Bug Summary

File:lib/Analysis/InstructionSimplify.cpp
Warning:line 421, column 20
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name InstructionSimplify.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn350071/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/lib/Analysis -fdebug-prefix-map=/build/llvm-toolchain-snapshot-8~svn350071=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-12-27-042839-1215-1 -x c++ /build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp -faddrsig

/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp

1//===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements routines for folding instructions into simpler forms
11// that do not require creating new instructions. This does constant folding
12// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
13// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
14// ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
15// simplified: This is usually true and assuming it simplifies the logic (if
16// they have not been simplified then results are correct but maybe suboptimal).
17//
18//===----------------------------------------------------------------------===//
19
20#include "llvm/Analysis/InstructionSimplify.h"
21#include "llvm/ADT/SetVector.h"
22#include "llvm/ADT/Statistic.h"
23#include "llvm/Analysis/AliasAnalysis.h"
24#include "llvm/Analysis/AssumptionCache.h"
25#include "llvm/Analysis/CaptureTracking.h"
26#include "llvm/Analysis/CmpInstAnalysis.h"
27#include "llvm/Analysis/ConstantFolding.h"
28#include "llvm/Analysis/LoopAnalysisManager.h"
29#include "llvm/Analysis/MemoryBuiltins.h"
30#include "llvm/Analysis/ValueTracking.h"
31#include "llvm/Analysis/VectorUtils.h"
32#include "llvm/IR/ConstantRange.h"
33#include "llvm/IR/DataLayout.h"
34#include "llvm/IR/Dominators.h"
35#include "llvm/IR/GetElementPtrTypeIterator.h"
36#include "llvm/IR/GlobalAlias.h"
37#include "llvm/IR/Operator.h"
38#include "llvm/IR/PatternMatch.h"
39#include "llvm/IR/ValueHandle.h"
40#include "llvm/Support/KnownBits.h"
41#include <algorithm>
42using namespace llvm;
43using namespace llvm::PatternMatch;
44
45#define DEBUG_TYPE"instsimplify" "instsimplify"
46
47enum { RecursionLimit = 3 };
48
49STATISTIC(NumExpand, "Number of expansions")static llvm::Statistic NumExpand = {"instsimplify", "NumExpand"
, "Number of expansions", {0}, {false}}
;
50STATISTIC(NumReassoc, "Number of reassociations")static llvm::Statistic NumReassoc = {"instsimplify", "NumReassoc"
, "Number of reassociations", {0}, {false}}
;
51
52static Value *SimplifyAndInst(Value *, Value *, const SimplifyQuery &, unsigned);
53static Value *SimplifyBinOp(unsigned, Value *, Value *, const SimplifyQuery &,
54 unsigned);
55static Value *SimplifyFPBinOp(unsigned, Value *, Value *, const FastMathFlags &,
56 const SimplifyQuery &, unsigned);
57static Value *SimplifyCmpInst(unsigned, Value *, Value *, const SimplifyQuery &,
58 unsigned);
59static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
60 const SimplifyQuery &Q, unsigned MaxRecurse);
61static Value *SimplifyOrInst(Value *, Value *, const SimplifyQuery &, unsigned);
62static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned);
63static Value *SimplifyCastInst(unsigned, Value *, Type *,
64 const SimplifyQuery &, unsigned);
65static Value *SimplifyGEPInst(Type *, ArrayRef<Value *>, const SimplifyQuery &,
66 unsigned);
67
68static Value *foldSelectWithBinaryOp(Value *Cond, Value *TrueVal,
69 Value *FalseVal) {
70 BinaryOperator::BinaryOps BinOpCode;
71 if (auto *BO = dyn_cast<BinaryOperator>(Cond))
72 BinOpCode = BO->getOpcode();
73 else
74 return nullptr;
75
76 CmpInst::Predicate ExpectedPred, Pred1, Pred2;
77 if (BinOpCode == BinaryOperator::Or) {
78 ExpectedPred = ICmpInst::ICMP_NE;
79 } else if (BinOpCode == BinaryOperator::And) {
80 ExpectedPred = ICmpInst::ICMP_EQ;
81 } else
82 return nullptr;
83
84 // %A = icmp eq %TV, %FV
85 // %B = icmp eq %X, %Y (and one of these is a select operand)
86 // %C = and %A, %B
87 // %D = select %C, %TV, %FV
88 // -->
89 // %FV
90
91 // %A = icmp ne %TV, %FV
92 // %B = icmp ne %X, %Y (and one of these is a select operand)
93 // %C = or %A, %B
94 // %D = select %C, %TV, %FV
95 // -->
96 // %TV
97 Value *X, *Y;
98 if (!match(Cond, m_c_BinOp(m_c_ICmp(Pred1, m_Specific(TrueVal),
99 m_Specific(FalseVal)),
100 m_ICmp(Pred2, m_Value(X), m_Value(Y)))) ||
101 Pred1 != Pred2 || Pred1 != ExpectedPred)
102 return nullptr;
103
104 if (X == TrueVal || X == FalseVal || Y == TrueVal || Y == FalseVal)
105 return BinOpCode == BinaryOperator::Or ? TrueVal : FalseVal;
106
107 return nullptr;
108}
109
110/// For a boolean type or a vector of boolean type, return false or a vector
111/// with every element false.
112static Constant *getFalse(Type *Ty) {
113 return ConstantInt::getFalse(Ty);
114}
115
116/// For a boolean type or a vector of boolean type, return true or a vector
117/// with every element true.
118static Constant *getTrue(Type *Ty) {
119 return ConstantInt::getTrue(Ty);
120}
121
122/// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
123static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
124 Value *RHS) {
125 CmpInst *Cmp = dyn_cast<CmpInst>(V);
126 if (!Cmp)
127 return false;
128 CmpInst::Predicate CPred = Cmp->getPredicate();
129 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
130 if (CPred == Pred && CLHS == LHS && CRHS == RHS)
131 return true;
132 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
133 CRHS == LHS;
134}
135
136/// Does the given value dominate the specified phi node?
137static bool valueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
138 Instruction *I = dyn_cast<Instruction>(V);
139 if (!I)
140 // Arguments and constants dominate all instructions.
141 return true;
142
143 // If we are processing instructions (and/or basic blocks) that have not been
144 // fully added to a function, the parent nodes may still be null. Simply
145 // return the conservative answer in these cases.
146 if (!I->getParent() || !P->getParent() || !I->getFunction())
147 return false;
148
149 // If we have a DominatorTree then do a precise test.
150 if (DT)
151 return DT->dominates(I, P);
152
153 // Otherwise, if the instruction is in the entry block and is not an invoke,
154 // then it obviously dominates all phi nodes.
155 if (I->getParent() == &I->getFunction()->getEntryBlock() &&
156 !isa<InvokeInst>(I))
157 return true;
158
159 return false;
160}
161
162/// Simplify "A op (B op' C)" by distributing op over op', turning it into
163/// "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
164/// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
165/// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
166/// Returns the simplified value, or null if no simplification was performed.
167static Value *ExpandBinOp(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS,
168 Instruction::BinaryOps OpcodeToExpand,
169 const SimplifyQuery &Q, unsigned MaxRecurse) {
170 // Recursion is always used, so bail out at once if we already hit the limit.
171 if (!MaxRecurse--)
172 return nullptr;
173
174 // Check whether the expression has the form "(A op' B) op C".
175 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
176 if (Op0->getOpcode() == OpcodeToExpand) {
177 // It does! Try turning it into "(A op C) op' (B op C)".
178 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
179 // Do "A op C" and "B op C" both simplify?
180 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
181 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
182 // They do! Return "L op' R" if it simplifies or is already available.
183 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
184 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
185 && L == B && R == A)) {
186 ++NumExpand;
187 return LHS;
188 }
189 // Otherwise return "L op' R" if it simplifies.
190 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
191 ++NumExpand;
192 return V;
193 }
194 }
195 }
196
197 // Check whether the expression has the form "A op (B op' C)".
198 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
199 if (Op1->getOpcode() == OpcodeToExpand) {
200 // It does! Try turning it into "(A op B) op' (A op C)".
201 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
202 // Do "A op B" and "A op C" both simplify?
203 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
204 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
205 // They do! Return "L op' R" if it simplifies or is already available.
206 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
207 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
208 && L == C && R == B)) {
209 ++NumExpand;
210 return RHS;
211 }
212 // Otherwise return "L op' R" if it simplifies.
213 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
214 ++NumExpand;
215 return V;
216 }
217 }
218 }
219
220 return nullptr;
221}
222
223/// Generic simplifications for associative binary operations.
224/// Returns the simpler value, or null if none was found.
225static Value *SimplifyAssociativeBinOp(Instruction::BinaryOps Opcode,
226 Value *LHS, Value *RHS,
227 const SimplifyQuery &Q,
228 unsigned MaxRecurse) {
229 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!")((Instruction::isAssociative(Opcode) && "Not an associative operation!"
) ? static_cast<void> (0) : __assert_fail ("Instruction::isAssociative(Opcode) && \"Not an associative operation!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 229, __PRETTY_FUNCTION__))
;
230
231 // Recursion is always used, so bail out at once if we already hit the limit.
232 if (!MaxRecurse--)
233 return nullptr;
234
235 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
236 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
237
238 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
239 if (Op0 && Op0->getOpcode() == Opcode) {
240 Value *A = Op0->getOperand(0);
241 Value *B = Op0->getOperand(1);
242 Value *C = RHS;
243
244 // Does "B op C" simplify?
245 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
246 // It does! Return "A op V" if it simplifies or is already available.
247 // If V equals B then "A op V" is just the LHS.
248 if (V == B) return LHS;
249 // Otherwise return "A op V" if it simplifies.
250 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
251 ++NumReassoc;
252 return W;
253 }
254 }
255 }
256
257 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
258 if (Op1 && Op1->getOpcode() == Opcode) {
259 Value *A = LHS;
260 Value *B = Op1->getOperand(0);
261 Value *C = Op1->getOperand(1);
262
263 // Does "A op B" simplify?
264 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
265 // It does! Return "V op C" if it simplifies or is already available.
266 // If V equals B then "V op C" is just the RHS.
267 if (V == B) return RHS;
268 // Otherwise return "V op C" if it simplifies.
269 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
270 ++NumReassoc;
271 return W;
272 }
273 }
274 }
275
276 // The remaining transforms require commutativity as well as associativity.
277 if (!Instruction::isCommutative(Opcode))
278 return nullptr;
279
280 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
281 if (Op0 && Op0->getOpcode() == Opcode) {
282 Value *A = Op0->getOperand(0);
283 Value *B = Op0->getOperand(1);
284 Value *C = RHS;
285
286 // Does "C op A" simplify?
287 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
288 // It does! Return "V op B" if it simplifies or is already available.
289 // If V equals A then "V op B" is just the LHS.
290 if (V == A) return LHS;
291 // Otherwise return "V op B" if it simplifies.
292 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
293 ++NumReassoc;
294 return W;
295 }
296 }
297 }
298
299 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
300 if (Op1 && Op1->getOpcode() == Opcode) {
301 Value *A = LHS;
302 Value *B = Op1->getOperand(0);
303 Value *C = Op1->getOperand(1);
304
305 // Does "C op A" simplify?
306 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
307 // It does! Return "B op V" if it simplifies or is already available.
308 // If V equals C then "B op V" is just the RHS.
309 if (V == C) return RHS;
310 // Otherwise return "B op V" if it simplifies.
311 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
312 ++NumReassoc;
313 return W;
314 }
315 }
316 }
317
318 return nullptr;
319}
320
321/// In the case of a binary operation with a select instruction as an operand,
322/// try to simplify the binop by seeing whether evaluating it on both branches
323/// of the select results in the same value. Returns the common value if so,
324/// otherwise returns null.
325static Value *ThreadBinOpOverSelect(Instruction::BinaryOps Opcode, Value *LHS,
326 Value *RHS, const SimplifyQuery &Q,
327 unsigned MaxRecurse) {
328 // Recursion is always used, so bail out at once if we already hit the limit.
329 if (!MaxRecurse--)
330 return nullptr;
331
332 SelectInst *SI;
333 if (isa<SelectInst>(LHS)) {
334 SI = cast<SelectInst>(LHS);
335 } else {
336 assert(isa<SelectInst>(RHS) && "No select instruction operand!")((isa<SelectInst>(RHS) && "No select instruction operand!"
) ? static_cast<void> (0) : __assert_fail ("isa<SelectInst>(RHS) && \"No select instruction operand!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 336, __PRETTY_FUNCTION__))
;
337 SI = cast<SelectInst>(RHS);
338 }
339
340 // Evaluate the BinOp on the true and false branches of the select.
341 Value *TV;
342 Value *FV;
343 if (SI == LHS) {
344 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
345 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
346 } else {
347 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
348 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
349 }
350
351 // If they simplified to the same value, then return the common value.
352 // If they both failed to simplify then return null.
353 if (TV == FV)
354 return TV;
355
356 // If one branch simplified to undef, return the other one.
357 if (TV && isa<UndefValue>(TV))
358 return FV;
359 if (FV && isa<UndefValue>(FV))
360 return TV;
361
362 // If applying the operation did not change the true and false select values,
363 // then the result of the binop is the select itself.
364 if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
365 return SI;
366
367 // If one branch simplified and the other did not, and the simplified
368 // value is equal to the unsimplified one, return the simplified value.
369 // For example, select (cond, X, X & Z) & Z -> X & Z.
370 if ((FV && !TV) || (TV && !FV)) {
371 // Check that the simplified value has the form "X op Y" where "op" is the
372 // same as the original operation.
373 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
374 if (Simplified && Simplified->getOpcode() == unsigned(Opcode)) {
375 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
376 // We already know that "op" is the same as for the simplified value. See
377 // if the operands match too. If so, return the simplified value.
378 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
379 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
380 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
381 if (Simplified->getOperand(0) == UnsimplifiedLHS &&
382 Simplified->getOperand(1) == UnsimplifiedRHS)
383 return Simplified;
384 if (Simplified->isCommutative() &&
385 Simplified->getOperand(1) == UnsimplifiedLHS &&
386 Simplified->getOperand(0) == UnsimplifiedRHS)
387 return Simplified;
388 }
389 }
390
391 return nullptr;
392}
393
394/// In the case of a comparison with a select instruction, try to simplify the
395/// comparison by seeing whether both branches of the select result in the same
396/// value. Returns the common value if so, otherwise returns null.
397static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
398 Value *RHS, const SimplifyQuery &Q,
399 unsigned MaxRecurse) {
400 // Recursion is always used, so bail out at once if we already hit the limit.
401 if (!MaxRecurse--)
25
Taking false branch
402 return nullptr;
403
404 // Make sure the select is on the LHS.
405 if (!isa<SelectInst>(LHS)) {
26
Taking true branch
406 std::swap(LHS, RHS);
407 Pred = CmpInst::getSwappedPredicate(Pred);
408 }
409 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!")((isa<SelectInst>(LHS) && "Not comparing with a select instruction!"
) ? static_cast<void> (0) : __assert_fail ("isa<SelectInst>(LHS) && \"Not comparing with a select instruction!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 409, __PRETTY_FUNCTION__))
;
27
'?' condition is true
410 SelectInst *SI = cast<SelectInst>(LHS);
411 Value *Cond = SI->getCondition();
28
Calling 'SelectInst::getCondition'
34
Returning from 'SelectInst::getCondition'
35
'Cond' initialized here
412 Value *TV = SI->getTrueValue();
413 Value *FV = SI->getFalseValue();
414
415 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
416 // Does "cmp TV, RHS" simplify?
417 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
418 if (TCmp == Cond) {
36
Assuming 'TCmp' is equal to 'Cond'
37
Assuming pointer value is null
38
Taking true branch
419 // It not only simplified, it simplified to the select condition. Replace
420 // it with 'true'.
421 TCmp = getTrue(Cond->getType());
39
Called C++ object pointer is null
422 } else if (!TCmp) {
423 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
424 // condition then we can replace it with 'true'. Otherwise give up.
425 if (!isSameCompare(Cond, Pred, TV, RHS))
426 return nullptr;
427 TCmp = getTrue(Cond->getType());
428 }
429
430 // Does "cmp FV, RHS" simplify?
431 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
432 if (FCmp == Cond) {
433 // It not only simplified, it simplified to the select condition. Replace
434 // it with 'false'.
435 FCmp = getFalse(Cond->getType());
436 } else if (!FCmp) {
437 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
438 // condition then we can replace it with 'false'. Otherwise give up.
439 if (!isSameCompare(Cond, Pred, FV, RHS))
440 return nullptr;
441 FCmp = getFalse(Cond->getType());
442 }
443
444 // If both sides simplified to the same value, then use it as the result of
445 // the original comparison.
446 if (TCmp == FCmp)
447 return TCmp;
448
449 // The remaining cases only make sense if the select condition has the same
450 // type as the result of the comparison, so bail out if this is not so.
451 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
452 return nullptr;
453 // If the false value simplified to false, then the result of the compare
454 // is equal to "Cond && TCmp". This also catches the case when the false
455 // value simplified to false and the true value to true, returning "Cond".
456 if (match(FCmp, m_Zero()))
457 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
458 return V;
459 // If the true value simplified to true, then the result of the compare
460 // is equal to "Cond || FCmp".
461 if (match(TCmp, m_One()))
462 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
463 return V;
464 // Finally, if the false value simplified to true and the true value to
465 // false, then the result of the compare is equal to "!Cond".
466 if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
467 if (Value *V =
468 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
469 Q, MaxRecurse))
470 return V;
471
472 return nullptr;
473}
474
475/// In the case of a binary operation with an operand that is a PHI instruction,
476/// try to simplify the binop by seeing whether evaluating it on the incoming
477/// phi values yields the same result for every value. If so returns the common
478/// value, otherwise returns null.
479static Value *ThreadBinOpOverPHI(Instruction::BinaryOps Opcode, Value *LHS,
480 Value *RHS, const SimplifyQuery &Q,
481 unsigned MaxRecurse) {
482 // Recursion is always used, so bail out at once if we already hit the limit.
483 if (!MaxRecurse--)
484 return nullptr;
485
486 PHINode *PI;
487 if (isa<PHINode>(LHS)) {
488 PI = cast<PHINode>(LHS);
489 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
490 if (!valueDominatesPHI(RHS, PI, Q.DT))
491 return nullptr;
492 } else {
493 assert(isa<PHINode>(RHS) && "No PHI instruction operand!")((isa<PHINode>(RHS) && "No PHI instruction operand!"
) ? static_cast<void> (0) : __assert_fail ("isa<PHINode>(RHS) && \"No PHI instruction operand!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 493, __PRETTY_FUNCTION__))
;
494 PI = cast<PHINode>(RHS);
495 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
496 if (!valueDominatesPHI(LHS, PI, Q.DT))
497 return nullptr;
498 }
499
500 // Evaluate the BinOp on the incoming phi values.
501 Value *CommonValue = nullptr;
502 for (Value *Incoming : PI->incoming_values()) {
503 // If the incoming value is the phi node itself, it can safely be skipped.
504 if (Incoming == PI) continue;
505 Value *V = PI == LHS ?
506 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
507 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
508 // If the operation failed to simplify, or simplified to a different value
509 // to previously, then give up.
510 if (!V || (CommonValue && V != CommonValue))
511 return nullptr;
512 CommonValue = V;
513 }
514
515 return CommonValue;
516}
517
518/// In the case of a comparison with a PHI instruction, try to simplify the
519/// comparison by seeing whether comparing with all of the incoming phi values
520/// yields the same result every time. If so returns the common result,
521/// otherwise returns null.
522static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
523 const SimplifyQuery &Q, unsigned MaxRecurse) {
524 // Recursion is always used, so bail out at once if we already hit the limit.
525 if (!MaxRecurse--)
526 return nullptr;
527
528 // Make sure the phi is on the LHS.
529 if (!isa<PHINode>(LHS)) {
530 std::swap(LHS, RHS);
531 Pred = CmpInst::getSwappedPredicate(Pred);
532 }
533 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!")((isa<PHINode>(LHS) && "Not comparing with a phi instruction!"
) ? static_cast<void> (0) : __assert_fail ("isa<PHINode>(LHS) && \"Not comparing with a phi instruction!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 533, __PRETTY_FUNCTION__))
;
534 PHINode *PI = cast<PHINode>(LHS);
535
536 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
537 if (!valueDominatesPHI(RHS, PI, Q.DT))
538 return nullptr;
539
540 // Evaluate the BinOp on the incoming phi values.
541 Value *CommonValue = nullptr;
542 for (Value *Incoming : PI->incoming_values()) {
543 // If the incoming value is the phi node itself, it can safely be skipped.
544 if (Incoming == PI) continue;
545 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
546 // If the operation failed to simplify, or simplified to a different value
547 // to previously, then give up.
548 if (!V || (CommonValue && V != CommonValue))
549 return nullptr;
550 CommonValue = V;
551 }
552
553 return CommonValue;
554}
555
556static Constant *foldOrCommuteConstant(Instruction::BinaryOps Opcode,
557 Value *&Op0, Value *&Op1,
558 const SimplifyQuery &Q) {
559 if (auto *CLHS = dyn_cast<Constant>(Op0)) {
560 if (auto *CRHS = dyn_cast<Constant>(Op1))
561 return ConstantFoldBinaryOpOperands(Opcode, CLHS, CRHS, Q.DL);
562
563 // Canonicalize the constant to the RHS if this is a commutative operation.
564 if (Instruction::isCommutative(Opcode))
565 std::swap(Op0, Op1);
566 }
567 return nullptr;
568}
569
570/// Given operands for an Add, see if we can fold the result.
571/// If not, this returns null.
572static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
573 const SimplifyQuery &Q, unsigned MaxRecurse) {
574 if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q))
575 return C;
576
577 // X + undef -> undef
578 if (match(Op1, m_Undef()))
579 return Op1;
580
581 // X + 0 -> X
582 if (match(Op1, m_Zero()))
583 return Op0;
584
585 // If two operands are negative, return 0.
586 if (isKnownNegation(Op0, Op1))
587 return Constant::getNullValue(Op0->getType());
588
589 // X + (Y - X) -> Y
590 // (Y - X) + X -> Y
591 // Eg: X + -X -> 0
592 Value *Y = nullptr;
593 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
594 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
595 return Y;
596
597 // X + ~X -> -1 since ~X = -X-1
598 Type *Ty = Op0->getType();
599 if (match(Op0, m_Not(m_Specific(Op1))) ||
600 match(Op1, m_Not(m_Specific(Op0))))
601 return Constant::getAllOnesValue(Ty);
602
603 // add nsw/nuw (xor Y, signmask), signmask --> Y
604 // The no-wrapping add guarantees that the top bit will be set by the add.
605 // Therefore, the xor must be clearing the already set sign bit of Y.
606 if ((IsNSW || IsNUW) && match(Op1, m_SignMask()) &&
607 match(Op0, m_Xor(m_Value(Y), m_SignMask())))
608 return Y;
609
610 // add nuw %x, -1 -> -1, because %x can only be 0.
611 if (IsNUW && match(Op1, m_AllOnes()))
612 return Op1; // Which is -1.
613
614 /// i1 add -> xor.
615 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
616 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
617 return V;
618
619 // Try some generic simplifications for associative operations.
620 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
621 MaxRecurse))
622 return V;
623
624 // Threading Add over selects and phi nodes is pointless, so don't bother.
625 // Threading over the select in "A + select(cond, B, C)" means evaluating
626 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
627 // only if B and C are equal. If B and C are equal then (since we assume
628 // that operands have already been simplified) "select(cond, B, C)" should
629 // have been simplified to the common value of B and C already. Analysing
630 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
631 // for threading over phi nodes.
632
633 return nullptr;
634}
635
636Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
637 const SimplifyQuery &Query) {
638 return ::SimplifyAddInst(Op0, Op1, IsNSW, IsNUW, Query, RecursionLimit);
639}
640
641/// Compute the base pointer and cumulative constant offsets for V.
642///
643/// This strips all constant offsets off of V, leaving it the base pointer, and
644/// accumulates the total constant offset applied in the returned constant. It
645/// returns 0 if V is not a pointer, and returns the constant '0' if there are
646/// no constant offsets applied.
647///
648/// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
649/// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
650/// folding.
651static Constant *stripAndComputeConstantOffsets(const DataLayout &DL, Value *&V,
652 bool AllowNonInbounds = false) {
653 assert(V->getType()->isPtrOrPtrVectorTy())((V->getType()->isPtrOrPtrVectorTy()) ? static_cast<
void> (0) : __assert_fail ("V->getType()->isPtrOrPtrVectorTy()"
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 653, __PRETTY_FUNCTION__))
;
654
655 Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
656 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
657
658 // Even though we don't look through PHI nodes, we could be called on an
659 // instruction in an unreachable block, which may be on a cycle.
660 SmallPtrSet<Value *, 4> Visited;
661 Visited.insert(V);
662 do {
663 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
664 if ((!AllowNonInbounds && !GEP->isInBounds()) ||
665 !GEP->accumulateConstantOffset(DL, Offset))
666 break;
667 V = GEP->getPointerOperand();
668 } else if (Operator::getOpcode(V) == Instruction::BitCast) {
669 V = cast<Operator>(V)->getOperand(0);
670 } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
671 if (GA->isInterposable())
672 break;
673 V = GA->getAliasee();
674 } else {
675 if (auto CS = CallSite(V))
676 if (Value *RV = CS.getReturnedArgOperand()) {
677 V = RV;
678 continue;
679 }
680 break;
681 }
682 assert(V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!")((V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!"
) ? static_cast<void> (0) : __assert_fail ("V->getType()->isPtrOrPtrVectorTy() && \"Unexpected operand type!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 682, __PRETTY_FUNCTION__))
;
683 } while (Visited.insert(V).second);
684
685 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
686 if (V->getType()->isVectorTy())
687 return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
688 OffsetIntPtr);
689 return OffsetIntPtr;
690}
691
692/// Compute the constant difference between two pointer values.
693/// If the difference is not a constant, returns zero.
694static Constant *computePointerDifference(const DataLayout &DL, Value *LHS,
695 Value *RHS) {
696 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
697 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
698
699 // If LHS and RHS are not related via constant offsets to the same base
700 // value, there is nothing we can do here.
701 if (LHS != RHS)
702 return nullptr;
703
704 // Otherwise, the difference of LHS - RHS can be computed as:
705 // LHS - RHS
706 // = (LHSOffset + Base) - (RHSOffset + Base)
707 // = LHSOffset - RHSOffset
708 return ConstantExpr::getSub(LHSOffset, RHSOffset);
709}
710
711/// Given operands for a Sub, see if we can fold the result.
712/// If not, this returns null.
713static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
714 const SimplifyQuery &Q, unsigned MaxRecurse) {
715 if (Constant *C = foldOrCommuteConstant(Instruction::Sub, Op0, Op1, Q))
716 return C;
717
718 // X - undef -> undef
719 // undef - X -> undef
720 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
721 return UndefValue::get(Op0->getType());
722
723 // X - 0 -> X
724 if (match(Op1, m_Zero()))
725 return Op0;
726
727 // X - X -> 0
728 if (Op0 == Op1)
729 return Constant::getNullValue(Op0->getType());
730
731 // Is this a negation?
732 if (match(Op0, m_Zero())) {
733 // 0 - X -> 0 if the sub is NUW.
734 if (isNUW)
735 return Constant::getNullValue(Op0->getType());
736
737 KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
738 if (Known.Zero.isMaxSignedValue()) {
739 // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
740 // Op1 must be 0 because negating the minimum signed value is undefined.
741 if (isNSW)
742 return Constant::getNullValue(Op0->getType());
743
744 // 0 - X -> X if X is 0 or the minimum signed value.
745 return Op1;
746 }
747 }
748
749 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
750 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
751 Value *X = nullptr, *Y = nullptr, *Z = Op1;
752 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
753 // See if "V === Y - Z" simplifies.
754 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
755 // It does! Now see if "X + V" simplifies.
756 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
757 // It does, we successfully reassociated!
758 ++NumReassoc;
759 return W;
760 }
761 // See if "V === X - Z" simplifies.
762 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
763 // It does! Now see if "Y + V" simplifies.
764 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
765 // It does, we successfully reassociated!
766 ++NumReassoc;
767 return W;
768 }
769 }
770
771 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
772 // For example, X - (X + 1) -> -1
773 X = Op0;
774 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
775 // See if "V === X - Y" simplifies.
776 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
777 // It does! Now see if "V - Z" simplifies.
778 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
779 // It does, we successfully reassociated!
780 ++NumReassoc;
781 return W;
782 }
783 // See if "V === X - Z" simplifies.
784 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
785 // It does! Now see if "V - Y" simplifies.
786 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
787 // It does, we successfully reassociated!
788 ++NumReassoc;
789 return W;
790 }
791 }
792
793 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
794 // For example, X - (X - Y) -> Y.
795 Z = Op0;
796 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
797 // See if "V === Z - X" simplifies.
798 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
799 // It does! Now see if "V + Y" simplifies.
800 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
801 // It does, we successfully reassociated!
802 ++NumReassoc;
803 return W;
804 }
805
806 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
807 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
808 match(Op1, m_Trunc(m_Value(Y))))
809 if (X->getType() == Y->getType())
810 // See if "V === X - Y" simplifies.
811 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
812 // It does! Now see if "trunc V" simplifies.
813 if (Value *W = SimplifyCastInst(Instruction::Trunc, V, Op0->getType(),
814 Q, MaxRecurse - 1))
815 // It does, return the simplified "trunc V".
816 return W;
817
818 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
819 if (match(Op0, m_PtrToInt(m_Value(X))) &&
820 match(Op1, m_PtrToInt(m_Value(Y))))
821 if (Constant *Result = computePointerDifference(Q.DL, X, Y))
822 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
823
824 // i1 sub -> xor.
825 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
826 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
827 return V;
828
829 // Threading Sub over selects and phi nodes is pointless, so don't bother.
830 // Threading over the select in "A - select(cond, B, C)" means evaluating
831 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
832 // only if B and C are equal. If B and C are equal then (since we assume
833 // that operands have already been simplified) "select(cond, B, C)" should
834 // have been simplified to the common value of B and C already. Analysing
835 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
836 // for threading over phi nodes.
837
838 return nullptr;
839}
840
841Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
842 const SimplifyQuery &Q) {
843 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
844}
845
846/// Given operands for a Mul, see if we can fold the result.
847/// If not, this returns null.
848static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
849 unsigned MaxRecurse) {
850 if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q))
851 return C;
852
853 // X * undef -> 0
854 // X * 0 -> 0
855 if (match(Op1, m_CombineOr(m_Undef(), m_Zero())))
856 return Constant::getNullValue(Op0->getType());
857
858 // X * 1 -> X
859 if (match(Op1, m_One()))
860 return Op0;
861
862 // (X / Y) * Y -> X if the division is exact.
863 Value *X = nullptr;
864 if (Q.IIQ.UseInstrInfo &&
865 (match(Op0,
866 m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
867 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0)))))) // Y * (X / Y)
868 return X;
869
870 // i1 mul -> and.
871 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
872 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
873 return V;
874
875 // Try some generic simplifications for associative operations.
876 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
877 MaxRecurse))
878 return V;
879
880 // Mul distributes over Add. Try some generic simplifications based on this.
881 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
882 Q, MaxRecurse))
883 return V;
884
885 // If the operation is with the result of a select instruction, check whether
886 // operating on either branch of the select always yields the same value.
887 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
888 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
889 MaxRecurse))
890 return V;
891
892 // If the operation is with the result of a phi instruction, check whether
893 // operating on all incoming values of the phi always yields the same value.
894 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
895 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
896 MaxRecurse))
897 return V;
898
899 return nullptr;
900}
901
902Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
903 return ::SimplifyMulInst(Op0, Op1, Q, RecursionLimit);
904}
905
906/// Check for common or similar folds of integer division or integer remainder.
907/// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
908static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
909 Type *Ty = Op0->getType();
910
911 // X / undef -> undef
912 // X % undef -> undef
913 if (match(Op1, m_Undef()))
914 return Op1;
915
916 // X / 0 -> undef
917 // X % 0 -> undef
918 // We don't need to preserve faults!
919 if (match(Op1, m_Zero()))
920 return UndefValue::get(Ty);
921
922 // If any element of a constant divisor vector is zero or undef, the whole op
923 // is undef.
924 auto *Op1C = dyn_cast<Constant>(Op1);
925 if (Op1C && Ty->isVectorTy()) {
926 unsigned NumElts = Ty->getVectorNumElements();
927 for (unsigned i = 0; i != NumElts; ++i) {
928 Constant *Elt = Op1C->getAggregateElement(i);
929 if (Elt && (Elt->isNullValue() || isa<UndefValue>(Elt)))
930 return UndefValue::get(Ty);
931 }
932 }
933
934 // undef / X -> 0
935 // undef % X -> 0
936 if (match(Op0, m_Undef()))
937 return Constant::getNullValue(Ty);
938
939 // 0 / X -> 0
940 // 0 % X -> 0
941 if (match(Op0, m_Zero()))
942 return Constant::getNullValue(Op0->getType());
943
944 // X / X -> 1
945 // X % X -> 0
946 if (Op0 == Op1)
947 return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty);
948
949 // X / 1 -> X
950 // X % 1 -> 0
951 // If this is a boolean op (single-bit element type), we can't have
952 // division-by-zero or remainder-by-zero, so assume the divisor is 1.
953 // Similarly, if we're zero-extending a boolean divisor, then assume it's a 1.
954 Value *X;
955 if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1) ||
956 (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
957 return IsDiv ? Op0 : Constant::getNullValue(Ty);
958
959 return nullptr;
960}
961
962/// Given a predicate and two operands, return true if the comparison is true.
963/// This is a helper for div/rem simplification where we return some other value
964/// when we can prove a relationship between the operands.
965static bool isICmpTrue(ICmpInst::Predicate Pred, Value *LHS, Value *RHS,
966 const SimplifyQuery &Q, unsigned MaxRecurse) {
967 Value *V = SimplifyICmpInst(Pred, LHS, RHS, Q, MaxRecurse);
968 Constant *C = dyn_cast_or_null<Constant>(V);
969 return (C && C->isAllOnesValue());
970}
971
972/// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
973/// to simplify X % Y to X.
974static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q,
975 unsigned MaxRecurse, bool IsSigned) {
976 // Recursion is always used, so bail out at once if we already hit the limit.
977 if (!MaxRecurse--)
978 return false;
979
980 if (IsSigned) {
981 // |X| / |Y| --> 0
982 //
983 // We require that 1 operand is a simple constant. That could be extended to
984 // 2 variables if we computed the sign bit for each.
985 //
986 // Make sure that a constant is not the minimum signed value because taking
987 // the abs() of that is undefined.
988 Type *Ty = X->getType();
989 const APInt *C;
990 if (match(X, m_APInt(C)) && !C->isMinSignedValue()) {
991 // Is the variable divisor magnitude always greater than the constant
992 // dividend magnitude?
993 // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
994 Constant *PosDividendC = ConstantInt::get(Ty, C->abs());
995 Constant *NegDividendC = ConstantInt::get(Ty, -C->abs());
996 if (isICmpTrue(CmpInst::ICMP_SLT, Y, NegDividendC, Q, MaxRecurse) ||
997 isICmpTrue(CmpInst::ICMP_SGT, Y, PosDividendC, Q, MaxRecurse))
998 return true;
999 }
1000 if (match(Y, m_APInt(C))) {
1001 // Special-case: we can't take the abs() of a minimum signed value. If
1002 // that's the divisor, then all we have to do is prove that the dividend
1003 // is also not the minimum signed value.
1004 if (C->isMinSignedValue())
1005 return isICmpTrue(CmpInst::ICMP_NE, X, Y, Q, MaxRecurse);
1006
1007 // Is the variable dividend magnitude always less than the constant
1008 // divisor magnitude?
1009 // |X| < |C| --> X > -abs(C) and X < abs(C)
1010 Constant *PosDivisorC = ConstantInt::get(Ty, C->abs());
1011 Constant *NegDivisorC = ConstantInt::get(Ty, -C->abs());
1012 if (isICmpTrue(CmpInst::ICMP_SGT, X, NegDivisorC, Q, MaxRecurse) &&
1013 isICmpTrue(CmpInst::ICMP_SLT, X, PosDivisorC, Q, MaxRecurse))
1014 return true;
1015 }
1016 return false;
1017 }
1018
1019 // IsSigned == false.
1020 // Is the dividend unsigned less than the divisor?
1021 return isICmpTrue(ICmpInst::ICMP_ULT, X, Y, Q, MaxRecurse);
1022}
1023
1024/// These are simplifications common to SDiv and UDiv.
1025static Value *simplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1026 const SimplifyQuery &Q, unsigned MaxRecurse) {
1027 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1028 return C;
1029
1030 if (Value *V = simplifyDivRem(Op0, Op1, true))
1031 return V;
1032
1033 bool IsSigned = Opcode == Instruction::SDiv;
1034
1035 // (X * Y) / Y -> X if the multiplication does not overflow.
1036 Value *X;
1037 if (match(Op0, m_c_Mul(m_Value(X), m_Specific(Op1)))) {
1038 auto *Mul = cast<OverflowingBinaryOperator>(Op0);
1039 // If the Mul does not overflow, then we are good to go.
1040 if ((IsSigned && Q.IIQ.hasNoSignedWrap(Mul)) ||
1041 (!IsSigned && Q.IIQ.hasNoUnsignedWrap(Mul)))
1042 return X;
1043 // If X has the form X = A / Y, then X * Y cannot overflow.
1044 if ((IsSigned && match(X, m_SDiv(m_Value(), m_Specific(Op1)))) ||
1045 (!IsSigned && match(X, m_UDiv(m_Value(), m_Specific(Op1)))))
1046 return X;
1047 }
1048
1049 // (X rem Y) / Y -> 0
1050 if ((IsSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1051 (!IsSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1052 return Constant::getNullValue(Op0->getType());
1053
1054 // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1055 ConstantInt *C1, *C2;
1056 if (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
1057 match(Op1, m_ConstantInt(C2))) {
1058 bool Overflow;
1059 (void)C1->getValue().umul_ov(C2->getValue(), Overflow);
1060 if (Overflow)
1061 return Constant::getNullValue(Op0->getType());
1062 }
1063
1064 // If the operation is with the result of a select instruction, check whether
1065 // operating on either branch of the select always yields the same value.
1066 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1067 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1068 return V;
1069
1070 // If the operation is with the result of a phi instruction, check whether
1071 // operating on all incoming values of the phi always yields the same value.
1072 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1073 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1074 return V;
1075
1076 if (isDivZero(Op0, Op1, Q, MaxRecurse, IsSigned))
1077 return Constant::getNullValue(Op0->getType());
1078
1079 return nullptr;
1080}
1081
1082/// These are simplifications common to SRem and URem.
1083static Value *simplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
1084 const SimplifyQuery &Q, unsigned MaxRecurse) {
1085 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1086 return C;
1087
1088 if (Value *V = simplifyDivRem(Op0, Op1, false))
1089 return V;
1090
1091 // (X % Y) % Y -> X % Y
1092 if ((Opcode == Instruction::SRem &&
1093 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
1094 (Opcode == Instruction::URem &&
1095 match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
1096 return Op0;
1097
1098 // (X << Y) % X -> 0
1099 if (Q.IIQ.UseInstrInfo &&
1100 ((Opcode == Instruction::SRem &&
1101 match(Op0, m_NSWShl(m_Specific(Op1), m_Value()))) ||
1102 (Opcode == Instruction::URem &&
1103 match(Op0, m_NUWShl(m_Specific(Op1), m_Value())))))
1104 return Constant::getNullValue(Op0->getType());
1105
1106 // If the operation is with the result of a select instruction, check whether
1107 // operating on either branch of the select always yields the same value.
1108 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1109 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1110 return V;
1111
1112 // If the operation is with the result of a phi instruction, check whether
1113 // operating on all incoming values of the phi always yields the same value.
1114 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1115 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1116 return V;
1117
1118 // If X / Y == 0, then X % Y == X.
1119 if (isDivZero(Op0, Op1, Q, MaxRecurse, Opcode == Instruction::SRem))
1120 return Op0;
1121
1122 return nullptr;
1123}
1124
1125/// Given operands for an SDiv, see if we can fold the result.
1126/// If not, this returns null.
1127static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1128 unsigned MaxRecurse) {
1129 // If two operands are negated and no signed overflow, return -1.
1130 if (isKnownNegation(Op0, Op1, /*NeedNSW=*/true))
1131 return Constant::getAllOnesValue(Op0->getType());
1132
1133 return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse);
1134}
1135
1136Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1137 return ::SimplifySDivInst(Op0, Op1, Q, RecursionLimit);
1138}
1139
1140/// Given operands for a UDiv, see if we can fold the result.
1141/// If not, this returns null.
1142static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1143 unsigned MaxRecurse) {
1144 return simplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse);
1145}
1146
1147Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1148 return ::SimplifyUDivInst(Op0, Op1, Q, RecursionLimit);
1149}
1150
1151/// Given operands for an SRem, see if we can fold the result.
1152/// If not, this returns null.
1153static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1154 unsigned MaxRecurse) {
1155 // If the divisor is 0, the result is undefined, so assume the divisor is -1.
1156 // srem Op0, (sext i1 X) --> srem Op0, -1 --> 0
1157 Value *X;
1158 if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
1159 return ConstantInt::getNullValue(Op0->getType());
1160
1161 // If the two operands are negated, return 0.
1162 if (isKnownNegation(Op0, Op1))
1163 return ConstantInt::getNullValue(Op0->getType());
1164
1165 return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
1166}
1167
1168Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1169 return ::SimplifySRemInst(Op0, Op1, Q, RecursionLimit);
1170}
1171
1172/// Given operands for a URem, see if we can fold the result.
1173/// If not, this returns null.
1174static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1175 unsigned MaxRecurse) {
1176 return simplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse);
1177}
1178
1179Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1180 return ::SimplifyURemInst(Op0, Op1, Q, RecursionLimit);
1181}
1182
1183/// Returns true if a shift by \c Amount always yields undef.
1184static bool isUndefShift(Value *Amount) {
1185 Constant *C = dyn_cast<Constant>(Amount);
1186 if (!C)
1187 return false;
1188
1189 // X shift by undef -> undef because it may shift by the bitwidth.
1190 if (isa<UndefValue>(C))
1191 return true;
1192
1193 // Shifting by the bitwidth or more is undefined.
1194 if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
1195 if (CI->getValue().getLimitedValue() >=
1196 CI->getType()->getScalarSizeInBits())
1197 return true;
1198
1199 // If all lanes of a vector shift are undefined the whole shift is.
1200 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
1201 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
1202 if (!isUndefShift(C->getAggregateElement(I)))
1203 return false;
1204 return true;
1205 }
1206
1207 return false;
1208}
1209
1210/// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1211/// If not, this returns null.
1212static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
1213 Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) {
1214 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
1215 return C;
1216
1217 // 0 shift by X -> 0
1218 if (match(Op0, m_Zero()))
1219 return Constant::getNullValue(Op0->getType());
1220
1221 // X shift by 0 -> X
1222 // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones
1223 // would be poison.
1224 Value *X;
1225 if (match(Op1, m_Zero()) ||
1226 (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
1227 return Op0;
1228
1229 // Fold undefined shifts.
1230 if (isUndefShift(Op1))
1231 return UndefValue::get(Op0->getType());
1232
1233 // If the operation is with the result of a select instruction, check whether
1234 // operating on either branch of the select always yields the same value.
1235 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1236 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
1237 return V;
1238
1239 // If the operation is with the result of a phi instruction, check whether
1240 // operating on all incoming values of the phi always yields the same value.
1241 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1242 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
1243 return V;
1244
1245 // If any bits in the shift amount make that value greater than or equal to
1246 // the number of bits in the type, the shift is undefined.
1247 KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1248 if (Known.One.getLimitedValue() >= Known.getBitWidth())
1249 return UndefValue::get(Op0->getType());
1250
1251 // If all valid bits in the shift amount are known zero, the first operand is
1252 // unchanged.
1253 unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
1254 if (Known.countMinTrailingZeros() >= NumValidShiftBits)
1255 return Op0;
1256
1257 return nullptr;
1258}
1259
1260/// Given operands for an Shl, LShr or AShr, see if we can
1261/// fold the result. If not, this returns null.
1262static Value *SimplifyRightShift(Instruction::BinaryOps Opcode, Value *Op0,
1263 Value *Op1, bool isExact, const SimplifyQuery &Q,
1264 unsigned MaxRecurse) {
1265 if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
1266 return V;
1267
1268 // X >> X -> 0
1269 if (Op0 == Op1)
1270 return Constant::getNullValue(Op0->getType());
1271
1272 // undef >> X -> 0
1273 // undef >> X -> undef (if it's exact)
1274 if (match(Op0, m_Undef()))
1275 return isExact ? Op0 : Constant::getNullValue(Op0->getType());
1276
1277 // The low bit cannot be shifted out of an exact shift if it is set.
1278 if (isExact) {
1279 KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
1280 if (Op0Known.One[0])
1281 return Op0;
1282 }
1283
1284 return nullptr;
1285}
1286
1287/// Given operands for an Shl, see if we can fold the result.
1288/// If not, this returns null.
1289static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1290 const SimplifyQuery &Q, unsigned MaxRecurse) {
1291 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
1292 return V;
1293
1294 // undef << X -> 0
1295 // undef << X -> undef if (if it's NSW/NUW)
1296 if (match(Op0, m_Undef()))
1297 return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());
1298
1299 // (X >> A) << A -> X
1300 Value *X;
1301 if (Q.IIQ.UseInstrInfo &&
1302 match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
1303 return X;
1304
1305 // shl nuw i8 C, %x -> C iff C has sign bit set.
1306 if (isNUW && match(Op0, m_Negative()))
1307 return Op0;
1308 // NOTE: could use computeKnownBits() / LazyValueInfo,
1309 // but the cost-benefit analysis suggests it isn't worth it.
1310
1311 return nullptr;
1312}
1313
1314Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
1315 const SimplifyQuery &Q) {
1316 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
1317}
1318
1319/// Given operands for an LShr, see if we can fold the result.
1320/// If not, this returns null.
1321static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1322 const SimplifyQuery &Q, unsigned MaxRecurse) {
1323 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
1324 MaxRecurse))
1325 return V;
1326
1327 // (X << A) >> A -> X
1328 Value *X;
1329 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
1330 return X;
1331
1332 // ((X << A) | Y) >> A -> X if effective width of Y is not larger than A.
1333 // We can return X as we do in the above case since OR alters no bits in X.
1334 // SimplifyDemandedBits in InstCombine can do more general optimization for
1335 // bit manipulation. This pattern aims to provide opportunities for other
1336 // optimizers by supporting a simple but common case in InstSimplify.
1337 Value *Y;
1338 const APInt *ShRAmt, *ShLAmt;
1339 if (match(Op1, m_APInt(ShRAmt)) &&
1340 match(Op0, m_c_Or(m_NUWShl(m_Value(X), m_APInt(ShLAmt)), m_Value(Y))) &&
1341 *ShRAmt == *ShLAmt) {
1342 const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1343 const unsigned Width = Op0->getType()->getScalarSizeInBits();
1344 const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
1345 if (ShRAmt->uge(EffWidthY))
1346 return X;
1347 }
1348
1349 return nullptr;
1350}
1351
1352Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
1353 const SimplifyQuery &Q) {
1354 return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1355}
1356
1357/// Given operands for an AShr, see if we can fold the result.
1358/// If not, this returns null.
1359static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1360 const SimplifyQuery &Q, unsigned MaxRecurse) {
1361 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
1362 MaxRecurse))
1363 return V;
1364
1365 // all ones >>a X -> -1
1366 // Do not return Op0 because it may contain undef elements if it's a vector.
1367 if (match(Op0, m_AllOnes()))
1368 return Constant::getAllOnesValue(Op0->getType());
1369
1370 // (X << A) >> A -> X
1371 Value *X;
1372 if (Q.IIQ.UseInstrInfo && match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
1373 return X;
1374
1375 // Arithmetic shifting an all-sign-bit value is a no-op.
1376 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1377 if (NumSignBits == Op0->getType()->getScalarSizeInBits())
1378 return Op0;
1379
1380 return nullptr;
1381}
1382
1383Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
1384 const SimplifyQuery &Q) {
1385 return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1386}
1387
1388/// Commuted variants are assumed to be handled by calling this function again
1389/// with the parameters swapped.
1390static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
1391 ICmpInst *UnsignedICmp, bool IsAnd) {
1392 Value *X, *Y;
1393
1394 ICmpInst::Predicate EqPred;
1395 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
1396 !ICmpInst::isEquality(EqPred))
1397 return nullptr;
1398
1399 ICmpInst::Predicate UnsignedPred;
1400 if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
1401 ICmpInst::isUnsigned(UnsignedPred))
1402 ;
1403 else if (match(UnsignedICmp,
1404 m_ICmp(UnsignedPred, m_Specific(Y), m_Value(X))) &&
1405 ICmpInst::isUnsigned(UnsignedPred))
1406 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
1407 else
1408 return nullptr;
1409
1410 // X < Y && Y != 0 --> X < Y
1411 // X < Y || Y != 0 --> Y != 0
1412 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
1413 return IsAnd ? UnsignedICmp : ZeroICmp;
1414
1415 // X >= Y || Y != 0 --> true
1416 // X >= Y || Y == 0 --> X >= Y
1417 if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
1418 if (EqPred == ICmpInst::ICMP_NE)
1419 return getTrue(UnsignedICmp->getType());
1420 return UnsignedICmp;
1421 }
1422
1423 // X < Y && Y == 0 --> false
1424 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
1425 IsAnd)
1426 return getFalse(UnsignedICmp->getType());
1427
1428 return nullptr;
1429}
1430
1431/// Commuted variants are assumed to be handled by calling this function again
1432/// with the parameters swapped.
1433static Value *simplifyAndOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
1434 ICmpInst::Predicate Pred0, Pred1;
1435 Value *A ,*B;
1436 if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1437 !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1438 return nullptr;
1439
1440 // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
1441 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1442 // can eliminate Op1 from this 'and'.
1443 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1444 return Op0;
1445
1446 // Check for any combination of predicates that are guaranteed to be disjoint.
1447 if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1448 (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) ||
1449 (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) ||
1450 (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT))
1451 return getFalse(Op0->getType());
1452
1453 return nullptr;
1454}
1455
1456/// Commuted variants are assumed to be handled by calling this function again
1457/// with the parameters swapped.
1458static Value *simplifyOrOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
1459 ICmpInst::Predicate Pred0, Pred1;
1460 Value *A ,*B;
1461 if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
1462 !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
1463 return nullptr;
1464
1465 // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
1466 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1467 // can eliminate Op0 from this 'or'.
1468 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
1469 return Op1;
1470
1471 // Check for any combination of predicates that cover the entire range of
1472 // possibilities.
1473 if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
1474 (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) ||
1475 (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) ||
1476 (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE))
1477 return getTrue(Op0->getType());
1478
1479 return nullptr;
1480}
1481
1482/// Test if a pair of compares with a shared operand and 2 constants has an
1483/// empty set intersection, full set union, or if one compare is a superset of
1484/// the other.
1485static Value *simplifyAndOrOfICmpsWithConstants(ICmpInst *Cmp0, ICmpInst *Cmp1,
1486 bool IsAnd) {
1487 // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1488 if (Cmp0->getOperand(0) != Cmp1->getOperand(0))
1489 return nullptr;
1490
1491 const APInt *C0, *C1;
1492 if (!match(Cmp0->getOperand(1), m_APInt(C0)) ||
1493 !match(Cmp1->getOperand(1), m_APInt(C1)))
1494 return nullptr;
1495
1496 auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0);
1497 auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1);
1498
1499 // For and-of-compares, check if the intersection is empty:
1500 // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1501 if (IsAnd && Range0.intersectWith(Range1).isEmptySet())
1502 return getFalse(Cmp0->getType());
1503
1504 // For or-of-compares, check if the union is full:
1505 // (icmp X, C0) || (icmp X, C1) --> full set --> true
1506 if (!IsAnd && Range0.unionWith(Range1).isFullSet())
1507 return getTrue(Cmp0->getType());
1508
1509 // Is one range a superset of the other?
1510 // If this is and-of-compares, take the smaller set:
1511 // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1512 // If this is or-of-compares, take the larger set:
1513 // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1514 if (Range0.contains(Range1))
1515 return IsAnd ? Cmp1 : Cmp0;
1516 if (Range1.contains(Range0))
1517 return IsAnd ? Cmp0 : Cmp1;
1518
1519 return nullptr;
1520}
1521
1522static Value *simplifyAndOrOfICmpsWithZero(ICmpInst *Cmp0, ICmpInst *Cmp1,
1523 bool IsAnd) {
1524 ICmpInst::Predicate P0 = Cmp0->getPredicate(), P1 = Cmp1->getPredicate();
1525 if (!match(Cmp0->getOperand(1), m_Zero()) ||
1526 !match(Cmp1->getOperand(1), m_Zero()) || P0 != P1)
1527 return nullptr;
1528
1529 if ((IsAnd && P0 != ICmpInst::ICMP_NE) || (!IsAnd && P1 != ICmpInst::ICMP_EQ))
1530 return nullptr;
1531
1532 // We have either "(X == 0 || Y == 0)" or "(X != 0 && Y != 0)".
1533 Value *X = Cmp0->getOperand(0);
1534 Value *Y = Cmp1->getOperand(0);
1535
1536 // If one of the compares is a masked version of a (not) null check, then
1537 // that compare implies the other, so we eliminate the other. Optionally, look
1538 // through a pointer-to-int cast to match a null check of a pointer type.
1539
1540 // (X == 0) || (([ptrtoint] X & ?) == 0) --> ([ptrtoint] X & ?) == 0
1541 // (X == 0) || ((? & [ptrtoint] X) == 0) --> (? & [ptrtoint] X) == 0
1542 // (X != 0) && (([ptrtoint] X & ?) != 0) --> ([ptrtoint] X & ?) != 0
1543 // (X != 0) && ((? & [ptrtoint] X) != 0) --> (? & [ptrtoint] X) != 0
1544 if (match(Y, m_c_And(m_Specific(X), m_Value())) ||
1545 match(Y, m_c_And(m_PtrToInt(m_Specific(X)), m_Value())))
1546 return Cmp1;
1547
1548 // (([ptrtoint] Y & ?) == 0) || (Y == 0) --> ([ptrtoint] Y & ?) == 0
1549 // ((? & [ptrtoint] Y) == 0) || (Y == 0) --> (? & [ptrtoint] Y) == 0
1550 // (([ptrtoint] Y & ?) != 0) && (Y != 0) --> ([ptrtoint] Y & ?) != 0
1551 // ((? & [ptrtoint] Y) != 0) && (Y != 0) --> (? & [ptrtoint] Y) != 0
1552 if (match(X, m_c_And(m_Specific(Y), m_Value())) ||
1553 match(X, m_c_And(m_PtrToInt(m_Specific(Y)), m_Value())))
1554 return Cmp0;
1555
1556 return nullptr;
1557}
1558
1559static Value *simplifyAndOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1,
1560 const InstrInfoQuery &IIQ) {
1561 // (icmp (add V, C0), C1) & (icmp V, C0)
1562 ICmpInst::Predicate Pred0, Pred1;
1563 const APInt *C0, *C1;
1564 Value *V;
1565 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1566 return nullptr;
1567
1568 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1569 return nullptr;
1570
1571 auto *AddInst = cast<OverflowingBinaryOperator>(Op0->getOperand(0));
1572 if (AddInst->getOperand(1) != Op1->getOperand(1))
1573 return nullptr;
1574
1575 Type *ITy = Op0->getType();
1576 bool isNSW = IIQ.hasNoSignedWrap(AddInst);
1577 bool isNUW = IIQ.hasNoUnsignedWrap(AddInst);
1578
1579 const APInt Delta = *C1 - *C0;
1580 if (C0->isStrictlyPositive()) {
1581 if (Delta == 2) {
1582 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
1583 return getFalse(ITy);
1584 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1585 return getFalse(ITy);
1586 }
1587 if (Delta == 1) {
1588 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
1589 return getFalse(ITy);
1590 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
1591 return getFalse(ITy);
1592 }
1593 }
1594 if (C0->getBoolValue() && isNUW) {
1595 if (Delta == 2)
1596 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
1597 return getFalse(ITy);
1598 if (Delta == 1)
1599 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
1600 return getFalse(ITy);
1601 }
1602
1603 return nullptr;
1604}
1605
1606static Value *simplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1,
1607 const InstrInfoQuery &IIQ) {
1608 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
1609 return X;
1610 if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true))
1611 return X;
1612
1613 if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1))
1614 return X;
1615 if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0))
1616 return X;
1617
1618 if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
1619 return X;
1620
1621 if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, true))
1622 return X;
1623
1624 if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1, IIQ))
1625 return X;
1626 if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0, IIQ))
1627 return X;
1628
1629 return nullptr;
1630}
1631
1632static Value *simplifyOrOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1,
1633 const InstrInfoQuery &IIQ) {
1634 // (icmp (add V, C0), C1) | (icmp V, C0)
1635 ICmpInst::Predicate Pred0, Pred1;
1636 const APInt *C0, *C1;
1637 Value *V;
1638 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
1639 return nullptr;
1640
1641 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
1642 return nullptr;
1643
1644 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
1645 if (AddInst->getOperand(1) != Op1->getOperand(1))
1646 return nullptr;
1647
1648 Type *ITy = Op0->getType();
1649 bool isNSW = IIQ.hasNoSignedWrap(AddInst);
1650 bool isNUW = IIQ.hasNoUnsignedWrap(AddInst);
1651
1652 const APInt Delta = *C1 - *C0;
1653 if (C0->isStrictlyPositive()) {
1654 if (Delta == 2) {
1655 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
1656 return getTrue(ITy);
1657 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1658 return getTrue(ITy);
1659 }
1660 if (Delta == 1) {
1661 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
1662 return getTrue(ITy);
1663 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
1664 return getTrue(ITy);
1665 }
1666 }
1667 if (C0->getBoolValue() && isNUW) {
1668 if (Delta == 2)
1669 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
1670 return getTrue(ITy);
1671 if (Delta == 1)
1672 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
1673 return getTrue(ITy);
1674 }
1675
1676 return nullptr;
1677}
1678
1679static Value *simplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1,
1680 const InstrInfoQuery &IIQ) {
1681 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
1682 return X;
1683 if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false))
1684 return X;
1685
1686 if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1))
1687 return X;
1688 if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0))
1689 return X;
1690
1691 if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
1692 return X;
1693
1694 if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, false))
1695 return X;
1696
1697 if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1, IIQ))
1698 return X;
1699 if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0, IIQ))
1700 return X;
1701
1702 return nullptr;
1703}
1704
1705static Value *simplifyAndOrOfFCmps(const TargetLibraryInfo *TLI,
1706 FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) {
1707 Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
1708 Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
1709 if (LHS0->getType() != RHS0->getType())
1710 return nullptr;
1711
1712 FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
1713 if ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
1714 (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO && !IsAnd)) {
1715 // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y
1716 // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X
1717 // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y
1718 // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X
1719 // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y
1720 // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X
1721 // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y
1722 // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X
1723 if ((isKnownNeverNaN(LHS0, TLI) && (LHS1 == RHS0 || LHS1 == RHS1)) ||
1724 (isKnownNeverNaN(LHS1, TLI) && (LHS0 == RHS0 || LHS0 == RHS1)))
1725 return RHS;
1726
1727 // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y
1728 // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X
1729 // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y
1730 // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X
1731 // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y
1732 // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X
1733 // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y
1734 // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X
1735 if ((isKnownNeverNaN(RHS0, TLI) && (RHS1 == LHS0 || RHS1 == LHS1)) ||
1736 (isKnownNeverNaN(RHS1, TLI) && (RHS0 == LHS0 || RHS0 == LHS1)))
1737 return LHS;
1738 }
1739
1740 return nullptr;
1741}
1742
1743static Value *simplifyAndOrOfCmps(const SimplifyQuery &Q,
1744 Value *Op0, Value *Op1, bool IsAnd) {
1745 // Look through casts of the 'and' operands to find compares.
1746 auto *Cast0 = dyn_cast<CastInst>(Op0);
1747 auto *Cast1 = dyn_cast<CastInst>(Op1);
1748 if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
1749 Cast0->getSrcTy() == Cast1->getSrcTy()) {
1750 Op0 = Cast0->getOperand(0);
1751 Op1 = Cast1->getOperand(0);
1752 }
1753
1754 Value *V = nullptr;
1755 auto *ICmp0 = dyn_cast<ICmpInst>(Op0);
1756 auto *ICmp1 = dyn_cast<ICmpInst>(Op1);
1757 if (ICmp0 && ICmp1)
1758 V = IsAnd ? simplifyAndOfICmps(ICmp0, ICmp1, Q.IIQ)
1759 : simplifyOrOfICmps(ICmp0, ICmp1, Q.IIQ);
1760
1761 auto *FCmp0 = dyn_cast<FCmpInst>(Op0);
1762 auto *FCmp1 = dyn_cast<FCmpInst>(Op1);
1763 if (FCmp0 && FCmp1)
1764 V = simplifyAndOrOfFCmps(Q.TLI, FCmp0, FCmp1, IsAnd);
1765
1766 if (!V)
1767 return nullptr;
1768 if (!Cast0)
1769 return V;
1770
1771 // If we looked through casts, we can only handle a constant simplification
1772 // because we are not allowed to create a cast instruction here.
1773 if (auto *C = dyn_cast<Constant>(V))
1774 return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());
1775
1776 return nullptr;
1777}
1778
1779/// Given operands for an And, see if we can fold the result.
1780/// If not, this returns null.
1781static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1782 unsigned MaxRecurse) {
1783 if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
1784 return C;
1785
1786 // X & undef -> 0
1787 if (match(Op1, m_Undef()))
1788 return Constant::getNullValue(Op0->getType());
1789
1790 // X & X = X
1791 if (Op0 == Op1)
1792 return Op0;
1793
1794 // X & 0 = 0
1795 if (match(Op1, m_Zero()))
1796 return Constant::getNullValue(Op0->getType());
1797
1798 // X & -1 = X
1799 if (match(Op1, m_AllOnes()))
1800 return Op0;
1801
1802 // A & ~A = ~A & A = 0
1803 if (match(Op0, m_Not(m_Specific(Op1))) ||
1804 match(Op1, m_Not(m_Specific(Op0))))
1805 return Constant::getNullValue(Op0->getType());
1806
1807 // (A | ?) & A = A
1808 if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
1809 return Op1;
1810
1811 // A & (A | ?) = A
1812 if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
1813 return Op0;
1814
1815 // A mask that only clears known zeros of a shifted value is a no-op.
1816 Value *X;
1817 const APInt *Mask;
1818 const APInt *ShAmt;
1819 if (match(Op1, m_APInt(Mask))) {
1820 // If all bits in the inverted and shifted mask are clear:
1821 // and (shl X, ShAmt), Mask --> shl X, ShAmt
1822 if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
1823 (~(*Mask)).lshr(*ShAmt).isNullValue())
1824 return Op0;
1825
1826 // If all bits in the inverted and shifted mask are clear:
1827 // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1828 if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
1829 (~(*Mask)).shl(*ShAmt).isNullValue())
1830 return Op0;
1831 }
1832
1833 // A & (-A) = A if A is a power of two or zero.
1834 if (match(Op0, m_Neg(m_Specific(Op1))) ||
1835 match(Op1, m_Neg(m_Specific(Op0)))) {
1836 if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1837 Q.DT))
1838 return Op0;
1839 if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
1840 Q.DT))
1841 return Op1;
1842 }
1843
1844 if (Value *V = simplifyAndOrOfCmps(Q, Op0, Op1, true))
1845 return V;
1846
1847 // Try some generic simplifications for associative operations.
1848 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
1849 MaxRecurse))
1850 return V;
1851
1852 // And distributes over Or. Try some generic simplifications based on this.
1853 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
1854 Q, MaxRecurse))
1855 return V;
1856
1857 // And distributes over Xor. Try some generic simplifications based on this.
1858 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
1859 Q, MaxRecurse))
1860 return V;
1861
1862 // If the operation is with the result of a select instruction, check whether
1863 // operating on either branch of the select always yields the same value.
1864 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
1865 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
1866 MaxRecurse))
1867 return V;
1868
1869 // If the operation is with the result of a phi instruction, check whether
1870 // operating on all incoming values of the phi always yields the same value.
1871 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
1872 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
1873 MaxRecurse))
1874 return V;
1875
1876 // Assuming the effective width of Y is not larger than A, i.e. all bits
1877 // from X and Y are disjoint in (X << A) | Y,
1878 // if the mask of this AND op covers all bits of X or Y, while it covers
1879 // no bits from the other, we can bypass this AND op. E.g.,
1880 // ((X << A) | Y) & Mask -> Y,
1881 // if Mask = ((1 << effective_width_of(Y)) - 1)
1882 // ((X << A) | Y) & Mask -> X << A,
1883 // if Mask = ((1 << effective_width_of(X)) - 1) << A
1884 // SimplifyDemandedBits in InstCombine can optimize the general case.
1885 // This pattern aims to help other passes for a common case.
1886 Value *Y, *XShifted;
1887 if (match(Op1, m_APInt(Mask)) &&
1888 match(Op0, m_c_Or(m_CombineAnd(m_NUWShl(m_Value(X), m_APInt(ShAmt)),
1889 m_Value(XShifted)),
1890 m_Value(Y)))) {
1891 const unsigned Width = Op0->getType()->getScalarSizeInBits();
1892 const unsigned ShftCnt = ShAmt->getLimitedValue(Width);
1893 const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
1894 const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
1895 if (EffWidthY <= ShftCnt) {
1896 const KnownBits XKnown = computeKnownBits(X, Q.DL, 0, Q.AC, Q.CxtI,
1897 Q.DT);
1898 const unsigned EffWidthX = Width - XKnown.countMinLeadingZeros();
1899 const APInt EffBitsY = APInt::getLowBitsSet(Width, EffWidthY);
1900 const APInt EffBitsX = APInt::getLowBitsSet(Width, EffWidthX) << ShftCnt;
1901 // If the mask is extracting all bits from X or Y as is, we can skip
1902 // this AND op.
1903 if (EffBitsY.isSubsetOf(*Mask) && !EffBitsX.intersects(*Mask))
1904 return Y;
1905 if (EffBitsX.isSubsetOf(*Mask) && !EffBitsY.intersects(*Mask))
1906 return XShifted;
1907 }
1908 }
1909
1910 return nullptr;
1911}
1912
1913Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
1914 return ::SimplifyAndInst(Op0, Op1, Q, RecursionLimit);
1915}
1916
1917/// Given operands for an Or, see if we can fold the result.
1918/// If not, this returns null.
1919static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
1920 unsigned MaxRecurse) {
1921 if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
1922 return C;
1923
1924 // X | undef -> -1
1925 // X | -1 = -1
1926 // Do not return Op1 because it may contain undef elements if it's a vector.
1927 if (match(Op1, m_Undef()) || match(Op1, m_AllOnes()))
1928 return Constant::getAllOnesValue(Op0->getType());
1929
1930 // X | X = X
1931 // X | 0 = X
1932 if (Op0 == Op1 || match(Op1, m_Zero()))
1933 return Op0;
1934
1935 // A | ~A = ~A | A = -1
1936 if (match(Op0, m_Not(m_Specific(Op1))) ||
1937 match(Op1, m_Not(m_Specific(Op0))))
1938 return Constant::getAllOnesValue(Op0->getType());
1939
1940 // (A & ?) | A = A
1941 if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
1942 return Op1;
1943
1944 // A | (A & ?) = A
1945 if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
1946 return Op0;
1947
1948 // ~(A & ?) | A = -1
1949 if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1950 return Constant::getAllOnesValue(Op1->getType());
1951
1952 // A | ~(A & ?) = -1
1953 if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
1954 return Constant::getAllOnesValue(Op0->getType());
1955
1956 Value *A, *B;
1957 // (A & ~B) | (A ^ B) -> (A ^ B)
1958 // (~B & A) | (A ^ B) -> (A ^ B)
1959 // (A & ~B) | (B ^ A) -> (B ^ A)
1960 // (~B & A) | (B ^ A) -> (B ^ A)
1961 if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
1962 (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1963 match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1964 return Op1;
1965
1966 // Commute the 'or' operands.
1967 // (A ^ B) | (A & ~B) -> (A ^ B)
1968 // (A ^ B) | (~B & A) -> (A ^ B)
1969 // (B ^ A) | (A & ~B) -> (B ^ A)
1970 // (B ^ A) | (~B & A) -> (B ^ A)
1971 if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
1972 (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
1973 match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
1974 return Op0;
1975
1976 // (A & B) | (~A ^ B) -> (~A ^ B)
1977 // (B & A) | (~A ^ B) -> (~A ^ B)
1978 // (A & B) | (B ^ ~A) -> (B ^ ~A)
1979 // (B & A) | (B ^ ~A) -> (B ^ ~A)
1980 if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
1981 (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1982 match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1983 return Op1;
1984
1985 // (~A ^ B) | (A & B) -> (~A ^ B)
1986 // (~A ^ B) | (B & A) -> (~A ^ B)
1987 // (B ^ ~A) | (A & B) -> (B ^ ~A)
1988 // (B ^ ~A) | (B & A) -> (B ^ ~A)
1989 if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
1990 (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
1991 match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
1992 return Op0;
1993
1994 if (Value *V = simplifyAndOrOfCmps(Q, Op0, Op1, false))
1995 return V;
1996
1997 // Try some generic simplifications for associative operations.
1998 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
1999 MaxRecurse))
2000 return V;
2001
2002 // Or distributes over And. Try some generic simplifications based on this.
2003 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
2004 MaxRecurse))
2005 return V;
2006
2007 // If the operation is with the result of a select instruction, check whether
2008 // operating on either branch of the select always yields the same value.
2009 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
2010 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
2011 MaxRecurse))
2012 return V;
2013
2014 // (A & C1)|(B & C2)
2015 const APInt *C1, *C2;
2016 if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
2017 match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
2018 if (*C1 == ~*C2) {
2019 // (A & C1)|(B & C2)
2020 // If we have: ((V + N) & C1) | (V & C2)
2021 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
2022 // replace with V+N.
2023 Value *N;
2024 if (C2->isMask() && // C2 == 0+1+
2025 match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
2026 // Add commutes, try both ways.
2027 if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2028 return A;
2029 }
2030 // Or commutes, try both ways.
2031 if (C1->isMask() &&
2032 match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
2033 // Add commutes, try both ways.
2034 if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2035 return B;
2036 }
2037 }
2038 }
2039
2040 // If the operation is with the result of a phi instruction, check whether
2041 // operating on all incoming values of the phi always yields the same value.
2042 if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
2043 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
2044 return V;
2045
2046 return nullptr;
2047}
2048
2049Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
2050 return ::SimplifyOrInst(Op0, Op1, Q, RecursionLimit);
2051}
2052
2053/// Given operands for a Xor, see if we can fold the result.
2054/// If not, this returns null.
2055static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
2056 unsigned MaxRecurse) {
2057 if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
2058 return C;
2059
2060 // A ^ undef -> undef
2061 if (match(Op1, m_Undef()))
2062 return Op1;
2063
2064 // A ^ 0 = A
2065 if (match(Op1, m_Zero()))
2066 return Op0;
2067
2068 // A ^ A = 0
2069 if (Op0 == Op1)
2070 return Constant::getNullValue(Op0->getType());
2071
2072 // A ^ ~A = ~A ^ A = -1
2073 if (match(Op0, m_Not(m_Specific(Op1))) ||
2074 match(Op1, m_Not(m_Specific(Op0))))
2075 return Constant::getAllOnesValue(Op0->getType());
2076
2077 // Try some generic simplifications for associative operations.
2078 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
2079 MaxRecurse))
2080 return V;
2081
2082 // Threading Xor over selects and phi nodes is pointless, so don't bother.
2083 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
2084 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
2085 // only if B and C are equal. If B and C are equal then (since we assume
2086 // that operands have already been simplified) "select(cond, B, C)" should
2087 // have been simplified to the common value of B and C already. Analysing
2088 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
2089 // for threading over phi nodes.
2090
2091 return nullptr;
2092}
2093
2094Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
2095 return ::SimplifyXorInst(Op0, Op1, Q, RecursionLimit);
2096}
2097
2098
2099static Type *GetCompareTy(Value *Op) {
2100 return CmpInst::makeCmpResultType(Op->getType());
2101}
2102
2103/// Rummage around inside V looking for something equivalent to the comparison
2104/// "LHS Pred RHS". Return such a value if found, otherwise return null.
2105/// Helper function for analyzing max/min idioms.
2106static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
2107 Value *LHS, Value *RHS) {
2108 SelectInst *SI = dyn_cast<SelectInst>(V);
2109 if (!SI)
2110 return nullptr;
2111 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
2112 if (!Cmp)
2113 return nullptr;
2114 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
2115 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
2116 return Cmp;
2117 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
2118 LHS == CmpRHS && RHS == CmpLHS)
2119 return Cmp;
2120 return nullptr;
2121}
2122
2123// A significant optimization not implemented here is assuming that alloca
2124// addresses are not equal to incoming argument values. They don't *alias*,
2125// as we say, but that doesn't mean they aren't equal, so we take a
2126// conservative approach.
2127//
2128// This is inspired in part by C++11 5.10p1:
2129// "Two pointers of the same type compare equal if and only if they are both
2130// null, both point to the same function, or both represent the same
2131// address."
2132//
2133// This is pretty permissive.
2134//
2135// It's also partly due to C11 6.5.9p6:
2136// "Two pointers compare equal if and only if both are null pointers, both are
2137// pointers to the same object (including a pointer to an object and a
2138// subobject at its beginning) or function, both are pointers to one past the
2139// last element of the same array object, or one is a pointer to one past the
2140// end of one array object and the other is a pointer to the start of a
2141// different array object that happens to immediately follow the first array
2142// object in the address space.)
2143//
2144// C11's version is more restrictive, however there's no reason why an argument
2145// couldn't be a one-past-the-end value for a stack object in the caller and be
2146// equal to the beginning of a stack object in the callee.
2147//
2148// If the C and C++ standards are ever made sufficiently restrictive in this
2149// area, it may be possible to update LLVM's semantics accordingly and reinstate
2150// this optimization.
2151static Constant *
2152computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI,
2153 const DominatorTree *DT, CmpInst::Predicate Pred,
2154 AssumptionCache *AC, const Instruction *CxtI,
2155 const InstrInfoQuery &IIQ, Value *LHS, Value *RHS) {
2156 // First, skip past any trivial no-ops.
2157 LHS = LHS->stripPointerCasts();
2158 RHS = RHS->stripPointerCasts();
2159
2160 // A non-null pointer is not equal to a null pointer.
2161 if (llvm::isKnownNonZero(LHS, DL, 0, nullptr, nullptr, nullptr,
2162 IIQ.UseInstrInfo) &&
2163 isa<ConstantPointerNull>(RHS) &&
2164 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
2165 return ConstantInt::get(GetCompareTy(LHS),
2166 !CmpInst::isTrueWhenEqual(Pred));
2167
2168 // We can only fold certain predicates on pointer comparisons.
2169 switch (Pred) {
2170 default:
2171 return nullptr;
2172
2173 // Equality comaprisons are easy to fold.
2174 case CmpInst::ICMP_EQ:
2175 case CmpInst::ICMP_NE:
2176 break;
2177
2178 // We can only handle unsigned relational comparisons because 'inbounds' on
2179 // a GEP only protects against unsigned wrapping.
2180 case CmpInst::ICMP_UGT:
2181 case CmpInst::ICMP_UGE:
2182 case CmpInst::ICMP_ULT:
2183 case CmpInst::ICMP_ULE:
2184 // However, we have to switch them to their signed variants to handle
2185 // negative indices from the base pointer.
2186 Pred = ICmpInst::getSignedPredicate(Pred);
2187 break;
2188 }
2189
2190 // Strip off any constant offsets so that we can reason about them.
2191 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2192 // here and compare base addresses like AliasAnalysis does, however there are
2193 // numerous hazards. AliasAnalysis and its utilities rely on special rules
2194 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2195 // doesn't need to guarantee pointer inequality when it says NoAlias.
2196 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
2197 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);
2198
2199 // If LHS and RHS are related via constant offsets to the same base
2200 // value, we can replace it with an icmp which just compares the offsets.
2201 if (LHS == RHS)
2202 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
2203
2204 // Various optimizations for (in)equality comparisons.
2205 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
2206 // Different non-empty allocations that exist at the same time have
2207 // different addresses (if the program can tell). Global variables always
2208 // exist, so they always exist during the lifetime of each other and all
2209 // allocas. Two different allocas usually have different addresses...
2210 //
2211 // However, if there's an @llvm.stackrestore dynamically in between two
2212 // allocas, they may have the same address. It's tempting to reduce the
2213 // scope of the problem by only looking at *static* allocas here. That would
2214 // cover the majority of allocas while significantly reducing the likelihood
2215 // of having an @llvm.stackrestore pop up in the middle. However, it's not
2216 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2217 // an entry block. Also, if we have a block that's not attached to a
2218 // function, we can't tell if it's "static" under the current definition.
2219 // Theoretically, this problem could be fixed by creating a new kind of
2220 // instruction kind specifically for static allocas. Such a new instruction
2221 // could be required to be at the top of the entry block, thus preventing it
2222 // from being subject to a @llvm.stackrestore. Instcombine could even
2223 // convert regular allocas into these special allocas. It'd be nifty.
2224 // However, until then, this problem remains open.
2225 //
2226 // So, we'll assume that two non-empty allocas have different addresses
2227 // for now.
2228 //
2229 // With all that, if the offsets are within the bounds of their allocations
2230 // (and not one-past-the-end! so we can't use inbounds!), and their
2231 // allocations aren't the same, the pointers are not equal.
2232 //
2233 // Note that it's not necessary to check for LHS being a global variable
2234 // address, due to canonicalization and constant folding.
2235 if (isa<AllocaInst>(LHS) &&
2236 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
2237 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
2238 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
2239 uint64_t LHSSize, RHSSize;
2240 ObjectSizeOpts Opts;
2241 Opts.NullIsUnknownSize =
2242 NullPointerIsDefined(cast<AllocaInst>(LHS)->getFunction());
2243 if (LHSOffsetCI && RHSOffsetCI &&
2244 getObjectSize(LHS, LHSSize, DL, TLI, Opts) &&
2245 getObjectSize(RHS, RHSSize, DL, TLI, Opts)) {
2246 const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
2247 const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
2248 if (!LHSOffsetValue.isNegative() &&
2249 !RHSOffsetValue.isNegative() &&
2250 LHSOffsetValue.ult(LHSSize) &&
2251 RHSOffsetValue.ult(RHSSize)) {
2252 return ConstantInt::get(GetCompareTy(LHS),
2253 !CmpInst::isTrueWhenEqual(Pred));
2254 }
2255 }
2256
2257 // Repeat the above check but this time without depending on DataLayout
2258 // or being able to compute a precise size.
2259 if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
2260 !cast<PointerType>(RHS->getType())->isEmptyTy() &&
2261 LHSOffset->isNullValue() &&
2262 RHSOffset->isNullValue())
2263 return ConstantInt::get(GetCompareTy(LHS),
2264 !CmpInst::isTrueWhenEqual(Pred));
2265 }
2266
2267 // Even if an non-inbounds GEP occurs along the path we can still optimize
2268 // equality comparisons concerning the result. We avoid walking the whole
2269 // chain again by starting where the last calls to
2270 // stripAndComputeConstantOffsets left off and accumulate the offsets.
2271 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
2272 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
2273 if (LHS == RHS)
2274 return ConstantExpr::getICmp(Pred,
2275 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
2276 ConstantExpr::getAdd(RHSOffset, RHSNoBound));
2277
2278 // If one side of the equality comparison must come from a noalias call
2279 // (meaning a system memory allocation function), and the other side must
2280 // come from a pointer that cannot overlap with dynamically-allocated
2281 // memory within the lifetime of the current function (allocas, byval
2282 // arguments, globals), then determine the comparison result here.
2283 SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
2284 GetUnderlyingObjects(LHS, LHSUObjs, DL);
2285 GetUnderlyingObjects(RHS, RHSUObjs, DL);
2286
2287 // Is the set of underlying objects all noalias calls?
2288 auto IsNAC = [](ArrayRef<Value *> Objects) {
2289 return all_of(Objects, isNoAliasCall);
2290 };
2291
2292 // Is the set of underlying objects all things which must be disjoint from
2293 // noalias calls. For allocas, we consider only static ones (dynamic
2294 // allocas might be transformed into calls to malloc not simultaneously
2295 // live with the compared-to allocation). For globals, we exclude symbols
2296 // that might be resolve lazily to symbols in another dynamically-loaded
2297 // library (and, thus, could be malloc'ed by the implementation).
2298 auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
2299 return all_of(Objects, [](Value *V) {
2300 if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
2301 return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
2302 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
2303 return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
2304 GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
2305 !GV->isThreadLocal();
2306 if (const Argument *A = dyn_cast<Argument>(V))
2307 return A->hasByValAttr();
2308 return false;
2309 });
2310 };
2311
2312 if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
2313 (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
2314 return ConstantInt::get(GetCompareTy(LHS),
2315 !CmpInst::isTrueWhenEqual(Pred));
2316
2317 // Fold comparisons for non-escaping pointer even if the allocation call
2318 // cannot be elided. We cannot fold malloc comparison to null. Also, the
2319 // dynamic allocation call could be either of the operands.
2320 Value *MI = nullptr;
2321 if (isAllocLikeFn(LHS, TLI) &&
2322 llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT))
2323 MI = LHS;
2324 else if (isAllocLikeFn(RHS, TLI) &&
2325 llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT))
2326 MI = RHS;
2327 // FIXME: We should also fold the compare when the pointer escapes, but the
2328 // compare dominates the pointer escape
2329 if (MI && !PointerMayBeCaptured(MI, true, true))
2330 return ConstantInt::get(GetCompareTy(LHS),
2331 CmpInst::isFalseWhenEqual(Pred));
2332 }
2333
2334 // Otherwise, fail.
2335 return nullptr;
2336}
2337
2338/// Fold an icmp when its operands have i1 scalar type.
2339static Value *simplifyICmpOfBools(CmpInst::Predicate Pred, Value *LHS,
2340 Value *RHS, const SimplifyQuery &Q) {
2341 Type *ITy = GetCompareTy(LHS); // The return type.
2342 Type *OpTy = LHS->getType(); // The operand type.
2343 if (!OpTy->isIntOrIntVectorTy(1))
2344 return nullptr;
2345
2346 // A boolean compared to true/false can be simplified in 14 out of the 20
2347 // (10 predicates * 2 constants) possible combinations. Cases not handled here
2348 // require a 'not' of the LHS, so those must be transformed in InstCombine.
2349 if (match(RHS, m_Zero())) {
2350 switch (Pred) {
2351 case CmpInst::ICMP_NE: // X != 0 -> X
2352 case CmpInst::ICMP_UGT: // X >u 0 -> X
2353 case CmpInst::ICMP_SLT: // X <s 0 -> X
2354 return LHS;
2355
2356 case CmpInst::ICMP_ULT: // X <u 0 -> false
2357 case CmpInst::ICMP_SGT: // X >s 0 -> false
2358 return getFalse(ITy);
2359
2360 case CmpInst::ICMP_UGE: // X >=u 0 -> true
2361 case CmpInst::ICMP_SLE: // X <=s 0 -> true
2362 return getTrue(ITy);
2363
2364 default: break;
2365 }
2366 } else if (match(RHS, m_One())) {
2367 switch (Pred) {
2368 case CmpInst::ICMP_EQ: // X == 1 -> X
2369 case CmpInst::ICMP_UGE: // X >=u 1 -> X
2370 case CmpInst::ICMP_SLE: // X <=s -1 -> X
2371 return LHS;
2372
2373 case CmpInst::ICMP_UGT: // X >u 1 -> false
2374 case CmpInst::ICMP_SLT: // X <s -1 -> false
2375 return getFalse(ITy);
2376
2377 case CmpInst::ICMP_ULE: // X <=u 1 -> true
2378 case CmpInst::ICMP_SGE: // X >=s -1 -> true
2379 return getTrue(ITy);
2380
2381 default: break;
2382 }
2383 }
2384
2385 switch (Pred) {
2386 default:
2387 break;
2388 case ICmpInst::ICMP_UGE:
2389 if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
2390 return getTrue(ITy);
2391 break;
2392 case ICmpInst::ICMP_SGE:
2393 /// For signed comparison, the values for an i1 are 0 and -1
2394 /// respectively. This maps into a truth table of:
2395 /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2396 /// 0 | 0 | 1 (0 >= 0) | 1
2397 /// 0 | 1 | 1 (0 >= -1) | 1
2398 /// 1 | 0 | 0 (-1 >= 0) | 0
2399 /// 1 | 1 | 1 (-1 >= -1) | 1
2400 if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2401 return getTrue(ITy);
2402 break;
2403 case ICmpInst::ICMP_ULE:
2404 if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
2405 return getTrue(ITy);
2406 break;
2407 }
2408
2409 return nullptr;
2410}
2411
2412/// Try hard to fold icmp with zero RHS because this is a common case.
2413static Value *simplifyICmpWithZero(CmpInst::Predicate Pred, Value *LHS,
2414 Value *RHS, const SimplifyQuery &Q) {
2415 if (!match(RHS, m_Zero()))
2416 return nullptr;
2417
2418 Type *ITy = GetCompareTy(LHS); // The return type.
2419 switch (Pred) {
2420 default:
2421 llvm_unreachable("Unknown ICmp predicate!")::llvm::llvm_unreachable_internal("Unknown ICmp predicate!", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 2421)
;
2422 case ICmpInst::ICMP_ULT:
2423 return getFalse(ITy);
2424 case ICmpInst::ICMP_UGE:
2425 return getTrue(ITy);
2426 case ICmpInst::ICMP_EQ:
2427 case ICmpInst::ICMP_ULE:
2428 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo))
2429 return getFalse(ITy);
2430 break;
2431 case ICmpInst::ICMP_NE:
2432 case ICmpInst::ICMP_UGT:
2433 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo))
2434 return getTrue(ITy);
2435 break;
2436 case ICmpInst::ICMP_SLT: {
2437 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2438 if (LHSKnown.isNegative())
2439 return getTrue(ITy);
2440 if (LHSKnown.isNonNegative())
2441 return getFalse(ITy);
2442 break;
2443 }
2444 case ICmpInst::ICMP_SLE: {
2445 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2446 if (LHSKnown.isNegative())
2447 return getTrue(ITy);
2448 if (LHSKnown.isNonNegative() &&
2449 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2450 return getFalse(ITy);
2451 break;
2452 }
2453 case ICmpInst::ICMP_SGE: {
2454 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2455 if (LHSKnown.isNegative())
2456 return getFalse(ITy);
2457 if (LHSKnown.isNonNegative())
2458 return getTrue(ITy);
2459 break;
2460 }
2461 case ICmpInst::ICMP_SGT: {
2462 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2463 if (LHSKnown.isNegative())
2464 return getFalse(ITy);
2465 if (LHSKnown.isNonNegative() &&
2466 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
2467 return getTrue(ITy);
2468 break;
2469 }
2470 }
2471
2472 return nullptr;
2473}
2474
2475/// Many binary operators with a constant operand have an easy-to-compute
2476/// range of outputs. This can be used to fold a comparison to always true or
2477/// always false.
2478static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper,
2479 const InstrInfoQuery &IIQ) {
2480 unsigned Width = Lower.getBitWidth();
2481 const APInt *C;
2482 switch (BO.getOpcode()) {
2483 case Instruction::Add:
2484 if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2485 // FIXME: If we have both nuw and nsw, we should reduce the range further.
2486 if (IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(&BO))) {
2487 // 'add nuw x, C' produces [C, UINT_MAX].
2488 Lower = *C;
2489 } else if (IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(&BO))) {
2490 if (C->isNegative()) {
2491 // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
2492 Lower = APInt::getSignedMinValue(Width);
2493 Upper = APInt::getSignedMaxValue(Width) + *C + 1;
2494 } else {
2495 // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
2496 Lower = APInt::getSignedMinValue(Width) + *C;
2497 Upper = APInt::getSignedMaxValue(Width) + 1;
2498 }
2499 }
2500 }
2501 break;
2502
2503 case Instruction::And:
2504 if (match(BO.getOperand(1), m_APInt(C)))
2505 // 'and x, C' produces [0, C].
2506 Upper = *C + 1;
2507 break;
2508
2509 case Instruction::Or:
2510 if (match(BO.getOperand(1), m_APInt(C)))
2511 // 'or x, C' produces [C, UINT_MAX].
2512 Lower = *C;
2513 break;
2514
2515 case Instruction::AShr:
2516 if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2517 // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
2518 Lower = APInt::getSignedMinValue(Width).ashr(*C);
2519 Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
2520 } else if (match(BO.getOperand(0), m_APInt(C))) {
2521 unsigned ShiftAmount = Width - 1;
2522 if (!C->isNullValue() && IIQ.isExact(&BO))
2523 ShiftAmount = C->countTrailingZeros();
2524 if (C->isNegative()) {
2525 // 'ashr C, x' produces [C, C >> (Width-1)]
2526 Lower = *C;
2527 Upper = C->ashr(ShiftAmount) + 1;
2528 } else {
2529 // 'ashr C, x' produces [C >> (Width-1), C]
2530 Lower = C->ashr(ShiftAmount);
2531 Upper = *C + 1;
2532 }
2533 }
2534 break;
2535
2536 case Instruction::LShr:
2537 if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
2538 // 'lshr x, C' produces [0, UINT_MAX >> C].
2539 Upper = APInt::getAllOnesValue(Width).lshr(*C) + 1;
2540 } else if (match(BO.getOperand(0), m_APInt(C))) {
2541 // 'lshr C, x' produces [C >> (Width-1), C].
2542 unsigned ShiftAmount = Width - 1;
2543 if (!C->isNullValue() && IIQ.isExact(&BO))
2544 ShiftAmount = C->countTrailingZeros();
2545 Lower = C->lshr(ShiftAmount);
2546 Upper = *C + 1;
2547 }
2548 break;
2549
2550 case Instruction::Shl:
2551 if (match(BO.getOperand(0), m_APInt(C))) {
2552 if (IIQ.hasNoUnsignedWrap(&BO)) {
2553 // 'shl nuw C, x' produces [C, C << CLZ(C)]
2554 Lower = *C;
2555 Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
2556 } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
2557 if (C->isNegative()) {
2558 // 'shl nsw C, x' produces [C << CLO(C)-1, C]
2559 unsigned ShiftAmount = C->countLeadingOnes() - 1;
2560 Lower = C->shl(ShiftAmount);
2561 Upper = *C + 1;
2562 } else {
2563 // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
2564 unsigned ShiftAmount = C->countLeadingZeros() - 1;
2565 Lower = *C;
2566 Upper = C->shl(ShiftAmount) + 1;
2567 }
2568 }
2569 }
2570 break;
2571
2572 case Instruction::SDiv:
2573 if (match(BO.getOperand(1), m_APInt(C))) {
2574 APInt IntMin = APInt::getSignedMinValue(Width);
2575 APInt IntMax = APInt::getSignedMaxValue(Width);
2576 if (C->isAllOnesValue()) {
2577 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2578 // where C != -1 and C != 0 and C != 1
2579 Lower = IntMin + 1;
2580 Upper = IntMax + 1;
2581 } else if (C->countLeadingZeros() < Width - 1) {
2582 // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
2583 // where C != -1 and C != 0 and C != 1
2584 Lower = IntMin.sdiv(*C);
2585 Upper = IntMax.sdiv(*C);
2586 if (Lower.sgt(Upper))
2587 std::swap(Lower, Upper);
2588 Upper = Upper + 1;
2589 assert(Upper != Lower && "Upper part of range has wrapped!")((Upper != Lower && "Upper part of range has wrapped!"
) ? static_cast<void> (0) : __assert_fail ("Upper != Lower && \"Upper part of range has wrapped!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 2589, __PRETTY_FUNCTION__))
;
2590 }
2591 } else if (match(BO.getOperand(0), m_APInt(C))) {
2592 if (C->isMinSignedValue()) {
2593 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2594 Lower = *C;
2595 Upper = Lower.lshr(1) + 1;
2596 } else {
2597 // 'sdiv C, x' produces [-|C|, |C|].
2598 Upper = C->abs() + 1;
2599 Lower = (-Upper) + 1;
2600 }
2601 }
2602 break;
2603
2604 case Instruction::UDiv:
2605 if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
2606 // 'udiv x, C' produces [0, UINT_MAX / C].
2607 Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
2608 } else if (match(BO.getOperand(0), m_APInt(C))) {
2609 // 'udiv C, x' produces [0, C].
2610 Upper = *C + 1;
2611 }
2612 break;
2613
2614 case Instruction::SRem:
2615 if (match(BO.getOperand(1), m_APInt(C))) {
2616 // 'srem x, C' produces (-|C|, |C|).
2617 Upper = C->abs();
2618 Lower = (-Upper) + 1;
2619 }
2620 break;
2621
2622 case Instruction::URem:
2623 if (match(BO.getOperand(1), m_APInt(C)))
2624 // 'urem x, C' produces [0, C).
2625 Upper = *C;
2626 break;
2627
2628 default:
2629 break;
2630 }
2631}
2632
2633/// Some intrinsics with a constant operand have an easy-to-compute range of
2634/// outputs. This can be used to fold a comparison to always true or always
2635/// false.
2636static void setLimitsForIntrinsic(IntrinsicInst &II, APInt &Lower,
2637 APInt &Upper) {
2638 unsigned Width = Lower.getBitWidth();
2639 const APInt *C;
2640 switch (II.getIntrinsicID()) {
2641 case Intrinsic::uadd_sat:
2642 // uadd.sat(x, C) produces [C, UINT_MAX].
2643 if (match(II.getOperand(0), m_APInt(C)) ||
2644 match(II.getOperand(1), m_APInt(C)))
2645 Lower = *C;
2646 break;
2647 case Intrinsic::sadd_sat:
2648 if (match(II.getOperand(0), m_APInt(C)) ||
2649 match(II.getOperand(1), m_APInt(C))) {
2650 if (C->isNegative()) {
2651 // sadd.sat(x, -C) produces [SINT_MIN, SINT_MAX + (-C)].
2652 Lower = APInt::getSignedMinValue(Width);
2653 Upper = APInt::getSignedMaxValue(Width) + *C + 1;
2654 } else {
2655 // sadd.sat(x, +C) produces [SINT_MIN + C, SINT_MAX].
2656 Lower = APInt::getSignedMinValue(Width) + *C;
2657 Upper = APInt::getSignedMaxValue(Width) + 1;
2658 }
2659 }
2660 break;
2661 case Intrinsic::usub_sat:
2662 // usub.sat(C, x) produces [0, C].
2663 if (match(II.getOperand(0), m_APInt(C)))
2664 Upper = *C + 1;
2665 // usub.sat(x, C) produces [0, UINT_MAX - C].
2666 else if (match(II.getOperand(1), m_APInt(C)))
2667 Upper = APInt::getMaxValue(Width) - *C + 1;
2668 break;
2669 case Intrinsic::ssub_sat:
2670 if (match(II.getOperand(0), m_APInt(C))) {
2671 if (C->isNegative()) {
2672 // ssub.sat(-C, x) produces [SINT_MIN, -SINT_MIN + (-C)].
2673 Lower = APInt::getSignedMinValue(Width);
2674 Upper = *C - APInt::getSignedMinValue(Width) + 1;
2675 } else {
2676 // ssub.sat(+C, x) produces [-SINT_MAX + C, SINT_MAX].
2677 Lower = *C - APInt::getSignedMaxValue(Width);
2678 Upper = APInt::getSignedMaxValue(Width) + 1;
2679 }
2680 } else if (match(II.getOperand(1), m_APInt(C))) {
2681 if (C->isNegative()) {
2682 // ssub.sat(x, -C) produces [SINT_MIN - (-C), SINT_MAX]:
2683 Lower = APInt::getSignedMinValue(Width) - *C;
2684 Upper = APInt::getSignedMaxValue(Width) + 1;
2685 } else {
2686 // ssub.sat(x, +C) produces [SINT_MIN, SINT_MAX - C].
2687 Lower = APInt::getSignedMinValue(Width);
2688 Upper = APInt::getSignedMaxValue(Width) - *C + 1;
2689 }
2690 }
2691 break;
2692 default:
2693 break;
2694 }
2695}
2696
2697static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
2698 Value *RHS, const InstrInfoQuery &IIQ) {
2699 Type *ITy = GetCompareTy(RHS); // The return type.
2700
2701 Value *X;
2702 // Sign-bit checks can be optimized to true/false after unsigned
2703 // floating-point casts:
2704 // icmp slt (bitcast (uitofp X)), 0 --> false
2705 // icmp sgt (bitcast (uitofp X)), -1 --> true
2706 if (match(LHS, m_BitCast(m_UIToFP(m_Value(X))))) {
2707 if (Pred == ICmpInst::ICMP_SLT && match(RHS, m_Zero()))
2708 return ConstantInt::getFalse(ITy);
2709 if (Pred == ICmpInst::ICMP_SGT && match(RHS, m_AllOnes()))
2710 return ConstantInt::getTrue(ITy);
2711 }
2712
2713 const APInt *C;
2714 if (!match(RHS, m_APInt(C)))
2715 return nullptr;
2716
2717 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2718 ConstantRange RHS_CR = ConstantRange::makeExactICmpRegion(Pred, *C);
2719 if (RHS_CR.isEmptySet())
2720 return ConstantInt::getFalse(ITy);
2721 if (RHS_CR.isFullSet())
2722 return ConstantInt::getTrue(ITy);
2723
2724 // Find the range of possible values for binary operators.
2725 unsigned Width = C->getBitWidth();
2726 APInt Lower = APInt(Width, 0);
2727 APInt Upper = APInt(Width, 0);
2728 if (auto *BO = dyn_cast<BinaryOperator>(LHS))
2729 setLimitsForBinOp(*BO, Lower, Upper, IIQ);
2730 else if (auto *II = dyn_cast<IntrinsicInst>(LHS))
2731 setLimitsForIntrinsic(*II, Lower, Upper);
2732
2733 ConstantRange LHS_CR =
2734 Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);
2735
2736 if (auto *I = dyn_cast<Instruction>(LHS))
2737 if (auto *Ranges = IIQ.getMetadata(I, LLVMContext::MD_range))
2738 LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
2739
2740 if (!LHS_CR.isFullSet()) {
2741 if (RHS_CR.contains(LHS_CR))
2742 return ConstantInt::getTrue(ITy);
2743 if (RHS_CR.inverse().contains(LHS_CR))
2744 return ConstantInt::getFalse(ITy);
2745 }
2746
2747 return nullptr;
2748}
2749
2750/// TODO: A large part of this logic is duplicated in InstCombine's
2751/// foldICmpBinOp(). We should be able to share that and avoid the code
2752/// duplication.
2753static Value *simplifyICmpWithBinOp(CmpInst::Predicate Pred, Value *LHS,
2754 Value *RHS, const SimplifyQuery &Q,
2755 unsigned MaxRecurse) {
2756 Type *ITy = GetCompareTy(LHS); // The return type.
2757
2758 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
2759 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
2760 if (MaxRecurse && (LBO || RBO)) {
2761 // Analyze the case when either LHS or RHS is an add instruction.
2762 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
2763 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2764 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
2765 if (LBO && LBO->getOpcode() == Instruction::Add) {
2766 A = LBO->getOperand(0);
2767 B = LBO->getOperand(1);
2768 NoLHSWrapProblem =
2769 ICmpInst::isEquality(Pred) ||
2770 (CmpInst::isUnsigned(Pred) &&
2771 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(LBO))) ||
2772 (CmpInst::isSigned(Pred) &&
2773 Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(LBO)));
2774 }
2775 if (RBO && RBO->getOpcode() == Instruction::Add) {
2776 C = RBO->getOperand(0);
2777 D = RBO->getOperand(1);
2778 NoRHSWrapProblem =
2779 ICmpInst::isEquality(Pred) ||
2780 (CmpInst::isUnsigned(Pred) &&
2781 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(RBO))) ||
2782 (CmpInst::isSigned(Pred) &&
2783 Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(RBO)));
2784 }
2785
2786 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2787 if ((A == RHS || B == RHS) && NoLHSWrapProblem)
2788 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
2789 Constant::getNullValue(RHS->getType()), Q,
2790 MaxRecurse - 1))
2791 return V;
2792
2793 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2794 if ((C == LHS || D == LHS) && NoRHSWrapProblem)
2795 if (Value *V =
2796 SimplifyICmpInst(Pred, Constant::getNullValue(LHS->getType()),
2797 C == LHS ? D : C, Q, MaxRecurse - 1))
2798 return V;
2799
2800 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2801 if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
2802 NoRHSWrapProblem) {
2803 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2804 Value *Y, *Z;
2805 if (A == C) {
2806 // C + B == C + D -> B == D
2807 Y = B;
2808 Z = D;
2809 } else if (A == D) {
2810 // D + B == C + D -> B == C
2811 Y = B;
2812 Z = C;
2813 } else if (B == C) {
2814 // A + C == C + D -> A == D
2815 Y = A;
2816 Z = D;
2817 } else {
2818 assert(B == D)((B == D) ? static_cast<void> (0) : __assert_fail ("B == D"
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 2818, __PRETTY_FUNCTION__))
;
2819 // A + D == C + D -> A == C
2820 Y = A;
2821 Z = C;
2822 }
2823 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
2824 return V;
2825 }
2826 }
2827
2828 {
2829 Value *Y = nullptr;
2830 // icmp pred (or X, Y), X
2831 if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
2832 if (Pred == ICmpInst::ICMP_ULT)
2833 return getFalse(ITy);
2834 if (Pred == ICmpInst::ICMP_UGE)
2835 return getTrue(ITy);
2836
2837 if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
2838 KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2839 KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2840 if (RHSKnown.isNonNegative() && YKnown.isNegative())
2841 return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
2842 if (RHSKnown.isNegative() || YKnown.isNonNegative())
2843 return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
2844 }
2845 }
2846 // icmp pred X, (or X, Y)
2847 if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
2848 if (Pred == ICmpInst::ICMP_ULE)
2849 return getTrue(ITy);
2850 if (Pred == ICmpInst::ICMP_UGT)
2851 return getFalse(ITy);
2852
2853 if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
2854 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2855 KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2856 if (LHSKnown.isNonNegative() && YKnown.isNegative())
2857 return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
2858 if (LHSKnown.isNegative() || YKnown.isNonNegative())
2859 return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
2860 }
2861 }
2862 }
2863
2864 // icmp pred (and X, Y), X
2865 if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
2866 if (Pred == ICmpInst::ICMP_UGT)
2867 return getFalse(ITy);
2868 if (Pred == ICmpInst::ICMP_ULE)
2869 return getTrue(ITy);
2870 }
2871 // icmp pred X, (and X, Y)
2872 if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
2873 if (Pred == ICmpInst::ICMP_UGE)
2874 return getTrue(ITy);
2875 if (Pred == ICmpInst::ICMP_ULT)
2876 return getFalse(ITy);
2877 }
2878
2879 // 0 - (zext X) pred C
2880 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
2881 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
2882 if (RHSC->getValue().isStrictlyPositive()) {
2883 if (Pred == ICmpInst::ICMP_SLT)
2884 return ConstantInt::getTrue(RHSC->getContext());
2885 if (Pred == ICmpInst::ICMP_SGE)
2886 return ConstantInt::getFalse(RHSC->getContext());
2887 if (Pred == ICmpInst::ICMP_EQ)
2888 return ConstantInt::getFalse(RHSC->getContext());
2889 if (Pred == ICmpInst::ICMP_NE)
2890 return ConstantInt::getTrue(RHSC->getContext());
2891 }
2892 if (RHSC->getValue().isNonNegative()) {
2893 if (Pred == ICmpInst::ICMP_SLE)
2894 return ConstantInt::getTrue(RHSC->getContext());
2895 if (Pred == ICmpInst::ICMP_SGT)
2896 return ConstantInt::getFalse(RHSC->getContext());
2897 }
2898 }
2899 }
2900
2901 // icmp pred (urem X, Y), Y
2902 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
2903 switch (Pred) {
2904 default:
2905 break;
2906 case ICmpInst::ICMP_SGT:
2907 case ICmpInst::ICMP_SGE: {
2908 KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2909 if (!Known.isNonNegative())
2910 break;
2911 LLVM_FALLTHROUGH[[clang::fallthrough]];
2912 }
2913 case ICmpInst::ICMP_EQ:
2914 case ICmpInst::ICMP_UGT:
2915 case ICmpInst::ICMP_UGE:
2916 return getFalse(ITy);
2917 case ICmpInst::ICMP_SLT:
2918 case ICmpInst::ICMP_SLE: {
2919 KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2920 if (!Known.isNonNegative())
2921 break;
2922 LLVM_FALLTHROUGH[[clang::fallthrough]];
2923 }
2924 case ICmpInst::ICMP_NE:
2925 case ICmpInst::ICMP_ULT:
2926 case ICmpInst::ICMP_ULE:
2927 return getTrue(ITy);
2928 }
2929 }
2930
2931 // icmp pred X, (urem Y, X)
2932 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
2933 switch (Pred) {
2934 default:
2935 break;
2936 case ICmpInst::ICMP_SGT:
2937 case ICmpInst::ICMP_SGE: {
2938 KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2939 if (!Known.isNonNegative())
2940 break;
2941 LLVM_FALLTHROUGH[[clang::fallthrough]];
2942 }
2943 case ICmpInst::ICMP_NE:
2944 case ICmpInst::ICMP_UGT:
2945 case ICmpInst::ICMP_UGE:
2946 return getTrue(ITy);
2947 case ICmpInst::ICMP_SLT:
2948 case ICmpInst::ICMP_SLE: {
2949 KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
2950 if (!Known.isNonNegative())
2951 break;
2952 LLVM_FALLTHROUGH[[clang::fallthrough]];
2953 }
2954 case ICmpInst::ICMP_EQ:
2955 case ICmpInst::ICMP_ULT:
2956 case ICmpInst::ICMP_ULE:
2957 return getFalse(ITy);
2958 }
2959 }
2960
2961 // x >> y <=u x
2962 // x udiv y <=u x.
2963 if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
2964 match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
2965 // icmp pred (X op Y), X
2966 if (Pred == ICmpInst::ICMP_UGT)
2967 return getFalse(ITy);
2968 if (Pred == ICmpInst::ICMP_ULE)
2969 return getTrue(ITy);
2970 }
2971
2972 // x >=u x >> y
2973 // x >=u x udiv y.
2974 if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
2975 match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
2976 // icmp pred X, (X op Y)
2977 if (Pred == ICmpInst::ICMP_ULT)
2978 return getFalse(ITy);
2979 if (Pred == ICmpInst::ICMP_UGE)
2980 return getTrue(ITy);
2981 }
2982
2983 // handle:
2984 // CI2 << X == CI
2985 // CI2 << X != CI
2986 //
2987 // where CI2 is a power of 2 and CI isn't
2988 if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
2989 const APInt *CI2Val, *CIVal = &CI->getValue();
2990 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
2991 CI2Val->isPowerOf2()) {
2992 if (!CIVal->isPowerOf2()) {
2993 // CI2 << X can equal zero in some circumstances,
2994 // this simplification is unsafe if CI is zero.
2995 //
2996 // We know it is safe if:
2997 // - The shift is nsw, we can't shift out the one bit.
2998 // - The shift is nuw, we can't shift out the one bit.
2999 // - CI2 is one
3000 // - CI isn't zero
3001 if (Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(LBO)) ||
3002 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(LBO)) ||
3003 CI2Val->isOneValue() || !CI->isZero()) {
3004 if (Pred == ICmpInst::ICMP_EQ)
3005 return ConstantInt::getFalse(RHS->getContext());
3006 if (Pred == ICmpInst::ICMP_NE)
3007 return ConstantInt::getTrue(RHS->getContext());
3008 }
3009 }
3010 if (CIVal->isSignMask() && CI2Val->isOneValue()) {
3011 if (Pred == ICmpInst::ICMP_UGT)
3012 return ConstantInt::getFalse(RHS->getContext());
3013 if (Pred == ICmpInst::ICMP_ULE)
3014 return ConstantInt::getTrue(RHS->getContext());
3015 }
3016 }
3017 }
3018
3019 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
3020 LBO->getOperand(1) == RBO->getOperand(1)) {
3021 switch (LBO->getOpcode()) {
3022 default:
3023 break;
3024 case Instruction::UDiv:
3025 case Instruction::LShr:
3026 if (ICmpInst::isSigned(Pred) || !Q.IIQ.isExact(LBO) ||
3027 !Q.IIQ.isExact(RBO))
3028 break;
3029 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
3030 RBO->getOperand(0), Q, MaxRecurse - 1))
3031 return V;
3032 break;
3033 case Instruction::SDiv:
3034 if (!ICmpInst::isEquality(Pred) || !Q.IIQ.isExact(LBO) ||
3035 !Q.IIQ.isExact(RBO))
3036 break;
3037 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
3038 RBO->getOperand(0), Q, MaxRecurse - 1))
3039 return V;
3040 break;
3041 case Instruction::AShr:
3042 if (!Q.IIQ.isExact(LBO) || !Q.IIQ.isExact(RBO))
3043 break;
3044 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
3045 RBO->getOperand(0), Q, MaxRecurse - 1))
3046 return V;
3047 break;
3048 case Instruction::Shl: {
3049 bool NUW = Q.IIQ.hasNoUnsignedWrap(LBO) && Q.IIQ.hasNoUnsignedWrap(RBO);
3050 bool NSW = Q.IIQ.hasNoSignedWrap(LBO) && Q.IIQ.hasNoSignedWrap(RBO);
3051 if (!NUW && !NSW)
3052 break;
3053 if (!NSW && ICmpInst::isSigned(Pred))
3054 break;
3055 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
3056 RBO->getOperand(0), Q, MaxRecurse - 1))
3057 return V;
3058 break;
3059 }
3060 }
3061 }
3062 return nullptr;
3063}
3064
3065static Value *simplifyICmpWithAbsNabs(CmpInst::Predicate Pred, Value *Op0,
3066 Value *Op1) {
3067 // We need a comparison with a constant.
3068 const APInt *C;
3069 if (!match(Op1, m_APInt(C)))
3070 return nullptr;
3071
3072 // matchSelectPattern returns the negation part of an abs pattern in SP1.
3073 // If the negate has an NSW flag, abs(INT_MIN) is undefined. Without that
3074 // constraint, we can't make a contiguous range for the result of abs.
3075 ICmpInst::Predicate AbsPred = ICmpInst::BAD_ICMP_PREDICATE;
3076 Value *SP0, *SP1;
3077 SelectPatternFlavor SPF = matchSelectPattern(Op0, SP0, SP1).Flavor;
3078 if (SPF == SelectPatternFlavor::SPF_ABS &&
3079 cast<Instruction>(SP1)->hasNoSignedWrap())
3080 // The result of abs(X) is >= 0 (with nsw).
3081 AbsPred = ICmpInst::ICMP_SGE;
3082 if (SPF == SelectPatternFlavor::SPF_NABS)
3083 // The result of -abs(X) is <= 0.
3084 AbsPred = ICmpInst::ICMP_SLE;
3085
3086 if (AbsPred == ICmpInst::BAD_ICMP_PREDICATE)
3087 return nullptr;
3088
3089 // If there is no intersection between abs/nabs and the range of this icmp,
3090 // the icmp must be false. If the abs/nabs range is a subset of the icmp
3091 // range, the icmp must be true.
3092 APInt Zero = APInt::getNullValue(C->getBitWidth());
3093 ConstantRange AbsRange = ConstantRange::makeExactICmpRegion(AbsPred, Zero);
3094 ConstantRange CmpRange = ConstantRange::makeExactICmpRegion(Pred, *C);
3095 if (AbsRange.intersectWith(CmpRange).isEmptySet())
3096 return getFalse(GetCompareTy(Op0));
3097 if (CmpRange.contains(AbsRange))
3098 return getTrue(GetCompareTy(Op0));
3099
3100 return nullptr;
3101}
3102
3103/// Simplify integer comparisons where at least one operand of the compare
3104/// matches an integer min/max idiom.
3105static Value *simplifyICmpWithMinMax(CmpInst::Predicate Pred, Value *LHS,
3106 Value *RHS, const SimplifyQuery &Q,
3107 unsigned MaxRecurse) {
3108 Type *ITy = GetCompareTy(LHS); // The return type.
3109 Value *A, *B;
3110 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
3111 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
3112
3113 // Signed variants on "max(a,b)>=a -> true".
3114 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
3115 if (A != RHS)
3116 std::swap(A, B); // smax(A, B) pred A.
3117 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
3118 // We analyze this as smax(A, B) pred A.
3119 P = Pred;
3120 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
3121 (A == LHS || B == LHS)) {
3122 if (A != LHS)
3123 std::swap(A, B); // A pred smax(A, B).
3124 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
3125 // We analyze this as smax(A, B) swapped-pred A.
3126 P = CmpInst::getSwappedPredicate(Pred);
3127 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
3128 (A == RHS || B == RHS)) {
3129 if (A != RHS)
3130 std::swap(A, B); // smin(A, B) pred A.
3131 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
3132 // We analyze this as smax(-A, -B) swapped-pred -A.
3133 // Note that we do not need to actually form -A or -B thanks to EqP.
3134 P = CmpInst::getSwappedPredicate(Pred);
3135 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
3136 (A == LHS || B == LHS)) {
3137 if (A != LHS)
3138 std::swap(A, B); // A pred smin(A, B).
3139 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
3140 // We analyze this as smax(-A, -B) pred -A.
3141 // Note that we do not need to actually form -A or -B thanks to EqP.
3142 P = Pred;
3143 }
3144 if (P != CmpInst::BAD_ICMP_PREDICATE) {
3145 // Cases correspond to "max(A, B) p A".
3146 switch (P) {
3147 default:
3148 break;
3149 case CmpInst::ICMP_EQ:
3150 case CmpInst::ICMP_SLE:
3151 // Equivalent to "A EqP B". This may be the same as the condition tested
3152 // in the max/min; if so, we can just return that.
3153 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
3154 return V;
3155 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
3156 return V;
3157 // Otherwise, see if "A EqP B" simplifies.
3158 if (MaxRecurse)
3159 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
3160 return V;
3161 break;
3162 case CmpInst::ICMP_NE:
3163 case CmpInst::ICMP_SGT: {
3164 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
3165 // Equivalent to "A InvEqP B". This may be the same as the condition
3166 // tested in the max/min; if so, we can just return that.
3167 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
3168 return V;
3169 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
3170 return V;
3171 // Otherwise, see if "A InvEqP B" simplifies.
3172 if (MaxRecurse)
3173 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
3174 return V;
3175 break;
3176 }
3177 case CmpInst::ICMP_SGE:
3178 // Always true.
3179 return getTrue(ITy);
3180 case CmpInst::ICMP_SLT:
3181 // Always false.
3182 return getFalse(ITy);
3183 }
3184 }
3185
3186 // Unsigned variants on "max(a,b)>=a -> true".
3187 P = CmpInst::BAD_ICMP_PREDICATE;
3188 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
3189 if (A != RHS)
3190 std::swap(A, B); // umax(A, B) pred A.
3191 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
3192 // We analyze this as umax(A, B) pred A.
3193 P = Pred;
3194 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
3195 (A == LHS || B == LHS)) {
3196 if (A != LHS)
3197 std::swap(A, B); // A pred umax(A, B).
3198 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
3199 // We analyze this as umax(A, B) swapped-pred A.
3200 P = CmpInst::getSwappedPredicate(Pred);
3201 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
3202 (A == RHS || B == RHS)) {
3203 if (A != RHS)
3204 std::swap(A, B); // umin(A, B) pred A.
3205 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
3206 // We analyze this as umax(-A, -B) swapped-pred -A.
3207 // Note that we do not need to actually form -A or -B thanks to EqP.
3208 P = CmpInst::getSwappedPredicate(Pred);
3209 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
3210 (A == LHS || B == LHS)) {
3211 if (A != LHS)
3212 std::swap(A, B); // A pred umin(A, B).
3213 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
3214 // We analyze this as umax(-A, -B) pred -A.
3215 // Note that we do not need to actually form -A or -B thanks to EqP.
3216 P = Pred;
3217 }
3218 if (P != CmpInst::BAD_ICMP_PREDICATE) {
3219 // Cases correspond to "max(A, B) p A".
3220 switch (P) {
3221 default:
3222 break;
3223 case CmpInst::ICMP_EQ:
3224 case CmpInst::ICMP_ULE:
3225 // Equivalent to "A EqP B". This may be the same as the condition tested
3226 // in the max/min; if so, we can just return that.
3227 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
3228 return V;
3229 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
3230 return V;
3231 // Otherwise, see if "A EqP B" simplifies.
3232 if (MaxRecurse)
3233 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
3234 return V;
3235 break;
3236 case CmpInst::ICMP_NE:
3237 case CmpInst::ICMP_UGT: {
3238 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
3239 // Equivalent to "A InvEqP B". This may be the same as the condition
3240 // tested in the max/min; if so, we can just return that.
3241 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
3242 return V;
3243 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
3244 return V;
3245 // Otherwise, see if "A InvEqP B" simplifies.
3246 if (MaxRecurse)
3247 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
3248 return V;
3249 break;
3250 }
3251 case CmpInst::ICMP_UGE:
3252 // Always true.
3253 return getTrue(ITy);
3254 case CmpInst::ICMP_ULT:
3255 // Always false.
3256 return getFalse(ITy);
3257 }
3258 }
3259
3260 // Variants on "max(x,y) >= min(x,z)".
3261 Value *C, *D;
3262 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
3263 match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
3264 (A == C || A == D || B == C || B == D)) {
3265 // max(x, ?) pred min(x, ?).
3266 if (Pred == CmpInst::ICMP_SGE)
3267 // Always true.
3268 return getTrue(ITy);
3269 if (Pred == CmpInst::ICMP_SLT)
3270 // Always false.
3271 return getFalse(ITy);
3272 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
3273 match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
3274 (A == C || A == D || B == C || B == D)) {
3275 // min(x, ?) pred max(x, ?).
3276 if (Pred == CmpInst::ICMP_SLE)
3277 // Always true.
3278 return getTrue(ITy);
3279 if (Pred == CmpInst::ICMP_SGT)
3280 // Always false.
3281 return getFalse(ITy);
3282 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
3283 match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
3284 (A == C || A == D || B == C || B == D)) {
3285 // max(x, ?) pred min(x, ?).
3286 if (Pred == CmpInst::ICMP_UGE)
3287 // Always true.
3288 return getTrue(ITy);
3289 if (Pred == CmpInst::ICMP_ULT)
3290 // Always false.
3291 return getFalse(ITy);
3292 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
3293 match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
3294 (A == C || A == D || B == C || B == D)) {
3295 // min(x, ?) pred max(x, ?).
3296 if (Pred == CmpInst::ICMP_ULE)
3297 // Always true.
3298 return getTrue(ITy);
3299 if (Pred == CmpInst::ICMP_UGT)
3300 // Always false.
3301 return getFalse(ITy);
3302 }
3303
3304 return nullptr;
3305}
3306
3307/// Given operands for an ICmpInst, see if we can fold the result.
3308/// If not, this returns null.
3309static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3310 const SimplifyQuery &Q, unsigned MaxRecurse) {
3311 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3312 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!")((CmpInst::isIntPredicate(Pred) && "Not an integer compare!"
) ? static_cast<void> (0) : __assert_fail ("CmpInst::isIntPredicate(Pred) && \"Not an integer compare!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 3312, __PRETTY_FUNCTION__))
;
3313
3314 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
3315 if (Constant *CRHS = dyn_cast<Constant>(RHS))
3316 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3317
3318 // If we have a constant, make sure it is on the RHS.
3319 std::swap(LHS, RHS);
3320 Pred = CmpInst::getSwappedPredicate(Pred);
3321 }
3322
3323 Type *ITy = GetCompareTy(LHS); // The return type.
3324
3325 // icmp X, X -> true/false
3326 // icmp X, undef -> true/false because undef could be X.
3327 if (LHS == RHS || isa<UndefValue>(RHS))
3328 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
3329
3330 if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
3331 return V;
3332
3333 if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
3334 return V;
3335
3336 if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS, Q.IIQ))
3337 return V;
3338
3339 // If both operands have range metadata, use the metadata
3340 // to simplify the comparison.
3341 if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
3342 auto RHS_Instr = cast<Instruction>(RHS);
3343 auto LHS_Instr = cast<Instruction>(LHS);
3344
3345 if (Q.IIQ.getMetadata(RHS_Instr, LLVMContext::MD_range) &&
3346 Q.IIQ.getMetadata(LHS_Instr, LLVMContext::MD_range)) {
3347 auto RHS_CR = getConstantRangeFromMetadata(
3348 *RHS_Instr->getMetadata(LLVMContext::MD_range));
3349 auto LHS_CR = getConstantRangeFromMetadata(
3350 *LHS_Instr->getMetadata(LLVMContext::MD_range));
3351
3352 auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
3353 if (Satisfied_CR.contains(LHS_CR))
3354 return ConstantInt::getTrue(RHS->getContext());
3355
3356 auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
3357 CmpInst::getInversePredicate(Pred), RHS_CR);
3358 if (InversedSatisfied_CR.contains(LHS_CR))
3359 return ConstantInt::getFalse(RHS->getContext());
3360 }
3361 }
3362
3363 // Compare of cast, for example (zext X) != 0 -> X != 0
3364 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
3365 Instruction *LI = cast<CastInst>(LHS);
3366 Value *SrcOp = LI->getOperand(0);
3367 Type *SrcTy = SrcOp->getType();
3368 Type *DstTy = LI->getType();
3369
3370 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3371 // if the integer type is the same size as the pointer type.
3372 if (MaxRecurse && isa<PtrToIntInst>(LI) &&
3373 Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
3374 if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
3375 // Transfer the cast to the constant.
3376 if (Value *V = SimplifyICmpInst(Pred, SrcOp,
3377 ConstantExpr::getIntToPtr(RHSC, SrcTy),
3378 Q, MaxRecurse-1))
3379 return V;
3380 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
3381 if (RI->getOperand(0)->getType() == SrcTy)
3382 // Compare without the cast.
3383 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3384 Q, MaxRecurse-1))
3385 return V;
3386 }
3387 }
3388
3389 if (isa<ZExtInst>(LHS)) {
3390 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3391 // same type.
3392 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
3393 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3394 // Compare X and Y. Note that signed predicates become unsigned.
3395 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
3396 SrcOp, RI->getOperand(0), Q,
3397 MaxRecurse-1))
3398 return V;
3399 }
3400 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3401 // too. If not, then try to deduce the result of the comparison.
3402 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3403 // Compute the constant that would happen if we truncated to SrcTy then
3404 // reextended to DstTy.
3405 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3406 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
3407
3408 // If the re-extended constant didn't change then this is effectively
3409 // also a case of comparing two zero-extended values.
3410 if (RExt == CI && MaxRecurse)
3411 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
3412 SrcOp, Trunc, Q, MaxRecurse-1))
3413 return V;
3414
3415 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3416 // there. Use this to work out the result of the comparison.
3417 if (RExt != CI) {
3418 switch (Pred) {
3419 default: llvm_unreachable("Unknown ICmp predicate!")::llvm::llvm_unreachable_internal("Unknown ICmp predicate!", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 3419)
;
3420 // LHS <u RHS.
3421 case ICmpInst::ICMP_EQ:
3422 case ICmpInst::ICMP_UGT:
3423 case ICmpInst::ICMP_UGE:
3424 return ConstantInt::getFalse(CI->getContext());
3425
3426 case ICmpInst::ICMP_NE:
3427 case ICmpInst::ICMP_ULT:
3428 case ICmpInst::ICMP_ULE:
3429 return ConstantInt::getTrue(CI->getContext());
3430
3431 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3432 // is non-negative then LHS <s RHS.
3433 case ICmpInst::ICMP_SGT:
3434 case ICmpInst::ICMP_SGE:
3435 return CI->getValue().isNegative() ?
3436 ConstantInt::getTrue(CI->getContext()) :
3437 ConstantInt::getFalse(CI->getContext());
3438
3439 case ICmpInst::ICMP_SLT:
3440 case ICmpInst::ICMP_SLE:
3441 return CI->getValue().isNegative() ?
3442 ConstantInt::getFalse(CI->getContext()) :
3443 ConstantInt::getTrue(CI->getContext());
3444 }
3445 }
3446 }
3447 }
3448
3449 if (isa<SExtInst>(LHS)) {
3450 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3451 // same type.
3452 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
3453 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
3454 // Compare X and Y. Note that the predicate does not change.
3455 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
3456 Q, MaxRecurse-1))
3457 return V;
3458 }
3459 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3460 // too. If not, then try to deduce the result of the comparison.
3461 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
3462 // Compute the constant that would happen if we truncated to SrcTy then
3463 // reextended to DstTy.
3464 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
3465 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
3466
3467 // If the re-extended constant didn't change then this is effectively
3468 // also a case of comparing two sign-extended values.
3469 if (RExt == CI && MaxRecurse)
3470 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
3471 return V;
3472
3473 // Otherwise the upper bits of LHS are all equal, while RHS has varying
3474 // bits there. Use this to work out the result of the comparison.
3475 if (RExt != CI) {
3476 switch (Pred) {
3477 default: llvm_unreachable("Unknown ICmp predicate!")::llvm::llvm_unreachable_internal("Unknown ICmp predicate!", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 3477)
;
3478 case ICmpInst::ICMP_EQ:
3479 return ConstantInt::getFalse(CI->getContext());
3480 case ICmpInst::ICMP_NE:
3481 return ConstantInt::getTrue(CI->getContext());
3482
3483 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3484 // LHS >s RHS.
3485 case ICmpInst::ICMP_SGT:
3486 case ICmpInst::ICMP_SGE:
3487 return CI->getValue().isNegative() ?
3488 ConstantInt::getTrue(CI->getContext()) :
3489 ConstantInt::getFalse(CI->getContext());
3490 case ICmpInst::ICMP_SLT:
3491 case ICmpInst::ICMP_SLE:
3492 return CI->getValue().isNegative() ?
3493 ConstantInt::getFalse(CI->getContext()) :
3494 ConstantInt::getTrue(CI->getContext());
3495
3496 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3497 // LHS >u RHS.
3498 case ICmpInst::ICMP_UGT:
3499 case ICmpInst::ICMP_UGE:
3500 // Comparison is true iff the LHS <s 0.
3501 if (MaxRecurse)
3502 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
3503 Constant::getNullValue(SrcTy),
3504 Q, MaxRecurse-1))
3505 return V;
3506 break;
3507 case ICmpInst::ICMP_ULT:
3508 case ICmpInst::ICMP_ULE:
3509 // Comparison is true iff the LHS >=s 0.
3510 if (MaxRecurse)
3511 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
3512 Constant::getNullValue(SrcTy),
3513 Q, MaxRecurse-1))
3514 return V;
3515 break;
3516 }
3517 }
3518 }
3519 }
3520 }
3521
3522 // icmp eq|ne X, Y -> false|true if X != Y
3523 if (ICmpInst::isEquality(Pred) &&
3524 isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo)) {
3525 return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
3526 }
3527
3528 if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
3529 return V;
3530
3531 if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
3532 return V;
3533
3534 if (Value *V = simplifyICmpWithAbsNabs(Pred, LHS, RHS))
3535 return V;
3536
3537 // Simplify comparisons of related pointers using a powerful, recursive
3538 // GEP-walk when we have target data available..
3539 if (LHS->getType()->isPointerTy())
3540 if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
3541 Q.IIQ, LHS, RHS))
3542 return C;
3543 if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
3544 if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
3545 if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
3546 Q.DL.getTypeSizeInBits(CLHS->getType()) &&
3547 Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
3548 Q.DL.getTypeSizeInBits(CRHS->getType()))
3549 if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
3550 Q.IIQ, CLHS->getPointerOperand(),
3551 CRHS->getPointerOperand()))
3552 return C;
3553
3554 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
3555 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
3556 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
3557 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
3558 (ICmpInst::isEquality(Pred) ||
3559 (GLHS->isInBounds() && GRHS->isInBounds() &&
3560 Pred == ICmpInst::getSignedPredicate(Pred)))) {
3561 // The bases are equal and the indices are constant. Build a constant
3562 // expression GEP with the same indices and a null base pointer to see
3563 // what constant folding can make out of it.
3564 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
3565 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
3566 Constant *NewLHS = ConstantExpr::getGetElementPtr(
3567 GLHS->getSourceElementType(), Null, IndicesLHS);
3568
3569 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
3570 Constant *NewRHS = ConstantExpr::getGetElementPtr(
3571 GLHS->getSourceElementType(), Null, IndicesRHS);
3572 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
3573 }
3574 }
3575 }
3576
3577 // If the comparison is with the result of a select instruction, check whether
3578 // comparing with either branch of the select always yields the same value.
3579 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3580 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
3581 return V;
3582
3583 // If the comparison is with the result of a phi instruction, check whether
3584 // doing the compare with each incoming phi value yields a common result.
3585 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3586 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3587 return V;
3588
3589 return nullptr;
3590}
3591
3592Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3593 const SimplifyQuery &Q) {
3594 return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3595}
3596
3597/// Given operands for an FCmpInst, see if we can fold the result.
3598/// If not, this returns null.
3599static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3600 FastMathFlags FMF, const SimplifyQuery &Q,
3601 unsigned MaxRecurse) {
3602 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
3603 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!")((CmpInst::isFPPredicate(Pred) && "Not an FP compare!"
) ? static_cast<void> (0) : __assert_fail ("CmpInst::isFPPredicate(Pred) && \"Not an FP compare!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 3603, __PRETTY_FUNCTION__))
;
4
'?' condition is true
3604
3605 if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
5
Taking false branch
3606 if (Constant *CRHS = dyn_cast<Constant>(RHS))
3607 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);
3608
3609 // If we have a constant, make sure it is on the RHS.
3610 std::swap(LHS, RHS);
3611 Pred = CmpInst::getSwappedPredicate(Pred);
3612 }
3613
3614 // Fold trivial predicates.
3615 Type *RetTy = GetCompareTy(LHS);
3616 if (Pred == FCmpInst::FCMP_FALSE)
6
Assuming 'Pred' is not equal to FCMP_FALSE
7
Taking false branch
3617 return getFalse(RetTy);
3618 if (Pred == FCmpInst::FCMP_TRUE)
8
Assuming 'Pred' is not equal to FCMP_TRUE
9
Taking false branch
3619 return getTrue(RetTy);
3620
3621 // Fold (un)ordered comparison if we can determine there are no NaNs.
3622 if (Pred == FCmpInst::FCMP_UNO || Pred == FCmpInst::FCMP_ORD)
10
Assuming 'Pred' is not equal to FCMP_UNO
11
Assuming 'Pred' is not equal to FCMP_ORD
12
Taking false branch
3623 if (FMF.noNaNs() ||
3624 (isKnownNeverNaN(LHS, Q.TLI) && isKnownNeverNaN(RHS, Q.TLI)))
3625 return ConstantInt::get(RetTy, Pred == FCmpInst::FCMP_ORD);
3626
3627 // NaN is unordered; NaN is not ordered.
3628 assert((FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) &&(((FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) &&
"Comparison must be either ordered or unordered") ? static_cast
<void> (0) : __assert_fail ("(FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) && \"Comparison must be either ordered or unordered\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 3629, __PRETTY_FUNCTION__))
13
Assuming the condition is true
14
'?' condition is true
3629 "Comparison must be either ordered or unordered")(((FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) &&
"Comparison must be either ordered or unordered") ? static_cast
<void> (0) : __assert_fail ("(FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) && \"Comparison must be either ordered or unordered\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 3629, __PRETTY_FUNCTION__))
;
3630 if (match(RHS, m_NaN()))
15
Calling 'match<llvm::Value, llvm::PatternMatch::cstfp_pred_ty<llvm::PatternMatch::is_nan>>'
17
Returning from 'match<llvm::Value, llvm::PatternMatch::cstfp_pred_ty<llvm::PatternMatch::is_nan>>'
18
Assuming the condition is false
19
Taking false branch
3631 return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3632
3633 // fcmp pred x, undef and fcmp pred undef, x
3634 // fold to true if unordered, false if ordered
3635 if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
20
Taking false branch
3636 // Choosing NaN for the undef will always make unordered comparison succeed
3637 // and ordered comparison fail.
3638 return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
3639 }
3640
3641 // fcmp x,x -> true/false. Not all compares are foldable.
3642 if (LHS == RHS) {
21
Assuming 'LHS' is not equal to 'RHS'
22
Taking false branch
3643 if (CmpInst::isTrueWhenEqual(Pred))
3644 return getTrue(RetTy);
3645 if (CmpInst::isFalseWhenEqual(Pred))
3646 return getFalse(RetTy);
3647 }
3648
3649 // Handle fcmp with constant RHS.
3650 const APFloat *C;
3651 if (match(RHS, m_APFloat(C))) {
23
Taking false branch
3652 // Check whether the constant is an infinity.
3653 if (C->isInfinity()) {
3654 if (C->isNegative()) {
3655 switch (Pred) {
3656 case FCmpInst::FCMP_OLT:
3657 // No value is ordered and less than negative infinity.
3658 return getFalse(RetTy);
3659 case FCmpInst::FCMP_UGE:
3660 // All values are unordered with or at least negative infinity.
3661 return getTrue(RetTy);
3662 default:
3663 break;
3664 }
3665 } else {
3666 switch (Pred) {
3667 case FCmpInst::FCMP_OGT:
3668 // No value is ordered and greater than infinity.
3669 return getFalse(RetTy);
3670 case FCmpInst::FCMP_ULE:
3671 // All values are unordered with and at most infinity.
3672 return getTrue(RetTy);
3673 default:
3674 break;
3675 }
3676 }
3677 }
3678 if (C->isZero()) {
3679 switch (Pred) {
3680 case FCmpInst::FCMP_OGE:
3681 if (FMF.noNaNs() && CannotBeOrderedLessThanZero(LHS, Q.TLI))
3682 return getTrue(RetTy);
3683 break;
3684 case FCmpInst::FCMP_UGE:
3685 if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3686 return getTrue(RetTy);
3687 break;
3688 case FCmpInst::FCMP_ULT:
3689 if (FMF.noNaNs() && CannotBeOrderedLessThanZero(LHS, Q.TLI))
3690 return getFalse(RetTy);
3691 break;
3692 case FCmpInst::FCMP_OLT:
3693 if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3694 return getFalse(RetTy);
3695 break;
3696 default:
3697 break;
3698 }
3699 } else if (C->isNegative()) {
3700 assert(!C->isNaN() && "Unexpected NaN constant!")((!C->isNaN() && "Unexpected NaN constant!") ? static_cast
<void> (0) : __assert_fail ("!C->isNaN() && \"Unexpected NaN constant!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 3700, __PRETTY_FUNCTION__))
;
3701 // TODO: We can catch more cases by using a range check rather than
3702 // relying on CannotBeOrderedLessThanZero.
3703 switch (Pred) {
3704 case FCmpInst::FCMP_UGE:
3705 case FCmpInst::FCMP_UGT:
3706 case FCmpInst::FCMP_UNE:
3707 // (X >= 0) implies (X > C) when (C < 0)
3708 if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3709 return getTrue(RetTy);
3710 break;
3711 case FCmpInst::FCMP_OEQ:
3712 case FCmpInst::FCMP_OLE:
3713 case FCmpInst::FCMP_OLT:
3714 // (X >= 0) implies !(X < C) when (C < 0)
3715 if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
3716 return getFalse(RetTy);
3717 break;
3718 default:
3719 break;
3720 }
3721 }
3722 }
3723
3724 // If the comparison is with the result of a select instruction, check whether
3725 // comparing with either branch of the select always yields the same value.
3726 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
3727 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
24
Calling 'ThreadCmpOverSelect'
3728 return V;
3729
3730 // If the comparison is with the result of a phi instruction, check whether
3731 // doing the compare with each incoming phi value yields a common result.
3732 if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
3733 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
3734 return V;
3735
3736 return nullptr;
3737}
3738
3739Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
3740 FastMathFlags FMF, const SimplifyQuery &Q) {
3741 return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
3742}
3743
3744/// See if V simplifies when its operand Op is replaced with RepOp.
3745static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
3746 const SimplifyQuery &Q,
3747 unsigned MaxRecurse) {
3748 // Trivial replacement.
3749 if (V == Op)
3750 return RepOp;
3751
3752 // We cannot replace a constant, and shouldn't even try.
3753 if (isa<Constant>(Op))
3754 return nullptr;
3755
3756 auto *I = dyn_cast<Instruction>(V);
3757 if (!I)
3758 return nullptr;
3759
3760 // If this is a binary operator, try to simplify it with the replaced op.
3761 if (auto *B = dyn_cast<BinaryOperator>(I)) {
3762 // Consider:
3763 // %cmp = icmp eq i32 %x, 2147483647
3764 // %add = add nsw i32 %x, 1
3765 // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3766 //
3767 // We can't replace %sel with %add unless we strip away the flags.
3768 if (isa<OverflowingBinaryOperator>(B))
3769 if (Q.IIQ.hasNoSignedWrap(B) || Q.IIQ.hasNoUnsignedWrap(B))
3770 return nullptr;
3771 if (isa<PossiblyExactOperator>(B) && Q.IIQ.isExact(B))
3772 return nullptr;
3773
3774 if (MaxRecurse) {
3775 if (B->getOperand(0) == Op)
3776 return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
3777 MaxRecurse - 1);
3778 if (B->getOperand(1) == Op)
3779 return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
3780 MaxRecurse - 1);
3781 }
3782 }
3783
3784 // Same for CmpInsts.
3785 if (CmpInst *C = dyn_cast<CmpInst>(I)) {
3786 if (MaxRecurse) {
3787 if (C->getOperand(0) == Op)
3788 return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
3789 MaxRecurse - 1);
3790 if (C->getOperand(1) == Op)
3791 return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
3792 MaxRecurse - 1);
3793 }
3794 }
3795
3796 // Same for GEPs.
3797 if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
3798 if (MaxRecurse) {
3799 SmallVector<Value *, 8> NewOps(GEP->getNumOperands());
3800 transform(GEP->operands(), NewOps.begin(),
3801 [&](Value *V) { return V == Op ? RepOp : V; });
3802 return SimplifyGEPInst(GEP->getSourceElementType(), NewOps, Q,
3803 MaxRecurse - 1);
3804 }
3805 }
3806
3807 // TODO: We could hand off more cases to instsimplify here.
3808
3809 // If all operands are constant after substituting Op for RepOp then we can
3810 // constant fold the instruction.
3811 if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
3812 // Build a list of all constant operands.
3813 SmallVector<Constant *, 8> ConstOps;
3814 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
3815 if (I->getOperand(i) == Op)
3816 ConstOps.push_back(CRepOp);
3817 else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
3818 ConstOps.push_back(COp);
3819 else
3820 break;
3821 }
3822
3823 // All operands were constants, fold it.
3824 if (ConstOps.size() == I->getNumOperands()) {
3825 if (CmpInst *C = dyn_cast<CmpInst>(I))
3826 return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
3827 ConstOps[1], Q.DL, Q.TLI);
3828
3829 if (LoadInst *LI = dyn_cast<LoadInst>(I))
3830 if (!LI->isVolatile())
3831 return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);
3832
3833 return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
3834 }
3835 }
3836
3837 return nullptr;
3838}
3839
3840/// Try to simplify a select instruction when its condition operand is an
3841/// integer comparison where one operand of the compare is a constant.
3842static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
3843 const APInt *Y, bool TrueWhenUnset) {
3844 const APInt *C;
3845
3846 // (X & Y) == 0 ? X & ~Y : X --> X
3847 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3848 if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
3849 *Y == ~*C)
3850 return TrueWhenUnset ? FalseVal : TrueVal;
3851
3852 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3853 // (X & Y) != 0 ? X : X & ~Y --> X
3854 if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
3855 *Y == ~*C)
3856 return TrueWhenUnset ? FalseVal : TrueVal;
3857
3858 if (Y->isPowerOf2()) {
3859 // (X & Y) == 0 ? X | Y : X --> X | Y
3860 // (X & Y) != 0 ? X | Y : X --> X
3861 if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
3862 *Y == *C)
3863 return TrueWhenUnset ? TrueVal : FalseVal;
3864
3865 // (X & Y) == 0 ? X : X | Y --> X
3866 // (X & Y) != 0 ? X : X | Y --> X | Y
3867 if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
3868 *Y == *C)
3869 return TrueWhenUnset ? TrueVal : FalseVal;
3870 }
3871
3872 return nullptr;
3873}
3874
3875/// An alternative way to test if a bit is set or not uses sgt/slt instead of
3876/// eq/ne.
3877static Value *simplifySelectWithFakeICmpEq(Value *CmpLHS, Value *CmpRHS,
3878 ICmpInst::Predicate Pred,
3879 Value *TrueVal, Value *FalseVal) {
3880 Value *X;
3881 APInt Mask;
3882 if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask))
3883 return nullptr;
3884
3885 return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask,
3886 Pred == ICmpInst::ICMP_EQ);
3887}
3888
3889/// Try to simplify a select instruction when its condition operand is an
3890/// integer comparison.
3891static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
3892 Value *FalseVal, const SimplifyQuery &Q,
3893 unsigned MaxRecurse) {
3894 ICmpInst::Predicate Pred;
3895 Value *CmpLHS, *CmpRHS;
3896 if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
3897 return nullptr;
3898
3899 if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
3900 Value *X;
3901 const APInt *Y;
3902 if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
3903 if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
3904 Pred == ICmpInst::ICMP_EQ))
3905 return V;
3906
3907 // Test for zero-shift-guard-ops around funnel shifts. These are used to
3908 // avoid UB from oversized shifts in raw IR rotate patterns, but the
3909 // intrinsics do not have that problem.
3910 Value *ShAmt;
3911 auto isFsh = m_CombineOr(m_Intrinsic<Intrinsic::fshl>(m_Value(X), m_Value(),
3912 m_Value(ShAmt)),
3913 m_Intrinsic<Intrinsic::fshr>(m_Value(), m_Value(X),
3914 m_Value(ShAmt)));
3915 // (ShAmt != 0) ? fshl(X, *, ShAmt) : X --> fshl(X, *, ShAmt)
3916 // (ShAmt != 0) ? fshr(*, X, ShAmt) : X --> fshr(*, X, ShAmt)
3917 // (ShAmt == 0) ? fshl(X, *, ShAmt) : X --> X
3918 // (ShAmt == 0) ? fshr(*, X, ShAmt) : X --> X
3919 if (match(TrueVal, isFsh) && FalseVal == X && CmpLHS == ShAmt)
3920 return Pred == ICmpInst::ICMP_NE ? TrueVal : X;
3921
3922 // (ShAmt == 0) ? X : fshl(X, *, ShAmt) --> fshl(X, *, ShAmt)
3923 // (ShAmt == 0) ? X : fshr(*, X, ShAmt) --> fshr(*, X, ShAmt)
3924 // (ShAmt != 0) ? X : fshl(X, *, ShAmt) --> X
3925 // (ShAmt != 0) ? X : fshr(*, X, ShAmt) --> X
3926 if (match(FalseVal, isFsh) && TrueVal == X && CmpLHS == ShAmt)
3927 return Pred == ICmpInst::ICMP_EQ ? FalseVal : X;
3928 }
3929
3930 // Check for other compares that behave like bit test.
3931 if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred,
3932 TrueVal, FalseVal))
3933 return V;
3934
3935 // If we have an equality comparison, then we know the value in one of the
3936 // arms of the select. See if substituting this value into the arm and
3937 // simplifying the result yields the same value as the other arm.
3938 if (Pred == ICmpInst::ICMP_EQ) {
3939 if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3940 TrueVal ||
3941 SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3942 TrueVal)
3943 return FalseVal;
3944 if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3945 FalseVal ||
3946 SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3947 FalseVal)
3948 return FalseVal;
3949 } else if (Pred == ICmpInst::ICMP_NE) {
3950 if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3951 FalseVal ||
3952 SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3953 FalseVal)
3954 return TrueVal;
3955 if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
3956 TrueVal ||
3957 SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
3958 TrueVal)
3959 return TrueVal;
3960 }
3961
3962 return nullptr;
3963}
3964
3965/// Try to simplify a select instruction when its condition operand is a
3966/// floating-point comparison.
3967static Value *simplifySelectWithFCmp(Value *Cond, Value *T, Value *F) {
3968 FCmpInst::Predicate Pred;
3969 if (!match(Cond, m_FCmp(Pred, m_Specific(T), m_Specific(F))) &&
3970 !match(Cond, m_FCmp(Pred, m_Specific(F), m_Specific(T))))
3971 return nullptr;
3972
3973 // TODO: The transform may not be valid with -0.0. An incomplete way of
3974 // testing for that possibility is to check if at least one operand is a
3975 // non-zero constant.
3976 const APFloat *C;
3977 if ((match(T, m_APFloat(C)) && C->isNonZero()) ||
3978 (match(F, m_APFloat(C)) && C->isNonZero())) {
3979 // (T == F) ? T : F --> F
3980 // (F == T) ? T : F --> F
3981 if (Pred == FCmpInst::FCMP_OEQ)
3982 return F;
3983
3984 // (T != F) ? T : F --> T
3985 // (F != T) ? T : F --> T
3986 if (Pred == FCmpInst::FCMP_UNE)
3987 return T;
3988 }
3989
3990 return nullptr;
3991}
3992
3993/// Given operands for a SelectInst, see if we can fold the result.
3994/// If not, this returns null.
3995static Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
3996 const SimplifyQuery &Q, unsigned MaxRecurse) {
3997 if (auto *CondC = dyn_cast<Constant>(Cond)) {
3998 if (auto *TrueC = dyn_cast<Constant>(TrueVal))
3999 if (auto *FalseC = dyn_cast<Constant>(FalseVal))
4000 return ConstantFoldSelectInstruction(CondC, TrueC, FalseC);
4001
4002 // select undef, X, Y -> X or Y
4003 if (isa<UndefValue>(CondC))
4004 return isa<Constant>(FalseVal) ? FalseVal : TrueVal;
4005
4006 // TODO: Vector constants with undef elements don't simplify.
4007
4008 // select true, X, Y -> X
4009 if (CondC->isAllOnesValue())
4010 return TrueVal;
4011 // select false, X, Y -> Y
4012 if (CondC->isNullValue())
4013 return FalseVal;
4014 }
4015
4016 // select ?, X, X -> X
4017 if (TrueVal == FalseVal)
4018 return TrueVal;
4019
4020 if (isa<UndefValue>(TrueVal)) // select ?, undef, X -> X
4021 return FalseVal;
4022 if (isa<UndefValue>(FalseVal)) // select ?, X, undef -> X
4023 return TrueVal;
4024
4025 if (Value *V =
4026 simplifySelectWithICmpCond(Cond, TrueVal, FalseVal, Q, MaxRecurse))
4027 return V;
4028
4029 if (Value *V = simplifySelectWithFCmp(Cond, TrueVal, FalseVal))
4030 return V;
4031
4032 if (Value *V = foldSelectWithBinaryOp(Cond, TrueVal, FalseVal))
4033 return V;
4034
4035 Optional<bool> Imp = isImpliedByDomCondition(Cond, Q.CxtI, Q.DL);
4036 if (Imp)
4037 return *Imp ? TrueVal : FalseVal;
4038
4039 return nullptr;
4040}
4041
4042Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
4043 const SimplifyQuery &Q) {
4044 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
4045}
4046
4047/// Given operands for an GetElementPtrInst, see if we can fold the result.
4048/// If not, this returns null.
4049static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
4050 const SimplifyQuery &Q, unsigned) {
4051 // The type of the GEP pointer operand.
4052 unsigned AS =
4053 cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();
4054
4055 // getelementptr P -> P.
4056 if (Ops.size() == 1)
4057 return Ops[0];
4058
4059 // Compute the (pointer) type returned by the GEP instruction.
4060 Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
4061 Type *GEPTy = PointerType::get(LastType, AS);
4062 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
4063 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
4064 else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
4065 GEPTy = VectorType::get(GEPTy, VT->getNumElements());
4066
4067 if (isa<UndefValue>(Ops[0]))
4068 return UndefValue::get(GEPTy);
4069
4070 if (Ops.size() == 2) {
4071 // getelementptr P, 0 -> P.
4072 if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy)
4073 return Ops[0];
4074
4075 Type *Ty = SrcTy;
4076 if (Ty->isSized()) {
4077 Value *P;
4078 uint64_t C;
4079 uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
4080 // getelementptr P, N -> P if P points to a type of zero size.
4081 if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy)
4082 return Ops[0];
4083
4084 // The following transforms are only safe if the ptrtoint cast
4085 // doesn't truncate the pointers.
4086 if (Ops[1]->getType()->getScalarSizeInBits() ==
4087 Q.DL.getIndexSizeInBits(AS)) {
4088 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
4089 if (match(P, m_Zero()))
4090 return Constant::getNullValue(GEPTy);
4091 Value *Temp;
4092 if (match(P, m_PtrToInt(m_Value(Temp))))
4093 if (Temp->getType() == GEPTy)
4094 return Temp;
4095 return nullptr;
4096 };
4097
4098 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
4099 if (TyAllocSize == 1 &&
4100 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
4101 if (Value *R = PtrToIntOrZero(P))
4102 return R;
4103
4104 // getelementptr V, (ashr (sub P, V), C) -> Q
4105 // if P points to a type of size 1 << C.
4106 if (match(Ops[1],
4107 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
4108 m_ConstantInt(C))) &&
4109 TyAllocSize == 1ULL << C)
4110 if (Value *R = PtrToIntOrZero(P))
4111 return R;
4112
4113 // getelementptr V, (sdiv (sub P, V), C) -> Q
4114 // if P points to a type of size C.
4115 if (match(Ops[1],
4116 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
4117 m_SpecificInt(TyAllocSize))))
4118 if (Value *R = PtrToIntOrZero(P))
4119 return R;
4120 }
4121 }
4122 }
4123
4124 if (Q.DL.getTypeAllocSize(LastType) == 1 &&
4125 all_of(Ops.slice(1).drop_back(1),
4126 [](Value *Idx) { return match(Idx, m_Zero()); })) {
4127 unsigned IdxWidth =
4128 Q.DL.getIndexSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
4129 if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == IdxWidth) {
4130 APInt BasePtrOffset(IdxWidth, 0);
4131 Value *StrippedBasePtr =
4132 Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
4133 BasePtrOffset);
4134
4135 // gep (gep V, C), (sub 0, V) -> C
4136 if (match(Ops.back(),
4137 m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
4138 auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
4139 return ConstantExpr::getIntToPtr(CI, GEPTy);
4140 }
4141 // gep (gep V, C), (xor V, -1) -> C-1
4142 if (match(Ops.back(),
4143 m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
4144 auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
4145 return ConstantExpr::getIntToPtr(CI, GEPTy);
4146 }
4147 }
4148 }
4149
4150 // Check to see if this is constant foldable.
4151 if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
4152 return nullptr;
4153
4154 auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
4155 Ops.slice(1));
4156 if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
4157 return CEFolded;
4158 return CE;
4159}
4160
4161Value *llvm::SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
4162 const SimplifyQuery &Q) {
4163 return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
4164}
4165
4166/// Given operands for an InsertValueInst, see if we can fold the result.
4167/// If not, this returns null.
4168static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
4169 ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
4170 unsigned) {
4171 if (Constant *CAgg = dyn_cast<Constant>(Agg))
4172 if (Constant *CVal = dyn_cast<Constant>(Val))
4173 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
4174
4175 // insertvalue x, undef, n -> x
4176 if (match(Val, m_Undef()))
4177 return Agg;
4178
4179 // insertvalue x, (extractvalue y, n), n
4180 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
4181 if (EV->getAggregateOperand()->getType() == Agg->getType() &&
4182 EV->getIndices() == Idxs) {
4183 // insertvalue undef, (extractvalue y, n), n -> y
4184 if (match(Agg, m_Undef()))
4185 return EV->getAggregateOperand();
4186
4187 // insertvalue y, (extractvalue y, n), n -> y
4188 if (Agg == EV->getAggregateOperand())
4189 return Agg;
4190 }
4191
4192 return nullptr;
4193}
4194
4195Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
4196 ArrayRef<unsigned> Idxs,
4197 const SimplifyQuery &Q) {
4198 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Q, RecursionLimit);
4199}
4200
4201Value *llvm::SimplifyInsertElementInst(Value *Vec, Value *Val, Value *Idx,
4202 const SimplifyQuery &Q) {
4203 // Try to constant fold.
4204 auto *VecC = dyn_cast<Constant>(Vec);
4205 auto *ValC = dyn_cast<Constant>(Val);
4206 auto *IdxC = dyn_cast<Constant>(Idx);
4207 if (VecC && ValC && IdxC)
4208 return ConstantFoldInsertElementInstruction(VecC, ValC, IdxC);
4209
4210 // Fold into undef if index is out of bounds.
4211 if (auto *CI = dyn_cast<ConstantInt>(Idx)) {
4212 uint64_t NumElements = cast<VectorType>(Vec->getType())->getNumElements();
4213 if (CI->uge(NumElements))
4214 return UndefValue::get(Vec->getType());
4215 }
4216
4217 // If index is undef, it might be out of bounds (see above case)
4218 if (isa<UndefValue>(Idx))
4219 return UndefValue::get(Vec->getType());
4220
4221 return nullptr;
4222}
4223
4224/// Given operands for an ExtractValueInst, see if we can fold the result.
4225/// If not, this returns null.
4226static Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
4227 const SimplifyQuery &, unsigned) {
4228 if (auto *CAgg = dyn_cast<Constant>(Agg))
4229 return ConstantFoldExtractValueInstruction(CAgg, Idxs);
4230
4231 // extractvalue x, (insertvalue y, elt, n), n -> elt
4232 unsigned NumIdxs = Idxs.size();
4233 for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
4234 IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
4235 ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
4236 unsigned NumInsertValueIdxs = InsertValueIdxs.size();
4237 unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
4238 if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
4239 Idxs.slice(0, NumCommonIdxs)) {
4240 if (NumIdxs == NumInsertValueIdxs)
4241 return IVI->getInsertedValueOperand();
4242 break;
4243 }
4244 }
4245
4246 return nullptr;
4247}
4248
4249Value *llvm::SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
4250 const SimplifyQuery &Q) {
4251 return ::SimplifyExtractValueInst(Agg, Idxs, Q, RecursionLimit);
4252}
4253
4254/// Given operands for an ExtractElementInst, see if we can fold the result.
4255/// If not, this returns null.
4256static Value *SimplifyExtractElementInst(Value *Vec, Value *Idx, const SimplifyQuery &,
4257 unsigned) {
4258 if (auto *CVec = dyn_cast<Constant>(Vec)) {
4259 if (auto *CIdx = dyn_cast<Constant>(Idx))
4260 return ConstantFoldExtractElementInstruction(CVec, CIdx);
4261
4262 // The index is not relevant if our vector is a splat.
4263 if (auto *Splat = CVec->getSplatValue())
4264 return Splat;
4265
4266 if (isa<UndefValue>(Vec))
4267 return UndefValue::get(Vec->getType()->getVectorElementType());
4268 }
4269
4270 // If extracting a specified index from the vector, see if we can recursively
4271 // find a previously computed scalar that was inserted into the vector.
4272 if (auto *IdxC = dyn_cast<ConstantInt>(Idx)) {
4273 if (IdxC->getValue().uge(Vec->getType()->getVectorNumElements()))
4274 // definitely out of bounds, thus undefined result
4275 return UndefValue::get(Vec->getType()->getVectorElementType());
4276 if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
4277 return Elt;
4278 }
4279
4280 // An undef extract index can be arbitrarily chosen to be an out-of-range
4281 // index value, which would result in the instruction being undef.
4282 if (isa<UndefValue>(Idx))
4283 return UndefValue::get(Vec->getType()->getVectorElementType());
4284
4285 return nullptr;
4286}
4287
4288Value *llvm::SimplifyExtractElementInst(Value *Vec, Value *Idx,
4289 const SimplifyQuery &Q) {
4290 return ::SimplifyExtractElementInst(Vec, Idx, Q, RecursionLimit);
4291}
4292
4293/// See if we can fold the given phi. If not, returns null.
4294static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
4295 // If all of the PHI's incoming values are the same then replace the PHI node
4296 // with the common value.
4297 Value *CommonValue = nullptr;
4298 bool HasUndefInput = false;
4299 for (Value *Incoming : PN->incoming_values()) {
4300 // If the incoming value is the phi node itself, it can safely be skipped.
4301 if (Incoming == PN) continue;
4302 if (isa<UndefValue>(Incoming)) {
4303 // Remember that we saw an undef value, but otherwise ignore them.
4304 HasUndefInput = true;
4305 continue;
4306 }
4307 if (CommonValue && Incoming != CommonValue)
4308 return nullptr; // Not the same, bail out.
4309 CommonValue = Incoming;
4310 }
4311
4312 // If CommonValue is null then all of the incoming values were either undef or
4313 // equal to the phi node itself.
4314 if (!CommonValue)
4315 return UndefValue::get(PN->getType());
4316
4317 // If we have a PHI node like phi(X, undef, X), where X is defined by some
4318 // instruction, we cannot return X as the result of the PHI node unless it
4319 // dominates the PHI block.
4320 if (HasUndefInput)
4321 return valueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
4322
4323 return CommonValue;
4324}
4325
4326static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
4327 Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
4328 if (auto *C = dyn_cast<Constant>(Op))
4329 return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);
4330
4331 if (auto *CI = dyn_cast<CastInst>(Op)) {
4332 auto *Src = CI->getOperand(0);
4333 Type *SrcTy = Src->getType();
4334 Type *MidTy = CI->getType();
4335 Type *DstTy = Ty;
4336 if (Src->getType() == Ty) {
4337 auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
4338 auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
4339 Type *SrcIntPtrTy =
4340 SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
4341 Type *MidIntPtrTy =
4342 MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
4343 Type *DstIntPtrTy =
4344 DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
4345 if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
4346 SrcIntPtrTy, MidIntPtrTy,
4347 DstIntPtrTy) == Instruction::BitCast)
4348 return Src;
4349 }
4350 }
4351
4352 // bitcast x -> x
4353 if (CastOpc == Instruction::BitCast)
4354 if (Op->getType() == Ty)
4355 return Op;
4356
4357 return nullptr;
4358}
4359
4360Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
4361 const SimplifyQuery &Q) {
4362 return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
4363}
4364
4365/// For the given destination element of a shuffle, peek through shuffles to
4366/// match a root vector source operand that contains that element in the same
4367/// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
4368static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
4369 int MaskVal, Value *RootVec,
4370 unsigned MaxRecurse) {
4371 if (!MaxRecurse--)
4372 return nullptr;
4373
4374 // Bail out if any mask value is undefined. That kind of shuffle may be
4375 // simplified further based on demanded bits or other folds.
4376 if (MaskVal == -1)
4377 return nullptr;
4378
4379 // The mask value chooses which source operand we need to look at next.
4380 int InVecNumElts = Op0->getType()->getVectorNumElements();
4381 int RootElt = MaskVal;
4382 Value *SourceOp = Op0;
4383 if (MaskVal >= InVecNumElts) {
4384 RootElt = MaskVal - InVecNumElts;
4385 SourceOp = Op1;
4386 }
4387
4388 // If the source operand is a shuffle itself, look through it to find the
4389 // matching root vector.
4390 if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
4391 return foldIdentityShuffles(
4392 DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
4393 SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
4394 }
4395
4396 // TODO: Look through bitcasts? What if the bitcast changes the vector element
4397 // size?
4398
4399 // The source operand is not a shuffle. Initialize the root vector value for
4400 // this shuffle if that has not been done yet.
4401 if (!RootVec)
4402 RootVec = SourceOp;
4403
4404 // Give up as soon as a source operand does not match the existing root value.
4405 if (RootVec != SourceOp)
4406 return nullptr;
4407
4408 // The element must be coming from the same lane in the source vector
4409 // (although it may have crossed lanes in intermediate shuffles).
4410 if (RootElt != DestElt)
4411 return nullptr;
4412
4413 return RootVec;
4414}
4415
4416static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
4417 Type *RetTy, const SimplifyQuery &Q,
4418 unsigned MaxRecurse) {
4419 if (isa<UndefValue>(Mask))
4420 return UndefValue::get(RetTy);
4421
4422 Type *InVecTy = Op0->getType();
4423 unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
4424 unsigned InVecNumElts = InVecTy->getVectorNumElements();
4425
4426 SmallVector<int, 32> Indices;
4427 ShuffleVectorInst::getShuffleMask(Mask, Indices);
4428 assert(MaskNumElts == Indices.size() &&((MaskNumElts == Indices.size() && "Size of Indices not same as number of mask elements?"
) ? static_cast<void> (0) : __assert_fail ("MaskNumElts == Indices.size() && \"Size of Indices not same as number of mask elements?\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 4429, __PRETTY_FUNCTION__))
4429 "Size of Indices not same as number of mask elements?")((MaskNumElts == Indices.size() && "Size of Indices not same as number of mask elements?"
) ? static_cast<void> (0) : __assert_fail ("MaskNumElts == Indices.size() && \"Size of Indices not same as number of mask elements?\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 4429, __PRETTY_FUNCTION__))
;
4430
4431 // Canonicalization: If mask does not select elements from an input vector,
4432 // replace that input vector with undef.
4433 bool MaskSelects0 = false, MaskSelects1 = false;
4434 for (unsigned i = 0; i != MaskNumElts; ++i) {
4435 if (Indices[i] == -1)
4436 continue;
4437 if ((unsigned)Indices[i] < InVecNumElts)
4438 MaskSelects0 = true;
4439 else
4440 MaskSelects1 = true;
4441 }
4442 if (!MaskSelects0)
4443 Op0 = UndefValue::get(InVecTy);
4444 if (!MaskSelects1)
4445 Op1 = UndefValue::get(InVecTy);
4446
4447 auto *Op0Const = dyn_cast<Constant>(Op0);
4448 auto *Op1Const = dyn_cast<Constant>(Op1);
4449
4450 // If all operands are constant, constant fold the shuffle.
4451 if (Op0Const && Op1Const)
4452 return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);
4453
4454 // Canonicalization: if only one input vector is constant, it shall be the
4455 // second one.
4456 if (Op0Const && !Op1Const) {
4457 std::swap(Op0, Op1);
4458 ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
4459 }
4460
4461 // A shuffle of a splat is always the splat itself. Legal if the shuffle's
4462 // value type is same as the input vectors' type.
4463 if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
4464 if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
4465 OpShuf->getMask()->getSplatValue())
4466 return Op0;
4467
4468 // Don't fold a shuffle with undef mask elements. This may get folded in a
4469 // better way using demanded bits or other analysis.
4470 // TODO: Should we allow this?
4471 if (find(Indices, -1) != Indices.end())
4472 return nullptr;
4473
4474 // Check if every element of this shuffle can be mapped back to the
4475 // corresponding element of a single root vector. If so, we don't need this
4476 // shuffle. This handles simple identity shuffles as well as chains of
4477 // shuffles that may widen/narrow and/or move elements across lanes and back.
4478 Value *RootVec = nullptr;
4479 for (unsigned i = 0; i != MaskNumElts; ++i) {
4480 // Note that recursion is limited for each vector element, so if any element
4481 // exceeds the limit, this will fail to simplify.
4482 RootVec =
4483 foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);
4484
4485 // We can't replace a widening/narrowing shuffle with one of its operands.
4486 if (!RootVec || RootVec->getType() != RetTy)
4487 return nullptr;
4488 }
4489 return RootVec;
4490}
4491
4492/// Given operands for a ShuffleVectorInst, fold the result or return null.
4493Value *llvm::SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
4494 Type *RetTy, const SimplifyQuery &Q) {
4495 return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
4496}
4497
4498static Constant *propagateNaN(Constant *In) {
4499 // If the input is a vector with undef elements, just return a default NaN.
4500 if (!In->isNaN())
4501 return ConstantFP::getNaN(In->getType());
4502
4503 // Propagate the existing NaN constant when possible.
4504 // TODO: Should we quiet a signaling NaN?
4505 return In;
4506}
4507
4508static Constant *simplifyFPBinop(Value *Op0, Value *Op1) {
4509 if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
4510 return ConstantFP::getNaN(Op0->getType());
4511
4512 if (match(Op0, m_NaN()))
4513 return propagateNaN(cast<Constant>(Op0));
4514 if (match(Op1, m_NaN()))
4515 return propagateNaN(cast<Constant>(Op1));
4516
4517 return nullptr;
4518}
4519
4520/// Given operands for an FAdd, see if we can fold the result. If not, this
4521/// returns null.
4522static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4523 const SimplifyQuery &Q, unsigned MaxRecurse) {
4524 if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
4525 return C;
4526
4527 if (Constant *C = simplifyFPBinop(Op0, Op1))
4528 return C;
4529
4530 // fadd X, -0 ==> X
4531 if (match(Op1, m_NegZeroFP()))
4532 return Op0;
4533
4534 // fadd X, 0 ==> X, when we know X is not -0
4535 if (match(Op1, m_PosZeroFP()) &&
4536 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4537 return Op0;
4538
4539 // With nnan: (+/-0.0 - X) + X --> 0.0 (and commuted variant)
4540 // We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN.
4541 // Negative zeros are allowed because we always end up with positive zero:
4542 // X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4543 // X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4544 // X = 0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0
4545 // X = 0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0
4546 if (FMF.noNaNs() && (match(Op0, m_FSub(m_AnyZeroFP(), m_Specific(Op1))) ||
4547 match(Op1, m_FSub(m_AnyZeroFP(), m_Specific(Op0)))))
4548 return ConstantFP::getNullValue(Op0->getType());
4549
4550 // (X - Y) + Y --> X
4551 // Y + (X - Y) --> X
4552 Value *X;
4553 if (FMF.noSignedZeros() && FMF.allowReassoc() &&
4554 (match(Op0, m_FSub(m_Value(X), m_Specific(Op1))) ||
4555 match(Op1, m_FSub(m_Value(X), m_Specific(Op0)))))
4556 return X;
4557
4558 return nullptr;
4559}
4560
4561/// Given operands for an FSub, see if we can fold the result. If not, this
4562/// returns null.
4563static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4564 const SimplifyQuery &Q, unsigned MaxRecurse) {
4565 if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
4566 return C;
4567
4568 if (Constant *C = simplifyFPBinop(Op0, Op1))
4569 return C;
4570
4571 // fsub X, +0 ==> X
4572 if (match(Op1, m_PosZeroFP()))
4573 return Op0;
4574
4575 // fsub X, -0 ==> X, when we know X is not -0
4576 if (match(Op1, m_NegZeroFP()) &&
4577 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
4578 return Op0;
4579
4580 // fsub -0.0, (fsub -0.0, X) ==> X
4581 Value *X;
4582 if (match(Op0, m_NegZeroFP()) &&
4583 match(Op1, m_FSub(m_NegZeroFP(), m_Value(X))))
4584 return X;
4585
4586 // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
4587 if (FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()) &&
4588 match(Op1, m_FSub(m_AnyZeroFP(), m_Value(X))))
4589 return X;
4590
4591 // fsub nnan x, x ==> 0.0
4592 if (FMF.noNaNs() && Op0 == Op1)
4593 return Constant::getNullValue(Op0->getType());
4594
4595 // Y - (Y - X) --> X
4596 // (X + Y) - Y --> X
4597 if (FMF.noSignedZeros() && FMF.allowReassoc() &&
4598 (match(Op1, m_FSub(m_Specific(Op0), m_Value(X))) ||
4599 match(Op0, m_c_FAdd(m_Specific(Op1), m_Value(X)))))
4600 return X;
4601
4602 return nullptr;
4603}
4604
4605/// Given the operands for an FMul, see if we can fold the result
4606static Value *SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4607 const SimplifyQuery &Q, unsigned MaxRecurse) {
4608 if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
4609 return C;
4610
4611 if (Constant *C = simplifyFPBinop(Op0, Op1))
4612 return C;
4613
4614 // fmul X, 1.0 ==> X
4615 if (match(Op1, m_FPOne()))
4616 return Op0;
4617
4618 // fmul nnan nsz X, 0 ==> 0
4619 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZeroFP()))
4620 return ConstantFP::getNullValue(Op0->getType());
4621
4622 // sqrt(X) * sqrt(X) --> X, if we can:
4623 // 1. Remove the intermediate rounding (reassociate).
4624 // 2. Ignore non-zero negative numbers because sqrt would produce NAN.
4625 // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
4626 Value *X;
4627 if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))) &&
4628 FMF.allowReassoc() && FMF.noNaNs() && FMF.noSignedZeros())
4629 return X;
4630
4631 return nullptr;
4632}
4633
4634Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4635 const SimplifyQuery &Q) {
4636 return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
4637}
4638
4639
4640Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4641 const SimplifyQuery &Q) {
4642 return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
4643}
4644
4645Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4646 const SimplifyQuery &Q) {
4647 return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
4648}
4649
4650static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4651 const SimplifyQuery &Q, unsigned) {
4652 if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
4653 return C;
4654
4655 if (Constant *C = simplifyFPBinop(Op0, Op1))
4656 return C;
4657
4658 // X / 1.0 -> X
4659 if (match(Op1, m_FPOne()))
4660 return Op0;
4661
4662 // 0 / X -> 0
4663 // Requires that NaNs are off (X could be zero) and signed zeroes are
4664 // ignored (X could be positive or negative, so the output sign is unknown).
4665 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()))
4666 return ConstantFP::getNullValue(Op0->getType());
4667
4668 if (FMF.noNaNs()) {
4669 // X / X -> 1.0 is legal when NaNs are ignored.
4670 // We can ignore infinities because INF/INF is NaN.
4671 if (Op0 == Op1)
4672 return ConstantFP::get(Op0->getType(), 1.0);
4673
4674 // (X * Y) / Y --> X if we can reassociate to the above form.
4675 Value *X;
4676 if (FMF.allowReassoc() && match(Op0, m_c_FMul(m_Value(X), m_Specific(Op1))))
4677 return X;
4678
4679 // -X / X -> -1.0 and
4680 // X / -X -> -1.0 are legal when NaNs are ignored.
4681 // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
4682 if (match(Op0, m_FNegNSZ(m_Specific(Op1))) ||
4683 match(Op1, m_FNegNSZ(m_Specific(Op0))))
4684 return ConstantFP::get(Op0->getType(), -1.0);
4685 }
4686
4687 return nullptr;
4688}
4689
4690Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4691 const SimplifyQuery &Q) {
4692 return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
4693}
4694
4695static Value *SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4696 const SimplifyQuery &Q, unsigned) {
4697 if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
4698 return C;
4699
4700 if (Constant *C = simplifyFPBinop(Op0, Op1))
4701 return C;
4702
4703 // Unlike fdiv, the result of frem always matches the sign of the dividend.
4704 // The constant match may include undef elements in a vector, so return a full
4705 // zero constant as the result.
4706 if (FMF.noNaNs()) {
4707 // +0 % X -> 0
4708 if (match(Op0, m_PosZeroFP()))
4709 return ConstantFP::getNullValue(Op0->getType());
4710 // -0 % X -> -0
4711 if (match(Op0, m_NegZeroFP()))
4712 return ConstantFP::getNegativeZero(Op0->getType());
4713 }
4714
4715 return nullptr;
4716}
4717
4718Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
4719 const SimplifyQuery &Q) {
4720 return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
4721}
4722
4723//=== Helper functions for higher up the class hierarchy.
4724
4725/// Given operands for a BinaryOperator, see if we can fold the result.
4726/// If not, this returns null.
4727static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4728 const SimplifyQuery &Q, unsigned MaxRecurse) {
4729 switch (Opcode) {
4730 case Instruction::Add:
4731 return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
4732 case Instruction::Sub:
4733 return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
4734 case Instruction::Mul:
4735 return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
4736 case Instruction::SDiv:
4737 return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
4738 case Instruction::UDiv:
4739 return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
4740 case Instruction::SRem:
4741 return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
4742 case Instruction::URem:
4743 return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
4744 case Instruction::Shl:
4745 return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
4746 case Instruction::LShr:
4747 return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
4748 case Instruction::AShr:
4749 return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
4750 case Instruction::And:
4751 return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
4752 case Instruction::Or:
4753 return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
4754 case Instruction::Xor:
4755 return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
4756 case Instruction::FAdd:
4757 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4758 case Instruction::FSub:
4759 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4760 case Instruction::FMul:
4761 return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4762 case Instruction::FDiv:
4763 return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4764 case Instruction::FRem:
4765 return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4766 default:
4767 llvm_unreachable("Unexpected opcode")::llvm::llvm_unreachable_internal("Unexpected opcode", "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 4767)
;
4768 }
4769}
4770
4771/// Given operands for a BinaryOperator, see if we can fold the result.
4772/// If not, this returns null.
4773/// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4774/// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4775static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4776 const FastMathFlags &FMF, const SimplifyQuery &Q,
4777 unsigned MaxRecurse) {
4778 switch (Opcode) {
4779 case Instruction::FAdd:
4780 return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
4781 case Instruction::FSub:
4782 return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
4783 case Instruction::FMul:
4784 return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
4785 case Instruction::FDiv:
4786 return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
4787 default:
4788 return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
4789 }
4790}
4791
4792Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4793 const SimplifyQuery &Q) {
4794 return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
4795}
4796
4797Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
4798 FastMathFlags FMF, const SimplifyQuery &Q) {
4799 return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
4800}
4801
4802/// Given operands for a CmpInst, see if we can fold the result.
4803static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4804 const SimplifyQuery &Q, unsigned MaxRecurse) {
4805 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
2
Taking false branch
4806 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
4807 return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
3
Calling 'SimplifyFCmpInst'
4808}
4809
4810Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
4811 const SimplifyQuery &Q) {
4812 return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
1
Calling 'SimplifyCmpInst'
4813}
4814
4815static bool IsIdempotent(Intrinsic::ID ID) {
4816 switch (ID) {
4817 default: return false;
4818
4819 // Unary idempotent: f(f(x)) = f(x)
4820 case Intrinsic::fabs:
4821 case Intrinsic::floor:
4822 case Intrinsic::ceil:
4823 case Intrinsic::trunc:
4824 case Intrinsic::rint:
4825 case Intrinsic::nearbyint:
4826 case Intrinsic::round:
4827 case Intrinsic::canonicalize:
4828 return true;
4829 }
4830}
4831
4832static Value *SimplifyRelativeLoad(Constant *Ptr, Constant *Offset,
4833 const DataLayout &DL) {
4834 GlobalValue *PtrSym;
4835 APInt PtrOffset;
4836 if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
4837 return nullptr;
4838
4839 Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
4840 Type *Int32Ty = Type::getInt32Ty(Ptr->getContext());
4841 Type *Int32PtrTy = Int32Ty->getPointerTo();
4842 Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());
4843
4844 auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
4845 if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
4846 return nullptr;
4847
4848 uint64_t OffsetInt = OffsetConstInt->getSExtValue();
4849 if (OffsetInt % 4 != 0)
4850 return nullptr;
4851
4852 Constant *C = ConstantExpr::getGetElementPtr(
4853 Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
4854 ConstantInt::get(Int64Ty, OffsetInt / 4));
4855 Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
4856 if (!Loaded)
4857 return nullptr;
4858
4859 auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
4860 if (!LoadedCE)
4861 return nullptr;
4862
4863 if (LoadedCE->getOpcode() == Instruction::Trunc) {
4864 LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4865 if (!LoadedCE)
4866 return nullptr;
4867 }
4868
4869 if (LoadedCE->getOpcode() != Instruction::Sub)
4870 return nullptr;
4871
4872 auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
4873 if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
4874 return nullptr;
4875 auto *LoadedLHSPtr = LoadedLHS->getOperand(0);
4876
4877 Constant *LoadedRHS = LoadedCE->getOperand(1);
4878 GlobalValue *LoadedRHSSym;
4879 APInt LoadedRHSOffset;
4880 if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
4881 DL) ||
4882 PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
4883 return nullptr;
4884
4885 return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4886}
4887
4888static bool maskIsAllZeroOrUndef(Value *Mask) {
4889 auto *ConstMask = dyn_cast<Constant>(Mask);
4890 if (!ConstMask)
4891 return false;
4892 if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
4893 return true;
4894 for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
4895 ++I) {
4896 if (auto *MaskElt = ConstMask->getAggregateElement(I))
4897 if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
4898 continue;
4899 return false;
4900 }
4901 return true;
4902}
4903
4904static Value *simplifyUnaryIntrinsic(Function *F, Value *Op0,
4905 const SimplifyQuery &Q) {
4906 // Idempotent functions return the same result when called repeatedly.
4907 Intrinsic::ID IID = F->getIntrinsicID();
4908 if (IsIdempotent(IID))
4909 if (auto *II = dyn_cast<IntrinsicInst>(Op0))
4910 if (II->getIntrinsicID() == IID)
4911 return II;
4912
4913 Value *X;
4914 switch (IID) {
4915 case Intrinsic::fabs:
4916 if (SignBitMustBeZero(Op0, Q.TLI)) return Op0;
4917 break;
4918 case Intrinsic::bswap:
4919 // bswap(bswap(x)) -> x
4920 if (match(Op0, m_BSwap(m_Value(X)))) return X;
4921 break;
4922 case Intrinsic::bitreverse:
4923 // bitreverse(bitreverse(x)) -> x
4924 if (match(Op0, m_BitReverse(m_Value(X)))) return X;
4925 break;
4926 case Intrinsic::exp:
4927 // exp(log(x)) -> x
4928 if (Q.CxtI->hasAllowReassoc() &&
4929 match(Op0, m_Intrinsic<Intrinsic::log>(m_Value(X)))) return X;
4930 break;
4931 case Intrinsic::exp2:
4932 // exp2(log2(x)) -> x
4933 if (Q.CxtI->hasAllowReassoc() &&
4934 match(Op0, m_Intrinsic<Intrinsic::log2>(m_Value(X)))) return X;
4935 break;
4936 case Intrinsic::log:
4937 // log(exp(x)) -> x
4938 if (Q.CxtI->hasAllowReassoc() &&
4939 match(Op0, m_Intrinsic<Intrinsic::exp>(m_Value(X)))) return X;
4940 break;
4941 case Intrinsic::log2:
4942 // log2(exp2(x)) -> x
4943 if (Q.CxtI->hasAllowReassoc() &&
4944 match(Op0, m_Intrinsic<Intrinsic::exp2>(m_Value(X)))) return X;
4945 break;
4946 default:
4947 break;
4948 }
4949
4950 return nullptr;
4951}
4952
4953static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
4954 const SimplifyQuery &Q) {
4955 Intrinsic::ID IID = F->getIntrinsicID();
4956 Type *ReturnType = F->getReturnType();
4957 switch (IID) {
4958 case Intrinsic::usub_with_overflow:
4959 case Intrinsic::ssub_with_overflow:
4960 // X - X -> { 0, false }
4961 if (Op0 == Op1)
4962 return Constant::getNullValue(ReturnType);
4963 // X - undef -> undef
4964 // undef - X -> undef
4965 if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
4966 return UndefValue::get(ReturnType);
4967 break;
4968 case Intrinsic::uadd_with_overflow:
4969 case Intrinsic::sadd_with_overflow:
4970 // X + undef -> undef
4971 if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
4972 return UndefValue::get(ReturnType);
4973 break;
4974 case Intrinsic::umul_with_overflow:
4975 case Intrinsic::smul_with_overflow:
4976 // 0 * X -> { 0, false }
4977 // X * 0 -> { 0, false }
4978 if (match(Op0, m_Zero()) || match(Op1, m_Zero()))
4979 return Constant::getNullValue(ReturnType);
4980 // undef * X -> { 0, false }
4981 // X * undef -> { 0, false }
4982 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
4983 return Constant::getNullValue(ReturnType);
4984 break;
4985 case Intrinsic::uadd_sat:
4986 // sat(MAX + X) -> MAX
4987 // sat(X + MAX) -> MAX
4988 if (match(Op0, m_AllOnes()) || match(Op1, m_AllOnes()))
4989 return Constant::getAllOnesValue(ReturnType);
4990 LLVM_FALLTHROUGH[[clang::fallthrough]];
4991 case Intrinsic::sadd_sat:
4992 // sat(X + undef) -> -1
4993 // sat(undef + X) -> -1
4994 // For unsigned: Assume undef is MAX, thus we saturate to MAX (-1).
4995 // For signed: Assume undef is ~X, in which case X + ~X = -1.
4996 if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
4997 return Constant::getAllOnesValue(ReturnType);
4998
4999 // X + 0 -> X
5000 if (match(Op1, m_Zero()))
5001 return Op0;
5002 // 0 + X -> X
5003 if (match(Op0, m_Zero()))
5004 return Op1;
5005 break;
5006 case Intrinsic::usub_sat:
5007 // sat(0 - X) -> 0, sat(X - MAX) -> 0
5008 if (match(Op0, m_Zero()) || match(Op1, m_AllOnes()))
5009 return Constant::getNullValue(ReturnType);
5010 LLVM_FALLTHROUGH[[clang::fallthrough]];
5011 case Intrinsic::ssub_sat:
5012 // X - X -> 0, X - undef -> 0, undef - X -> 0
5013 if (Op0 == Op1 || match(Op0, m_Undef()) || match(Op1, m_Undef()))
5014 return Constant::getNullValue(ReturnType);
5015 // X - 0 -> X
5016 if (match(Op1, m_Zero()))
5017 return Op0;
5018 break;
5019 case Intrinsic::load_relative:
5020 if (auto *C0 = dyn_cast<Constant>(Op0))
5021 if (auto *C1 = dyn_cast<Constant>(Op1))
5022 return SimplifyRelativeLoad(C0, C1, Q.DL);
5023 break;
5024 case Intrinsic::powi:
5025 if (auto *Power = dyn_cast<ConstantInt>(Op1)) {
5026 // powi(x, 0) -> 1.0
5027 if (Power->isZero())
5028 return ConstantFP::get(Op0->getType(), 1.0);
5029 // powi(x, 1) -> x
5030 if (Power->isOne())
5031 return Op0;
5032 }
5033 break;
5034 case Intrinsic::maxnum:
5035 case Intrinsic::minnum:
5036 case Intrinsic::maximum:
5037 case Intrinsic::minimum: {
5038 // If the arguments are the same, this is a no-op.
5039 if (Op0 == Op1) return Op0;
5040
5041 // If one argument is undef, return the other argument.
5042 if (match(Op0, m_Undef()))
5043 return Op1;
5044 if (match(Op1, m_Undef()))
5045 return Op0;
5046
5047 // If one argument is NaN, return other or NaN appropriately.
5048 bool PropagateNaN = IID == Intrinsic::minimum || IID == Intrinsic::maximum;
5049 if (match(Op0, m_NaN()))
5050 return PropagateNaN ? Op0 : Op1;
5051 if (match(Op1, m_NaN()))
5052 return PropagateNaN ? Op1 : Op0;
5053
5054 // Min/max of the same operation with common operand:
5055 // m(m(X, Y)), X --> m(X, Y) (4 commuted variants)
5056 if (auto *M0 = dyn_cast<IntrinsicInst>(Op0))
5057 if (M0->getIntrinsicID() == IID &&
5058 (M0->getOperand(0) == Op1 || M0->getOperand(1) == Op1))
5059 return Op0;
5060 if (auto *M1 = dyn_cast<IntrinsicInst>(Op1))
5061 if (M1->getIntrinsicID() == IID &&
5062 (M1->getOperand(0) == Op0 || M1->getOperand(1) == Op0))
5063 return Op1;
5064
5065 // min(X, -Inf) --> -Inf (and commuted variant)
5066 // max(X, +Inf) --> +Inf (and commuted variant)
5067 bool UseNegInf = IID == Intrinsic::minnum || IID == Intrinsic::minimum;
5068 const APFloat *C;
5069 if ((match(Op0, m_APFloat(C)) && C->isInfinity() &&
5070 C->isNegative() == UseNegInf) ||
5071 (match(Op1, m_APFloat(C)) && C->isInfinity() &&
5072 C->isNegative() == UseNegInf))
5073 return ConstantFP::getInfinity(ReturnType, UseNegInf);
5074
5075 // TODO: minnum(nnan x, inf) -> x
5076 // TODO: minnum(nnan ninf x, flt_max) -> x
5077 // TODO: maxnum(nnan x, -inf) -> x
5078 // TODO: maxnum(nnan ninf x, -flt_max) -> x
5079 break;
5080 }
5081 default:
5082 break;
5083 }
5084
5085 return nullptr;
5086}
5087
5088template <typename IterTy>
5089static Value *simplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
5090 const SimplifyQuery &Q) {
5091 // Intrinsics with no operands have some kind of side effect. Don't simplify.
5092 unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
5093 if (NumOperands == 0)
5094 return nullptr;
5095
5096 Intrinsic::ID IID = F->getIntrinsicID();
5097 if (NumOperands == 1)
5098 return simplifyUnaryIntrinsic(F, ArgBegin[0], Q);
5099
5100 if (NumOperands == 2)
5101 return simplifyBinaryIntrinsic(F, ArgBegin[0], ArgBegin[1], Q);
5102
5103 // Handle intrinsics with 3 or more arguments.
5104 switch (IID) {
5105 case Intrinsic::masked_load: {
5106 Value *MaskArg = ArgBegin[2];
5107 Value *PassthruArg = ArgBegin[3];
5108 // If the mask is all zeros or undef, the "passthru" argument is the result.
5109 if (maskIsAllZeroOrUndef(MaskArg))
5110 return PassthruArg;
5111 return nullptr;
5112 }
5113 case Intrinsic::fshl:
5114 case Intrinsic::fshr: {
5115 Value *Op0 = ArgBegin[0], *Op1 = ArgBegin[1], *ShAmtArg = ArgBegin[2];
5116
5117 // If both operands are undef, the result is undef.
5118 if (match(Op0, m_Undef()) && match(Op1, m_Undef()))
5119 return UndefValue::get(F->getReturnType());
5120
5121 // If shift amount is undef, assume it is zero.
5122 if (match(ShAmtArg, m_Undef()))
5123 return ArgBegin[IID == Intrinsic::fshl ? 0 : 1];
5124
5125 const APInt *ShAmtC;
5126 if (match(ShAmtArg, m_APInt(ShAmtC))) {
5127 // If there's effectively no shift, return the 1st arg or 2nd arg.
5128 // TODO: For vectors, we could check each element of a non-splat constant.
5129 APInt BitWidth = APInt(ShAmtC->getBitWidth(), ShAmtC->getBitWidth());
5130 if (ShAmtC->urem(BitWidth).isNullValue())
5131 return ArgBegin[IID == Intrinsic::fshl ? 0 : 1];
5132 }
5133 return nullptr;
5134 }
5135 default:
5136 return nullptr;
5137 }
5138}
5139
5140template <typename IterTy>
5141static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
5142 IterTy ArgEnd, const SimplifyQuery &Q,
5143 unsigned MaxRecurse) {
5144 Type *Ty = V->getType();
5145 if (PointerType *PTy = dyn_cast<PointerType>(Ty))
5146 Ty = PTy->getElementType();
5147 FunctionType *FTy = cast<FunctionType>(Ty);
5148
5149 // call undef -> undef
5150 // call null -> undef
5151 if (isa<UndefValue>(V) || isa<ConstantPointerNull>(V))
5152 return UndefValue::get(FTy->getReturnType());
5153
5154 Function *F = dyn_cast<Function>(V);
5155 if (!F)
5156 return nullptr;
5157
5158 if (F->isIntrinsic())
5159 if (Value *Ret = simplifyIntrinsic(F, ArgBegin, ArgEnd, Q))
5160 return Ret;
5161
5162 if (!canConstantFoldCallTo(CS, F))
5163 return nullptr;
5164
5165 SmallVector<Constant *, 4> ConstantArgs;
5166 ConstantArgs.reserve(ArgEnd - ArgBegin);
5167 for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
5168 Constant *C = dyn_cast<Constant>(*I);
5169 if (!C)
5170 return nullptr;
5171 ConstantArgs.push_back(C);
5172 }
5173
5174 return ConstantFoldCall(CS, F, ConstantArgs, Q.TLI);
5175}
5176
5177Value *llvm::SimplifyCall(ImmutableCallSite CS, Value *V,
5178 User::op_iterator ArgBegin, User::op_iterator ArgEnd,
5179 const SimplifyQuery &Q) {
5180 return ::SimplifyCall(CS, V, ArgBegin, ArgEnd, Q, RecursionLimit);
5181}
5182
5183Value *llvm::SimplifyCall(ImmutableCallSite CS, Value *V,
5184 ArrayRef<Value *> Args, const SimplifyQuery &Q) {
5185 return ::SimplifyCall(CS, V, Args.begin(), Args.end(), Q, RecursionLimit);
5186}
5187
5188Value *llvm::SimplifyCall(ImmutableCallSite ICS, const SimplifyQuery &Q) {
5189 CallSite CS(const_cast<Instruction*>(ICS.getInstruction()));
5190 return ::SimplifyCall(CS, CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
5191 Q, RecursionLimit);
5192}
5193
5194/// See if we can compute a simplified version of this instruction.
5195/// If not, this returns null.
5196
5197Value *llvm::SimplifyInstruction(Instruction *I, const SimplifyQuery &SQ,
5198 OptimizationRemarkEmitter *ORE) {
5199 const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
5200 Value *Result;
5201
5202 switch (I->getOpcode()) {
5203 default:
5204 Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
5205 break;
5206 case Instruction::FAdd:
5207 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
5208 I->getFastMathFlags(), Q);
5209 break;
5210 case Instruction::Add:
5211 Result =
5212 SimplifyAddInst(I->getOperand(0), I->getOperand(1),
5213 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)),
5214 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q);
5215 break;
5216 case Instruction::FSub:
5217 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
5218 I->getFastMathFlags(), Q);
5219 break;
5220 case Instruction::Sub:
5221 Result =
5222 SimplifySubInst(I->getOperand(0), I->getOperand(1),
5223 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)),
5224 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q);
5225 break;
5226 case Instruction::FMul:
5227 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
5228 I->getFastMathFlags(), Q);
5229 break;
5230 case Instruction::Mul:
5231 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
5232 break;
5233 case Instruction::SDiv:
5234 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
5235 break;
5236 case Instruction::UDiv:
5237 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
5238 break;
5239 case Instruction::FDiv:
5240 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
5241 I->getFastMathFlags(), Q);
5242 break;
5243 case Instruction::SRem:
5244 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
5245 break;
5246 case Instruction::URem:
5247 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
5248 break;
5249 case Instruction::FRem:
5250 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
5251 I->getFastMathFlags(), Q);
5252 break;
5253 case Instruction::Shl:
5254 Result =
5255 SimplifyShlInst(I->getOperand(0), I->getOperand(1),
5256 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)),
5257 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q);
5258 break;
5259 case Instruction::LShr:
5260 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
5261 Q.IIQ.isExact(cast<BinaryOperator>(I)), Q);
5262 break;
5263 case Instruction::AShr:
5264 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
5265 Q.IIQ.isExact(cast<BinaryOperator>(I)), Q);
5266 break;
5267 case Instruction::And:
5268 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q);
5269 break;
5270 case Instruction::Or:
5271 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q);
5272 break;
5273 case Instruction::Xor:
5274 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q);
5275 break;
5276 case Instruction::ICmp:
5277 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
5278 I->getOperand(0), I->getOperand(1), Q);
5279 break;
5280 case Instruction::FCmp:
5281 Result =
5282 SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
5283 I->getOperand(1), I->getFastMathFlags(), Q);
5284 break;
5285 case Instruction::Select:
5286 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
5287 I->getOperand(2), Q);
5288 break;
5289 case Instruction::GetElementPtr: {
5290 SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end());
5291 Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
5292 Ops, Q);
5293 break;
5294 }
5295 case Instruction::InsertValue: {
5296 InsertValueInst *IV = cast<InsertValueInst>(I);
5297 Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
5298 IV->getInsertedValueOperand(),
5299 IV->getIndices(), Q);
5300 break;
5301 }
5302 case Instruction::InsertElement: {
5303 auto *IE = cast<InsertElementInst>(I);
5304 Result = SimplifyInsertElementInst(IE->getOperand(0), IE->getOperand(1),
5305 IE->getOperand(2), Q);
5306 break;
5307 }
5308 case Instruction::ExtractValue: {
5309 auto *EVI = cast<ExtractValueInst>(I);
5310 Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
5311 EVI->getIndices(), Q);
5312 break;
5313 }
5314 case Instruction::ExtractElement: {
5315 auto *EEI = cast<ExtractElementInst>(I);
5316 Result = SimplifyExtractElementInst(EEI->getVectorOperand(),
5317 EEI->getIndexOperand(), Q);
5318 break;
5319 }
5320 case Instruction::ShuffleVector: {
5321 auto *SVI = cast<ShuffleVectorInst>(I);
5322 Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
5323 SVI->getMask(), SVI->getType(), Q);
5324 break;
5325 }
5326 case Instruction::PHI:
5327 Result = SimplifyPHINode(cast<PHINode>(I), Q);
5328 break;
5329 case Instruction::Call: {
5330 CallSite CS(cast<CallInst>(I));
5331 Result = SimplifyCall(CS, Q);
5332 break;
5333 }
5334#define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
5335#include "llvm/IR/Instruction.def"
5336#undef HANDLE_CAST_INST
5337 Result =
5338 SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q);
5339 break;
5340 case Instruction::Alloca:
5341 // No simplifications for Alloca and it can't be constant folded.
5342 Result = nullptr;
5343 break;
5344 }
5345
5346 // In general, it is possible for computeKnownBits to determine all bits in a
5347 // value even when the operands are not all constants.
5348 if (!Result && I->getType()->isIntOrIntVectorTy()) {
5349 KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
5350 if (Known.isConstant())
5351 Result = ConstantInt::get(I->getType(), Known.getConstant());
5352 }
5353
5354 /// If called on unreachable code, the above logic may report that the
5355 /// instruction simplified to itself. Make life easier for users by
5356 /// detecting that case here, returning a safe value instead.
5357 return Result == I ? UndefValue::get(I->getType()) : Result;
5358}
5359
5360/// Implementation of recursive simplification through an instruction's
5361/// uses.
5362///
5363/// This is the common implementation of the recursive simplification routines.
5364/// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
5365/// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
5366/// instructions to process and attempt to simplify it using
5367/// InstructionSimplify.
5368///
5369/// This routine returns 'true' only when *it* simplifies something. The passed
5370/// in simplified value does not count toward this.
5371static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
5372 const TargetLibraryInfo *TLI,
5373 const DominatorTree *DT,
5374 AssumptionCache *AC) {
5375 bool Simplified = false;
5376 SmallSetVector<Instruction *, 8> Worklist;
5377 const DataLayout &DL = I->getModule()->getDataLayout();
5378
5379 // If we have an explicit value to collapse to, do that round of the
5380 // simplification loop by hand initially.
5381 if (SimpleV) {
5382 for (User *U : I->users())
5383 if (U != I)
5384 Worklist.insert(cast<Instruction>(U));
5385
5386 // Replace the instruction with its simplified value.
5387 I->replaceAllUsesWith(SimpleV);
5388
5389 // Gracefully handle edge cases where the instruction is not wired into any
5390 // parent block.
5391 if (I->getParent() && !I->isEHPad() && !I->isTerminator() &&
5392 !I->mayHaveSideEffects())
5393 I->eraseFromParent();
5394 } else {
5395 Worklist.insert(I);
5396 }
5397
5398 // Note that we must test the size on each iteration, the worklist can grow.
5399 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
5400 I = Worklist[Idx];
5401
5402 // See if this instruction simplifies.
5403 SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC});
5404 if (!SimpleV)
5405 continue;
5406
5407 Simplified = true;
5408
5409 // Stash away all the uses of the old instruction so we can check them for
5410 // recursive simplifications after a RAUW. This is cheaper than checking all
5411 // uses of To on the recursive step in most cases.
5412 for (User *U : I->users())
5413 Worklist.insert(cast<Instruction>(U));
5414
5415 // Replace the instruction with its simplified value.
5416 I->replaceAllUsesWith(SimpleV);
5417
5418 // Gracefully handle edge cases where the instruction is not wired into any
5419 // parent block.
5420 if (I->getParent() && !I->isEHPad() && !I->isTerminator() &&
5421 !I->mayHaveSideEffects())
5422 I->eraseFromParent();
5423 }
5424 return Simplified;
5425}
5426
5427bool llvm::recursivelySimplifyInstruction(Instruction *I,
5428 const TargetLibraryInfo *TLI,
5429 const DominatorTree *DT,
5430 AssumptionCache *AC) {
5431 return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC);
5432}
5433
5434bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
5435 const TargetLibraryInfo *TLI,
5436 const DominatorTree *DT,
5437 AssumptionCache *AC) {
5438 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!")((I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!"
) ? static_cast<void> (0) : __assert_fail ("I != SimpleV && \"replaceAndRecursivelySimplify(X,X) is not valid!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 5438, __PRETTY_FUNCTION__))
;
5439 assert(SimpleV && "Must provide a simplified value.")((SimpleV && "Must provide a simplified value.") ? static_cast
<void> (0) : __assert_fail ("SimpleV && \"Must provide a simplified value.\""
, "/build/llvm-toolchain-snapshot-8~svn350071/lib/Analysis/InstructionSimplify.cpp"
, 5439, __PRETTY_FUNCTION__))
;
5440 return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC);
5441}
5442
5443namespace llvm {
5444const SimplifyQuery getBestSimplifyQuery(Pass &P, Function &F) {
5445 auto *DTWP = P.getAnalysisIfAvailable<DominatorTreeWrapperPass>();
5446 auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
5447 auto *TLIWP = P.getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
5448 auto *TLI = TLIWP ? &TLIWP->getTLI() : nullptr;
5449 auto *ACWP = P.getAnalysisIfAvailable<AssumptionCacheTracker>();
5450 auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr;
5451 return {F.getParent()->getDataLayout(), TLI, DT, AC};
5452}
5453
5454const SimplifyQuery getBestSimplifyQuery(LoopStandardAnalysisResults &AR,
5455 const DataLayout &DL) {
5456 return {DL, &AR.TLI, &AR.DT, &AR.AC};
5457}
5458
5459template <class T, class... TArgs>
5460const SimplifyQuery getBestSimplifyQuery(AnalysisManager<T, TArgs...> &AM,
5461 Function &F) {
5462 auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F);
5463 auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F);
5464 auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F);
5465 return {F.getParent()->getDataLayout(), TLI, DT, AC};
5466}
5467template const SimplifyQuery getBestSimplifyQuery(AnalysisManager<Function> &,
5468 Function &);
5469}

/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/IR/PatternMatch.h

1//===- PatternMatch.h - Match on the LLVM IR --------------------*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file provides a simple and efficient mechanism for performing general
11// tree-based pattern matches on the LLVM IR. The power of these routines is
12// that it allows you to write concise patterns that are expressive and easy to
13// understand. The other major advantage of this is that it allows you to
14// trivially capture/bind elements in the pattern to variables. For example,
15// you can do something like this:
16//
17// Value *Exp = ...
18// Value *X, *Y; ConstantInt *C1, *C2; // (X & C1) | (Y & C2)
19// if (match(Exp, m_Or(m_And(m_Value(X), m_ConstantInt(C1)),
20// m_And(m_Value(Y), m_ConstantInt(C2))))) {
21// ... Pattern is matched and variables are bound ...
22// }
23//
24// This is primarily useful to things like the instruction combiner, but can
25// also be useful for static analysis tools or code generators.
26//
27//===----------------------------------------------------------------------===//
28
29#ifndef LLVM_IR_PATTERNMATCH_H
30#define LLVM_IR_PATTERNMATCH_H
31
32#include "llvm/ADT/APFloat.h"
33#include "llvm/ADT/APInt.h"
34#include "llvm/IR/CallSite.h"
35#include "llvm/IR/Constant.h"
36#include "llvm/IR/Constants.h"
37#include "llvm/IR/InstrTypes.h"
38#include "llvm/IR/Instruction.h"
39#include "llvm/IR/Instructions.h"
40#include "llvm/IR/Intrinsics.h"
41#include "llvm/IR/Operator.h"
42#include "llvm/IR/Value.h"
43#include "llvm/Support/Casting.h"
44#include <cstdint>
45
46namespace llvm {
47namespace PatternMatch {
48
49template <typename Val, typename Pattern> bool match(Val *V, const Pattern &P) {
50 return const_cast<Pattern &>(P).match(V);
16
Value assigned to field 'Val'
51}
52
53template <typename SubPattern_t> struct OneUse_match {
54 SubPattern_t SubPattern;
55
56 OneUse_match(const SubPattern_t &SP) : SubPattern(SP) {}
57
58 template <typename OpTy> bool match(OpTy *V) {
59 return V->hasOneUse() && SubPattern.match(V);
60 }
61};
62
63template <typename T> inline OneUse_match<T> m_OneUse(const T &SubPattern) {
64 return SubPattern;
65}
66
67template <typename Class> struct class_match {
68 template <typename ITy> bool match(ITy *V) { return isa<Class>(V); }
69};
70
71/// Match an arbitrary value and ignore it.
72inline class_match<Value> m_Value() { return class_match<Value>(); }
73
74/// Match an arbitrary binary operation and ignore it.
75inline class_match<BinaryOperator> m_BinOp() {
76 return class_match<BinaryOperator>();
77}
78
79/// Matches any compare instruction and ignore it.
80inline class_match<CmpInst> m_Cmp() { return class_match<CmpInst>(); }
81
82/// Match an arbitrary ConstantInt and ignore it.
83inline class_match<ConstantInt> m_ConstantInt() {
84 return class_match<ConstantInt>();
85}
86
87/// Match an arbitrary undef constant.
88inline class_match<UndefValue> m_Undef() { return class_match<UndefValue>(); }
89
90/// Match an arbitrary Constant and ignore it.
91inline class_match<Constant> m_Constant() { return class_match<Constant>(); }
92
93/// Matching combinators
94template <typename LTy, typename RTy> struct match_combine_or {
95 LTy L;
96 RTy R;
97
98 match_combine_or(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
99
100 template <typename ITy> bool match(ITy *V) {
101 if (L.match(V))
102 return true;
103 if (R.match(V))
104 return true;
105 return false;
106 }
107};
108
109template <typename LTy, typename RTy> struct match_combine_and {
110 LTy L;
111 RTy R;
112
113 match_combine_and(const LTy &Left, const RTy &Right) : L(Left), R(Right) {}
114
115 template <typename ITy> bool match(ITy *V) {
116 if (L.match(V))
117 if (R.match(V))
118 return true;
119 return false;
120 }
121};
122
123/// Combine two pattern matchers matching L || R
124template <typename LTy, typename RTy>
125inline match_combine_or<LTy, RTy> m_CombineOr(const LTy &L, const RTy &R) {
126 return match_combine_or<LTy, RTy>(L, R);
127}
128
129/// Combine two pattern matchers matching L && R
130template <typename LTy, typename RTy>
131inline match_combine_and<LTy, RTy> m_CombineAnd(const LTy &L, const RTy &R) {
132 return match_combine_and<LTy, RTy>(L, R);
133}
134
135struct apint_match {
136 const APInt *&Res;
137
138 apint_match(const APInt *&R) : Res(R) {}
139
140 template <typename ITy> bool match(ITy *V) {
141 if (auto *CI = dyn_cast<ConstantInt>(V)) {
142 Res = &CI->getValue();
143 return true;
144 }
145 if (V->getType()->isVectorTy())
146 if (const auto *C = dyn_cast<Constant>(V))
147 if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue())) {
148 Res = &CI->getValue();
149 return true;
150 }
151 return false;
152 }
153};
154// Either constexpr if or renaming ConstantFP::getValueAPF to
155// ConstantFP::getValue is needed to do it via single template
156// function for both apint/apfloat.
157struct apfloat_match {
158 const APFloat *&Res;
159 apfloat_match(const APFloat *&R) : Res(R) {}
160 template <typename ITy> bool match(ITy *V) {
161 if (auto *CI = dyn_cast<ConstantFP>(V)) {
162 Res = &CI->getValueAPF();
163 return true;
164 }
165 if (V->getType()->isVectorTy())
166 if (const auto *C = dyn_cast<Constant>(V))
167 if (auto *CI = dyn_cast_or_null<ConstantFP>(C->getSplatValue())) {
168 Res = &CI->getValueAPF();
169 return true;
170 }
171 return false;
172 }
173};
174
175/// Match a ConstantInt or splatted ConstantVector, binding the
176/// specified pointer to the contained APInt.
177inline apint_match m_APInt(const APInt *&Res) { return Res; }
178
179/// Match a ConstantFP or splatted ConstantVector, binding the
180/// specified pointer to the contained APFloat.
181inline apfloat_match m_APFloat(const APFloat *&Res) { return Res; }
182
183template <int64_t Val> struct constantint_match {
184 template <typename ITy> bool match(ITy *V) {
185 if (const auto *CI = dyn_cast<ConstantInt>(V)) {
186 const APInt &CIV = CI->getValue();
187 if (Val >= 0)
188 return CIV == static_cast<uint64_t>(Val);
189 // If Val is negative, and CI is shorter than it, truncate to the right
190 // number of bits. If it is larger, then we have to sign extend. Just
191 // compare their negated values.
192 return -CIV == -Val;
193 }
194 return false;
195 }
196};
197
198/// Match a ConstantInt with a specific value.
199template <int64_t Val> inline constantint_match<Val> m_ConstantInt() {
200 return constantint_match<Val>();
201}
202
203/// This helper class is used to match scalar and vector integer constants that
204/// satisfy a specified predicate.
205/// For vector constants, undefined elements are ignored.
206template <typename Predicate> struct cst_pred_ty : public Predicate {
207 template <typename ITy> bool match(ITy *V) {
208 if (const auto *CI = dyn_cast<ConstantInt>(V))
209 return this->isValue(CI->getValue());
210 if (V->getType()->isVectorTy()) {
211 if (const auto *C = dyn_cast<Constant>(V)) {
212 if (const auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
213 return this->isValue(CI->getValue());
214
215 // Non-splat vector constant: check each element for a match.
216 unsigned NumElts = V->getType()->getVectorNumElements();
217 assert(NumElts != 0 && "Constant vector with no elements?")((NumElts != 0 && "Constant vector with no elements?"
) ? static_cast<void> (0) : __assert_fail ("NumElts != 0 && \"Constant vector with no elements?\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/IR/PatternMatch.h"
, 217, __PRETTY_FUNCTION__))
;
218 bool HasNonUndefElements = false;
219 for (unsigned i = 0; i != NumElts; ++i) {
220 Constant *Elt = C->getAggregateElement(i);
221 if (!Elt)
222 return false;
223 if (isa<UndefValue>(Elt))
224 continue;
225 auto *CI = dyn_cast<ConstantInt>(Elt);
226 if (!CI || !this->isValue(CI->getValue()))
227 return false;
228 HasNonUndefElements = true;
229 }
230 return HasNonUndefElements;
231 }
232 }
233 return false;
234 }
235};
236
237/// This helper class is used to match scalar and vector constants that
238/// satisfy a specified predicate, and bind them to an APInt.
239template <typename Predicate> struct api_pred_ty : public Predicate {
240 const APInt *&Res;
241
242 api_pred_ty(const APInt *&R) : Res(R) {}
243
244 template <typename ITy> bool match(ITy *V) {
245 if (const auto *CI = dyn_cast<ConstantInt>(V))
246 if (this->isValue(CI->getValue())) {
247 Res = &CI->getValue();
248 return true;
249 }
250 if (V->getType()->isVectorTy())
251 if (const auto *C = dyn_cast<Constant>(V))
252 if (auto *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue()))
253 if (this->isValue(CI->getValue())) {
254 Res = &CI->getValue();
255 return true;
256 }
257
258 return false;
259 }
260};
261
262/// This helper class is used to match scalar and vector floating-point
263/// constants that satisfy a specified predicate.
264/// For vector constants, undefined elements are ignored.
265template <typename Predicate> struct cstfp_pred_ty : public Predicate {
266 template <typename ITy> bool match(ITy *V) {
267 if (const auto *CF = dyn_cast<ConstantFP>(V))
268 return this->isValue(CF->getValueAPF());
269 if (V->getType()->isVectorTy()) {
270 if (const auto *C = dyn_cast<Constant>(V)) {
271 if (const auto *CF = dyn_cast_or_null<ConstantFP>(C->getSplatValue()))
272 return this->isValue(CF->getValueAPF());
273
274 // Non-splat vector constant: check each element for a match.
275 unsigned NumElts = V->getType()->getVectorNumElements();
276 assert(NumElts != 0 && "Constant vector with no elements?")((NumElts != 0 && "Constant vector with no elements?"
) ? static_cast<void> (0) : __assert_fail ("NumElts != 0 && \"Constant vector with no elements?\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/IR/PatternMatch.h"
, 276, __PRETTY_FUNCTION__))
;
277 bool HasNonUndefElements = false;
278 for (unsigned i = 0; i != NumElts; ++i) {
279 Constant *Elt = C->getAggregateElement(i);
280 if (!Elt)
281 return false;
282 if (isa<UndefValue>(Elt))
283 continue;
284 auto *CF = dyn_cast<ConstantFP>(Elt);
285 if (!CF || !this->isValue(CF->getValueAPF()))
286 return false;
287 HasNonUndefElements = true;
288 }
289 return HasNonUndefElements;
290 }
291 }
292 return false;
293 }
294};
295
296///////////////////////////////////////////////////////////////////////////////
297//
298// Encapsulate constant value queries for use in templated predicate matchers.
299// This allows checking if constants match using compound predicates and works
300// with vector constants, possibly with relaxed constraints. For example, ignore
301// undef values.
302//
303///////////////////////////////////////////////////////////////////////////////
304
305struct is_all_ones {
306 bool isValue(const APInt &C) { return C.isAllOnesValue(); }
307};
308/// Match an integer or vector with all bits set.
309/// For vectors, this includes constants with undefined elements.
310inline cst_pred_ty<is_all_ones> m_AllOnes() {
311 return cst_pred_ty<is_all_ones>();
312}
313
314struct is_maxsignedvalue {
315 bool isValue(const APInt &C) { return C.isMaxSignedValue(); }
316};
317/// Match an integer or vector with values having all bits except for the high
318/// bit set (0x7f...).
319/// For vectors, this includes constants with undefined elements.
320inline cst_pred_ty<is_maxsignedvalue> m_MaxSignedValue() {
321 return cst_pred_ty<is_maxsignedvalue>();
322}
323inline api_pred_ty<is_maxsignedvalue> m_MaxSignedValue(const APInt *&V) {
324 return V;
325}
326
327struct is_negative {
328 bool isValue(const APInt &C) { return C.isNegative(); }
329};
330/// Match an integer or vector of negative values.
331/// For vectors, this includes constants with undefined elements.
332inline cst_pred_ty<is_negative> m_Negative() {
333 return cst_pred_ty<is_negative>();
334}
335inline api_pred_ty<is_negative> m_Negative(const APInt *&V) {
336 return V;
337}
338
339struct is_nonnegative {
340 bool isValue(const APInt &C) { return C.isNonNegative(); }
341};
342/// Match an integer or vector of nonnegative values.
343/// For vectors, this includes constants with undefined elements.
344inline cst_pred_ty<is_nonnegative> m_NonNegative() {
345 return cst_pred_ty<is_nonnegative>();
346}
347inline api_pred_ty<is_nonnegative> m_NonNegative(const APInt *&V) {
348 return V;
349}
350
351struct is_one {
352 bool isValue(const APInt &C) { return C.isOneValue(); }
353};
354/// Match an integer 1 or a vector with all elements equal to 1.
355/// For vectors, this includes constants with undefined elements.
356inline cst_pred_ty<is_one> m_One() {
357 return cst_pred_ty<is_one>();
358}
359
360struct is_zero_int {
361 bool isValue(const APInt &C) { return C.isNullValue(); }
362};
363/// Match an integer 0 or a vector with all elements equal to 0.
364/// For vectors, this includes constants with undefined elements.
365inline cst_pred_ty<is_zero_int> m_ZeroInt() {
366 return cst_pred_ty<is_zero_int>();
367}
368
369struct is_zero {
370 template <typename ITy> bool match(ITy *V) {
371 auto *C = dyn_cast<Constant>(V);
372 return C && (C->isNullValue() || cst_pred_ty<is_zero_int>().match(C));
373 }
374};
375/// Match any null constant or a vector with all elements equal to 0.
376/// For vectors, this includes constants with undefined elements.
377inline is_zero m_Zero() {
378 return is_zero();
379}
380
381struct is_power2 {
382 bool isValue(const APInt &C) { return C.isPowerOf2(); }
383};
384/// Match an integer or vector power-of-2.
385/// For vectors, this includes constants with undefined elements.
386inline cst_pred_ty<is_power2> m_Power2() {
387 return cst_pred_ty<is_power2>();
388}
389inline api_pred_ty<is_power2> m_Power2(const APInt *&V) {
390 return V;
391}
392
393struct is_power2_or_zero {
394 bool isValue(const APInt &C) { return !C || C.isPowerOf2(); }
395};
396/// Match an integer or vector of 0 or power-of-2 values.
397/// For vectors, this includes constants with undefined elements.
398inline cst_pred_ty<is_power2_or_zero> m_Power2OrZero() {
399 return cst_pred_ty<is_power2_or_zero>();
400}
401inline api_pred_ty<is_power2_or_zero> m_Power2OrZero(const APInt *&V) {
402 return V;
403}
404
405struct is_sign_mask {
406 bool isValue(const APInt &C) { return C.isSignMask(); }
407};
408/// Match an integer or vector with only the sign bit(s) set.
409/// For vectors, this includes constants with undefined elements.
410inline cst_pred_ty<is_sign_mask> m_SignMask() {
411 return cst_pred_ty<is_sign_mask>();
412}
413
414struct is_lowbit_mask {
415 bool isValue(const APInt &C) { return C.isMask(); }
416};
417/// Match an integer or vector with only the low bit(s) set.
418/// For vectors, this includes constants with undefined elements.
419inline cst_pred_ty<is_lowbit_mask> m_LowBitMask() {
420 return cst_pred_ty<is_lowbit_mask>();
421}
422
423struct is_nan {
424 bool isValue(const APFloat &C) { return C.isNaN(); }
425};
426/// Match an arbitrary NaN constant. This includes quiet and signalling nans.
427/// For vectors, this includes constants with undefined elements.
428inline cstfp_pred_ty<is_nan> m_NaN() {
429 return cstfp_pred_ty<is_nan>();
430}
431
432struct is_any_zero_fp {
433 bool isValue(const APFloat &C) { return C.isZero(); }
434};
435/// Match a floating-point negative zero or positive zero.
436/// For vectors, this includes constants with undefined elements.
437inline cstfp_pred_ty<is_any_zero_fp> m_AnyZeroFP() {
438 return cstfp_pred_ty<is_any_zero_fp>();
439}
440
441struct is_pos_zero_fp {
442 bool isValue(const APFloat &C) { return C.isPosZero(); }
443};
444/// Match a floating-point positive zero.
445/// For vectors, this includes constants with undefined elements.
446inline cstfp_pred_ty<is_pos_zero_fp> m_PosZeroFP() {
447 return cstfp_pred_ty<is_pos_zero_fp>();
448}
449
450struct is_neg_zero_fp {
451 bool isValue(const APFloat &C) { return C.isNegZero(); }
452};
453/// Match a floating-point negative zero.
454/// For vectors, this includes constants with undefined elements.
455inline cstfp_pred_ty<is_neg_zero_fp> m_NegZeroFP() {
456 return cstfp_pred_ty<is_neg_zero_fp>();
457}
458
459///////////////////////////////////////////////////////////////////////////////
460
461template <typename Class> struct bind_ty {
462 Class *&VR;
463
464 bind_ty(Class *&V) : VR(V) {}
465
466 template <typename ITy> bool match(ITy *V) {
467 if (auto *CV = dyn_cast<Class>(V)) {
468 VR = CV;
469 return true;
470 }
471 return false;
472 }
473};
474
475/// Match a value, capturing it if we match.
476inline bind_ty<Value> m_Value(Value *&V) { return V; }
477inline bind_ty<const Value> m_Value(const Value *&V) { return V; }
478
479/// Match an instruction, capturing it if we match.
480inline bind_ty<Instruction> m_Instruction(Instruction *&I) { return I; }
481/// Match a binary operator, capturing it if we match.
482inline bind_ty<BinaryOperator> m_BinOp(BinaryOperator *&I) { return I; }
483
484/// Match a ConstantInt, capturing the value if we match.
485inline bind_ty<ConstantInt> m_ConstantInt(ConstantInt *&CI) { return CI; }
486
487/// Match a Constant, capturing the value if we match.
488inline bind_ty<Constant> m_Constant(Constant *&C) { return C; }
489
490/// Match a ConstantFP, capturing the value if we match.
491inline bind_ty<ConstantFP> m_ConstantFP(ConstantFP *&C) { return C; }
492
493/// Match a specified Value*.
494struct specificval_ty {
495 const Value *Val;
496
497 specificval_ty(const Value *V) : Val(V) {}
498
499 template <typename ITy> bool match(ITy *V) { return V == Val; }
500};
501
502/// Match if we have a specific specified value.
503inline specificval_ty m_Specific(const Value *V) { return V; }
504
505/// Stores a reference to the Value *, not the Value * itself,
506/// thus can be used in commutative matchers.
507template <typename Class> struct deferredval_ty {
508 Class *const &Val;
509
510