedgeGuardedByCond garbage!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11578, __PRETTY_FUNCTION__)); | ||||||
11579 | assert(!ProvingSplitPredicate && "ProvingSplitPredicate garbage!")((!ProvingSplitPredicate && "ProvingSplitPredicate garbage!" ) ? static_cast<void> (0) : __assert_fail ("!ProvingSplitPredicate && \"ProvingSplitPredicate garbage!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11579, __PRETTY_FUNCTION__)); | ||||||
11580 | } | ||||||
11581 | |||||||
11582 | bool ScalarEvolution::hasLoopInvariantBackedgeTakenCount(const Loop *L) { | ||||||
11583 | return !isa<SCEVCouldNotCompute>(getBackedgeTakenCount(L)); | ||||||
11584 | } | ||||||
11585 | |||||||
11586 | static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE, | ||||||
11587 | const Loop *L) { | ||||||
11588 | // Print all inner loops first | ||||||
11589 | for (Loop *I : *L) | ||||||
11590 | PrintLoopInfo(OS, SE, I); | ||||||
11591 | |||||||
11592 | OS << "Loop "; | ||||||
11593 | L->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
11594 | OS << ": "; | ||||||
11595 | |||||||
11596 | SmallVector<BasicBlock *, 8> ExitingBlocks; | ||||||
11597 | L->getExitingBlocks(ExitingBlocks); | ||||||
11598 | if (ExitingBlocks.size() != 1) | ||||||
11599 | OS << "<multiple exits> "; | ||||||
11600 | |||||||
11601 | if (SE->hasLoopInvariantBackedgeTakenCount(L)) | ||||||
11602 | OS << "backedge-taken count is " << *SE->getBackedgeTakenCount(L) << "\n"; | ||||||
11603 | else | ||||||
11604 | OS << "Unpredictable backedge-taken count.\n"; | ||||||
11605 | |||||||
11606 | if (ExitingBlocks.size() > 1) | ||||||
11607 | for (BasicBlock *ExitingBlock : ExitingBlocks) { | ||||||
11608 | OS << " exit count for " << ExitingBlock->getName() << ": " | ||||||
11609 | << *SE->getExitCount(L, ExitingBlock) << "\n"; | ||||||
11610 | } | ||||||
11611 | |||||||
11612 | OS << "Loop "; | ||||||
11613 | L->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
11614 | OS << ": "; | ||||||
11615 | |||||||
11616 | if (!isa<SCEVCouldNotCompute>(SE->getConstantMaxBackedgeTakenCount(L))) { | ||||||
11617 | OS << "max backedge-taken count is " << *SE->getConstantMaxBackedgeTakenCount(L); | ||||||
11618 | if (SE->isBackedgeTakenCountMaxOrZero(L)) | ||||||
11619 | OS << ", actual taken count either this or zero."; | ||||||
11620 | } else { | ||||||
11621 | OS << "Unpredictable max backedge-taken count. "; | ||||||
11622 | } | ||||||
11623 | |||||||
11624 | OS << "\n" | ||||||
11625 | "Loop "; | ||||||
11626 | L->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
11627 | OS << ": "; | ||||||
11628 | |||||||
11629 | SCEVUnionPredicate Pred; | ||||||
11630 | auto PBT = SE->getPredicatedBackedgeTakenCount(L, Pred); | ||||||
11631 | if (!isa<SCEVCouldNotCompute>(PBT)) { | ||||||
11632 | OS << "Predicated backedge-taken count is " << *PBT << "\n"; | ||||||
11633 | OS << " Predicates:\n"; | ||||||
11634 | Pred.print(OS, 4); | ||||||
11635 | } else { | ||||||
11636 | OS << "Unpredictable predicated backedge-taken count. "; | ||||||
11637 | } | ||||||
11638 | OS << "\n"; | ||||||
11639 | |||||||
11640 | if (SE->hasLoopInvariantBackedgeTakenCount(L)) { | ||||||
11641 | OS << "Loop "; | ||||||
11642 | L->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
11643 | OS << ": "; | ||||||
11644 | OS << "Trip multiple is " << SE->getSmallConstantTripMultiple(L) << "\n"; | ||||||
11645 | } | ||||||
11646 | } | ||||||
11647 | |||||||
11648 | static StringRef loopDispositionToStr(ScalarEvolution::LoopDisposition LD) { | ||||||
11649 | switch (LD) { | ||||||
11650 | case ScalarEvolution::LoopVariant: | ||||||
11651 | return "Variant"; | ||||||
11652 | case ScalarEvolution::LoopInvariant: | ||||||
11653 | return "Invariant"; | ||||||
11654 | case ScalarEvolution::LoopComputable: | ||||||
11655 | return "Computable"; | ||||||
11656 | } | ||||||
11657 | llvm_unreachable("Unknown ScalarEvolution::LoopDisposition kind!")::llvm::llvm_unreachable_internal("Unknown ScalarEvolution::LoopDisposition kind!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11657); | ||||||
11658 | } | ||||||
11659 | |||||||
11660 | void ScalarEvolution::print(raw_ostream &OS) const { | ||||||
11661 | // ScalarEvolution's implementation of the print method is to print | ||||||
11662 | // out SCEV values of all instructions that are interesting. Doing | ||||||
11663 | // this potentially causes it to create new SCEV objects though, | ||||||
11664 | // which technically conflicts with the const qualifier. This isn't | ||||||
11665 | // observable from outside the class though, so casting away the | ||||||
11666 | // const isn't dangerous. | ||||||
11667 | ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this); | ||||||
11668 | |||||||
11669 | if (ClassifyExpressions) { | ||||||
11670 | OS << "Classifying expressions for: "; | ||||||
11671 | F.printAsOperand(OS, /*PrintType=*/false); | ||||||
11672 | OS << "\n"; | ||||||
11673 | for (Instruction &I : instructions(F)) | ||||||
11674 | if (isSCEVable(I.getType()) && !isa<CmpInst>(I)) { | ||||||
11675 | OS << I << '\n'; | ||||||
11676 | OS << " --> "; | ||||||
11677 | const SCEV *SV = SE.getSCEV(&I); | ||||||
11678 | SV->print(OS); | ||||||
11679 | if (!isa<SCEVCouldNotCompute>(SV)) { | ||||||
11680 | OS << " U: "; | ||||||
11681 | SE.getUnsignedRange(SV).print(OS); | ||||||
11682 | OS << " S: "; | ||||||
11683 | SE.getSignedRange(SV).print(OS); | ||||||
11684 | } | ||||||
11685 | |||||||
11686 | const Loop *L = LI.getLoopFor(I.getParent()); | ||||||
11687 | |||||||
11688 | const SCEV *AtUse = SE.getSCEVAtScope(SV, L); | ||||||
11689 | if (AtUse != SV) { | ||||||
11690 | OS << " --> "; | ||||||
11691 | AtUse->print(OS); | ||||||
11692 | if (!isa<SCEVCouldNotCompute>(AtUse)) { | ||||||
11693 | OS << " U: "; | ||||||
11694 | SE.getUnsignedRange(AtUse).print(OS); | ||||||
11695 | OS << " S: "; | ||||||
11696 | SE.getSignedRange(AtUse).print(OS); | ||||||
11697 | } | ||||||
11698 | } | ||||||
11699 | |||||||
11700 | if (L) { | ||||||
11701 | OS << "\t\t" "Exits: "; | ||||||
11702 | const SCEV *ExitValue = SE.getSCEVAtScope(SV, L->getParentLoop()); | ||||||
11703 | if (!SE.isLoopInvariant(ExitValue, L)) { | ||||||
11704 | OS << "<<Unknown>>"; | ||||||
11705 | } else { | ||||||
11706 | OS << *ExitValue; | ||||||
11707 | } | ||||||
11708 | |||||||
11709 | bool First = true; | ||||||
11710 | for (auto *Iter = L; Iter; Iter = Iter->getParentLoop()) { | ||||||
11711 | if (First) { | ||||||
11712 | OS << "\t\t" "LoopDispositions: { "; | ||||||
11713 | First = false; | ||||||
11714 | } else { | ||||||
11715 | OS << ", "; | ||||||
11716 | } | ||||||
11717 | |||||||
11718 | Iter->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
11719 | OS << ": " << loopDispositionToStr(SE.getLoopDisposition(SV, Iter)); | ||||||
11720 | } | ||||||
11721 | |||||||
11722 | for (auto *InnerL : depth_first(L)) { | ||||||
11723 | if (InnerL == L) | ||||||
11724 | continue; | ||||||
11725 | if (First) { | ||||||
11726 | OS << "\t\t" "LoopDispositions: { "; | ||||||
11727 | First = false; | ||||||
11728 | } else { | ||||||
11729 | OS << ", "; | ||||||
11730 | } | ||||||
11731 | |||||||
11732 | InnerL->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
11733 | OS << ": " << loopDispositionToStr(SE.getLoopDisposition(SV, InnerL)); | ||||||
11734 | } | ||||||
11735 | |||||||
11736 | OS << " }"; | ||||||
11737 | } | ||||||
11738 | |||||||
11739 | OS << "\n"; | ||||||
11740 | } | ||||||
11741 | } | ||||||
11742 | |||||||
11743 | OS << "Determining loop execution counts for: "; | ||||||
11744 | F.printAsOperand(OS, /*PrintType=*/false); | ||||||
11745 | OS << "\n"; | ||||||
11746 | for (Loop *I : LI) | ||||||
11747 | PrintLoopInfo(OS, &SE, I); | ||||||
11748 | } | ||||||
11749 | |||||||
11750 | ScalarEvolution::LoopDisposition | ||||||
11751 | ScalarEvolution::getLoopDisposition(const SCEV *S, const Loop *L) { | ||||||
11752 | auto &Values = LoopDispositions[S]; | ||||||
11753 | for (auto &V : Values) { | ||||||
11754 | if (V.getPointer() == L) | ||||||
11755 | return V.getInt(); | ||||||
11756 | } | ||||||
11757 | Values.emplace_back(L, LoopVariant); | ||||||
11758 | LoopDisposition D = computeLoopDisposition(S, L); | ||||||
11759 | auto &Values2 = LoopDispositions[S]; | ||||||
11760 | for (auto &V : make_range(Values2.rbegin(), Values2.rend())) { | ||||||
11761 | if (V.getPointer() == L) { | ||||||
11762 | V.setInt(D); | ||||||
11763 | break; | ||||||
11764 | } | ||||||
11765 | } | ||||||
11766 | return D; | ||||||
11767 | } | ||||||
11768 | |||||||
11769 | ScalarEvolution::LoopDisposition | ||||||
11770 | ScalarEvolution::computeLoopDisposition(const SCEV *S, const Loop *L) { | ||||||
11771 | switch (static_cast<SCEVTypes>(S->getSCEVType())) { | ||||||
11772 | case scConstant: | ||||||
11773 | return LoopInvariant; | ||||||
11774 | case scTruncate: | ||||||
11775 | case scZeroExtend: | ||||||
11776 | case scSignExtend: | ||||||
11777 | return getLoopDisposition(cast<SCEVCastExpr>(S)->getOperand(), L); | ||||||
11778 | case scAddRecExpr: { | ||||||
11779 | const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S); | ||||||
11780 | |||||||
11781 | // If L is the addrec's loop, it's computable. | ||||||
11782 | if (AR->getLoop() == L) | ||||||
11783 | return LoopComputable; | ||||||
11784 | |||||||
11785 | // Add recurrences are never invariant in the function-body (null loop). | ||||||
11786 | if (!L) | ||||||
11787 | return LoopVariant; | ||||||
11788 | |||||||
11789 | // Everything that is not defined at loop entry is variant. | ||||||
11790 | if (DT.dominates(L->getHeader(), AR->getLoop()->getHeader())) | ||||||
11791 | return LoopVariant; | ||||||
11792 | assert(!L->contains(AR->getLoop()) && "Containing loop's header does not"((!L->contains(AR->getLoop()) && "Containing loop's header does not" " dominate the contained loop's header?") ? static_cast<void > (0) : __assert_fail ("!L->contains(AR->getLoop()) && \"Containing loop's header does not\" \" dominate the contained loop's header?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11793, __PRETTY_FUNCTION__)) | ||||||
11793 | " dominate the contained loop's header?")((!L->contains(AR->getLoop()) && "Containing loop's header does not" " dominate the contained loop's header?") ? static_cast<void > (0) : __assert_fail ("!L->contains(AR->getLoop()) && \"Containing loop's header does not\" \" dominate the contained loop's header?\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11793, __PRETTY_FUNCTION__)); | ||||||
11794 | |||||||
11795 | // This recurrence is invariant w.r.t. L if AR's loop contains L. | ||||||
11796 | if (AR->getLoop()->contains(L)) | ||||||
11797 | return LoopInvariant; | ||||||
11798 | |||||||
11799 | // This recurrence is variant w.r.t. L if any of its operands | ||||||
11800 | // are variant. | ||||||
11801 | for (auto *Op : AR->operands()) | ||||||
11802 | if (!isLoopInvariant(Op, L)) | ||||||
11803 | return LoopVariant; | ||||||
11804 | |||||||
11805 | // Otherwise it's loop-invariant. | ||||||
11806 | return LoopInvariant; | ||||||
11807 | } | ||||||
11808 | case scAddExpr: | ||||||
11809 | case scMulExpr: | ||||||
11810 | case scUMaxExpr: | ||||||
11811 | case scSMaxExpr: | ||||||
11812 | case scUMinExpr: | ||||||
11813 | case scSMinExpr: { | ||||||
11814 | bool HasVarying = false; | ||||||
11815 | for (auto *Op : cast<SCEVNAryExpr>(S)->operands()) { | ||||||
11816 | LoopDisposition D = getLoopDisposition(Op, L); | ||||||
11817 | if (D == LoopVariant) | ||||||
11818 | return LoopVariant; | ||||||
11819 | if (D == LoopComputable) | ||||||
11820 | HasVarying = true; | ||||||
11821 | } | ||||||
11822 | return HasVarying ? LoopComputable : LoopInvariant; | ||||||
11823 | } | ||||||
11824 | case scUDivExpr: { | ||||||
11825 | const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S); | ||||||
11826 | LoopDisposition LD = getLoopDisposition(UDiv->getLHS(), L); | ||||||
11827 | if (LD == LoopVariant) | ||||||
11828 | return LoopVariant; | ||||||
11829 | LoopDisposition RD = getLoopDisposition(UDiv->getRHS(), L); | ||||||
11830 | if (RD == LoopVariant) | ||||||
11831 | return LoopVariant; | ||||||
11832 | return (LD == LoopInvariant && RD == LoopInvariant) ? | ||||||
11833 | LoopInvariant : LoopComputable; | ||||||
11834 | } | ||||||
11835 | case scUnknown: | ||||||
11836 | // All non-instruction values are loop invariant. All instructions are loop | ||||||
11837 | // invariant if they are not contained in the specified loop. | ||||||
11838 | // Instructions are never considered invariant in the function body | ||||||
11839 | // (null loop) because they are defined within the "loop". | ||||||
11840 | if (auto *I = dyn_cast<Instruction>(cast<SCEVUnknown>(S)->getValue())) | ||||||
11841 | return (L && !L->contains(I)) ? LoopInvariant : LoopVariant; | ||||||
11842 | return LoopInvariant; | ||||||
11843 | case scCouldNotCompute: | ||||||
11844 | llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11844); | ||||||
11845 | } | ||||||
11846 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11846); | ||||||
11847 | } | ||||||
11848 | |||||||
11849 | bool ScalarEvolution::isLoopInvariant(const SCEV *S, const Loop *L) { | ||||||
11850 | return getLoopDisposition(S, L) == LoopInvariant; | ||||||
11851 | } | ||||||
11852 | |||||||
11853 | bool ScalarEvolution::hasComputableLoopEvolution(const SCEV *S, const Loop *L) { | ||||||
11854 | return getLoopDisposition(S, L) == LoopComputable; | ||||||
11855 | } | ||||||
11856 | |||||||
11857 | ScalarEvolution::BlockDisposition | ||||||
11858 | ScalarEvolution::getBlockDisposition(const SCEV *S, const BasicBlock *BB) { | ||||||
11859 | auto &Values = BlockDispositions[S]; | ||||||
11860 | for (auto &V : Values) { | ||||||
11861 | if (V.getPointer() == BB) | ||||||
11862 | return V.getInt(); | ||||||
11863 | } | ||||||
11864 | Values.emplace_back(BB, DoesNotDominateBlock); | ||||||
11865 | BlockDisposition D = computeBlockDisposition(S, BB); | ||||||
11866 | auto &Values2 = BlockDispositions[S]; | ||||||
11867 | for (auto &V : make_range(Values2.rbegin(), Values2.rend())) { | ||||||
11868 | if (V.getPointer() == BB) { | ||||||
11869 | V.setInt(D); | ||||||
11870 | break; | ||||||
11871 | } | ||||||
11872 | } | ||||||
11873 | return D; | ||||||
11874 | } | ||||||
11875 | |||||||
11876 | ScalarEvolution::BlockDisposition | ||||||
11877 | ScalarEvolution::computeBlockDisposition(const SCEV *S, const BasicBlock *BB) { | ||||||
11878 | switch (static_cast<SCEVTypes>(S->getSCEVType())) { | ||||||
11879 | case scConstant: | ||||||
11880 | return ProperlyDominatesBlock; | ||||||
11881 | case scTruncate: | ||||||
11882 | case scZeroExtend: | ||||||
11883 | case scSignExtend: | ||||||
11884 | return getBlockDisposition(cast<SCEVCastExpr>(S)->getOperand(), BB); | ||||||
11885 | case scAddRecExpr: { | ||||||
11886 | // This uses a "dominates" query instead of "properly dominates" query | ||||||
11887 | // to test for proper dominance too, because the instruction which | ||||||
11888 | // produces the addrec's value is a PHI, and a PHI effectively properly | ||||||
11889 | // dominates its entire containing block. | ||||||
11890 | const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S); | ||||||
11891 | if (!DT.dominates(AR->getLoop()->getHeader(), BB)) | ||||||
11892 | return DoesNotDominateBlock; | ||||||
11893 | |||||||
11894 | // Fall through into SCEVNAryExpr handling. | ||||||
11895 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
11896 | } | ||||||
11897 | case scAddExpr: | ||||||
11898 | case scMulExpr: | ||||||
11899 | case scUMaxExpr: | ||||||
11900 | case scSMaxExpr: | ||||||
11901 | case scUMinExpr: | ||||||
11902 | case scSMinExpr: { | ||||||
11903 | const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(S); | ||||||
11904 | bool Proper = true; | ||||||
11905 | for (const SCEV *NAryOp : NAry->operands()) { | ||||||
11906 | BlockDisposition D = getBlockDisposition(NAryOp, BB); | ||||||
11907 | if (D == DoesNotDominateBlock) | ||||||
11908 | return DoesNotDominateBlock; | ||||||
11909 | if (D == DominatesBlock) | ||||||
11910 | Proper = false; | ||||||
11911 | } | ||||||
11912 | return Proper ? ProperlyDominatesBlock : DominatesBlock; | ||||||
11913 | } | ||||||
11914 | case scUDivExpr: { | ||||||
11915 | const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S); | ||||||
11916 | const SCEV *LHS = UDiv->getLHS(), *RHS = UDiv->getRHS(); | ||||||
11917 | BlockDisposition LD = getBlockDisposition(LHS, BB); | ||||||
11918 | if (LD == DoesNotDominateBlock) | ||||||
11919 | return DoesNotDominateBlock; | ||||||
11920 | BlockDisposition RD = getBlockDisposition(RHS, BB); | ||||||
11921 | if (RD == DoesNotDominateBlock) | ||||||
11922 | return DoesNotDominateBlock; | ||||||
11923 | return (LD == ProperlyDominatesBlock && RD == ProperlyDominatesBlock) ? | ||||||
11924 | ProperlyDominatesBlock : DominatesBlock; | ||||||
11925 | } | ||||||
11926 | case scUnknown: | ||||||
11927 | if (Instruction *I = | ||||||
11928 | dyn_cast<Instruction>(cast<SCEVUnknown>(S)->getValue())) { | ||||||
11929 | if (I->getParent() == BB) | ||||||
11930 | return DominatesBlock; | ||||||
11931 | if (DT.properlyDominates(I->getParent(), BB)) | ||||||
11932 | return ProperlyDominatesBlock; | ||||||
11933 | return DoesNotDominateBlock; | ||||||
11934 | } | ||||||
11935 | return ProperlyDominatesBlock; | ||||||
11936 | case scCouldNotCompute: | ||||||
11937 | llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11937); | ||||||
11938 | } | ||||||
11939 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 11939); | ||||||
11940 | } | ||||||
11941 | |||||||
11942 | bool ScalarEvolution::dominates(const SCEV *S, const BasicBlock *BB) { | ||||||
11943 | return getBlockDisposition(S, BB) >= DominatesBlock; | ||||||
11944 | } | ||||||
11945 | |||||||
11946 | bool ScalarEvolution::properlyDominates(const SCEV *S, const BasicBlock *BB) { | ||||||
11947 | return getBlockDisposition(S, BB) == ProperlyDominatesBlock; | ||||||
11948 | } | ||||||
11949 | |||||||
11950 | bool ScalarEvolution::hasOperand(const SCEV *S, const SCEV *Op) const { | ||||||
11951 | return SCEVExprContains(S, [&](const SCEV *Expr) { return Expr == Op; }); | ||||||
11952 | } | ||||||
11953 | |||||||
11954 | bool ScalarEvolution::ExitLimit::hasOperand(const SCEV *S) const { | ||||||
11955 | auto IsS = [&](const SCEV *X) { return S == X; }; | ||||||
11956 | auto ContainsS = [&](const SCEV *X) { | ||||||
11957 | return !isa<SCEVCouldNotCompute>(X) && SCEVExprContains(X, IsS); | ||||||
11958 | }; | ||||||
11959 | return ContainsS(ExactNotTaken) || ContainsS(MaxNotTaken); | ||||||
11960 | } | ||||||
11961 | |||||||
11962 | void | ||||||
11963 | ScalarEvolution::forgetMemoizedResults(const SCEV *S) { | ||||||
11964 | ValuesAtScopes.erase(S); | ||||||
11965 | LoopDispositions.erase(S); | ||||||
11966 | BlockDispositions.erase(S); | ||||||
11967 | UnsignedRanges.erase(S); | ||||||
11968 | SignedRanges.erase(S); | ||||||
11969 | ExprValueMap.erase(S); | ||||||
11970 | HasRecMap.erase(S); | ||||||
11971 | MinTrailingZerosCache.erase(S); | ||||||
11972 | |||||||
11973 | for (auto I = PredicatedSCEVRewrites.begin(); | ||||||
11974 | I != PredicatedSCEVRewrites.end();) { | ||||||
11975 | std::pair<const SCEV *, const Loop *> Entry = I->first; | ||||||
11976 | if (Entry.first == S) | ||||||
11977 | PredicatedSCEVRewrites.erase(I++); | ||||||
11978 | else | ||||||
11979 | ++I; | ||||||
11980 | } | ||||||
11981 | |||||||
11982 | auto RemoveSCEVFromBackedgeMap = | ||||||
11983 | [S, this](DenseMap<const Loop *, BackedgeTakenInfo> &Map) { | ||||||
11984 | for (auto I = Map.begin(), E = Map.end(); I != E;) { | ||||||
11985 | BackedgeTakenInfo &BEInfo = I->second; | ||||||
11986 | if (BEInfo.hasOperand(S, this)) { | ||||||
11987 | BEInfo.clear(); | ||||||
11988 | Map.erase(I++); | ||||||
11989 | } else | ||||||
11990 | ++I; | ||||||
11991 | } | ||||||
11992 | }; | ||||||
11993 | |||||||
11994 | RemoveSCEVFromBackedgeMap(BackedgeTakenCounts); | ||||||
11995 | RemoveSCEVFromBackedgeMap(PredicatedBackedgeTakenCounts); | ||||||
11996 | } | ||||||
11997 | |||||||
11998 | void | ||||||
11999 | ScalarEvolution::getUsedLoops(const SCEV *S, | ||||||
12000 | SmallPtrSetImpl<const Loop *> &LoopsUsed) { | ||||||
12001 | struct FindUsedLoops { | ||||||
12002 | FindUsedLoops(SmallPtrSetImpl<const Loop *> &LoopsUsed) | ||||||
12003 | : LoopsUsed(LoopsUsed) {} | ||||||
12004 | SmallPtrSetImpl<const Loop *> &LoopsUsed; | ||||||
12005 | bool follow(const SCEV *S) { | ||||||
12006 | if (auto *AR = dyn_cast<SCEVAddRecExpr>(S)) | ||||||
12007 | LoopsUsed.insert(AR->getLoop()); | ||||||
12008 | return true; | ||||||
12009 | } | ||||||
12010 | |||||||
12011 | bool isDone() const { return false; } | ||||||
12012 | }; | ||||||
12013 | |||||||
12014 | FindUsedLoops F(LoopsUsed); | ||||||
12015 | SCEVTraversal<FindUsedLoops>(F).visitAll(S); | ||||||
12016 | } | ||||||
12017 | |||||||
12018 | void ScalarEvolution::addToLoopUseLists(const SCEV *S) { | ||||||
12019 | SmallPtrSet<const Loop *, 8> LoopsUsed; | ||||||
12020 | getUsedLoops(S, LoopsUsed); | ||||||
12021 | for (auto *L : LoopsUsed) | ||||||
12022 | LoopUsers[L].push_back(S); | ||||||
12023 | } | ||||||
12024 | |||||||
12025 | void ScalarEvolution::verify() const { | ||||||
12026 | ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this); | ||||||
12027 | ScalarEvolution SE2(F, TLI, AC, DT, LI); | ||||||
12028 | |||||||
12029 | SmallVector<Loop *, 8> LoopStack(LI.begin(), LI.end()); | ||||||
12030 | |||||||
12031 | // Map's SCEV expressions from one ScalarEvolution "universe" to another. | ||||||
12032 | struct SCEVMapper : public SCEVRewriteVisitor<SCEVMapper> { | ||||||
12033 | SCEVMapper(ScalarEvolution &SE) : SCEVRewriteVisitor<SCEVMapper>(SE) {} | ||||||
12034 | |||||||
12035 | const SCEV *visitConstant(const SCEVConstant *Constant) { | ||||||
12036 | return SE.getConstant(Constant->getAPInt()); | ||||||
12037 | } | ||||||
12038 | |||||||
12039 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
12040 | return SE.getUnknown(Expr->getValue()); | ||||||
12041 | } | ||||||
12042 | |||||||
12043 | const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) { | ||||||
12044 | return SE.getCouldNotCompute(); | ||||||
12045 | } | ||||||
12046 | }; | ||||||
12047 | |||||||
12048 | SCEVMapper SCM(SE2); | ||||||
12049 | |||||||
12050 | while (!LoopStack.empty()) { | ||||||
12051 | auto *L = LoopStack.pop_back_val(); | ||||||
12052 | LoopStack.insert(LoopStack.end(), L->begin(), L->end()); | ||||||
12053 | |||||||
12054 | auto *CurBECount = SCM.visit( | ||||||
12055 | const_cast<ScalarEvolution *>(this)->getBackedgeTakenCount(L)); | ||||||
12056 | auto *NewBECount = SE2.getBackedgeTakenCount(L); | ||||||
12057 | |||||||
12058 | if (CurBECount == SE2.getCouldNotCompute() || | ||||||
12059 | NewBECount == SE2.getCouldNotCompute()) { | ||||||
12060 | // NB! This situation is legal, but is very suspicious -- whatever pass | ||||||
12061 | // change the loop to make a trip count go from could not compute to | ||||||
12062 | // computable or vice-versa *should have* invalidated SCEV. However, we | ||||||
12063 | // choose not to assert here (for now) since we don't want false | ||||||
12064 | // positives. | ||||||
12065 | continue; | ||||||
12066 | } | ||||||
12067 | |||||||
12068 | if (containsUndefs(CurBECount) || containsUndefs(NewBECount)) { | ||||||
12069 | // SCEV treats "undef" as an unknown but consistent value (i.e. it does | ||||||
12070 | // not propagate undef aggressively). This means we can (and do) fail | ||||||
12071 | // verification in cases where a transform makes the trip count of a loop | ||||||
12072 | // go from "undef" to "undef+1" (say). The transform is fine, since in | ||||||
12073 | // both cases the loop iterates "undef" times, but SCEV thinks we | ||||||
12074 | // increased the trip count of the loop by 1 incorrectly. | ||||||
12075 | continue; | ||||||
12076 | } | ||||||
12077 | |||||||
12078 | if (SE.getTypeSizeInBits(CurBECount->getType()) > | ||||||
12079 | SE.getTypeSizeInBits(NewBECount->getType())) | ||||||
12080 | NewBECount = SE2.getZeroExtendExpr(NewBECount, CurBECount->getType()); | ||||||
12081 | else if (SE.getTypeSizeInBits(CurBECount->getType()) < | ||||||
12082 | SE.getTypeSizeInBits(NewBECount->getType())) | ||||||
12083 | CurBECount = SE2.getZeroExtendExpr(CurBECount, NewBECount->getType()); | ||||||
12084 | |||||||
12085 | const SCEV *Delta = SE2.getMinusSCEV(CurBECount, NewBECount); | ||||||
12086 | |||||||
12087 | // Unless VerifySCEVStrict is set, we only compare constant deltas. | ||||||
12088 | if ((VerifySCEVStrict || isa<SCEVConstant>(Delta)) && !Delta->isZero()) { | ||||||
12089 | dbgs() << "Trip Count for " << *L << " Changed!\n"; | ||||||
12090 | dbgs() << "Old: " << *CurBECount << "\n"; | ||||||
12091 | dbgs() << "New: " << *NewBECount << "\n"; | ||||||
12092 | dbgs() << "Delta: " << *Delta << "\n"; | ||||||
12093 | std::abort(); | ||||||
12094 | } | ||||||
12095 | } | ||||||
12096 | } | ||||||
12097 | |||||||
12098 | bool ScalarEvolution::invalidate( | ||||||
12099 | Function &F, const PreservedAnalyses &PA, | ||||||
12100 | FunctionAnalysisManager::Invalidator &Inv) { | ||||||
12101 | // Invalidate the ScalarEvolution object whenever it isn't preserved or one | ||||||
12102 | // of its dependencies is invalidated. | ||||||
12103 | auto PAC = PA.getChecker<ScalarEvolutionAnalysis>(); | ||||||
12104 | return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>()) || | ||||||
12105 | Inv.invalidate<AssumptionAnalysis>(F, PA) || | ||||||
12106 | Inv.invalidate<DominatorTreeAnalysis>(F, PA) || | ||||||
12107 | Inv.invalidate<LoopAnalysis>(F, PA); | ||||||
12108 | } | ||||||
12109 | |||||||
12110 | AnalysisKey ScalarEvolutionAnalysis::Key; | ||||||
12111 | |||||||
12112 | ScalarEvolution ScalarEvolutionAnalysis::run(Function &F, | ||||||
12113 | FunctionAnalysisManager &AM) { | ||||||
12114 | return ScalarEvolution(F, AM.getResult<TargetLibraryAnalysis>(F), | ||||||
12115 | AM.getResult<AssumptionAnalysis>(F), | ||||||
12116 | AM.getResult<DominatorTreeAnalysis>(F), | ||||||
12117 | AM.getResult<LoopAnalysis>(F)); | ||||||
12118 | } | ||||||
12119 | |||||||
12120 | PreservedAnalyses | ||||||
12121 | ScalarEvolutionVerifierPass::run(Function &F, FunctionAnalysisManager &AM) { | ||||||
12122 | AM.getResult<ScalarEvolutionAnalysis>(F).verify(); | ||||||
12123 | return PreservedAnalyses::all(); | ||||||
12124 | } | ||||||
12125 | |||||||
12126 | PreservedAnalyses | ||||||
12127 | ScalarEvolutionPrinterPass::run(Function &F, FunctionAnalysisManager &AM) { | ||||||
12128 | AM.getResult<ScalarEvolutionAnalysis>(F).print(OS); | ||||||
12129 | return PreservedAnalyses::all(); | ||||||
12130 | } | ||||||
12131 | |||||||
12132 | INITIALIZE_PASS_BEGIN(ScalarEvolutionWrapperPass, "scalar-evolution",static void *initializeScalarEvolutionWrapperPassPassOnce(PassRegistry &Registry) { | ||||||
12133 | "Scalar Evolution Analysis", false, true)static void *initializeScalarEvolutionWrapperPassPassOnce(PassRegistry &Registry) { | ||||||
12134 | INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry); | ||||||
12135 | INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)initializeLoopInfoWrapperPassPass(Registry); | ||||||
12136 | INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry); | ||||||
12137 | INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry); | ||||||
12138 | INITIALIZE_PASS_END(ScalarEvolutionWrapperPass, "scalar-evolution",PassInfo *PI = new PassInfo( "Scalar Evolution Analysis", "scalar-evolution" , &ScalarEvolutionWrapperPass::ID, PassInfo::NormalCtor_t (callDefaultCtor<ScalarEvolutionWrapperPass>), false, true ); Registry.registerPass(*PI, true); return PI; } static llvm ::once_flag InitializeScalarEvolutionWrapperPassPassFlag; void llvm::initializeScalarEvolutionWrapperPassPass(PassRegistry & Registry) { llvm::call_once(InitializeScalarEvolutionWrapperPassPassFlag , initializeScalarEvolutionWrapperPassPassOnce, std::ref(Registry )); } | ||||||
12139 | "Scalar Evolution Analysis", false, true)PassInfo *PI = new PassInfo( "Scalar Evolution Analysis", "scalar-evolution" , &ScalarEvolutionWrapperPass::ID, PassInfo::NormalCtor_t (callDefaultCtor<ScalarEvolutionWrapperPass>), false, true ); Registry.registerPass(*PI, true); return PI; } static llvm ::once_flag InitializeScalarEvolutionWrapperPassPassFlag; void llvm::initializeScalarEvolutionWrapperPassPass(PassRegistry & Registry) { llvm::call_once(InitializeScalarEvolutionWrapperPassPassFlag , initializeScalarEvolutionWrapperPassPassOnce, std::ref(Registry )); } | ||||||
12140 | |||||||
12141 | char ScalarEvolutionWrapperPass::ID = 0; | ||||||
12142 | |||||||
12143 | ScalarEvolutionWrapperPass::ScalarEvolutionWrapperPass() : FunctionPass(ID) { | ||||||
12144 | initializeScalarEvolutionWrapperPassPass(*PassRegistry::getPassRegistry()); | ||||||
12145 | } | ||||||
12146 | |||||||
12147 | bool ScalarEvolutionWrapperPass::runOnFunction(Function &F) { | ||||||
12148 | SE.reset(new ScalarEvolution( | ||||||
12149 | F, getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F), | ||||||
12150 | getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F), | ||||||
12151 | getAnalysis<DominatorTreeWrapperPass>().getDomTree(), | ||||||
12152 | getAnalysis<LoopInfoWrapperPass>().getLoopInfo())); | ||||||
12153 | return false; | ||||||
12154 | } | ||||||
12155 | |||||||
12156 | void ScalarEvolutionWrapperPass::releaseMemory() { SE.reset(); } | ||||||
12157 | |||||||
12158 | void ScalarEvolutionWrapperPass::print(raw_ostream &OS, const Module *) const { | ||||||
12159 | SE->print(OS); | ||||||
12160 | } | ||||||
12161 | |||||||
12162 | void ScalarEvolutionWrapperPass::verifyAnalysis() const { | ||||||
12163 | if (!VerifySCEV) | ||||||
12164 | return; | ||||||
12165 | |||||||
12166 | SE->verify(); | ||||||
12167 | } | ||||||
12168 | |||||||
12169 | void ScalarEvolutionWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { | ||||||
12170 | AU.setPreservesAll(); | ||||||
12171 | AU.addRequiredTransitive<AssumptionCacheTracker>(); | ||||||
12172 | AU.addRequiredTransitive<LoopInfoWrapperPass>(); | ||||||
12173 | AU.addRequiredTransitive<DominatorTreeWrapperPass>(); | ||||||
12174 | AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>(); | ||||||
12175 | } | ||||||
12176 | |||||||
12177 | const SCEVPredicate *ScalarEvolution::getEqualPredicate(const SCEV *LHS, | ||||||
12178 | const SCEV *RHS) { | ||||||
12179 | FoldingSetNodeID ID; | ||||||
12180 | assert(LHS->getType() == RHS->getType() &&((LHS->getType() == RHS->getType() && "Type mismatch between LHS and RHS" ) ? static_cast<void> (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"Type mismatch between LHS and RHS\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 12181, __PRETTY_FUNCTION__)) | ||||||
12181 | "Type mismatch between LHS and RHS")((LHS->getType() == RHS->getType() && "Type mismatch between LHS and RHS" ) ? static_cast<void> (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"Type mismatch between LHS and RHS\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 12181, __PRETTY_FUNCTION__)); | ||||||
12182 | // Unique this node based on the arguments | ||||||
12183 | ID.AddInteger(SCEVPredicate::P_Equal); | ||||||
12184 | ID.AddPointer(LHS); | ||||||
12185 | ID.AddPointer(RHS); | ||||||
12186 | void *IP = nullptr; | ||||||
12187 | if (const auto *S = UniquePreds.FindNodeOrInsertPos(ID, IP)) | ||||||
12188 | return S; | ||||||
12189 | SCEVEqualPredicate *Eq = new (SCEVAllocator) | ||||||
12190 | SCEVEqualPredicate(ID.Intern(SCEVAllocator), LHS, RHS); | ||||||
12191 | UniquePreds.InsertNode(Eq, IP); | ||||||
12192 | return Eq; | ||||||
12193 | } | ||||||
12194 | |||||||
12195 | const SCEVPredicate *ScalarEvolution::getWrapPredicate( | ||||||
12196 | const SCEVAddRecExpr *AR, | ||||||
12197 | SCEVWrapPredicate::IncrementWrapFlags AddedFlags) { | ||||||
12198 | FoldingSetNodeID ID; | ||||||
12199 | // Unique this node based on the arguments | ||||||
12200 | ID.AddInteger(SCEVPredicate::P_Wrap); | ||||||
12201 | ID.AddPointer(AR); | ||||||
12202 | ID.AddInteger(AddedFlags); | ||||||
12203 | void *IP = nullptr; | ||||||
12204 | if (const auto *S = UniquePreds.FindNodeOrInsertPos(ID, IP)) | ||||||
12205 | return S; | ||||||
12206 | auto *OF = new (SCEVAllocator) | ||||||
12207 | SCEVWrapPredicate(ID.Intern(SCEVAllocator), AR, AddedFlags); | ||||||
12208 | UniquePreds.InsertNode(OF, IP); | ||||||
12209 | return OF; | ||||||
12210 | } | ||||||
12211 | |||||||
12212 | namespace { | ||||||
12213 | |||||||
12214 | class SCEVPredicateRewriter : public SCEVRewriteVisitor<SCEVPredicateRewriter> { | ||||||
12215 | public: | ||||||
12216 | |||||||
12217 | /// Rewrites \p S in the context of a loop L and the SCEV predication | ||||||
12218 | /// infrastructure. | ||||||
12219 | /// | ||||||
12220 | /// If \p Pred is non-null, the SCEV expression is rewritten to respect the | ||||||
12221 | /// equivalences present in \p Pred. | ||||||
12222 | /// | ||||||
12223 | /// If \p NewPreds is non-null, rewrite is free to add further predicates to | ||||||
12224 | /// \p NewPreds such that the result will be an AddRecExpr. | ||||||
12225 | static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE, | ||||||
12226 | SmallPtrSetImpl<const SCEVPredicate *> *NewPreds, | ||||||
12227 | SCEVUnionPredicate *Pred) { | ||||||
12228 | SCEVPredicateRewriter Rewriter(L, SE, NewPreds, Pred); | ||||||
12229 | return Rewriter.visit(S); | ||||||
12230 | } | ||||||
12231 | |||||||
12232 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
12233 | if (Pred) { | ||||||
12234 | auto ExprPreds = Pred->getPredicatesForExpr(Expr); | ||||||
12235 | for (auto *Pred : ExprPreds) | ||||||
12236 | if (const auto *IPred = dyn_cast<SCEVEqualPredicate>(Pred)) | ||||||
12237 | if (IPred->getLHS() == Expr) | ||||||
12238 | return IPred->getRHS(); | ||||||
12239 | } | ||||||
12240 | return convertToAddRecWithPreds(Expr); | ||||||
12241 | } | ||||||
12242 | |||||||
12243 | const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) { | ||||||
12244 | const SCEV *Operand = visit(Expr->getOperand()); | ||||||
12245 | const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Operand); | ||||||
12246 | if (AR && AR->getLoop() == L && AR->isAffine()) { | ||||||
12247 | // This couldn't be folded because the operand didn't have the nuw | ||||||
12248 | // flag. Add the nusw flag as an assumption that we could make. | ||||||
12249 | const SCEV *Step = AR->getStepRecurrence(SE); | ||||||
12250 | Type *Ty = Expr->getType(); | ||||||
12251 | if (addOverflowAssumption(AR, SCEVWrapPredicate::IncrementNUSW)) | ||||||
12252 | return SE.getAddRecExpr(SE.getZeroExtendExpr(AR->getStart(), Ty), | ||||||
12253 | SE.getSignExtendExpr(Step, Ty), L, | ||||||
12254 | AR->getNoWrapFlags()); | ||||||
12255 | } | ||||||
12256 | return SE.getZeroExtendExpr(Operand, Expr->getType()); | ||||||
12257 | } | ||||||
12258 | |||||||
12259 | const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) { | ||||||
12260 | const SCEV *Operand = visit(Expr->getOperand()); | ||||||
12261 | const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Operand); | ||||||
12262 | if (AR && AR->getLoop() == L && AR->isAffine()) { | ||||||
12263 | // This couldn't be folded because the operand didn't have the nsw | ||||||
12264 | // flag. Add the nssw flag as an assumption that we could make. | ||||||
12265 | const SCEV *Step = AR->getStepRecurrence(SE); | ||||||
12266 | Type *Ty = Expr->getType(); | ||||||
12267 | if (addOverflowAssumption(AR, SCEVWrapPredicate::IncrementNSSW)) | ||||||
12268 | return SE.getAddRecExpr(SE.getSignExtendExpr(AR->getStart(), Ty), | ||||||
12269 | SE.getSignExtendExpr(Step, Ty), L, | ||||||
12270 | AR->getNoWrapFlags()); | ||||||
12271 | } | ||||||
12272 | return SE.getSignExtendExpr(Operand, Expr->getType()); | ||||||
12273 | } | ||||||
12274 | |||||||
12275 | private: | ||||||
12276 | explicit SCEVPredicateRewriter(const Loop *L, ScalarEvolution &SE, | ||||||
12277 | SmallPtrSetImpl<const SCEVPredicate *> *NewPreds, | ||||||
12278 | SCEVUnionPredicate *Pred) | ||||||
12279 | : SCEVRewriteVisitor(SE), NewPreds(NewPreds), Pred(Pred), L(L) {} | ||||||
12280 | |||||||
12281 | bool addOverflowAssumption(const SCEVPredicate *P) { | ||||||
12282 | if (!NewPreds) { | ||||||
12283 | // Check if we've already made this assumption. | ||||||
12284 | return Pred && Pred->implies(P); | ||||||
12285 | } | ||||||
12286 | NewPreds->insert(P); | ||||||
12287 | return true; | ||||||
12288 | } | ||||||
12289 | |||||||
12290 | bool addOverflowAssumption(const SCEVAddRecExpr *AR, | ||||||
12291 | SCEVWrapPredicate::IncrementWrapFlags AddedFlags) { | ||||||
12292 | auto *A = SE.getWrapPredicate(AR, AddedFlags); | ||||||
12293 | return addOverflowAssumption(A); | ||||||
12294 | } | ||||||
12295 | |||||||
12296 | // If \p Expr represents a PHINode, we try to see if it can be represented | ||||||
12297 | // as an AddRec, possibly under a predicate (PHISCEVPred). If it is possible | ||||||
12298 | // to add this predicate as a runtime overflow check, we return the AddRec. | ||||||
12299 | // If \p Expr does not meet these conditions (is not a PHI node, or we | ||||||
12300 | // couldn't create an AddRec for it, or couldn't add the predicate), we just | ||||||
12301 | // return \p Expr. | ||||||
12302 | const SCEV *convertToAddRecWithPreds(const SCEVUnknown *Expr) { | ||||||
12303 | if (!isa<PHINode>(Expr->getValue())) | ||||||
12304 | return Expr; | ||||||
12305 | Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>> | ||||||
12306 | PredicatedRewrite = SE.createAddRecFromPHIWithCasts(Expr); | ||||||
12307 | if (!PredicatedRewrite) | ||||||
12308 | return Expr; | ||||||
12309 | for (auto *P : PredicatedRewrite->second){ | ||||||
12310 | // Wrap predicates from outer loops are not supported. | ||||||
12311 | if (auto *WP = dyn_cast<const SCEVWrapPredicate>(P)) { | ||||||
12312 | auto *AR = cast<const SCEVAddRecExpr>(WP->getExpr()); | ||||||
12313 | if (L != AR->getLoop()) | ||||||
12314 | return Expr; | ||||||
12315 | } | ||||||
12316 | if (!addOverflowAssumption(P)) | ||||||
12317 | return Expr; | ||||||
12318 | } | ||||||
12319 | return PredicatedRewrite->first; | ||||||
12320 | } | ||||||
12321 | |||||||
12322 | SmallPtrSetImpl<const SCEVPredicate *> *NewPreds; | ||||||
12323 | SCEVUnionPredicate *Pred; | ||||||
12324 | const Loop *L; | ||||||
12325 | }; | ||||||
12326 | |||||||
12327 | } // end anonymous namespace | ||||||
12328 | |||||||
12329 | const SCEV *ScalarEvolution::rewriteUsingPredicate(const SCEV *S, const Loop *L, | ||||||
12330 | SCEVUnionPredicate &Preds) { | ||||||
12331 | return SCEVPredicateRewriter::rewrite(S, L, *this, nullptr, &Preds); | ||||||
12332 | } | ||||||
12333 | |||||||
12334 | const SCEVAddRecExpr *ScalarEvolution::convertSCEVToAddRecWithPredicates( | ||||||
12335 | const SCEV *S, const Loop *L, | ||||||
12336 | SmallPtrSetImpl<const SCEVPredicate *> &Preds) { | ||||||
12337 | SmallPtrSet<const SCEVPredicate *, 4> TransformPreds; | ||||||
12338 | S = SCEVPredicateRewriter::rewrite(S, L, *this, &TransformPreds, nullptr); | ||||||
12339 | auto *AddRec = dyn_cast<SCEVAddRecExpr>(S); | ||||||
12340 | |||||||
12341 | if (!AddRec) | ||||||
12342 | return nullptr; | ||||||
12343 | |||||||
12344 | // Since the transformation was successful, we can now transfer the SCEV | ||||||
12345 | // predicates. | ||||||
12346 | for (auto *P : TransformPreds) | ||||||
12347 | Preds.insert(P); | ||||||
12348 | |||||||
12349 | return AddRec; | ||||||
12350 | } | ||||||
12351 | |||||||
12352 | /// SCEV predicates | ||||||
12353 | SCEVPredicate::SCEVPredicate(const FoldingSetNodeIDRef ID, | ||||||
12354 | SCEVPredicateKind Kind) | ||||||
12355 | : FastID(ID), Kind(Kind) {} | ||||||
12356 | |||||||
12357 | SCEVEqualPredicate::SCEVEqualPredicate(const FoldingSetNodeIDRef ID, | ||||||
12358 | const SCEV *LHS, const SCEV *RHS) | ||||||
12359 | : SCEVPredicate(ID, P_Equal), LHS(LHS), RHS(RHS) { | ||||||
12360 | assert(LHS->getType() == RHS->getType() && "LHS and RHS types don't match")((LHS->getType() == RHS->getType() && "LHS and RHS types don't match" ) ? static_cast<void> (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"LHS and RHS types don't match\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 12360, __PRETTY_FUNCTION__)); | ||||||
12361 | assert(LHS != RHS && "LHS and RHS are the same SCEV")((LHS != RHS && "LHS and RHS are the same SCEV") ? static_cast <void> (0) : __assert_fail ("LHS != RHS && \"LHS and RHS are the same SCEV\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 12361, __PRETTY_FUNCTION__)); | ||||||
12362 | } | ||||||
12363 | |||||||
12364 | bool SCEVEqualPredicate::implies(const SCEVPredicate *N) const { | ||||||
12365 | const auto *Op = dyn_cast<SCEVEqualPredicate>(N); | ||||||
12366 | |||||||
12367 | if (!Op) | ||||||
12368 | return false; | ||||||
12369 | |||||||
12370 | return Op->LHS == LHS && Op->RHS == RHS; | ||||||
12371 | } | ||||||
12372 | |||||||
12373 | bool SCEVEqualPredicate::isAlwaysTrue() const { return false; } | ||||||
12374 | |||||||
12375 | const SCEV *SCEVEqualPredicate::getExpr() const { return LHS; } | ||||||
12376 | |||||||
12377 | void SCEVEqualPredicate::print(raw_ostream &OS, unsigned Depth) const { | ||||||
12378 | OS.indent(Depth) << "Equal predicate: " << *LHS << " == " << *RHS << "\n"; | ||||||
12379 | } | ||||||
12380 | |||||||
12381 | SCEVWrapPredicate::SCEVWrapPredicate(const FoldingSetNodeIDRef ID, | ||||||
12382 | const SCEVAddRecExpr *AR, | ||||||
12383 | IncrementWrapFlags Flags) | ||||||
12384 | : SCEVPredicate(ID, P_Wrap), AR(AR), Flags(Flags) {} | ||||||
12385 | |||||||
12386 | const SCEV *SCEVWrapPredicate::getExpr() const { return AR; } | ||||||
12387 | |||||||
12388 | bool SCEVWrapPredicate::implies(const SCEVPredicate *N) const { | ||||||
12389 | const auto *Op = dyn_cast<SCEVWrapPredicate>(N); | ||||||
12390 | |||||||
12391 | return Op && Op->AR == AR && setFlags(Flags, Op->Flags) == Flags; | ||||||
12392 | } | ||||||
12393 | |||||||
12394 | bool SCEVWrapPredicate::isAlwaysTrue() const { | ||||||
12395 | SCEV::NoWrapFlags ScevFlags = AR->getNoWrapFlags(); | ||||||
12396 | IncrementWrapFlags IFlags = Flags; | ||||||
12397 | |||||||
12398 | if (ScalarEvolution::setFlags(ScevFlags, SCEV::FlagNSW) == ScevFlags) | ||||||
12399 | IFlags = clearFlags(IFlags, IncrementNSSW); | ||||||
12400 | |||||||
12401 | return IFlags == IncrementAnyWrap; | ||||||
12402 | } | ||||||
12403 | |||||||
12404 | void SCEVWrapPredicate::print(raw_ostream &OS, unsigned Depth) const { | ||||||
12405 | OS.indent(Depth) << *getExpr() << " Added Flags: "; | ||||||
12406 | if (SCEVWrapPredicate::IncrementNUSW & getFlags()) | ||||||
12407 | OS << "<nusw>"; | ||||||
12408 | if (SCEVWrapPredicate::IncrementNSSW & getFlags()) | ||||||
12409 | OS << "<nssw>"; | ||||||
12410 | OS << "\n"; | ||||||
12411 | } | ||||||
12412 | |||||||
12413 | SCEVWrapPredicate::IncrementWrapFlags | ||||||
12414 | SCEVWrapPredicate::getImpliedFlags(const SCEVAddRecExpr *AR, | ||||||
12415 | ScalarEvolution &SE) { | ||||||
12416 | IncrementWrapFlags ImpliedFlags = IncrementAnyWrap; | ||||||
12417 | SCEV::NoWrapFlags StaticFlags = AR->getNoWrapFlags(); | ||||||
12418 | |||||||
12419 | // We can safely transfer the NSW flag as NSSW. | ||||||
12420 | if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNSW) == StaticFlags) | ||||||
12421 | ImpliedFlags = IncrementNSSW; | ||||||
12422 | |||||||
12423 | if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNUW) == StaticFlags) { | ||||||
12424 | // If the increment is positive, the SCEV NUW flag will also imply the | ||||||
12425 | // WrapPredicate NUSW flag. | ||||||
12426 | if (const auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE))) | ||||||
12427 | if (Step->getValue()->getValue().isNonNegative()) | ||||||
12428 | ImpliedFlags = setFlags(ImpliedFlags, IncrementNUSW); | ||||||
12429 | } | ||||||
12430 | |||||||
12431 | return ImpliedFlags; | ||||||
12432 | } | ||||||
12433 | |||||||
12434 | /// Union predicates don't get cached so create a dummy set ID for it. | ||||||
12435 | SCEVUnionPredicate::SCEVUnionPredicate() | ||||||
12436 | : SCEVPredicate(FoldingSetNodeIDRef(nullptr, 0), P_Union) {} | ||||||
12437 | |||||||
12438 | bool SCEVUnionPredicate::isAlwaysTrue() const { | ||||||
12439 | return all_of(Preds, | ||||||
12440 | [](const SCEVPredicate *I) { return I->isAlwaysTrue(); }); | ||||||
12441 | } | ||||||
12442 | |||||||
12443 | ArrayRef<const SCEVPredicate *> | ||||||
12444 | SCEVUnionPredicate::getPredicatesForExpr(const SCEV *Expr) { | ||||||
12445 | auto I = SCEVToPreds.find(Expr); | ||||||
12446 | if (I == SCEVToPreds.end()) | ||||||
12447 | return ArrayRef<const SCEVPredicate *>(); | ||||||
12448 | return I->second; | ||||||
12449 | } | ||||||
12450 | |||||||
12451 | bool SCEVUnionPredicate::implies(const SCEVPredicate *N) const { | ||||||
12452 | if (const auto *Set = dyn_cast<SCEVUnionPredicate>(N)) | ||||||
12453 | return all_of(Set->Preds, | ||||||
12454 | [this](const SCEVPredicate *I) { return this->implies(I); }); | ||||||
12455 | |||||||
12456 | auto ScevPredsIt = SCEVToPreds.find(N->getExpr()); | ||||||
12457 | if (ScevPredsIt == SCEVToPreds.end()) | ||||||
12458 | return false; | ||||||
12459 | auto &SCEVPreds = ScevPredsIt->second; | ||||||
12460 | |||||||
12461 | return any_of(SCEVPreds, | ||||||
12462 | [N](const SCEVPredicate *I) { return I->implies(N); }); | ||||||
12463 | } | ||||||
12464 | |||||||
12465 | const SCEV *SCEVUnionPredicate::getExpr() const { return nullptr; } | ||||||
12466 | |||||||
12467 | void SCEVUnionPredicate::print(raw_ostream &OS, unsigned Depth) const { | ||||||
12468 | for (auto Pred : Preds) | ||||||
12469 | Pred->print(OS, Depth); | ||||||
12470 | } | ||||||
12471 | |||||||
12472 | void SCEVUnionPredicate::add(const SCEVPredicate *N) { | ||||||
12473 | if (const auto *Set = dyn_cast<SCEVUnionPredicate>(N)) { | ||||||
12474 | for (auto Pred : Set->Preds) | ||||||
12475 | add(Pred); | ||||||
12476 | return; | ||||||
12477 | } | ||||||
12478 | |||||||
12479 | if (implies(N)) | ||||||
12480 | return; | ||||||
12481 | |||||||
12482 | const SCEV *Key = N->getExpr(); | ||||||
12483 | assert(Key && "Only SCEVUnionPredicate doesn't have an "((Key && "Only SCEVUnionPredicate doesn't have an " " associated expression!" ) ? static_cast<void> (0) : __assert_fail ("Key && \"Only SCEVUnionPredicate doesn't have an \" \" associated expression!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 12484, __PRETTY_FUNCTION__)) | ||||||
12484 | " associated expression!")((Key && "Only SCEVUnionPredicate doesn't have an " " associated expression!" ) ? static_cast<void> (0) : __assert_fail ("Key && \"Only SCEVUnionPredicate doesn't have an \" \" associated expression!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/Analysis/ScalarEvolution.cpp" , 12484, __PRETTY_FUNCTION__)); | ||||||
12485 | |||||||
12486 | SCEVToPreds[Key].push_back(N); | ||||||
12487 | Preds.push_back(N); | ||||||
12488 | } | ||||||
12489 | |||||||
12490 | PredicatedScalarEvolution::PredicatedScalarEvolution(ScalarEvolution &SE, | ||||||
12491 | Loop &L) | ||||||
12492 | : SE(SE), L(L) {} | ||||||
12493 | |||||||
12494 | const SCEV *PredicatedScalarEvolution::getSCEV(Value *V) { | ||||||
12495 | const SCEV *Expr = SE.getSCEV(V); | ||||||
12496 | RewriteEntry &Entry = RewriteMap[Expr]; | ||||||
12497 | |||||||
12498 | // If we already have an entry and the version matches, return it. | ||||||
12499 | if (Entry.second && Generation == Entry.first) | ||||||
12500 | return Entry.second; | ||||||
12501 | |||||||
12502 | // We found an entry but it's stale. Rewrite the stale entry | ||||||
12503 | // according to the current predicate. | ||||||
12504 | if (Entry.second) | ||||||
12505 | Expr = Entry.second; | ||||||
12506 | |||||||
12507 | const SCEV *NewSCEV = SE.rewriteUsingPredicate(Expr, &L, Preds); | ||||||
12508 | Entry = {Generation, NewSCEV}; | ||||||
12509 | |||||||
12510 | return NewSCEV; | ||||||
12511 | } | ||||||
12512 | |||||||
12513 | const SCEV *PredicatedScalarEvolution::getBackedgeTakenCount() { | ||||||
12514 | if (!BackedgeCount) { | ||||||
12515 | SCEVUnionPredicate BackedgePred; | ||||||
12516 | BackedgeCount = SE.getPredicatedBackedgeTakenCount(&L, BackedgePred); | ||||||
12517 | addPredicate(BackedgePred); | ||||||
12518 | } | ||||||
12519 | return BackedgeCount; | ||||||
12520 | } | ||||||
12521 | |||||||
12522 | void PredicatedScalarEvolution::addPredicate(const SCEVPredicate &Pred) { | ||||||
12523 | if (Preds.implies(&Pred)) | ||||||
12524 | return; | ||||||
12525 | Preds.add(&Pred); | ||||||
12526 | updateGeneration(); | ||||||
12527 | } | ||||||
12528 | |||||||
12529 | const SCEVUnionPredicate &PredicatedScalarEvolution::getUnionPredicate() const { | ||||||
12530 | return Preds; | ||||||
12531 | } | ||||||
12532 | |||||||
12533 | void PredicatedScalarEvolution::updateGeneration() { | ||||||
12534 | // If the generation number wrapped recompute everything. | ||||||
12535 | if (++Generation == 0) { | ||||||
12536 | for (auto &II : RewriteMap) { | ||||||
12537 | const SCEV *Rewritten = II.second.second; | ||||||
12538 | II.second = {Generation, SE.rewriteUsingPredicate(Rewritten, &L, Preds)}; | ||||||
12539 | } | ||||||
12540 | } | ||||||
12541 | } | ||||||
12542 | |||||||
12543 | void PredicatedScalarEvolution::setNoOverflow( | ||||||
12544 | Value *V, SCEVWrapPredicate::IncrementWrapFlags Flags) { | ||||||
12545 | const SCEV *Expr = getSCEV(V); | ||||||
12546 | const auto *AR = cast<SCEVAddRecExpr>(Expr); | ||||||
12547 | |||||||
12548 | auto ImpliedFlags = SCEVWrapPredicate::getImpliedFlags(AR, SE); | ||||||
12549 | |||||||
12550 | // Clear the statically implied flags. | ||||||
12551 | Flags = SCEVWrapPredicate::clearFlags(Flags, ImpliedFlags); | ||||||
12552 | addPredicate(*SE.getWrapPredicate(AR, Flags)); | ||||||
12553 | |||||||
12554 | auto II = FlagsMap.insert({V, Flags}); | ||||||
12555 | if (!II.second) | ||||||
12556 | II.first->second = SCEVWrapPredicate::setFlags(Flags, II.first->second); | ||||||
12557 | } | ||||||
12558 | |||||||
12559 | bool PredicatedScalarEvolution::hasNoOverflow( | ||||||
12560 | Value *V, SCEVWrapPredicate::IncrementWrapFlags Flags) { | ||||||
12561 | const SCEV *Expr = getSCEV(V); | ||||||
12562 | const auto *AR = cast<SCEVAddRecExpr>(Expr); | ||||||
12563 | |||||||
12564 | Flags = SCEVWrapPredicate::clearFlags( | ||||||
12565 | Flags, SCEVWrapPredicate::getImpliedFlags(AR, SE)); | ||||||
12566 | |||||||
12567 | auto II = FlagsMap.find(V); | ||||||
12568 | |||||||
12569 | if (II != FlagsMap.end()) | ||||||
12570 | Flags = SCEVWrapPredicate::clearFlags(Flags, II->second); | ||||||
12571 | |||||||
12572 | return Flags == SCEVWrapPredicate::IncrementAnyWrap; | ||||||
12573 | } | ||||||
12574 | |||||||
12575 | const SCEVAddRecExpr *PredicatedScalarEvolution::getAsAddRec(Value *V) { | ||||||
12576 | const SCEV *Expr = this->getSCEV(V); | ||||||
12577 | SmallPtrSet<const SCEVPredicate *, 4> NewPreds; | ||||||
12578 | auto *New = SE.convertSCEVToAddRecWithPredicates(Expr, &L, NewPreds); | ||||||
12579 | |||||||
12580 | if (!New) | ||||||
12581 | return nullptr; | ||||||
12582 | |||||||
12583 | for (auto *P : NewPreds) | ||||||
12584 | Preds.add(P); | ||||||
12585 | |||||||
12586 | updateGeneration(); | ||||||
12587 | RewriteMap[SE.getSCEV(V)] = {Generation, New}; | ||||||
12588 | return New; | ||||||
12589 | } | ||||||
12590 | |||||||
12591 | PredicatedScalarEvolution::PredicatedScalarEvolution( | ||||||
12592 | const PredicatedScalarEvolution &Init) | ||||||
12593 | : RewriteMap(Init.RewriteMap), SE(Init.SE), L(Init.L), Preds(Init.Preds), | ||||||
12594 | Generation(Init.Generation), BackedgeCount(Init.BackedgeCount) { | ||||||
12595 | for (auto I : Init.FlagsMap) | ||||||
12596 | FlagsMap.insert(I); | ||||||
12597 | } | ||||||
12598 | |||||||
12599 | void PredicatedScalarEvolution::print(raw_ostream &OS, unsigned Depth) const { | ||||||
12600 | // For each block. | ||||||
12601 | for (auto *BB : L.getBlocks()) | ||||||
12602 | for (auto &I : *BB) { | ||||||
12603 | if (!SE.isSCEVable(I.getType())) | ||||||
12604 | continue; | ||||||
12605 | |||||||
12606 | auto *Expr = SE.getSCEV(&I); | ||||||
12607 | auto II = RewriteMap.find(Expr); | ||||||
12608 | |||||||
12609 | if (II == RewriteMap.end()) | ||||||
12610 | continue; | ||||||
12611 | |||||||
12612 | // Don't print things that are not interesting. | ||||||
12613 | if (II->second.second == Expr) | ||||||
12614 | continue; | ||||||
12615 | |||||||
12616 | OS.indent(Depth) << "[PSE]" << I << ":\n"; | ||||||
12617 | OS.indent(Depth + 2) << *Expr << "\n"; | ||||||
12618 | OS.indent(Depth + 2) << "--> " << *II->second.second << "\n"; | ||||||
12619 | } | ||||||
12620 | } | ||||||
12621 | |||||||
12622 | // Match the mathematical pattern A - (A / B) * B, where A and B can be | ||||||
12623 | // arbitrary expressions. | ||||||
12624 | // It's not always easy, as A and B can be folded (imagine A is X / 2, and B is | ||||||
12625 | // 4, A / B becomes X / 8). | ||||||
12626 | bool ScalarEvolution::matchURem(const SCEV *Expr, const SCEV *&LHS, | ||||||
12627 | const SCEV *&RHS) { | ||||||
12628 | const auto *Add = dyn_cast<SCEVAddExpr>(Expr); | ||||||
12629 | if (Add == nullptr || Add->getNumOperands() != 2) | ||||||
12630 | return false; | ||||||
12631 | |||||||
12632 | const SCEV *A = Add->getOperand(1); | ||||||
12633 | const auto *Mul = dyn_cast<SCEVMulExpr>(Add->getOperand(0)); | ||||||
12634 | |||||||
12635 | if (Mul == nullptr) | ||||||
12636 | return false; | ||||||
12637 | |||||||
12638 | const auto MatchURemWithDivisor = [&](const SCEV *B) { | ||||||
12639 | // (SomeExpr + (-(SomeExpr / B) * B)). | ||||||
12640 | if (Expr == getURemExpr(A, B)) { | ||||||
12641 | LHS = A; | ||||||
12642 | RHS = B; | ||||||
12643 | return true; | ||||||
12644 | } | ||||||
12645 | return false; | ||||||
12646 | }; | ||||||
12647 | |||||||
12648 | // (SomeExpr + (-1 * (SomeExpr / B) * B)). | ||||||
12649 | if (Mul->getNumOperands() == 3 && isa<SCEVConstant>(Mul->getOperand(0))) | ||||||
12650 | return MatchURemWithDivisor(Mul->getOperand(1)) || | ||||||
12651 | MatchURemWithDivisor(Mul->getOperand(2)); | ||||||
12652 | |||||||
12653 | // (SomeExpr + ((-SomeExpr / B) * B)) or (SomeExpr + ((SomeExpr / B) * -B)). | ||||||
12654 | if (Mul->getNumOperands() == 2) | ||||||
12655 | return MatchURemWithDivisor(Mul->getOperand(1)) || | ||||||
12656 | MatchURemWithDivisor(Mul->getOperand(0)) || | ||||||
12657 | MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(1))) || | ||||||
12658 | MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(0))); | ||||||
12659 | return false; | ||||||
12660 | } |
1 | //===- llvm/Type.h - Classes for handling data types ------------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This file contains the declaration of the Type class. For more "Type" |
10 | // stuff, look in DerivedTypes.h. |
11 | // |
12 | //===----------------------------------------------------------------------===// |
13 | |
14 | #ifndef LLVM_IR_TYPE_H |
15 | #define LLVM_IR_TYPE_H |
16 | |
17 | #include "llvm/ADT/APFloat.h" |
18 | #include "llvm/ADT/ArrayRef.h" |
19 | #include "llvm/ADT/SmallPtrSet.h" |
20 | #include "llvm/Support/CBindingWrapping.h" |
21 | #include "llvm/Support/Casting.h" |
22 | #include "llvm/Support/Compiler.h" |
23 | #include "llvm/Support/ErrorHandling.h" |
24 | #include "llvm/Support/TypeSize.h" |
25 | #include <cassert> |
26 | #include <cstdint> |
27 | #include <iterator> |
28 | |
29 | namespace llvm { |
30 | |
31 | template<class GraphType> struct GraphTraits; |
32 | class IntegerType; |
33 | class LLVMContext; |
34 | class PointerType; |
35 | class raw_ostream; |
36 | class StringRef; |
37 | |
38 | /// The instances of the Type class are immutable: once they are created, |
39 | /// they are never changed. Also note that only one instance of a particular |
40 | /// type is ever created. Thus seeing if two types are equal is a matter of |
41 | /// doing a trivial pointer comparison. To enforce that no two equal instances |
42 | /// are created, Type instances can only be created via static factory methods |
43 | /// in class Type and in derived classes. Once allocated, Types are never |
44 | /// free'd. |
45 | /// |
46 | class Type { |
47 | public: |
48 | //===--------------------------------------------------------------------===// |
49 | /// Definitions of all of the base types for the Type system. Based on this |
50 | /// value, you can cast to a class defined in DerivedTypes.h. |
51 | /// Note: If you add an element to this, you need to add an element to the |
52 | /// Type::getPrimitiveType function, or else things will break! |
53 | /// Also update LLVMTypeKind and LLVMGetTypeKind () in the C binding. |
54 | /// |
55 | enum TypeID { |
56 | // PrimitiveTypes - make sure LastPrimitiveTyID stays up to date. |
57 | VoidTyID = 0, ///< 0: type with no size |
58 | HalfTyID, ///< 1: 16-bit floating point type |
59 | FloatTyID, ///< 2: 32-bit floating point type |
60 | DoubleTyID, ///< 3: 64-bit floating point type |
61 | X86_FP80TyID, ///< 4: 80-bit floating point type (X87) |
62 | FP128TyID, ///< 5: 128-bit floating point type (112-bit mantissa) |
63 | PPC_FP128TyID, ///< 6: 128-bit floating point type (two 64-bits, PowerPC) |
64 | LabelTyID, ///< 7: Labels |
65 | MetadataTyID, ///< 8: Metadata |
66 | X86_MMXTyID, ///< 9: MMX vectors (64 bits, X86 specific) |
67 | TokenTyID, ///< 10: Tokens |
68 | |
69 | // Derived types... see DerivedTypes.h file. |
70 | // Make sure FirstDerivedTyID stays up to date! |
71 | IntegerTyID, ///< 11: Arbitrary bit width integers |
72 | FunctionTyID, ///< 12: Functions |
73 | StructTyID, ///< 13: Structures |
74 | ArrayTyID, ///< 14: Arrays |
75 | PointerTyID, ///< 15: Pointers |
76 | VectorTyID ///< 16: SIMD 'packed' format, or other vector type |
77 | }; |
78 | |
79 | private: |
80 | /// This refers to the LLVMContext in which this type was uniqued. |
81 | LLVMContext &Context; |
82 | |
83 | TypeID ID : 8; // The current base type of this type. |
84 | unsigned SubclassData : 24; // Space for subclasses to store data. |
85 | // Note that this should be synchronized with |
86 | // MAX_INT_BITS value in IntegerType class. |
87 | |
88 | protected: |
89 | friend class LLVMContextImpl; |
90 | |
91 | explicit Type(LLVMContext &C, TypeID tid) |
92 | : Context(C), ID(tid), SubclassData(0) {} |
93 | ~Type() = default; |
94 | |
95 | unsigned getSubclassData() const { return SubclassData; } |
96 | |
97 | void setSubclassData(unsigned val) { |
98 | SubclassData = val; |
99 | // Ensure we don't have any accidental truncation. |
100 | assert(getSubclassData() == val && "Subclass data too large for field")((getSubclassData() == val && "Subclass data too large for field" ) ? static_cast<void> (0) : __assert_fail ("getSubclassData() == val && \"Subclass data too large for field\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 100, __PRETTY_FUNCTION__)); |
101 | } |
102 | |
103 | /// Keeps track of how many Type*'s there are in the ContainedTys list. |
104 | unsigned NumContainedTys = 0; |
105 | |
106 | /// A pointer to the array of Types contained by this Type. For example, this |
107 | /// includes the arguments of a function type, the elements of a structure, |
108 | /// the pointee of a pointer, the element type of an array, etc. This pointer |
109 | /// may be 0 for types that don't contain other types (Integer, Double, |
110 | /// Float). |
111 | Type * const *ContainedTys = nullptr; |
112 | |
113 | static bool isSequentialType(TypeID TyID) { |
114 | return TyID == ArrayTyID || TyID == VectorTyID; |
115 | } |
116 | |
117 | public: |
118 | /// Print the current type. |
119 | /// Omit the type details if \p NoDetails == true. |
120 | /// E.g., let %st = type { i32, i16 } |
121 | /// When \p NoDetails is true, we only print %st. |
122 | /// Put differently, \p NoDetails prints the type as if |
123 | /// inlined with the operands when printing an instruction. |
124 | void print(raw_ostream &O, bool IsForDebug = false, |
125 | bool NoDetails = false) const; |
126 | |
127 | void dump() const; |
128 | |
129 | /// Return the LLVMContext in which this type was uniqued. |
130 | LLVMContext &getContext() const { return Context; } |
131 | |
132 | //===--------------------------------------------------------------------===// |
133 | // Accessors for working with types. |
134 | // |
135 | |
136 | /// Return the type id for the type. This will return one of the TypeID enum |
137 | /// elements defined above. |
138 | TypeID getTypeID() const { return ID; } |
139 | |
140 | /// Return true if this is 'void'. |
141 | bool isVoidTy() const { return getTypeID() == VoidTyID; } |
142 | |
143 | /// Return true if this is 'half', a 16-bit IEEE fp type. |
144 | bool isHalfTy() const { return getTypeID() == HalfTyID; } |
145 | |
146 | /// Return true if this is 'float', a 32-bit IEEE fp type. |
147 | bool isFloatTy() const { return getTypeID() == FloatTyID; } |
148 | |
149 | /// Return true if this is 'double', a 64-bit IEEE fp type. |
150 | bool isDoubleTy() const { return getTypeID() == DoubleTyID; } |
151 | |
152 | /// Return true if this is x86 long double. |
153 | bool isX86_FP80Ty() const { return getTypeID() == X86_FP80TyID; } |
154 | |
155 | /// Return true if this is 'fp128'. |
156 | bool isFP128Ty() const { return getTypeID() == FP128TyID; } |
157 | |
158 | /// Return true if this is powerpc long double. |
159 | bool isPPC_FP128Ty() const { return getTypeID() == PPC_FP128TyID; } |
160 | |
161 | /// Return true if this is one of the six floating-point types |
162 | bool isFloatingPointTy() const { |
163 | return getTypeID() == HalfTyID || getTypeID() == FloatTyID || |
164 | getTypeID() == DoubleTyID || |
165 | getTypeID() == X86_FP80TyID || getTypeID() == FP128TyID || |
166 | getTypeID() == PPC_FP128TyID; |
167 | } |
168 | |
169 | const fltSemantics &getFltSemantics() const { |
170 | switch (getTypeID()) { |
171 | case HalfTyID: return APFloat::IEEEhalf(); |
172 | case FloatTyID: return APFloat::IEEEsingle(); |
173 | case DoubleTyID: return APFloat::IEEEdouble(); |
174 | case X86_FP80TyID: return APFloat::x87DoubleExtended(); |
175 | case FP128TyID: return APFloat::IEEEquad(); |
176 | case PPC_FP128TyID: return APFloat::PPCDoubleDouble(); |
177 | default: llvm_unreachable("Invalid floating type")::llvm::llvm_unreachable_internal("Invalid floating type", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 177); |
178 | } |
179 | } |
180 | |
181 | /// Return true if this is X86 MMX. |
182 | bool isX86_MMXTy() const { return getTypeID() == X86_MMXTyID; } |
183 | |
184 | /// Return true if this is a FP type or a vector of FP. |
185 | bool isFPOrFPVectorTy() const { return getScalarType()->isFloatingPointTy(); } |
186 | |
187 | /// Return true if this is 'label'. |
188 | bool isLabelTy() const { return getTypeID() == LabelTyID; } |
189 | |
190 | /// Return true if this is 'metadata'. |
191 | bool isMetadataTy() const { return getTypeID() == MetadataTyID; } |
192 | |
193 | /// Return true if this is 'token'. |
194 | bool isTokenTy() const { return getTypeID() == TokenTyID; } |
195 | |
196 | /// True if this is an instance of IntegerType. |
197 | bool isIntegerTy() const { return getTypeID() == IntegerTyID; } |
198 | |
199 | /// Return true if this is an IntegerType of the given width. |
200 | bool isIntegerTy(unsigned Bitwidth) const; |
201 | |
202 | /// Return true if this is an integer type or a vector of integer types. |
203 | bool isIntOrIntVectorTy() const { return getScalarType()->isIntegerTy(); } |
204 | |
205 | /// Return true if this is an integer type or a vector of integer types of |
206 | /// the given width. |
207 | bool isIntOrIntVectorTy(unsigned BitWidth) const { |
208 | return getScalarType()->isIntegerTy(BitWidth); |
209 | } |
210 | |
211 | /// Return true if this is an integer type or a pointer type. |
212 | bool isIntOrPtrTy() const { return isIntegerTy() || isPointerTy(); } |
213 | |
214 | /// True if this is an instance of FunctionType. |
215 | bool isFunctionTy() const { return getTypeID() == FunctionTyID; } |
216 | |
217 | /// True if this is an instance of StructType. |
218 | bool isStructTy() const { return getTypeID() == StructTyID; } |
219 | |
220 | /// True if this is an instance of ArrayType. |
221 | bool isArrayTy() const { return getTypeID() == ArrayTyID; } |
222 | |
223 | /// True if this is an instance of PointerType. |
224 | bool isPointerTy() const { return getTypeID() == PointerTyID; } |
225 | |
226 | /// Return true if this is a pointer type or a vector of pointer types. |
227 | bool isPtrOrPtrVectorTy() const { return getScalarType()->isPointerTy(); } |
228 | |
229 | /// True if this is an instance of VectorType. |
230 | bool isVectorTy() const { return getTypeID() == VectorTyID; } |
231 | |
232 | /// Return true if this type could be converted with a lossless BitCast to |
233 | /// type 'Ty'. For example, i8* to i32*. BitCasts are valid for types of the |
234 | /// same size only where no re-interpretation of the bits is done. |
235 | /// Determine if this type could be losslessly bitcast to Ty |
236 | bool canLosslesslyBitCastTo(Type *Ty) const; |
237 | |
238 | /// Return true if this type is empty, that is, it has no elements or all of |
239 | /// its elements are empty. |
240 | bool isEmptyTy() const; |
241 | |
242 | /// Return true if the type is "first class", meaning it is a valid type for a |
243 | /// Value. |
244 | bool isFirstClassType() const { |
245 | return getTypeID() != FunctionTyID && getTypeID() != VoidTyID; |
246 | } |
247 | |
248 | /// Return true if the type is a valid type for a register in codegen. This |
249 | /// includes all first-class types except struct and array types. |
250 | bool isSingleValueType() const { |
251 | return isFloatingPointTy() || isX86_MMXTy() || isIntegerTy() || |
252 | isPointerTy() || isVectorTy(); |
253 | } |
254 | |
255 | /// Return true if the type is an aggregate type. This means it is valid as |
256 | /// the first operand of an insertvalue or extractvalue instruction. This |
257 | /// includes struct and array types, but does not include vector types. |
258 | bool isAggregateType() const { |
259 | return getTypeID() == StructTyID || getTypeID() == ArrayTyID; |
260 | } |
261 | |
262 | /// Return true if it makes sense to take the size of this type. To get the |
263 | /// actual size for a particular target, it is reasonable to use the |
264 | /// DataLayout subsystem to do this. |
265 | bool isSized(SmallPtrSetImpl<Type*> *Visited = nullptr) const { |
266 | // If it's a primitive, it is always sized. |
267 | if (getTypeID() == IntegerTyID || isFloatingPointTy() || |
268 | getTypeID() == PointerTyID || |
269 | getTypeID() == X86_MMXTyID) |
270 | return true; |
271 | // If it is not something that can have a size (e.g. a function or label), |
272 | // it doesn't have a size. |
273 | if (getTypeID() != StructTyID && getTypeID() != ArrayTyID && |
274 | getTypeID() != VectorTyID) |
275 | return false; |
276 | // Otherwise we have to try harder to decide. |
277 | return isSizedDerivedType(Visited); |
278 | } |
279 | |
280 | /// Return the basic size of this type if it is a primitive type. These are |
281 | /// fixed by LLVM and are not target-dependent. |
282 | /// This will return zero if the type does not have a size or is not a |
283 | /// primitive type. |
284 | /// |
285 | /// If this is a scalable vector type, the scalable property will be set and |
286 | /// the runtime size will be a positive integer multiple of the base size. |
287 | /// |
288 | /// Note that this may not reflect the size of memory allocated for an |
289 | /// instance of the type or the number of bytes that are written when an |
290 | /// instance of the type is stored to memory. The DataLayout class provides |
291 | /// additional query functions to provide this information. |
292 | /// |
293 | TypeSize getPrimitiveSizeInBits() const LLVM_READONLY__attribute__((__pure__)); |
294 | |
295 | /// If this is a vector type, return the getPrimitiveSizeInBits value for the |
296 | /// element type. Otherwise return the getPrimitiveSizeInBits value for this |
297 | /// type. |
298 | unsigned getScalarSizeInBits() const LLVM_READONLY__attribute__((__pure__)); |
299 | |
300 | /// Return the width of the mantissa of this type. This is only valid on |
301 | /// floating-point types. If the FP type does not have a stable mantissa (e.g. |
302 | /// ppc long double), this method returns -1. |
303 | int getFPMantissaWidth() const; |
304 | |
305 | /// If this is a vector type, return the element type, otherwise return |
306 | /// 'this'. |
307 | Type *getScalarType() const { |
308 | if (isVectorTy()) |
309 | return getVectorElementType(); |
310 | return const_cast<Type*>(this); |
311 | } |
312 | |
313 | //===--------------------------------------------------------------------===// |
314 | // Type Iteration support. |
315 | // |
316 | using subtype_iterator = Type * const *; |
317 | |
318 | subtype_iterator subtype_begin() const { return ContainedTys; } |
319 | subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];} |
320 | ArrayRef<Type*> subtypes() const { |
321 | return makeArrayRef(subtype_begin(), subtype_end()); |
322 | } |
323 | |
324 | using subtype_reverse_iterator = std::reverse_iterator<subtype_iterator>; |
325 | |
326 | subtype_reverse_iterator subtype_rbegin() const { |
327 | return subtype_reverse_iterator(subtype_end()); |
328 | } |
329 | subtype_reverse_iterator subtype_rend() const { |
330 | return subtype_reverse_iterator(subtype_begin()); |
331 | } |
332 | |
333 | /// This method is used to implement the type iterator (defined at the end of |
334 | /// the file). For derived types, this returns the types 'contained' in the |
335 | /// derived type. |
336 | Type *getContainedType(unsigned i) const { |
337 | assert(i < NumContainedTys && "Index out of range!")((i < NumContainedTys && "Index out of range!") ? static_cast <void> (0) : __assert_fail ("i < NumContainedTys && \"Index out of range!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 337, __PRETTY_FUNCTION__)); |
338 | return ContainedTys[i]; |
339 | } |
340 | |
341 | /// Return the number of types in the derived type. |
342 | unsigned getNumContainedTypes() const { return NumContainedTys; } |
343 | |
344 | //===--------------------------------------------------------------------===// |
345 | // Helper methods corresponding to subclass methods. This forces a cast to |
346 | // the specified subclass and calls its accessor. "getVectorNumElements" (for |
347 | // example) is shorthand for cast<VectorType>(Ty)->getNumElements(). This is |
348 | // only intended to cover the core methods that are frequently used, helper |
349 | // methods should not be added here. |
350 | |
351 | inline unsigned getIntegerBitWidth() const; |
352 | |
353 | inline Type *getFunctionParamType(unsigned i) const; |
354 | inline unsigned getFunctionNumParams() const; |
355 | inline bool isFunctionVarArg() const; |
356 | |
357 | inline StringRef getStructName() const; |
358 | inline unsigned getStructNumElements() const; |
359 | inline Type *getStructElementType(unsigned N) const; |
360 | |
361 | inline Type *getSequentialElementType() const { |
362 | assert(isSequentialType(getTypeID()) && "Not a sequential type!")((isSequentialType(getTypeID()) && "Not a sequential type!" ) ? static_cast<void> (0) : __assert_fail ("isSequentialType(getTypeID()) && \"Not a sequential type!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 362, __PRETTY_FUNCTION__)); |
363 | return ContainedTys[0]; |
364 | } |
365 | |
366 | inline uint64_t getArrayNumElements() const; |
367 | |
368 | Type *getArrayElementType() const { |
369 | assert(getTypeID() == ArrayTyID)((getTypeID() == ArrayTyID) ? static_cast<void> (0) : __assert_fail ("getTypeID() == ArrayTyID", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 369, __PRETTY_FUNCTION__)); |
370 | return ContainedTys[0]; |
371 | } |
372 | |
373 | inline bool getVectorIsScalable() const; |
374 | inline unsigned getVectorNumElements() const; |
375 | inline ElementCount getVectorElementCount() const; |
376 | Type *getVectorElementType() const { |
377 | assert(getTypeID() == VectorTyID)((getTypeID() == VectorTyID) ? static_cast<void> (0) : __assert_fail ("getTypeID() == VectorTyID", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 377, __PRETTY_FUNCTION__)); |
378 | return ContainedTys[0]; |
379 | } |
380 | |
381 | Type *getPointerElementType() const { |
382 | assert(getTypeID() == PointerTyID)((getTypeID() == PointerTyID) ? static_cast<void> (0) : __assert_fail ("getTypeID() == PointerTyID", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 382, __PRETTY_FUNCTION__)); |
383 | return ContainedTys[0]; |
384 | } |
385 | |
386 | /// Given an integer or vector type, change the lane bitwidth to NewBitwidth, |
387 | /// whilst keeping the old number of lanes. |
388 | inline Type *getWithNewBitWidth(unsigned NewBitWidth) const; |
389 | |
390 | /// Given scalar/vector integer type, returns a type with elements twice as |
391 | /// wide as in the original type. For vectors, preserves element count. |
392 | inline Type *getExtendedType() const; |
393 | |
394 | /// Get the address space of this pointer or pointer vector type. |
395 | inline unsigned getPointerAddressSpace() const; |
396 | |
397 | //===--------------------------------------------------------------------===// |
398 | // Static members exported by the Type class itself. Useful for getting |
399 | // instances of Type. |
400 | // |
401 | |
402 | /// Return a type based on an identifier. |
403 | static Type *getPrimitiveType(LLVMContext &C, TypeID IDNumber); |
404 | |
405 | //===--------------------------------------------------------------------===// |
406 | // These are the builtin types that are always available. |
407 | // |
408 | static Type *getVoidTy(LLVMContext &C); |
409 | static Type *getLabelTy(LLVMContext &C); |
410 | static Type *getHalfTy(LLVMContext &C); |
411 | static Type *getFloatTy(LLVMContext &C); |
412 | static Type *getDoubleTy(LLVMContext &C); |
413 | static Type *getMetadataTy(LLVMContext &C); |
414 | static Type *getX86_FP80Ty(LLVMContext &C); |
415 | static Type *getFP128Ty(LLVMContext &C); |
416 | static Type *getPPC_FP128Ty(LLVMContext &C); |
417 | static Type *getX86_MMXTy(LLVMContext &C); |
418 | static Type *getTokenTy(LLVMContext &C); |
419 | static IntegerType *getIntNTy(LLVMContext &C, unsigned N); |
420 | static IntegerType *getInt1Ty(LLVMContext &C); |
421 | static IntegerType *getInt8Ty(LLVMContext &C); |
422 | static IntegerType *getInt16Ty(LLVMContext &C); |
423 | static IntegerType *getInt32Ty(LLVMContext &C); |
424 | static IntegerType *getInt64Ty(LLVMContext &C); |
425 | static IntegerType *getInt128Ty(LLVMContext &C); |
426 | template <typename ScalarTy> static Type *getScalarTy(LLVMContext &C) { |
427 | int noOfBits = sizeof(ScalarTy) * CHAR_BIT8; |
428 | if (std::is_integral<ScalarTy>::value) { |
429 | return (Type*) Type::getIntNTy(C, noOfBits); |
430 | } else if (std::is_floating_point<ScalarTy>::value) { |
431 | switch (noOfBits) { |
432 | case 32: |
433 | return Type::getFloatTy(C); |
434 | case 64: |
435 | return Type::getDoubleTy(C); |
436 | } |
437 | } |
438 | llvm_unreachable("Unsupported type in Type::getScalarTy")::llvm::llvm_unreachable_internal("Unsupported type in Type::getScalarTy" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/IR/Type.h" , 438); |
439 | } |
440 | |
441 | //===--------------------------------------------------------------------===// |
442 | // Convenience methods for getting pointer types with one of the above builtin |
443 | // types as pointee. |
444 | // |
445 | static PointerType *getHalfPtrTy(LLVMContext &C, unsigned AS = 0); |
446 | static PointerType *getFloatPtrTy(LLVMContext &C, unsigned AS = 0); |
447 | static PointerType *getDoublePtrTy(LLVMContext &C, unsigned AS = 0); |
448 | static PointerType *getX86_FP80PtrTy(LLVMContext &C, unsigned AS = 0); |
449 | static PointerType *getFP128PtrTy(LLVMContext &C, unsigned AS = 0); |
450 | static PointerType *getPPC_FP128PtrTy(LLVMContext &C, unsigned AS = 0); |
451 | static PointerType *getX86_MMXPtrTy(LLVMContext &C, unsigned AS = 0); |
452 | static PointerType *getIntNPtrTy(LLVMContext &C, unsigned N, unsigned AS = 0); |
453 | static PointerType *getInt1PtrTy(LLVMContext &C, unsigned AS = 0); |
454 | static PointerType *getInt8PtrTy(LLVMContext &C, unsigned AS = 0); |
455 | static PointerType *getInt16PtrTy(LLVMContext &C, unsigned AS = 0); |
456 | static PointerType *getInt32PtrTy(LLVMContext &C, unsigned AS = 0); |
457 | static PointerType *getInt64PtrTy(LLVMContext &C, unsigned AS = 0); |
458 | |
459 | /// Return a pointer to the current type. This is equivalent to |
460 | /// PointerType::get(Foo, AddrSpace). |
461 | PointerType *getPointerTo(unsigned AddrSpace = 0) const; |
462 | |
463 | private: |
464 | /// Derived types like structures and arrays are sized iff all of the members |
465 | /// of the type are sized as well. Since asking for their size is relatively |
466 | /// uncommon, move this operation out-of-line. |
467 | bool isSizedDerivedType(SmallPtrSetImpl<Type*> *Visited = nullptr) const; |
468 | }; |
469 | |
470 | // Printing of types. |
471 | inline raw_ostream &operator<<(raw_ostream &OS, const Type &T) { |
472 | T.print(OS); |
473 | return OS; |
474 | } |
475 | |
476 | // allow isa<PointerType>(x) to work without DerivedTypes.h included. |
477 | template <> struct isa_impl<PointerType, Type> { |
478 | static inline bool doit(const Type &Ty) { |
479 | return Ty.getTypeID() == Type::PointerTyID; |
480 | } |
481 | }; |
482 | |
483 | // Create wrappers for C Binding types (see CBindingWrapping.h). |
484 | DEFINE_ISA_CONVERSION_FUNCTIONS(Type, LLVMTypeRef)inline Type *unwrap(LLVMTypeRef P) { return reinterpret_cast< Type*>(P); } inline LLVMTypeRef wrap(const Type *P) { return reinterpret_cast<LLVMTypeRef>(const_cast<Type*>( P)); } template<typename T> inline T *unwrap(LLVMTypeRef P) { return cast<T>(unwrap(P)); } |
485 | |
486 | /* Specialized opaque type conversions. |
487 | */ |
488 | inline Type **unwrap(LLVMTypeRef* Tys) { |
489 | return reinterpret_cast<Type**>(Tys); |
490 | } |
491 | |
492 | inline LLVMTypeRef *wrap(Type **Tys) { |
493 | return reinterpret_cast<LLVMTypeRef*>(const_cast<Type**>(Tys)); |
494 | } |
495 | |
496 | } // end namespace llvm |
497 | |
498 | #endif // LLVM_IR_TYPE_H |
1 | //===- Optional.h - Simple variant for passing optional values --*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This file provides Optional, a template class modeled in the spirit of |
10 | // OCaml's 'opt' variant. The idea is to strongly type whether or not |
11 | // a value can be optional. |
12 | // |
13 | //===----------------------------------------------------------------------===// |
14 | |
15 | #ifndef LLVM_ADT_OPTIONAL_H |
16 | #define LLVM_ADT_OPTIONAL_H |
17 | |
18 | #include "llvm/ADT/None.h" |
19 | #include "llvm/Support/Compiler.h" |
20 | #include "llvm/Support/type_traits.h" |
21 | #include <cassert> |
22 | #include <memory> |
23 | #include <new> |
24 | #include <utility> |
25 | |
26 | namespace llvm { |
27 | |
28 | class raw_ostream; |
29 | |
30 | namespace optional_detail { |
31 | |
32 | struct in_place_t {}; |
33 | |
34 | /// Storage for any type. |
35 | template <typename T, bool = is_trivially_copyable<T>::value> |
36 | class OptionalStorage { |
37 | union { |
38 | char empty; |
39 | T value; |
40 | }; |
41 | bool hasVal; |
42 | |
43 | public: |
44 | ~OptionalStorage() { reset(); } |
45 | |
46 | OptionalStorage() noexcept : empty(), hasVal(false) {} |
47 | |
48 | OptionalStorage(OptionalStorage const &other) : OptionalStorage() { |
49 | if (other.hasValue()) { |
50 | emplace(other.value); |
51 | } |
52 | } |
53 | OptionalStorage(OptionalStorage &&other) : OptionalStorage() { |
54 | if (other.hasValue()) { |
55 | emplace(std::move(other.value)); |
56 | } |
57 | } |
58 | |
59 | template <class... Args> |
60 | explicit OptionalStorage(in_place_t, Args &&... args) |
61 | : value(std::forward<Args>(args)...), hasVal(true) {} |
62 | |
63 | void reset() noexcept { |
64 | if (hasVal) { |
65 | value.~T(); |
66 | hasVal = false; |
67 | } |
68 | } |
69 | |
70 | bool hasValue() const noexcept { return hasVal; } |
71 | |
72 | T &getValue() LLVM_LVALUE_FUNCTION& noexcept { |
73 | assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/Optional.h" , 73, __PRETTY_FUNCTION__)); |
74 | return value; |
75 | } |
76 | T const &getValue() const LLVM_LVALUE_FUNCTION& noexcept { |
77 | assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/Optional.h" , 77, __PRETTY_FUNCTION__)); |
78 | return value; |
79 | } |
80 | #if LLVM_HAS_RVALUE_REFERENCE_THIS1 |
81 | T &&getValue() && noexcept { |
82 | assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/Optional.h" , 82, __PRETTY_FUNCTION__)); |
83 | return std::move(value); |
84 | } |
85 | #endif |
86 | |
87 | template <class... Args> void emplace(Args &&... args) { |
88 | reset(); |
89 | ::new ((void *)std::addressof(value)) T(std::forward<Args>(args)...); |
90 | hasVal = true; |
91 | } |
92 | |
93 | OptionalStorage &operator=(T const &y) { |
94 | if (hasValue()) { |
95 | value = y; |
96 | } else { |
97 | ::new ((void *)std::addressof(value)) T(y); |
98 | hasVal = true; |
99 | } |
100 | return *this; |
101 | } |
102 | OptionalStorage &operator=(T &&y) { |
103 | if (hasValue()) { |
104 | value = std::move(y); |
105 | } else { |
106 | ::new ((void *)std::addressof(value)) T(std::move(y)); |
107 | hasVal = true; |
108 | } |
109 | return *this; |
110 | } |
111 | |
112 | OptionalStorage &operator=(OptionalStorage const &other) { |
113 | if (other.hasValue()) { |
114 | if (hasValue()) { |
115 | value = other.value; |
116 | } else { |
117 | ::new ((void *)std::addressof(value)) T(other.value); |
118 | hasVal = true; |
119 | } |
120 | } else { |
121 | reset(); |
122 | } |
123 | return *this; |
124 | } |
125 | |
126 | OptionalStorage &operator=(OptionalStorage &&other) { |
127 | if (other.hasValue()) { |
128 | if (hasValue()) { |
129 | value = std::move(other.value); |
130 | } else { |
131 | ::new ((void *)std::addressof(value)) T(std::move(other.value)); |
132 | hasVal = true; |
133 | } |
134 | } else { |
135 | reset(); |
136 | } |
137 | return *this; |
138 | } |
139 | }; |
140 | |
141 | template <typename T> class OptionalStorage<T, true> { |
142 | union { |
143 | char empty; |
144 | T value; |
145 | }; |
146 | bool hasVal = false; |
147 | |
148 | public: |
149 | ~OptionalStorage() = default; |
150 | |
151 | OptionalStorage() noexcept : empty{} {} |
152 | |
153 | OptionalStorage(OptionalStorage const &other) = default; |
154 | OptionalStorage(OptionalStorage &&other) = default; |
155 | |
156 | OptionalStorage &operator=(OptionalStorage const &other) = default; |
157 | OptionalStorage &operator=(OptionalStorage &&other) = default; |
158 | |
159 | template <class... Args> |
160 | explicit OptionalStorage(in_place_t, Args &&... args) |
161 | : value(std::forward<Args>(args)...), hasVal(true) {} |
162 | |
163 | void reset() noexcept { |
164 | if (hasVal) { |
165 | value.~T(); |
166 | hasVal = false; |
167 | } |
168 | } |
169 | |
170 | bool hasValue() const noexcept { return hasVal; } |
171 | |
172 | T &getValue() LLVM_LVALUE_FUNCTION& noexcept { |
173 | assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/Optional.h" , 173, __PRETTY_FUNCTION__)); |
174 | return value; |
175 | } |
176 | T const &getValue() const LLVM_LVALUE_FUNCTION& noexcept { |
177 | assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/Optional.h" , 177, __PRETTY_FUNCTION__)); |
178 | return value; |
179 | } |
180 | #if LLVM_HAS_RVALUE_REFERENCE_THIS1 |
181 | T &&getValue() && noexcept { |
182 | assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/Optional.h" , 182, __PRETTY_FUNCTION__)); |
183 | return std::move(value); |
184 | } |
185 | #endif |
186 | |
187 | template <class... Args> void emplace(Args &&... args) { |
188 | reset(); |
189 | ::new ((void *)std::addressof(value)) T(std::forward<Args>(args)...); |
190 | hasVal = true; |
191 | } |
192 | |
193 | OptionalStorage &operator=(T const &y) { |
194 | if (hasValue()) { |
195 | value = y; |
196 | } else { |
197 | ::new ((void *)std::addressof(value)) T(y); |
198 | hasVal = true; |
199 | } |
200 | return *this; |
201 | } |
202 | OptionalStorage &operator=(T &&y) { |
203 | if (hasValue()) { |
204 | value = std::move(y); |
205 | } else { |
206 | ::new ((void *)std::addressof(value)) T(std::move(y)); |
207 | hasVal = true; |
208 | } |
209 | return *this; |
210 | } |
211 | }; |
212 | |
213 | } // namespace optional_detail |
214 | |
215 | template <typename T> class Optional { |
216 | optional_detail::OptionalStorage<T> Storage; |
217 | |
218 | public: |
219 | using value_type = T; |
220 | |
221 | constexpr Optional() {} |
222 | constexpr Optional(NoneType) {} |
223 | |
224 | Optional(const T &y) : Storage(optional_detail::in_place_t{}, y) {} |
225 | Optional(const Optional &O) = default; |
226 | |
227 | Optional(T &&y) : Storage(optional_detail::in_place_t{}, std::move(y)) {} |
228 | Optional(Optional &&O) = default; |
229 | |
230 | Optional &operator=(T &&y) { |
231 | Storage = std::move(y); |
232 | return *this; |
233 | } |
234 | Optional &operator=(Optional &&O) = default; |
235 | |
236 | /// Create a new object by constructing it in place with the given arguments. |
237 | template <typename... ArgTypes> void emplace(ArgTypes &&... Args) { |
238 | Storage.emplace(std::forward<ArgTypes>(Args)...); |
239 | } |
240 | |
241 | static inline Optional create(const T *y) { |
242 | return y ? Optional(*y) : Optional(); |
243 | } |
244 | |
245 | Optional &operator=(const T &y) { |
246 | Storage = y; |
247 | return *this; |
248 | } |
249 | Optional &operator=(const Optional &O) = default; |
250 | |
251 | void reset() { Storage.reset(); } |
252 | |
253 | const T *getPointer() const { return &Storage.getValue(); } |
254 | T *getPointer() { return &Storage.getValue(); } |
255 | const T &getValue() const LLVM_LVALUE_FUNCTION& { return Storage.getValue(); } |
256 | T &getValue() LLVM_LVALUE_FUNCTION& { return Storage.getValue(); } |
257 | |
258 | explicit operator bool() const { return hasValue(); } |
259 | bool hasValue() const { return Storage.hasValue(); } |
260 | const T *operator->() const { return getPointer(); } |
261 | T *operator->() { return getPointer(); } |
262 | const T &operator*() const LLVM_LVALUE_FUNCTION& { return getValue(); } |
263 | T &operator*() LLVM_LVALUE_FUNCTION& { return getValue(); } |
264 | |
265 | template <typename U> |
266 | constexpr T getValueOr(U &&value) const LLVM_LVALUE_FUNCTION& { |
267 | return hasValue() ? getValue() : std::forward<U>(value); |
268 | } |
269 | |
270 | /// Apply a function to the value if present; otherwise return None. |
271 | template <class Function> |
272 | auto map(const Function &F) const LLVM_LVALUE_FUNCTION& |
273 | -> Optional<decltype(F(getValue()))> { |
274 | if (*this) return F(getValue()); |
275 | return None; |
276 | } |
277 | |
278 | #if LLVM_HAS_RVALUE_REFERENCE_THIS1 |
279 | T &&getValue() && { return std::move(Storage.getValue()); } |
280 | T &&operator*() && { return std::move(Storage.getValue()); } |
281 | |
282 | template <typename U> |
283 | T getValueOr(U &&value) && { |
284 | return hasValue() ? std::move(getValue()) : std::forward<U>(value); |
285 | } |
286 | |
287 | /// Apply a function to the value if present; otherwise return None. |
288 | template <class Function> |
289 | auto map(const Function &F) && |
290 | -> Optional<decltype(F(std::move(*this).getValue()))> { |
291 | if (*this) return F(std::move(*this).getValue()); |
292 | return None; |
293 | } |
294 | #endif |
295 | }; |
296 | |
297 | template <typename T, typename U> |
298 | bool operator==(const Optional<T> &X, const Optional<U> &Y) { |
299 | if (X && Y) |
300 | return *X == *Y; |
301 | return X.hasValue() == Y.hasValue(); |
302 | } |
303 | |
304 | template <typename T, typename U> |
305 | bool operator!=(const Optional<T> &X, const Optional<U> &Y) { |
306 | return !(X == Y); |
307 | } |
308 | |
309 | template <typename T, typename U> |
310 | bool operator<(const Optional<T> &X, const Optional<U> &Y) { |
311 | if (X && Y) |
312 | return *X < *Y; |
313 | return X.hasValue() < Y.hasValue(); |
314 | } |
315 | |
316 | template <typename T, typename U> |
317 | bool operator<=(const Optional<T> &X, const Optional<U> &Y) { |
318 | return !(Y < X); |
319 | } |
320 | |
321 | template <typename T, typename U> |
322 | bool operator>(const Optional<T> &X, const Optional<U> &Y) { |
323 | return Y < X; |
324 | } |
325 | |
326 | template <typename T, typename U> |
327 | bool operator>=(const Optional<T> &X, const Optional<U> &Y) { |
328 | return !(X < Y); |
329 | } |
330 | |
331 | template<typename T> |
332 | bool operator==(const Optional<T> &X, NoneType) { |
333 | return !X; |
334 | } |
335 | |
336 | template<typename T> |
337 | bool operator==(NoneType, const Optional<T> &X) { |
338 | return X == None; |
339 | } |
340 | |
341 | template<typename T> |
342 | bool operator!=(const Optional<T> &X, NoneType) { |
343 | return !(X == None); |
344 | } |
345 | |
346 | template<typename T> |
347 | bool operator!=(NoneType, const Optional<T> &X) { |
348 | return X != None; |
349 | } |
350 | |
351 | template <typename T> bool operator<(const Optional<T> &X, NoneType) { |
352 | return false; |
353 | } |
354 | |
355 | template <typename T> bool operator<(NoneType, const Optional<T> &X) { |
356 | return X.hasValue(); |
357 | } |
358 | |
359 | template <typename T> bool operator<=(const Optional<T> &X, NoneType) { |
360 | return !(None < X); |
361 | } |
362 | |
363 | template <typename T> bool operator<=(NoneType, const Optional<T> &X) { |
364 | return !(X < None); |
365 | } |
366 | |
367 | template <typename T> bool operator>(const Optional<T> &X, NoneType) { |
368 | return None < X; |
369 | } |
370 | |
371 | template <typename T> bool operator>(NoneType, const Optional<T> &X) { |
372 | return X < None; |
373 | } |
374 | |
375 | template <typename T> bool operator>=(const Optional<T> &X, NoneType) { |
376 | return None <= X; |
377 | } |
378 | |
379 | template <typename T> bool operator>=(NoneType, const Optional<T> &X) { |
380 | return X <= None; |
381 | } |
382 | |
383 | template <typename T> bool operator==(const Optional<T> &X, const T &Y) { |
384 | return X && *X == Y; |
385 | } |
386 | |
387 | template <typename T> bool operator==(const T &X, const Optional<T> &Y) { |
388 | return Y && X == *Y; |
389 | } |
390 | |
391 | template <typename T> bool operator!=(const Optional<T> &X, const T &Y) { |
392 | return !(X == Y); |
393 | } |
394 | |
395 | template <typename T> bool operator!=(const T &X, const Optional<T> &Y) { |
396 | return !(X == Y); |
397 | } |
398 | |
399 | template <typename T> bool operator<(const Optional<T> &X, const T &Y) { |
400 | return !X || *X < Y; |
401 | } |
402 | |
403 | template <typename T> bool operator<(const T &X, const Optional<T> &Y) { |
404 | return Y && X < *Y; |
405 | } |
406 | |
407 | template <typename T> bool operator<=(const Optional<T> &X, const T &Y) { |
408 | return !(Y < X); |
409 | } |
410 | |
411 | template <typename T> bool operator<=(const T &X, const Optional<T> &Y) { |
412 | return !(Y < X); |
413 | } |
414 | |
415 | template <typename T> bool operator>(const Optional<T> &X, const T &Y) { |
416 | return Y < X; |
417 | } |
418 | |
419 | template <typename T> bool operator>(const T &X, const Optional<T> &Y) { |
420 | return Y < X; |
421 | } |
422 | |
423 | template <typename T> bool operator>=(const Optional<T> &X, const T &Y) { |
424 | return !(X < Y); |
425 | } |
426 | |
427 | template <typename T> bool operator>=(const T &X, const Optional<T> &Y) { |
428 | return !(X < Y); |
429 | } |
430 | |
431 | raw_ostream &operator<<(raw_ostream &OS, NoneType); |
432 | |
433 | template <typename T, typename = decltype(std::declval<raw_ostream &>() |
434 | << std::declval<const T &>())> |
435 | raw_ostream &operator<<(raw_ostream &OS, const Optional<T> &O) { |
436 | if (O) |
437 | OS << *O; |
438 | else |
439 | OS << None; |
440 | return OS; |
441 | } |
442 | |
443 | } // end namespace llvm |
444 | |
445 | #endif // LLVM_ADT_OPTIONAL_H |