| File: | lib/Analysis/ScalarEvolution.cpp |
| Warning: | line 6397, column 23 Called C++ object pointer is null |
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| 1 | //===- ScalarEvolution.cpp - Scalar Evolution Analysis --------------------===// | ||||||
| 2 | // | ||||||
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||||||
| 4 | // See https://llvm.org/LICENSE.txt for license information. | ||||||
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||||||
| 6 | // | ||||||
| 7 | //===----------------------------------------------------------------------===// | ||||||
| 8 | // | ||||||
| 9 | // This file contains the implementation of the scalar evolution analysis | ||||||
| 10 | // engine, which is used primarily to analyze expressions involving induction | ||||||
| 11 | // variables in loops. | ||||||
| 12 | // | ||||||
| 13 | // There are several aspects to this library. First is the representation of | ||||||
| 14 | // scalar expressions, which are represented as subclasses of the SCEV class. | ||||||
| 15 | // These classes are used to represent certain types of subexpressions that we | ||||||
| 16 | // can handle. We only create one SCEV of a particular shape, so | ||||||
| 17 | // pointer-comparisons for equality are legal. | ||||||
| 18 | // | ||||||
| 19 | // One important aspect of the SCEV objects is that they are never cyclic, even | ||||||
| 20 | // if there is a cycle in the dataflow for an expression (ie, a PHI node). If | ||||||
| 21 | // the PHI node is one of the idioms that we can represent (e.g., a polynomial | ||||||
| 22 | // recurrence) then we represent it directly as a recurrence node, otherwise we | ||||||
| 23 | // represent it as a SCEVUnknown node. | ||||||
| 24 | // | ||||||
| 25 | // In addition to being able to represent expressions of various types, we also | ||||||
| 26 | // have folders that are used to build the *canonical* representation for a | ||||||
| 27 | // particular expression. These folders are capable of using a variety of | ||||||
| 28 | // rewrite rules to simplify the expressions. | ||||||
| 29 | // | ||||||
| 30 | // Once the folders are defined, we can implement the more interesting | ||||||
| 31 | // higher-level code, such as the code that recognizes PHI nodes of various | ||||||
| 32 | // types, computes the execution count of a loop, etc. | ||||||
| 33 | // | ||||||
| 34 | // TODO: We should use these routines and value representations to implement | ||||||
| 35 | // dependence analysis! | ||||||
| 36 | // | ||||||
| 37 | //===----------------------------------------------------------------------===// | ||||||
| 38 | // | ||||||
| 39 | // There are several good references for the techniques used in this analysis. | ||||||
| 40 | // | ||||||
| 41 | // Chains of recurrences -- a method to expedite the evaluation | ||||||
| 42 | // of closed-form functions | ||||||
| 43 | // Olaf Bachmann, Paul S. Wang, Eugene V. Zima | ||||||
| 44 | // | ||||||
| 45 | // On computational properties of chains of recurrences | ||||||
| 46 | // Eugene V. Zima | ||||||
| 47 | // | ||||||
| 48 | // Symbolic Evaluation of Chains of Recurrences for Loop Optimization | ||||||
| 49 | // Robert A. van Engelen | ||||||
| 50 | // | ||||||
| 51 | // Efficient Symbolic Analysis for Optimizing Compilers | ||||||
| 52 | // Robert A. van Engelen | ||||||
| 53 | // | ||||||
| 54 | // Using the chains of recurrences algebra for data dependence testing and | ||||||
| 55 | // induction variable substitution | ||||||
| 56 | // MS Thesis, Johnie Birch | ||||||
| 57 | // | ||||||
| 58 | //===----------------------------------------------------------------------===// | ||||||
| 59 | |||||||
| 60 | #include "llvm/Analysis/ScalarEvolution.h" | ||||||
| 61 | #include "llvm/ADT/APInt.h" | ||||||
| 62 | #include "llvm/ADT/ArrayRef.h" | ||||||
| 63 | #include "llvm/ADT/DenseMap.h" | ||||||
| 64 | #include "llvm/ADT/DepthFirstIterator.h" | ||||||
| 65 | #include "llvm/ADT/EquivalenceClasses.h" | ||||||
| 66 | #include "llvm/ADT/FoldingSet.h" | ||||||
| 67 | #include "llvm/ADT/None.h" | ||||||
| 68 | #include "llvm/ADT/Optional.h" | ||||||
| 69 | #include "llvm/ADT/STLExtras.h" | ||||||
| 70 | #include "llvm/ADT/ScopeExit.h" | ||||||
| 71 | #include "llvm/ADT/Sequence.h" | ||||||
| 72 | #include "llvm/ADT/SetVector.h" | ||||||
| 73 | #include "llvm/ADT/SmallPtrSet.h" | ||||||
| 74 | #include "llvm/ADT/SmallSet.h" | ||||||
| 75 | #include "llvm/ADT/SmallVector.h" | ||||||
| 76 | #include "llvm/ADT/Statistic.h" | ||||||
| 77 | #include "llvm/ADT/StringRef.h" | ||||||
| 78 | #include "llvm/Analysis/AssumptionCache.h" | ||||||
| 79 | #include "llvm/Analysis/ConstantFolding.h" | ||||||
| 80 | #include "llvm/Analysis/InstructionSimplify.h" | ||||||
| 81 | #include "llvm/Analysis/LoopInfo.h" | ||||||
| 82 | #include "llvm/Analysis/ScalarEvolutionExpressions.h" | ||||||
| 83 | #include "llvm/Analysis/TargetLibraryInfo.h" | ||||||
| 84 | #include "llvm/Analysis/ValueTracking.h" | ||||||
| 85 | #include "llvm/Config/llvm-config.h" | ||||||
| 86 | #include "llvm/IR/Argument.h" | ||||||
| 87 | #include "llvm/IR/BasicBlock.h" | ||||||
| 88 | #include "llvm/IR/CFG.h" | ||||||
| 89 | #include "llvm/IR/CallSite.h" | ||||||
| 90 | #include "llvm/IR/Constant.h" | ||||||
| 91 | #include "llvm/IR/ConstantRange.h" | ||||||
| 92 | #include "llvm/IR/Constants.h" | ||||||
| 93 | #include "llvm/IR/DataLayout.h" | ||||||
| 94 | #include "llvm/IR/DerivedTypes.h" | ||||||
| 95 | #include "llvm/IR/Dominators.h" | ||||||
| 96 | #include "llvm/IR/Function.h" | ||||||
| 97 | #include "llvm/IR/GlobalAlias.h" | ||||||
| 98 | #include "llvm/IR/GlobalValue.h" | ||||||
| 99 | #include "llvm/IR/GlobalVariable.h" | ||||||
| 100 | #include "llvm/IR/InstIterator.h" | ||||||
| 101 | #include "llvm/IR/InstrTypes.h" | ||||||
| 102 | #include "llvm/IR/Instruction.h" | ||||||
| 103 | #include "llvm/IR/Instructions.h" | ||||||
| 104 | #include "llvm/IR/IntrinsicInst.h" | ||||||
| 105 | #include "llvm/IR/Intrinsics.h" | ||||||
| 106 | #include "llvm/IR/LLVMContext.h" | ||||||
| 107 | #include "llvm/IR/Metadata.h" | ||||||
| 108 | #include "llvm/IR/Operator.h" | ||||||
| 109 | #include "llvm/IR/PatternMatch.h" | ||||||
| 110 | #include "llvm/IR/Type.h" | ||||||
| 111 | #include "llvm/IR/Use.h" | ||||||
| 112 | #include "llvm/IR/User.h" | ||||||
| 113 | #include "llvm/IR/Value.h" | ||||||
| 114 | #include "llvm/IR/Verifier.h" | ||||||
| 115 | #include "llvm/Pass.h" | ||||||
| 116 | #include "llvm/Support/Casting.h" | ||||||
| 117 | #include "llvm/Support/CommandLine.h" | ||||||
| 118 | #include "llvm/Support/Compiler.h" | ||||||
| 119 | #include "llvm/Support/Debug.h" | ||||||
| 120 | #include "llvm/Support/ErrorHandling.h" | ||||||
| 121 | #include "llvm/Support/KnownBits.h" | ||||||
| 122 | #include "llvm/Support/SaveAndRestore.h" | ||||||
| 123 | #include "llvm/Support/raw_ostream.h" | ||||||
| 124 | #include <algorithm> | ||||||
| 125 | #include <cassert> | ||||||
| 126 | #include <climits> | ||||||
| 127 | #include <cstddef> | ||||||
| 128 | #include <cstdint> | ||||||
| 129 | #include <cstdlib> | ||||||
| 130 | #include <map> | ||||||
| 131 | #include <memory> | ||||||
| 132 | #include <tuple> | ||||||
| 133 | #include <utility> | ||||||
| 134 | #include <vector> | ||||||
| 135 | |||||||
| 136 | using namespace llvm; | ||||||
| 137 | |||||||
| 138 | #define DEBUG_TYPE"scalar-evolution" "scalar-evolution" | ||||||
| 139 | |||||||
| 140 | STATISTIC(NumArrayLenItCounts,static llvm::Statistic NumArrayLenItCounts = {"scalar-evolution" , "NumArrayLenItCounts", "Number of trip counts computed with array length" } | ||||||
| 141 | "Number of trip counts computed with array length")static llvm::Statistic NumArrayLenItCounts = {"scalar-evolution" , "NumArrayLenItCounts", "Number of trip counts computed with array length" }; | ||||||
| 142 | STATISTIC(NumTripCountsComputed,static llvm::Statistic NumTripCountsComputed = {"scalar-evolution" , "NumTripCountsComputed", "Number of loops with predictable loop counts" } | ||||||
| 143 | "Number of loops with predictable loop counts")static llvm::Statistic NumTripCountsComputed = {"scalar-evolution" , "NumTripCountsComputed", "Number of loops with predictable loop counts" }; | ||||||
| 144 | STATISTIC(NumTripCountsNotComputed,static llvm::Statistic NumTripCountsNotComputed = {"scalar-evolution" , "NumTripCountsNotComputed", "Number of loops without predictable loop counts" } | ||||||
| 145 | "Number of loops without predictable loop counts")static llvm::Statistic NumTripCountsNotComputed = {"scalar-evolution" , "NumTripCountsNotComputed", "Number of loops without predictable loop counts" }; | ||||||
| 146 | STATISTIC(NumBruteForceTripCountsComputed,static llvm::Statistic NumBruteForceTripCountsComputed = {"scalar-evolution" , "NumBruteForceTripCountsComputed", "Number of loops with trip counts computed by force" } | ||||||
| 147 | "Number of loops with trip counts computed by force")static llvm::Statistic NumBruteForceTripCountsComputed = {"scalar-evolution" , "NumBruteForceTripCountsComputed", "Number of loops with trip counts computed by force" }; | ||||||
| 148 | |||||||
| 149 | static cl::opt<unsigned> | ||||||
| 150 | MaxBruteForceIterations("scalar-evolution-max-iterations", cl::ReallyHidden, | ||||||
| 151 | cl::ZeroOrMore, | ||||||
| 152 | cl::desc("Maximum number of iterations SCEV will " | ||||||
| 153 | "symbolically execute a constant " | ||||||
| 154 | "derived loop"), | ||||||
| 155 | cl::init(100)); | ||||||
| 156 | |||||||
| 157 | // FIXME: Enable this with EXPENSIVE_CHECKS when the test suite is clean. | ||||||
| 158 | static cl::opt<bool> VerifySCEV( | ||||||
| 159 | "verify-scev", cl::Hidden, | ||||||
| 160 | cl::desc("Verify ScalarEvolution's backedge taken counts (slow)")); | ||||||
| 161 | static cl::opt<bool> VerifySCEVStrict( | ||||||
| 162 | "verify-scev-strict", cl::Hidden, | ||||||
| 163 | cl::desc("Enable stricter verification with -verify-scev is passed")); | ||||||
| 164 | static cl::opt<bool> | ||||||
| 165 | VerifySCEVMap("verify-scev-maps", cl::Hidden, | ||||||
| 166 | cl::desc("Verify no dangling value in ScalarEvolution's " | ||||||
| 167 | "ExprValueMap (slow)")); | ||||||
| 168 | |||||||
| 169 | static cl::opt<bool> VerifyIR( | ||||||
| 170 | "scev-verify-ir", cl::Hidden, | ||||||
| 171 | cl::desc("Verify IR correctness when making sensitive SCEV queries (slow)"), | ||||||
| 172 | cl::init(false)); | ||||||
| 173 | |||||||
| 174 | static cl::opt<unsigned> MulOpsInlineThreshold( | ||||||
| 175 | "scev-mulops-inline-threshold", cl::Hidden, | ||||||
| 176 | cl::desc("Threshold for inlining multiplication operands into a SCEV"), | ||||||
| 177 | cl::init(32)); | ||||||
| 178 | |||||||
| 179 | static cl::opt<unsigned> AddOpsInlineThreshold( | ||||||
| 180 | "scev-addops-inline-threshold", cl::Hidden, | ||||||
| 181 | cl::desc("Threshold for inlining addition operands into a SCEV"), | ||||||
| 182 | cl::init(500)); | ||||||
| 183 | |||||||
| 184 | static cl::opt<unsigned> MaxSCEVCompareDepth( | ||||||
| 185 | "scalar-evolution-max-scev-compare-depth", cl::Hidden, | ||||||
| 186 | cl::desc("Maximum depth of recursive SCEV complexity comparisons"), | ||||||
| 187 | cl::init(32)); | ||||||
| 188 | |||||||
| 189 | static cl::opt<unsigned> MaxSCEVOperationsImplicationDepth( | ||||||
| 190 | "scalar-evolution-max-scev-operations-implication-depth", cl::Hidden, | ||||||
| 191 | cl::desc("Maximum depth of recursive SCEV operations implication analysis"), | ||||||
| 192 | cl::init(2)); | ||||||
| 193 | |||||||
| 194 | static cl::opt<unsigned> MaxValueCompareDepth( | ||||||
| 195 | "scalar-evolution-max-value-compare-depth", cl::Hidden, | ||||||
| 196 | cl::desc("Maximum depth of recursive value complexity comparisons"), | ||||||
| 197 | cl::init(2)); | ||||||
| 198 | |||||||
| 199 | static cl::opt<unsigned> | ||||||
| 200 | MaxArithDepth("scalar-evolution-max-arith-depth", cl::Hidden, | ||||||
| 201 | cl::desc("Maximum depth of recursive arithmetics"), | ||||||
| 202 | cl::init(32)); | ||||||
| 203 | |||||||
| 204 | static cl::opt<unsigned> MaxConstantEvolvingDepth( | ||||||
| 205 | "scalar-evolution-max-constant-evolving-depth", cl::Hidden, | ||||||
| 206 | cl::desc("Maximum depth of recursive constant evolving"), cl::init(32)); | ||||||
| 207 | |||||||
| 208 | static cl::opt<unsigned> | ||||||
| 209 | MaxCastDepth("scalar-evolution-max-cast-depth", cl::Hidden, | ||||||
| 210 | cl::desc("Maximum depth of recursive SExt/ZExt/Trunc"), | ||||||
| 211 | cl::init(8)); | ||||||
| 212 | |||||||
| 213 | static cl::opt<unsigned> | ||||||
| 214 | MaxAddRecSize("scalar-evolution-max-add-rec-size", cl::Hidden, | ||||||
| 215 | cl::desc("Max coefficients in AddRec during evolving"), | ||||||
| 216 | cl::init(8)); | ||||||
| 217 | |||||||
| 218 | static cl::opt<unsigned> | ||||||
| 219 | HugeExprThreshold("scalar-evolution-huge-expr-threshold", cl::Hidden, | ||||||
| 220 | cl::desc("Size of the expression which is considered huge"), | ||||||
| 221 | cl::init(4096)); | ||||||
| 222 | |||||||
| 223 | //===----------------------------------------------------------------------===// | ||||||
| 224 | // SCEV class definitions | ||||||
| 225 | //===----------------------------------------------------------------------===// | ||||||
| 226 | |||||||
| 227 | //===----------------------------------------------------------------------===// | ||||||
| 228 | // Implementation of the SCEV class. | ||||||
| 229 | // | ||||||
| 230 | |||||||
| 231 | #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) | ||||||
| 232 | LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void SCEV::dump() const { | ||||||
| 233 | print(dbgs()); | ||||||
| 234 | dbgs() << '\n'; | ||||||
| 235 | } | ||||||
| 236 | #endif | ||||||
| 237 | |||||||
| 238 | void SCEV::print(raw_ostream &OS) const { | ||||||
| 239 | switch (static_cast<SCEVTypes>(getSCEVType())) { | ||||||
| 240 | case scConstant: | ||||||
| 241 | cast<SCEVConstant>(this)->getValue()->printAsOperand(OS, false); | ||||||
| 242 | return; | ||||||
| 243 | case scTruncate: { | ||||||
| 244 | const SCEVTruncateExpr *Trunc = cast<SCEVTruncateExpr>(this); | ||||||
| 245 | const SCEV *Op = Trunc->getOperand(); | ||||||
| 246 | OS << "(trunc " << *Op->getType() << " " << *Op << " to " | ||||||
| 247 | << *Trunc->getType() << ")"; | ||||||
| 248 | return; | ||||||
| 249 | } | ||||||
| 250 | case scZeroExtend: { | ||||||
| 251 | const SCEVZeroExtendExpr *ZExt = cast<SCEVZeroExtendExpr>(this); | ||||||
| 252 | const SCEV *Op = ZExt->getOperand(); | ||||||
| 253 | OS << "(zext " << *Op->getType() << " " << *Op << " to " | ||||||
| 254 | << *ZExt->getType() << ")"; | ||||||
| 255 | return; | ||||||
| 256 | } | ||||||
| 257 | case scSignExtend: { | ||||||
| 258 | const SCEVSignExtendExpr *SExt = cast<SCEVSignExtendExpr>(this); | ||||||
| 259 | const SCEV *Op = SExt->getOperand(); | ||||||
| 260 | OS << "(sext " << *Op->getType() << " " << *Op << " to " | ||||||
| 261 | << *SExt->getType() << ")"; | ||||||
| 262 | return; | ||||||
| 263 | } | ||||||
| 264 | case scAddRecExpr: { | ||||||
| 265 | const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(this); | ||||||
| 266 | OS << "{" << *AR->getOperand(0); | ||||||
| 267 | for (unsigned i = 1, e = AR->getNumOperands(); i != e; ++i) | ||||||
| 268 | OS << ",+," << *AR->getOperand(i); | ||||||
| 269 | OS << "}<"; | ||||||
| 270 | if (AR->hasNoUnsignedWrap()) | ||||||
| 271 | OS << "nuw><"; | ||||||
| 272 | if (AR->hasNoSignedWrap()) | ||||||
| 273 | OS << "nsw><"; | ||||||
| 274 | if (AR->hasNoSelfWrap() && | ||||||
| 275 | !AR->getNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW))) | ||||||
| 276 | OS << "nw><"; | ||||||
| 277 | AR->getLoop()->getHeader()->printAsOperand(OS, /*PrintType=*/false); | ||||||
| 278 | OS << ">"; | ||||||
| 279 | return; | ||||||
| 280 | } | ||||||
| 281 | case scAddExpr: | ||||||
| 282 | case scMulExpr: | ||||||
| 283 | case scUMaxExpr: | ||||||
| 284 | case scSMaxExpr: | ||||||
| 285 | case scUMinExpr: | ||||||
| 286 | case scSMinExpr: { | ||||||
| 287 | const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(this); | ||||||
| 288 | const char *OpStr = nullptr; | ||||||
| 289 | switch (NAry->getSCEVType()) { | ||||||
| 290 | case scAddExpr: OpStr = " + "; break; | ||||||
| 291 | case scMulExpr: OpStr = " * "; break; | ||||||
| 292 | case scUMaxExpr: OpStr = " umax "; break; | ||||||
| 293 | case scSMaxExpr: OpStr = " smax "; break; | ||||||
| 294 | case scUMinExpr: | ||||||
| 295 | OpStr = " umin "; | ||||||
| 296 | break; | ||||||
| 297 | case scSMinExpr: | ||||||
| 298 | OpStr = " smin "; | ||||||
| 299 | break; | ||||||
| 300 | } | ||||||
| 301 | OS << "("; | ||||||
| 302 | for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end(); | ||||||
| 303 | I != E; ++I) { | ||||||
| 304 | OS << **I; | ||||||
| 305 | if (std::next(I) != E) | ||||||
| 306 | OS << OpStr; | ||||||
| 307 | } | ||||||
| 308 | OS << ")"; | ||||||
| 309 | switch (NAry->getSCEVType()) { | ||||||
| 310 | case scAddExpr: | ||||||
| 311 | case scMulExpr: | ||||||
| 312 | if (NAry->hasNoUnsignedWrap()) | ||||||
| 313 | OS << "<nuw>"; | ||||||
| 314 | if (NAry->hasNoSignedWrap()) | ||||||
| 315 | OS << "<nsw>"; | ||||||
| 316 | } | ||||||
| 317 | return; | ||||||
| 318 | } | ||||||
| 319 | case scUDivExpr: { | ||||||
| 320 | const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(this); | ||||||
| 321 | OS << "(" << *UDiv->getLHS() << " /u " << *UDiv->getRHS() << ")"; | ||||||
| 322 | return; | ||||||
| 323 | } | ||||||
| 324 | case scUnknown: { | ||||||
| 325 | const SCEVUnknown *U = cast<SCEVUnknown>(this); | ||||||
| 326 | Type *AllocTy; | ||||||
| 327 | if (U->isSizeOf(AllocTy)) { | ||||||
| 328 | OS << "sizeof(" << *AllocTy << ")"; | ||||||
| 329 | return; | ||||||
| 330 | } | ||||||
| 331 | if (U->isAlignOf(AllocTy)) { | ||||||
| 332 | OS << "alignof(" << *AllocTy << ")"; | ||||||
| 333 | return; | ||||||
| 334 | } | ||||||
| 335 | |||||||
| 336 | Type *CTy; | ||||||
| 337 | Constant *FieldNo; | ||||||
| 338 | if (U->isOffsetOf(CTy, FieldNo)) { | ||||||
| 339 | OS << "offsetof(" << *CTy << ", "; | ||||||
| 340 | FieldNo->printAsOperand(OS, false); | ||||||
| 341 | OS << ")"; | ||||||
| 342 | return; | ||||||
| 343 | } | ||||||
| 344 | |||||||
| 345 | // Otherwise just print it normally. | ||||||
| 346 | U->getValue()->printAsOperand(OS, false); | ||||||
| 347 | return; | ||||||
| 348 | } | ||||||
| 349 | case scCouldNotCompute: | ||||||
| 350 | OS << "***COULDNOTCOMPUTE***"; | ||||||
| 351 | return; | ||||||
| 352 | } | ||||||
| 353 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 353); | ||||||
| 354 | } | ||||||
| 355 | |||||||
| 356 | Type *SCEV::getType() const { | ||||||
| 357 | switch (static_cast<SCEVTypes>(getSCEVType())) { | ||||||
| 358 | case scConstant: | ||||||
| 359 | return cast<SCEVConstant>(this)->getType(); | ||||||
| 360 | case scTruncate: | ||||||
| 361 | case scZeroExtend: | ||||||
| 362 | case scSignExtend: | ||||||
| 363 | return cast<SCEVCastExpr>(this)->getType(); | ||||||
| 364 | case scAddRecExpr: | ||||||
| 365 | case scMulExpr: | ||||||
| 366 | case scUMaxExpr: | ||||||
| 367 | case scSMaxExpr: | ||||||
| 368 | case scUMinExpr: | ||||||
| 369 | case scSMinExpr: | ||||||
| 370 | return cast<SCEVNAryExpr>(this)->getType(); | ||||||
| 371 | case scAddExpr: | ||||||
| 372 | return cast<SCEVAddExpr>(this)->getType(); | ||||||
| 373 | case scUDivExpr: | ||||||
| 374 | return cast<SCEVUDivExpr>(this)->getType(); | ||||||
| 375 | case scUnknown: | ||||||
| 376 | return cast<SCEVUnknown>(this)->getType(); | ||||||
| 377 | case scCouldNotCompute: | ||||||
| 378 | llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 378); | ||||||
| 379 | } | ||||||
| 380 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 380); | ||||||
| 381 | } | ||||||
| 382 | |||||||
| 383 | bool SCEV::isZero() const { | ||||||
| 384 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this)) | ||||||
| 385 | return SC->getValue()->isZero(); | ||||||
| 386 | return false; | ||||||
| 387 | } | ||||||
| 388 | |||||||
| 389 | bool SCEV::isOne() const { | ||||||
| 390 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this)) | ||||||
| 391 | return SC->getValue()->isOne(); | ||||||
| 392 | return false; | ||||||
| 393 | } | ||||||
| 394 | |||||||
| 395 | bool SCEV::isAllOnesValue() const { | ||||||
| 396 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this)) | ||||||
| 397 | return SC->getValue()->isMinusOne(); | ||||||
| 398 | return false; | ||||||
| 399 | } | ||||||
| 400 | |||||||
| 401 | bool SCEV::isNonConstantNegative() const { | ||||||
| 402 | const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(this); | ||||||
| 403 | if (!Mul) return false; | ||||||
| 404 | |||||||
| 405 | // If there is a constant factor, it will be first. | ||||||
| 406 | const SCEVConstant *SC = dyn_cast<SCEVConstant>(Mul->getOperand(0)); | ||||||
| 407 | if (!SC) return false; | ||||||
| 408 | |||||||
| 409 | // Return true if the value is negative, this matches things like (-42 * V). | ||||||
| 410 | return SC->getAPInt().isNegative(); | ||||||
| 411 | } | ||||||
| 412 | |||||||
| 413 | SCEVCouldNotCompute::SCEVCouldNotCompute() : | ||||||
| 414 | SCEV(FoldingSetNodeIDRef(), scCouldNotCompute, 0) {} | ||||||
| 415 | |||||||
| 416 | bool SCEVCouldNotCompute::classof(const SCEV *S) { | ||||||
| 417 | return S->getSCEVType() == scCouldNotCompute; | ||||||
| 418 | } | ||||||
| 419 | |||||||
| 420 | const SCEV *ScalarEvolution::getConstant(ConstantInt *V) { | ||||||
| 421 | FoldingSetNodeID ID; | ||||||
| 422 | ID.AddInteger(scConstant); | ||||||
| 423 | ID.AddPointer(V); | ||||||
| 424 | void *IP = nullptr; | ||||||
| 425 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
| 426 | SCEV *S = new (SCEVAllocator) SCEVConstant(ID.Intern(SCEVAllocator), V); | ||||||
| 427 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 428 | return S; | ||||||
| 429 | } | ||||||
| 430 | |||||||
| 431 | const SCEV *ScalarEvolution::getConstant(const APInt &Val) { | ||||||
| 432 | return getConstant(ConstantInt::get(getContext(), Val)); | ||||||
| 433 | } | ||||||
| 434 | |||||||
| 435 | const SCEV * | ||||||
| 436 | ScalarEvolution::getConstant(Type *Ty, uint64_t V, bool isSigned) { | ||||||
| 437 | IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty)); | ||||||
| 438 | return getConstant(ConstantInt::get(ITy, V, isSigned)); | ||||||
| 439 | } | ||||||
| 440 | |||||||
| 441 | SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeIDRef ID, | ||||||
| 442 | unsigned SCEVTy, const SCEV *op, Type *ty) | ||||||
| 443 | : SCEV(ID, SCEVTy, computeExpressionSize(op)), Op(op), Ty(ty) {} | ||||||
| 444 | |||||||
| 445 | SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeIDRef ID, | ||||||
| 446 | const SCEV *op, Type *ty) | ||||||
| 447 | : SCEVCastExpr(ID, scTruncate, op, ty) { | ||||||
| 448 | assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot truncate non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate non-integer value!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 449, __PRETTY_FUNCTION__)) | ||||||
| 449 | "Cannot truncate non-integer value!")((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot truncate non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate non-integer value!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 449, __PRETTY_FUNCTION__)); | ||||||
| 450 | } | ||||||
| 451 | |||||||
| 452 | SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID, | ||||||
| 453 | const SCEV *op, Type *ty) | ||||||
| 454 | : SCEVCastExpr(ID, scZeroExtend, op, ty) { | ||||||
| 455 | assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot zero extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot zero extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 456, __PRETTY_FUNCTION__)) | ||||||
| 456 | "Cannot zero extend non-integer value!")((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot zero extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot zero extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 456, __PRETTY_FUNCTION__)); | ||||||
| 457 | } | ||||||
| 458 | |||||||
| 459 | SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeIDRef ID, | ||||||
| 460 | const SCEV *op, Type *ty) | ||||||
| 461 | : SCEVCastExpr(ID, scSignExtend, op, ty) { | ||||||
| 462 | assert(Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot sign extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot sign extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 463, __PRETTY_FUNCTION__)) | ||||||
| 463 | "Cannot sign extend non-integer value!")((Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy () && "Cannot sign extend non-integer value!") ? static_cast <void> (0) : __assert_fail ("Op->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot sign extend non-integer value!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 463, __PRETTY_FUNCTION__)); | ||||||
| 464 | } | ||||||
| 465 | |||||||
| 466 | void SCEVUnknown::deleted() { | ||||||
| 467 | // Clear this SCEVUnknown from various maps. | ||||||
| 468 | SE->forgetMemoizedResults(this); | ||||||
| 469 | |||||||
| 470 | // Remove this SCEVUnknown from the uniquing map. | ||||||
| 471 | SE->UniqueSCEVs.RemoveNode(this); | ||||||
| 472 | |||||||
| 473 | // Release the value. | ||||||
| 474 | setValPtr(nullptr); | ||||||
| 475 | } | ||||||
| 476 | |||||||
| 477 | void SCEVUnknown::allUsesReplacedWith(Value *New) { | ||||||
| 478 | // Remove this SCEVUnknown from the uniquing map. | ||||||
| 479 | SE->UniqueSCEVs.RemoveNode(this); | ||||||
| 480 | |||||||
| 481 | // Update this SCEVUnknown to point to the new value. This is needed | ||||||
| 482 | // because there may still be outstanding SCEVs which still point to | ||||||
| 483 | // this SCEVUnknown. | ||||||
| 484 | setValPtr(New); | ||||||
| 485 | } | ||||||
| 486 | |||||||
| 487 | bool SCEVUnknown::isSizeOf(Type *&AllocTy) const { | ||||||
| 488 | if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue())) | ||||||
| 489 | if (VCE->getOpcode() == Instruction::PtrToInt) | ||||||
| 490 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0))) | ||||||
| 491 | if (CE->getOpcode() == Instruction::GetElementPtr && | ||||||
| 492 | CE->getOperand(0)->isNullValue() && | ||||||
| 493 | CE->getNumOperands() == 2) | ||||||
| 494 | if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(1))) | ||||||
| 495 | if (CI->isOne()) { | ||||||
| 496 | AllocTy = cast<PointerType>(CE->getOperand(0)->getType()) | ||||||
| 497 | ->getElementType(); | ||||||
| 498 | return true; | ||||||
| 499 | } | ||||||
| 500 | |||||||
| 501 | return false; | ||||||
| 502 | } | ||||||
| 503 | |||||||
| 504 | bool SCEVUnknown::isAlignOf(Type *&AllocTy) const { | ||||||
| 505 | if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue())) | ||||||
| 506 | if (VCE->getOpcode() == Instruction::PtrToInt) | ||||||
| 507 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0))) | ||||||
| 508 | if (CE->getOpcode() == Instruction::GetElementPtr && | ||||||
| 509 | CE->getOperand(0)->isNullValue()) { | ||||||
| 510 | Type *Ty = | ||||||
| 511 | cast<PointerType>(CE->getOperand(0)->getType())->getElementType(); | ||||||
| 512 | if (StructType *STy = dyn_cast<StructType>(Ty)) | ||||||
| 513 | if (!STy->isPacked() && | ||||||
| 514 | CE->getNumOperands() == 3 && | ||||||
| 515 | CE->getOperand(1)->isNullValue()) { | ||||||
| 516 | if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(2))) | ||||||
| 517 | if (CI->isOne() && | ||||||
| 518 | STy->getNumElements() == 2 && | ||||||
| 519 | STy->getElementType(0)->isIntegerTy(1)) { | ||||||
| 520 | AllocTy = STy->getElementType(1); | ||||||
| 521 | return true; | ||||||
| 522 | } | ||||||
| 523 | } | ||||||
| 524 | } | ||||||
| 525 | |||||||
| 526 | return false; | ||||||
| 527 | } | ||||||
| 528 | |||||||
| 529 | bool SCEVUnknown::isOffsetOf(Type *&CTy, Constant *&FieldNo) const { | ||||||
| 530 | if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue())) | ||||||
| 531 | if (VCE->getOpcode() == Instruction::PtrToInt) | ||||||
| 532 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0))) | ||||||
| 533 | if (CE->getOpcode() == Instruction::GetElementPtr && | ||||||
| 534 | CE->getNumOperands() == 3 && | ||||||
| 535 | CE->getOperand(0)->isNullValue() && | ||||||
| 536 | CE->getOperand(1)->isNullValue()) { | ||||||
| 537 | Type *Ty = | ||||||
| 538 | cast<PointerType>(CE->getOperand(0)->getType())->getElementType(); | ||||||
| 539 | // Ignore vector types here so that ScalarEvolutionExpander doesn't | ||||||
| 540 | // emit getelementptrs that index into vectors. | ||||||
| 541 | if (Ty->isStructTy() || Ty->isArrayTy()) { | ||||||
| 542 | CTy = Ty; | ||||||
| 543 | FieldNo = CE->getOperand(2); | ||||||
| 544 | return true; | ||||||
| 545 | } | ||||||
| 546 | } | ||||||
| 547 | |||||||
| 548 | return false; | ||||||
| 549 | } | ||||||
| 550 | |||||||
| 551 | //===----------------------------------------------------------------------===// | ||||||
| 552 | // SCEV Utilities | ||||||
| 553 | //===----------------------------------------------------------------------===// | ||||||
| 554 | |||||||
| 555 | /// Compare the two values \p LV and \p RV in terms of their "complexity" where | ||||||
| 556 | /// "complexity" is a partial (and somewhat ad-hoc) relation used to order | ||||||
| 557 | /// operands in SCEV expressions. \p EqCache is a set of pairs of values that | ||||||
| 558 | /// have been previously deemed to be "equally complex" by this routine. It is | ||||||
| 559 | /// intended to avoid exponential time complexity in cases like: | ||||||
| 560 | /// | ||||||
| 561 | /// %a = f(%x, %y) | ||||||
| 562 | /// %b = f(%a, %a) | ||||||
| 563 | /// %c = f(%b, %b) | ||||||
| 564 | /// | ||||||
| 565 | /// %d = f(%x, %y) | ||||||
| 566 | /// %e = f(%d, %d) | ||||||
| 567 | /// %f = f(%e, %e) | ||||||
| 568 | /// | ||||||
| 569 | /// CompareValueComplexity(%f, %c) | ||||||
| 570 | /// | ||||||
| 571 | /// Since we do not continue running this routine on expression trees once we | ||||||
| 572 | /// have seen unequal values, there is no need to track them in the cache. | ||||||
| 573 | static int | ||||||
| 574 | CompareValueComplexity(EquivalenceClasses<const Value *> &EqCacheValue, | ||||||
| 575 | const LoopInfo *const LI, Value *LV, Value *RV, | ||||||
| 576 | unsigned Depth) { | ||||||
| 577 | if (Depth > MaxValueCompareDepth || EqCacheValue.isEquivalent(LV, RV)) | ||||||
| 578 | return 0; | ||||||
| 579 | |||||||
| 580 | // Order pointer values after integer values. This helps SCEVExpander form | ||||||
| 581 | // GEPs. | ||||||
| 582 | bool LIsPointer = LV->getType()->isPointerTy(), | ||||||
| 583 | RIsPointer = RV->getType()->isPointerTy(); | ||||||
| 584 | if (LIsPointer != RIsPointer) | ||||||
| 585 | return (int)LIsPointer - (int)RIsPointer; | ||||||
| 586 | |||||||
| 587 | // Compare getValueID values. | ||||||
| 588 | unsigned LID = LV->getValueID(), RID = RV->getValueID(); | ||||||
| 589 | if (LID != RID) | ||||||
| 590 | return (int)LID - (int)RID; | ||||||
| 591 | |||||||
| 592 | // Sort arguments by their position. | ||||||
| 593 | if (const auto *LA = dyn_cast<Argument>(LV)) { | ||||||
| 594 | const auto *RA = cast<Argument>(RV); | ||||||
| 595 | unsigned LArgNo = LA->getArgNo(), RArgNo = RA->getArgNo(); | ||||||
| 596 | return (int)LArgNo - (int)RArgNo; | ||||||
| 597 | } | ||||||
| 598 | |||||||
| 599 | if (const auto *LGV = dyn_cast<GlobalValue>(LV)) { | ||||||
| 600 | const auto *RGV = cast<GlobalValue>(RV); | ||||||
| 601 | |||||||
| 602 | const auto IsGVNameSemantic = [&](const GlobalValue *GV) { | ||||||
| 603 | auto LT = GV->getLinkage(); | ||||||
| 604 | return !(GlobalValue::isPrivateLinkage(LT) || | ||||||
| 605 | GlobalValue::isInternalLinkage(LT)); | ||||||
| 606 | }; | ||||||
| 607 | |||||||
| 608 | // Use the names to distinguish the two values, but only if the | ||||||
| 609 | // names are semantically important. | ||||||
| 610 | if (IsGVNameSemantic(LGV) && IsGVNameSemantic(RGV)) | ||||||
| 611 | return LGV->getName().compare(RGV->getName()); | ||||||
| 612 | } | ||||||
| 613 | |||||||
| 614 | // For instructions, compare their loop depth, and their operand count. This | ||||||
| 615 | // is pretty loose. | ||||||
| 616 | if (const auto *LInst = dyn_cast<Instruction>(LV)) { | ||||||
| 617 | const auto *RInst = cast<Instruction>(RV); | ||||||
| 618 | |||||||
| 619 | // Compare loop depths. | ||||||
| 620 | const BasicBlock *LParent = LInst->getParent(), | ||||||
| 621 | *RParent = RInst->getParent(); | ||||||
| 622 | if (LParent != RParent) { | ||||||
| 623 | unsigned LDepth = LI->getLoopDepth(LParent), | ||||||
| 624 | RDepth = LI->getLoopDepth(RParent); | ||||||
| 625 | if (LDepth != RDepth) | ||||||
| 626 | return (int)LDepth - (int)RDepth; | ||||||
| 627 | } | ||||||
| 628 | |||||||
| 629 | // Compare the number of operands. | ||||||
| 630 | unsigned LNumOps = LInst->getNumOperands(), | ||||||
| 631 | RNumOps = RInst->getNumOperands(); | ||||||
| 632 | if (LNumOps != RNumOps) | ||||||
| 633 | return (int)LNumOps - (int)RNumOps; | ||||||
| 634 | |||||||
| 635 | for (unsigned Idx : seq(0u, LNumOps)) { | ||||||
| 636 | int Result = | ||||||
| 637 | CompareValueComplexity(EqCacheValue, LI, LInst->getOperand(Idx), | ||||||
| 638 | RInst->getOperand(Idx), Depth + 1); | ||||||
| 639 | if (Result != 0) | ||||||
| 640 | return Result; | ||||||
| 641 | } | ||||||
| 642 | } | ||||||
| 643 | |||||||
| 644 | EqCacheValue.unionSets(LV, RV); | ||||||
| 645 | return 0; | ||||||
| 646 | } | ||||||
| 647 | |||||||
| 648 | // Return negative, zero, or positive, if LHS is less than, equal to, or greater | ||||||
| 649 | // than RHS, respectively. A three-way result allows recursive comparisons to be | ||||||
| 650 | // more efficient. | ||||||
| 651 | static int CompareSCEVComplexity( | ||||||
| 652 | EquivalenceClasses<const SCEV *> &EqCacheSCEV, | ||||||
| 653 | EquivalenceClasses<const Value *> &EqCacheValue, | ||||||
| 654 | const LoopInfo *const LI, const SCEV *LHS, const SCEV *RHS, | ||||||
| 655 | DominatorTree &DT, unsigned Depth = 0) { | ||||||
| 656 | // Fast-path: SCEVs are uniqued so we can do a quick equality check. | ||||||
| 657 | if (LHS == RHS) | ||||||
| 658 | return 0; | ||||||
| 659 | |||||||
| 660 | // Primarily, sort the SCEVs by their getSCEVType(). | ||||||
| 661 | unsigned LType = LHS->getSCEVType(), RType = RHS->getSCEVType(); | ||||||
| 662 | if (LType != RType) | ||||||
| 663 | return (int)LType - (int)RType; | ||||||
| 664 | |||||||
| 665 | if (Depth > MaxSCEVCompareDepth || EqCacheSCEV.isEquivalent(LHS, RHS)) | ||||||
| 666 | return 0; | ||||||
| 667 | // Aside from the getSCEVType() ordering, the particular ordering | ||||||
| 668 | // isn't very important except that it's beneficial to be consistent, | ||||||
| 669 | // so that (a + b) and (b + a) don't end up as different expressions. | ||||||
| 670 | switch (static_cast<SCEVTypes>(LType)) { | ||||||
| 671 | case scUnknown: { | ||||||
| 672 | const SCEVUnknown *LU = cast<SCEVUnknown>(LHS); | ||||||
| 673 | const SCEVUnknown *RU = cast<SCEVUnknown>(RHS); | ||||||
| 674 | |||||||
| 675 | int X = CompareValueComplexity(EqCacheValue, LI, LU->getValue(), | ||||||
| 676 | RU->getValue(), Depth + 1); | ||||||
| 677 | if (X == 0) | ||||||
| 678 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
| 679 | return X; | ||||||
| 680 | } | ||||||
| 681 | |||||||
| 682 | case scConstant: { | ||||||
| 683 | const SCEVConstant *LC = cast<SCEVConstant>(LHS); | ||||||
| 684 | const SCEVConstant *RC = cast<SCEVConstant>(RHS); | ||||||
| 685 | |||||||
| 686 | // Compare constant values. | ||||||
| 687 | const APInt &LA = LC->getAPInt(); | ||||||
| 688 | const APInt &RA = RC->getAPInt(); | ||||||
| 689 | unsigned LBitWidth = LA.getBitWidth(), RBitWidth = RA.getBitWidth(); | ||||||
| 690 | if (LBitWidth != RBitWidth) | ||||||
| 691 | return (int)LBitWidth - (int)RBitWidth; | ||||||
| 692 | return LA.ult(RA) ? -1 : 1; | ||||||
| 693 | } | ||||||
| 694 | |||||||
| 695 | case scAddRecExpr: { | ||||||
| 696 | const SCEVAddRecExpr *LA = cast<SCEVAddRecExpr>(LHS); | ||||||
| 697 | const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS); | ||||||
| 698 | |||||||
| 699 | // There is always a dominance between two recs that are used by one SCEV, | ||||||
| 700 | // so we can safely sort recs by loop header dominance. We require such | ||||||
| 701 | // order in getAddExpr. | ||||||
| 702 | const Loop *LLoop = LA->getLoop(), *RLoop = RA->getLoop(); | ||||||
| 703 | if (LLoop != RLoop) { | ||||||
| 704 | const BasicBlock *LHead = LLoop->getHeader(), *RHead = RLoop->getHeader(); | ||||||
| 705 | assert(LHead != RHead && "Two loops share the same header?")((LHead != RHead && "Two loops share the same header?" ) ? static_cast<void> (0) : __assert_fail ("LHead != RHead && \"Two loops share the same header?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 705, __PRETTY_FUNCTION__)); | ||||||
| 706 | if (DT.dominates(LHead, RHead)) | ||||||
| 707 | return 1; | ||||||
| 708 | else | ||||||
| 709 | assert(DT.dominates(RHead, LHead) &&((DT.dominates(RHead, LHead) && "No dominance between recurrences used by one SCEV?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(RHead, LHead) && \"No dominance between recurrences used by one SCEV?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 710, __PRETTY_FUNCTION__)) | ||||||
| 710 | "No dominance between recurrences used by one SCEV?")((DT.dominates(RHead, LHead) && "No dominance between recurrences used by one SCEV?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates(RHead, LHead) && \"No dominance between recurrences used by one SCEV?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 710, __PRETTY_FUNCTION__)); | ||||||
| 711 | return -1; | ||||||
| 712 | } | ||||||
| 713 | |||||||
| 714 | // Addrec complexity grows with operand count. | ||||||
| 715 | unsigned LNumOps = LA->getNumOperands(), RNumOps = RA->getNumOperands(); | ||||||
| 716 | if (LNumOps != RNumOps) | ||||||
| 717 | return (int)LNumOps - (int)RNumOps; | ||||||
| 718 | |||||||
| 719 | // Lexicographically compare. | ||||||
| 720 | for (unsigned i = 0; i != LNumOps; ++i) { | ||||||
| 721 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, | ||||||
| 722 | LA->getOperand(i), RA->getOperand(i), DT, | ||||||
| 723 | Depth + 1); | ||||||
| 724 | if (X != 0) | ||||||
| 725 | return X; | ||||||
| 726 | } | ||||||
| 727 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
| 728 | return 0; | ||||||
| 729 | } | ||||||
| 730 | |||||||
| 731 | case scAddExpr: | ||||||
| 732 | case scMulExpr: | ||||||
| 733 | case scSMaxExpr: | ||||||
| 734 | case scUMaxExpr: | ||||||
| 735 | case scSMinExpr: | ||||||
| 736 | case scUMinExpr: { | ||||||
| 737 | const SCEVNAryExpr *LC = cast<SCEVNAryExpr>(LHS); | ||||||
| 738 | const SCEVNAryExpr *RC = cast<SCEVNAryExpr>(RHS); | ||||||
| 739 | |||||||
| 740 | // Lexicographically compare n-ary expressions. | ||||||
| 741 | unsigned LNumOps = LC->getNumOperands(), RNumOps = RC->getNumOperands(); | ||||||
| 742 | if (LNumOps != RNumOps) | ||||||
| 743 | return (int)LNumOps - (int)RNumOps; | ||||||
| 744 | |||||||
| 745 | for (unsigned i = 0; i != LNumOps; ++i) { | ||||||
| 746 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, | ||||||
| 747 | LC->getOperand(i), RC->getOperand(i), DT, | ||||||
| 748 | Depth + 1); | ||||||
| 749 | if (X != 0) | ||||||
| 750 | return X; | ||||||
| 751 | } | ||||||
| 752 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
| 753 | return 0; | ||||||
| 754 | } | ||||||
| 755 | |||||||
| 756 | case scUDivExpr: { | ||||||
| 757 | const SCEVUDivExpr *LC = cast<SCEVUDivExpr>(LHS); | ||||||
| 758 | const SCEVUDivExpr *RC = cast<SCEVUDivExpr>(RHS); | ||||||
| 759 | |||||||
| 760 | // Lexicographically compare udiv expressions. | ||||||
| 761 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getLHS(), | ||||||
| 762 | RC->getLHS(), DT, Depth + 1); | ||||||
| 763 | if (X != 0) | ||||||
| 764 | return X; | ||||||
| 765 | X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getRHS(), | ||||||
| 766 | RC->getRHS(), DT, Depth + 1); | ||||||
| 767 | if (X == 0) | ||||||
| 768 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
| 769 | return X; | ||||||
| 770 | } | ||||||
| 771 | |||||||
| 772 | case scTruncate: | ||||||
| 773 | case scZeroExtend: | ||||||
| 774 | case scSignExtend: { | ||||||
| 775 | const SCEVCastExpr *LC = cast<SCEVCastExpr>(LHS); | ||||||
| 776 | const SCEVCastExpr *RC = cast<SCEVCastExpr>(RHS); | ||||||
| 777 | |||||||
| 778 | // Compare cast expressions by operand. | ||||||
| 779 | int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, | ||||||
| 780 | LC->getOperand(), RC->getOperand(), DT, | ||||||
| 781 | Depth + 1); | ||||||
| 782 | if (X == 0) | ||||||
| 783 | EqCacheSCEV.unionSets(LHS, RHS); | ||||||
| 784 | return X; | ||||||
| 785 | } | ||||||
| 786 | |||||||
| 787 | case scCouldNotCompute: | ||||||
| 788 | llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 788); | ||||||
| 789 | } | ||||||
| 790 | llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 790); | ||||||
| 791 | } | ||||||
| 792 | |||||||
| 793 | /// Given a list of SCEV objects, order them by their complexity, and group | ||||||
| 794 | /// objects of the same complexity together by value. When this routine is | ||||||
| 795 | /// finished, we know that any duplicates in the vector are consecutive and that | ||||||
| 796 | /// complexity is monotonically increasing. | ||||||
| 797 | /// | ||||||
| 798 | /// Note that we go take special precautions to ensure that we get deterministic | ||||||
| 799 | /// results from this routine. In other words, we don't want the results of | ||||||
| 800 | /// this to depend on where the addresses of various SCEV objects happened to | ||||||
| 801 | /// land in memory. | ||||||
| 802 | static void GroupByComplexity(SmallVectorImpl<const SCEV *> &Ops, | ||||||
| 803 | LoopInfo *LI, DominatorTree &DT) { | ||||||
| 804 | if (Ops.size() < 2) return; // Noop | ||||||
| 805 | |||||||
| 806 | EquivalenceClasses<const SCEV *> EqCacheSCEV; | ||||||
| 807 | EquivalenceClasses<const Value *> EqCacheValue; | ||||||
| 808 | if (Ops.size() == 2) { | ||||||
| 809 | // This is the common case, which also happens to be trivially simple. | ||||||
| 810 | // Special case it. | ||||||
| 811 | const SCEV *&LHS = Ops[0], *&RHS = Ops[1]; | ||||||
| 812 | if (CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, RHS, LHS, DT) < 0) | ||||||
| 813 | std::swap(LHS, RHS); | ||||||
| 814 | return; | ||||||
| 815 | } | ||||||
| 816 | |||||||
| 817 | // Do the rough sort by complexity. | ||||||
| 818 | llvm::stable_sort(Ops, [&](const SCEV *LHS, const SCEV *RHS) { | ||||||
| 819 | return CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LHS, RHS, DT) < | ||||||
| 820 | 0; | ||||||
| 821 | }); | ||||||
| 822 | |||||||
| 823 | // Now that we are sorted by complexity, group elements of the same | ||||||
| 824 | // complexity. Note that this is, at worst, N^2, but the vector is likely to | ||||||
| 825 | // be extremely short in practice. Note that we take this approach because we | ||||||
| 826 | // do not want to depend on the addresses of the objects we are grouping. | ||||||
| 827 | for (unsigned i = 0, e = Ops.size(); i != e-2; ++i) { | ||||||
| 828 | const SCEV *S = Ops[i]; | ||||||
| 829 | unsigned Complexity = S->getSCEVType(); | ||||||
| 830 | |||||||
| 831 | // If there are any objects of the same complexity and same value as this | ||||||
| 832 | // one, group them. | ||||||
| 833 | for (unsigned j = i+1; j != e && Ops[j]->getSCEVType() == Complexity; ++j) { | ||||||
| 834 | if (Ops[j] == S) { // Found a duplicate. | ||||||
| 835 | // Move it to immediately after i'th element. | ||||||
| 836 | std::swap(Ops[i+1], Ops[j]); | ||||||
| 837 | ++i; // no need to rescan it. | ||||||
| 838 | if (i == e-2) return; // Done! | ||||||
| 839 | } | ||||||
| 840 | } | ||||||
| 841 | } | ||||||
| 842 | } | ||||||
| 843 | |||||||
| 844 | // Returns the size of the SCEV S. | ||||||
| 845 | static inline int sizeOfSCEV(const SCEV *S) { | ||||||
| 846 | struct FindSCEVSize { | ||||||
| 847 | int Size = 0; | ||||||
| 848 | |||||||
| 849 | FindSCEVSize() = default; | ||||||
| 850 | |||||||
| 851 | bool follow(const SCEV *S) { | ||||||
| 852 | ++Size; | ||||||
| 853 | // Keep looking at all operands of S. | ||||||
| 854 | return true; | ||||||
| 855 | } | ||||||
| 856 | |||||||
| 857 | bool isDone() const { | ||||||
| 858 | return false; | ||||||
| 859 | } | ||||||
| 860 | }; | ||||||
| 861 | |||||||
| 862 | FindSCEVSize F; | ||||||
| 863 | SCEVTraversal<FindSCEVSize> ST(F); | ||||||
| 864 | ST.visitAll(S); | ||||||
| 865 | return F.Size; | ||||||
| 866 | } | ||||||
| 867 | |||||||
| 868 | /// Returns true if the subtree of \p S contains at least HugeExprThreshold | ||||||
| 869 | /// nodes. | ||||||
| 870 | static bool isHugeExpression(const SCEV *S) { | ||||||
| 871 | return S->getExpressionSize() >= HugeExprThreshold; | ||||||
| 872 | } | ||||||
| 873 | |||||||
| 874 | /// Returns true of \p Ops contains a huge SCEV (see definition above). | ||||||
| 875 | static bool hasHugeExpression(ArrayRef<const SCEV *> Ops) { | ||||||
| 876 | return any_of(Ops, isHugeExpression); | ||||||
| 877 | } | ||||||
| 878 | |||||||
| 879 | namespace { | ||||||
| 880 | |||||||
| 881 | struct SCEVDivision : public SCEVVisitor<SCEVDivision, void> { | ||||||
| 882 | public: | ||||||
| 883 | // Computes the Quotient and Remainder of the division of Numerator by | ||||||
| 884 | // Denominator. | ||||||
| 885 | static void divide(ScalarEvolution &SE, const SCEV *Numerator, | ||||||
| 886 | const SCEV *Denominator, const SCEV **Quotient, | ||||||
| 887 | const SCEV **Remainder) { | ||||||
| 888 | assert(Numerator && Denominator && "Uninitialized SCEV")((Numerator && Denominator && "Uninitialized SCEV" ) ? static_cast<void> (0) : __assert_fail ("Numerator && Denominator && \"Uninitialized SCEV\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 888, __PRETTY_FUNCTION__)); | ||||||
| 889 | |||||||
| 890 | SCEVDivision D(SE, Numerator, Denominator); | ||||||
| 891 | |||||||
| 892 | // Check for the trivial case here to avoid having to check for it in the | ||||||
| 893 | // rest of the code. | ||||||
| 894 | if (Numerator == Denominator) { | ||||||
| 895 | *Quotient = D.One; | ||||||
| 896 | *Remainder = D.Zero; | ||||||
| 897 | return; | ||||||
| 898 | } | ||||||
| 899 | |||||||
| 900 | if (Numerator->isZero()) { | ||||||
| 901 | *Quotient = D.Zero; | ||||||
| 902 | *Remainder = D.Zero; | ||||||
| 903 | return; | ||||||
| 904 | } | ||||||
| 905 | |||||||
| 906 | // A simple case when N/1. The quotient is N. | ||||||
| 907 | if (Denominator->isOne()) { | ||||||
| 908 | *Quotient = Numerator; | ||||||
| 909 | *Remainder = D.Zero; | ||||||
| 910 | return; | ||||||
| 911 | } | ||||||
| 912 | |||||||
| 913 | // Split the Denominator when it is a product. | ||||||
| 914 | if (const SCEVMulExpr *T = dyn_cast<SCEVMulExpr>(Denominator)) { | ||||||
| 915 | const SCEV *Q, *R; | ||||||
| 916 | *Quotient = Numerator; | ||||||
| 917 | for (const SCEV *Op : T->operands()) { | ||||||
| 918 | divide(SE, *Quotient, Op, &Q, &R); | ||||||
| 919 | *Quotient = Q; | ||||||
| 920 | |||||||
| 921 | // Bail out when the Numerator is not divisible by one of the terms of | ||||||
| 922 | // the Denominator. | ||||||
| 923 | if (!R->isZero()) { | ||||||
| 924 | *Quotient = D.Zero; | ||||||
| 925 | *Remainder = Numerator; | ||||||
| 926 | return; | ||||||
| 927 | } | ||||||
| 928 | } | ||||||
| 929 | *Remainder = D.Zero; | ||||||
| 930 | return; | ||||||
| 931 | } | ||||||
| 932 | |||||||
| 933 | D.visit(Numerator); | ||||||
| 934 | *Quotient = D.Quotient; | ||||||
| 935 | *Remainder = D.Remainder; | ||||||
| 936 | } | ||||||
| 937 | |||||||
| 938 | // Except in the trivial case described above, we do not know how to divide | ||||||
| 939 | // Expr by Denominator for the following functions with empty implementation. | ||||||
| 940 | void visitTruncateExpr(const SCEVTruncateExpr *Numerator) {} | ||||||
| 941 | void visitZeroExtendExpr(const SCEVZeroExtendExpr *Numerator) {} | ||||||
| 942 | void visitSignExtendExpr(const SCEVSignExtendExpr *Numerator) {} | ||||||
| 943 | void visitUDivExpr(const SCEVUDivExpr *Numerator) {} | ||||||
| 944 | void visitSMaxExpr(const SCEVSMaxExpr *Numerator) {} | ||||||
| 945 | void visitUMaxExpr(const SCEVUMaxExpr *Numerator) {} | ||||||
| 946 | void visitSMinExpr(const SCEVSMinExpr *Numerator) {} | ||||||
| 947 | void visitUMinExpr(const SCEVUMinExpr *Numerator) {} | ||||||
| 948 | void visitUnknown(const SCEVUnknown *Numerator) {} | ||||||
| 949 | void visitCouldNotCompute(const SCEVCouldNotCompute *Numerator) {} | ||||||
| 950 | |||||||
| 951 | void visitConstant(const SCEVConstant *Numerator) { | ||||||
| 952 | if (const SCEVConstant *D = dyn_cast<SCEVConstant>(Denominator)) { | ||||||
| 953 | APInt NumeratorVal = Numerator->getAPInt(); | ||||||
| 954 | APInt DenominatorVal = D->getAPInt(); | ||||||
| 955 | uint32_t NumeratorBW = NumeratorVal.getBitWidth(); | ||||||
| 956 | uint32_t DenominatorBW = DenominatorVal.getBitWidth(); | ||||||
| 957 | |||||||
| 958 | if (NumeratorBW > DenominatorBW) | ||||||
| 959 | DenominatorVal = DenominatorVal.sext(NumeratorBW); | ||||||
| 960 | else if (NumeratorBW < DenominatorBW) | ||||||
| 961 | NumeratorVal = NumeratorVal.sext(DenominatorBW); | ||||||
| 962 | |||||||
| 963 | APInt QuotientVal(NumeratorVal.getBitWidth(), 0); | ||||||
| 964 | APInt RemainderVal(NumeratorVal.getBitWidth(), 0); | ||||||
| 965 | APInt::sdivrem(NumeratorVal, DenominatorVal, QuotientVal, RemainderVal); | ||||||
| 966 | Quotient = SE.getConstant(QuotientVal); | ||||||
| 967 | Remainder = SE.getConstant(RemainderVal); | ||||||
| 968 | return; | ||||||
| 969 | } | ||||||
| 970 | } | ||||||
| 971 | |||||||
| 972 | void visitAddRecExpr(const SCEVAddRecExpr *Numerator) { | ||||||
| 973 | const SCEV *StartQ, *StartR, *StepQ, *StepR; | ||||||
| 974 | if (!Numerator->isAffine()) | ||||||
| 975 | return cannotDivide(Numerator); | ||||||
| 976 | divide(SE, Numerator->getStart(), Denominator, &StartQ, &StartR); | ||||||
| 977 | divide(SE, Numerator->getStepRecurrence(SE), Denominator, &StepQ, &StepR); | ||||||
| 978 | // Bail out if the types do not match. | ||||||
| 979 | Type *Ty = Denominator->getType(); | ||||||
| 980 | if (Ty != StartQ->getType() || Ty != StartR->getType() || | ||||||
| 981 | Ty != StepQ->getType() || Ty != StepR->getType()) | ||||||
| 982 | return cannotDivide(Numerator); | ||||||
| 983 | Quotient = SE.getAddRecExpr(StartQ, StepQ, Numerator->getLoop(), | ||||||
| 984 | Numerator->getNoWrapFlags()); | ||||||
| 985 | Remainder = SE.getAddRecExpr(StartR, StepR, Numerator->getLoop(), | ||||||
| 986 | Numerator->getNoWrapFlags()); | ||||||
| 987 | } | ||||||
| 988 | |||||||
| 989 | void visitAddExpr(const SCEVAddExpr *Numerator) { | ||||||
| 990 | SmallVector<const SCEV *, 2> Qs, Rs; | ||||||
| 991 | Type *Ty = Denominator->getType(); | ||||||
| 992 | |||||||
| 993 | for (const SCEV *Op : Numerator->operands()) { | ||||||
| 994 | const SCEV *Q, *R; | ||||||
| 995 | divide(SE, Op, Denominator, &Q, &R); | ||||||
| 996 | |||||||
| 997 | // Bail out if types do not match. | ||||||
| 998 | if (Ty != Q->getType() || Ty != R->getType()) | ||||||
| 999 | return cannotDivide(Numerator); | ||||||
| 1000 | |||||||
| 1001 | Qs.push_back(Q); | ||||||
| 1002 | Rs.push_back(R); | ||||||
| 1003 | } | ||||||
| 1004 | |||||||
| 1005 | if (Qs.size() == 1) { | ||||||
| 1006 | Quotient = Qs[0]; | ||||||
| 1007 | Remainder = Rs[0]; | ||||||
| 1008 | return; | ||||||
| 1009 | } | ||||||
| 1010 | |||||||
| 1011 | Quotient = SE.getAddExpr(Qs); | ||||||
| 1012 | Remainder = SE.getAddExpr(Rs); | ||||||
| 1013 | } | ||||||
| 1014 | |||||||
| 1015 | void visitMulExpr(const SCEVMulExpr *Numerator) { | ||||||
| 1016 | SmallVector<const SCEV *, 2> Qs; | ||||||
| 1017 | Type *Ty = Denominator->getType(); | ||||||
| 1018 | |||||||
| 1019 | bool FoundDenominatorTerm = false; | ||||||
| 1020 | for (const SCEV *Op : Numerator->operands()) { | ||||||
| 1021 | // Bail out if types do not match. | ||||||
| 1022 | if (Ty != Op->getType()) | ||||||
| 1023 | return cannotDivide(Numerator); | ||||||
| 1024 | |||||||
| 1025 | if (FoundDenominatorTerm) { | ||||||
| 1026 | Qs.push_back(Op); | ||||||
| 1027 | continue; | ||||||
| 1028 | } | ||||||
| 1029 | |||||||
| 1030 | // Check whether Denominator divides one of the product operands. | ||||||
| 1031 | const SCEV *Q, *R; | ||||||
| 1032 | divide(SE, Op, Denominator, &Q, &R); | ||||||
| 1033 | if (!R->isZero()) { | ||||||
| 1034 | Qs.push_back(Op); | ||||||
| 1035 | continue; | ||||||
| 1036 | } | ||||||
| 1037 | |||||||
| 1038 | // Bail out if types do not match. | ||||||
| 1039 | if (Ty != Q->getType()) | ||||||
| 1040 | return cannotDivide(Numerator); | ||||||
| 1041 | |||||||
| 1042 | FoundDenominatorTerm = true; | ||||||
| 1043 | Qs.push_back(Q); | ||||||
| 1044 | } | ||||||
| 1045 | |||||||
| 1046 | if (FoundDenominatorTerm) { | ||||||
| 1047 | Remainder = Zero; | ||||||
| 1048 | if (Qs.size() == 1) | ||||||
| 1049 | Quotient = Qs[0]; | ||||||
| 1050 | else | ||||||
| 1051 | Quotient = SE.getMulExpr(Qs); | ||||||
| 1052 | return; | ||||||
| 1053 | } | ||||||
| 1054 | |||||||
| 1055 | if (!isa<SCEVUnknown>(Denominator)) | ||||||
| 1056 | return cannotDivide(Numerator); | ||||||
| 1057 | |||||||
| 1058 | // The Remainder is obtained by replacing Denominator by 0 in Numerator. | ||||||
| 1059 | ValueToValueMap RewriteMap; | ||||||
| 1060 | RewriteMap[cast<SCEVUnknown>(Denominator)->getValue()] = | ||||||
| 1061 | cast<SCEVConstant>(Zero)->getValue(); | ||||||
| 1062 | Remainder = SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true); | ||||||
| 1063 | |||||||
| 1064 | if (Remainder->isZero()) { | ||||||
| 1065 | // The Quotient is obtained by replacing Denominator by 1 in Numerator. | ||||||
| 1066 | RewriteMap[cast<SCEVUnknown>(Denominator)->getValue()] = | ||||||
| 1067 | cast<SCEVConstant>(One)->getValue(); | ||||||
| 1068 | Quotient = | ||||||
| 1069 | SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true); | ||||||
| 1070 | return; | ||||||
| 1071 | } | ||||||
| 1072 | |||||||
| 1073 | // Quotient is (Numerator - Remainder) divided by Denominator. | ||||||
| 1074 | const SCEV *Q, *R; | ||||||
| 1075 | const SCEV *Diff = SE.getMinusSCEV(Numerator, Remainder); | ||||||
| 1076 | // This SCEV does not seem to simplify: fail the division here. | ||||||
| 1077 | if (sizeOfSCEV(Diff) > sizeOfSCEV(Numerator)) | ||||||
| 1078 | return cannotDivide(Numerator); | ||||||
| 1079 | divide(SE, Diff, Denominator, &Q, &R); | ||||||
| 1080 | if (R != Zero) | ||||||
| 1081 | return cannotDivide(Numerator); | ||||||
| 1082 | Quotient = Q; | ||||||
| 1083 | } | ||||||
| 1084 | |||||||
| 1085 | private: | ||||||
| 1086 | SCEVDivision(ScalarEvolution &S, const SCEV *Numerator, | ||||||
| 1087 | const SCEV *Denominator) | ||||||
| 1088 | : SE(S), Denominator(Denominator) { | ||||||
| 1089 | Zero = SE.getZero(Denominator->getType()); | ||||||
| 1090 | One = SE.getOne(Denominator->getType()); | ||||||
| 1091 | |||||||
| 1092 | // We generally do not know how to divide Expr by Denominator. We | ||||||
| 1093 | // initialize the division to a "cannot divide" state to simplify the rest | ||||||
| 1094 | // of the code. | ||||||
| 1095 | cannotDivide(Numerator); | ||||||
| 1096 | } | ||||||
| 1097 | |||||||
| 1098 | // Convenience function for giving up on the division. We set the quotient to | ||||||
| 1099 | // be equal to zero and the remainder to be equal to the numerator. | ||||||
| 1100 | void cannotDivide(const SCEV *Numerator) { | ||||||
| 1101 | Quotient = Zero; | ||||||
| 1102 | Remainder = Numerator; | ||||||
| 1103 | } | ||||||
| 1104 | |||||||
| 1105 | ScalarEvolution &SE; | ||||||
| 1106 | const SCEV *Denominator, *Quotient, *Remainder, *Zero, *One; | ||||||
| 1107 | }; | ||||||
| 1108 | |||||||
| 1109 | } // end anonymous namespace | ||||||
| 1110 | |||||||
| 1111 | //===----------------------------------------------------------------------===// | ||||||
| 1112 | // Simple SCEV method implementations | ||||||
| 1113 | //===----------------------------------------------------------------------===// | ||||||
| 1114 | |||||||
| 1115 | /// Compute BC(It, K). The result has width W. Assume, K > 0. | ||||||
| 1116 | static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K, | ||||||
| 1117 | ScalarEvolution &SE, | ||||||
| 1118 | Type *ResultTy) { | ||||||
| 1119 | // Handle the simplest case efficiently. | ||||||
| 1120 | if (K == 1) | ||||||
| 1121 | return SE.getTruncateOrZeroExtend(It, ResultTy); | ||||||
| 1122 | |||||||
| 1123 | // We are using the following formula for BC(It, K): | ||||||
| 1124 | // | ||||||
| 1125 | // BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / K! | ||||||
| 1126 | // | ||||||
| 1127 | // Suppose, W is the bitwidth of the return value. We must be prepared for | ||||||
| 1128 | // overflow. Hence, we must assure that the result of our computation is | ||||||
| 1129 | // equal to the accurate one modulo 2^W. Unfortunately, division isn't | ||||||
| 1130 | // safe in modular arithmetic. | ||||||
| 1131 | // | ||||||
| 1132 | // However, this code doesn't use exactly that formula; the formula it uses | ||||||
| 1133 | // is something like the following, where T is the number of factors of 2 in | ||||||
| 1134 | // K! (i.e. trailing zeros in the binary representation of K!), and ^ is | ||||||
| 1135 | // exponentiation: | ||||||
| 1136 | // | ||||||
| 1137 | // BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / 2^T / (K! / 2^T) | ||||||
| 1138 | // | ||||||
| 1139 | // This formula is trivially equivalent to the previous formula. However, | ||||||
| 1140 | // this formula can be implemented much more efficiently. The trick is that | ||||||
| 1141 | // K! / 2^T is odd, and exact division by an odd number *is* safe in modular | ||||||
| 1142 | // arithmetic. To do exact division in modular arithmetic, all we have | ||||||
| 1143 | // to do is multiply by the inverse. Therefore, this step can be done at | ||||||
| 1144 | // width W. | ||||||
| 1145 | // | ||||||
| 1146 | // The next issue is how to safely do the division by 2^T. The way this | ||||||
| 1147 | // is done is by doing the multiplication step at a width of at least W + T | ||||||
| 1148 | // bits. This way, the bottom W+T bits of the product are accurate. Then, | ||||||
| 1149 | // when we perform the division by 2^T (which is equivalent to a right shift | ||||||
| 1150 | // by T), the bottom W bits are accurate. Extra bits are okay; they'll get | ||||||
| 1151 | // truncated out after the division by 2^T. | ||||||
| 1152 | // | ||||||
| 1153 | // In comparison to just directly using the first formula, this technique | ||||||
| 1154 | // is much more efficient; using the first formula requires W * K bits, | ||||||
| 1155 | // but this formula less than W + K bits. Also, the first formula requires | ||||||
| 1156 | // a division step, whereas this formula only requires multiplies and shifts. | ||||||
| 1157 | // | ||||||
| 1158 | // It doesn't matter whether the subtraction step is done in the calculation | ||||||
| 1159 | // width or the input iteration count's width; if the subtraction overflows, | ||||||
| 1160 | // the result must be zero anyway. We prefer here to do it in the width of | ||||||
| 1161 | // the induction variable because it helps a lot for certain cases; CodeGen | ||||||
| 1162 | // isn't smart enough to ignore the overflow, which leads to much less | ||||||
| 1163 | // efficient code if the width of the subtraction is wider than the native | ||||||
| 1164 | // register width. | ||||||
| 1165 | // | ||||||
| 1166 | // (It's possible to not widen at all by pulling out factors of 2 before | ||||||
| 1167 | // the multiplication; for example, K=2 can be calculated as | ||||||
| 1168 | // It/2*(It+(It*INT_MIN/INT_MIN)+-1). However, it requires | ||||||
| 1169 | // extra arithmetic, so it's not an obvious win, and it gets | ||||||
| 1170 | // much more complicated for K > 3.) | ||||||
| 1171 | |||||||
| 1172 | // Protection from insane SCEVs; this bound is conservative, | ||||||
| 1173 | // but it probably doesn't matter. | ||||||
| 1174 | if (K > 1000) | ||||||
| 1175 | return SE.getCouldNotCompute(); | ||||||
| 1176 | |||||||
| 1177 | unsigned W = SE.getTypeSizeInBits(ResultTy); | ||||||
| 1178 | |||||||
| 1179 | // Calculate K! / 2^T and T; we divide out the factors of two before | ||||||
| 1180 | // multiplying for calculating K! / 2^T to avoid overflow. | ||||||
| 1181 | // Other overflow doesn't matter because we only care about the bottom | ||||||
| 1182 | // W bits of the result. | ||||||
| 1183 | APInt OddFactorial(W, 1); | ||||||
| 1184 | unsigned T = 1; | ||||||
| 1185 | for (unsigned i = 3; i <= K; ++i) { | ||||||
| 1186 | APInt Mult(W, i); | ||||||
| 1187 | unsigned TwoFactors = Mult.countTrailingZeros(); | ||||||
| 1188 | T += TwoFactors; | ||||||
| 1189 | Mult.lshrInPlace(TwoFactors); | ||||||
| 1190 | OddFactorial *= Mult; | ||||||
| 1191 | } | ||||||
| 1192 | |||||||
| 1193 | // We need at least W + T bits for the multiplication step | ||||||
| 1194 | unsigned CalculationBits = W + T; | ||||||
| 1195 | |||||||
| 1196 | // Calculate 2^T, at width T+W. | ||||||
| 1197 | APInt DivFactor = APInt::getOneBitSet(CalculationBits, T); | ||||||
| 1198 | |||||||
| 1199 | // Calculate the multiplicative inverse of K! / 2^T; | ||||||
| 1200 | // this multiplication factor will perform the exact division by | ||||||
| 1201 | // K! / 2^T. | ||||||
| 1202 | APInt Mod = APInt::getSignedMinValue(W+1); | ||||||
| 1203 | APInt MultiplyFactor = OddFactorial.zext(W+1); | ||||||
| 1204 | MultiplyFactor = MultiplyFactor.multiplicativeInverse(Mod); | ||||||
| 1205 | MultiplyFactor = MultiplyFactor.trunc(W); | ||||||
| 1206 | |||||||
| 1207 | // Calculate the product, at width T+W | ||||||
| 1208 | IntegerType *CalculationTy = IntegerType::get(SE.getContext(), | ||||||
| 1209 | CalculationBits); | ||||||
| 1210 | const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy); | ||||||
| 1211 | for (unsigned i = 1; i != K; ++i) { | ||||||
| 1212 | const SCEV *S = SE.getMinusSCEV(It, SE.getConstant(It->getType(), i)); | ||||||
| 1213 | Dividend = SE.getMulExpr(Dividend, | ||||||
| 1214 | SE.getTruncateOrZeroExtend(S, CalculationTy)); | ||||||
| 1215 | } | ||||||
| 1216 | |||||||
| 1217 | // Divide by 2^T | ||||||
| 1218 | const SCEV *DivResult = SE.getUDivExpr(Dividend, SE.getConstant(DivFactor)); | ||||||
| 1219 | |||||||
| 1220 | // Truncate the result, and divide by K! / 2^T. | ||||||
| 1221 | |||||||
| 1222 | return SE.getMulExpr(SE.getConstant(MultiplyFactor), | ||||||
| 1223 | SE.getTruncateOrZeroExtend(DivResult, ResultTy)); | ||||||
| 1224 | } | ||||||
| 1225 | |||||||
| 1226 | /// Return the value of this chain of recurrences at the specified iteration | ||||||
| 1227 | /// number. We can evaluate this recurrence by multiplying each element in the | ||||||
| 1228 | /// chain by the binomial coefficient corresponding to it. In other words, we | ||||||
| 1229 | /// can evaluate {A,+,B,+,C,+,D} as: | ||||||
| 1230 | /// | ||||||
| 1231 | /// A*BC(It, 0) + B*BC(It, 1) + C*BC(It, 2) + D*BC(It, 3) | ||||||
| 1232 | /// | ||||||
| 1233 | /// where BC(It, k) stands for binomial coefficient. | ||||||
| 1234 | const SCEV *SCEVAddRecExpr::evaluateAtIteration(const SCEV *It, | ||||||
| 1235 | ScalarEvolution &SE) const { | ||||||
| 1236 | const SCEV *Result = getStart(); | ||||||
| 1237 | for (unsigned i = 1, e = getNumOperands(); i != e; ++i) { | ||||||
| 1238 | // The computation is correct in the face of overflow provided that the | ||||||
| 1239 | // multiplication is performed _after_ the evaluation of the binomial | ||||||
| 1240 | // coefficient. | ||||||
| 1241 | const SCEV *Coeff = BinomialCoefficient(It, i, SE, getType()); | ||||||
| 1242 | if (isa<SCEVCouldNotCompute>(Coeff)) | ||||||
| 1243 | return Coeff; | ||||||
| 1244 | |||||||
| 1245 | Result = SE.getAddExpr(Result, SE.getMulExpr(getOperand(i), Coeff)); | ||||||
| 1246 | } | ||||||
| 1247 | return Result; | ||||||
| 1248 | } | ||||||
| 1249 | |||||||
| 1250 | //===----------------------------------------------------------------------===// | ||||||
| 1251 | // SCEV Expression folder implementations | ||||||
| 1252 | //===----------------------------------------------------------------------===// | ||||||
| 1253 | |||||||
| 1254 | const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op, Type *Ty, | ||||||
| 1255 | unsigned Depth) { | ||||||
| 1256 | assert(getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) > getTypeSizeInBits( Ty) && "This is not a truncating conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) && \"This is not a truncating conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1257, __PRETTY_FUNCTION__)) | ||||||
| 1257 | "This is not a truncating conversion!")((getTypeSizeInBits(Op->getType()) > getTypeSizeInBits( Ty) && "This is not a truncating conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) && \"This is not a truncating conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1257, __PRETTY_FUNCTION__)); | ||||||
| 1258 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1259, __PRETTY_FUNCTION__)) | ||||||
| 1259 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1259, __PRETTY_FUNCTION__)); | ||||||
| 1260 | Ty = getEffectiveSCEVType(Ty); | ||||||
| 1261 | |||||||
| 1262 | FoldingSetNodeID ID; | ||||||
| 1263 | ID.AddInteger(scTruncate); | ||||||
| 1264 | ID.AddPointer(Op); | ||||||
| 1265 | ID.AddPointer(Ty); | ||||||
| 1266 | void *IP = nullptr; | ||||||
| 1267 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
| 1268 | |||||||
| 1269 | // Fold if the operand is constant. | ||||||
| 1270 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
| 1271 | return getConstant( | ||||||
| 1272 | cast<ConstantInt>(ConstantExpr::getTrunc(SC->getValue(), Ty))); | ||||||
| 1273 | |||||||
| 1274 | // trunc(trunc(x)) --> trunc(x) | ||||||
| 1275 | if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) | ||||||
| 1276 | return getTruncateExpr(ST->getOperand(), Ty, Depth + 1); | ||||||
| 1277 | |||||||
| 1278 | // trunc(sext(x)) --> sext(x) if widening or trunc(x) if narrowing | ||||||
| 1279 | if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op)) | ||||||
| 1280 | return getTruncateOrSignExtend(SS->getOperand(), Ty, Depth + 1); | ||||||
| 1281 | |||||||
| 1282 | // trunc(zext(x)) --> zext(x) if widening or trunc(x) if narrowing | ||||||
| 1283 | if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op)) | ||||||
| 1284 | return getTruncateOrZeroExtend(SZ->getOperand(), Ty, Depth + 1); | ||||||
| 1285 | |||||||
| 1286 | if (Depth > MaxCastDepth) { | ||||||
| 1287 | SCEV *S = | ||||||
| 1288 | new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator), Op, Ty); | ||||||
| 1289 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 1290 | addToLoopUseLists(S); | ||||||
| 1291 | return S; | ||||||
| 1292 | } | ||||||
| 1293 | |||||||
| 1294 | // trunc(x1 + ... + xN) --> trunc(x1) + ... + trunc(xN) and | ||||||
| 1295 | // trunc(x1 * ... * xN) --> trunc(x1) * ... * trunc(xN), | ||||||
| 1296 | // if after transforming we have at most one truncate, not counting truncates | ||||||
| 1297 | // that replace other casts. | ||||||
| 1298 | if (isa<SCEVAddExpr>(Op) || isa<SCEVMulExpr>(Op)) { | ||||||
| 1299 | auto *CommOp = cast<SCEVCommutativeExpr>(Op); | ||||||
| 1300 | SmallVector<const SCEV *, 4> Operands; | ||||||
| 1301 | unsigned numTruncs = 0; | ||||||
| 1302 | for (unsigned i = 0, e = CommOp->getNumOperands(); i != e && numTruncs < 2; | ||||||
| 1303 | ++i) { | ||||||
| 1304 | const SCEV *S = getTruncateExpr(CommOp->getOperand(i), Ty, Depth + 1); | ||||||
| 1305 | if (!isa<SCEVCastExpr>(CommOp->getOperand(i)) && isa<SCEVTruncateExpr>(S)) | ||||||
| 1306 | numTruncs++; | ||||||
| 1307 | Operands.push_back(S); | ||||||
| 1308 | } | ||||||
| 1309 | if (numTruncs < 2) { | ||||||
| 1310 | if (isa<SCEVAddExpr>(Op)) | ||||||
| 1311 | return getAddExpr(Operands); | ||||||
| 1312 | else if (isa<SCEVMulExpr>(Op)) | ||||||
| 1313 | return getMulExpr(Operands); | ||||||
| 1314 | else | ||||||
| 1315 | llvm_unreachable("Unexpected SCEV type for Op.")::llvm::llvm_unreachable_internal("Unexpected SCEV type for Op." , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1315); | ||||||
| 1316 | } | ||||||
| 1317 | // Although we checked in the beginning that ID is not in the cache, it is | ||||||
| 1318 | // possible that during recursion and different modification ID was inserted | ||||||
| 1319 | // into the cache. So if we find it, just return it. | ||||||
| 1320 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) | ||||||
| 1321 | return S; | ||||||
| 1322 | } | ||||||
| 1323 | |||||||
| 1324 | // If the input value is a chrec scev, truncate the chrec's operands. | ||||||
| 1325 | if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) { | ||||||
| 1326 | SmallVector<const SCEV *, 4> Operands; | ||||||
| 1327 | for (const SCEV *Op : AddRec->operands()) | ||||||
| 1328 | Operands.push_back(getTruncateExpr(Op, Ty, Depth + 1)); | ||||||
| 1329 | return getAddRecExpr(Operands, AddRec->getLoop(), SCEV::FlagAnyWrap); | ||||||
| 1330 | } | ||||||
| 1331 | |||||||
| 1332 | // The cast wasn't folded; create an explicit cast node. We can reuse | ||||||
| 1333 | // the existing insert position since if we get here, we won't have | ||||||
| 1334 | // made any changes which would invalidate it. | ||||||
| 1335 | SCEV *S = new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator), | ||||||
| 1336 | Op, Ty); | ||||||
| 1337 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 1338 | addToLoopUseLists(S); | ||||||
| 1339 | return S; | ||||||
| 1340 | } | ||||||
| 1341 | |||||||
| 1342 | // Get the limit of a recurrence such that incrementing by Step cannot cause | ||||||
| 1343 | // signed overflow as long as the value of the recurrence within the | ||||||
| 1344 | // loop does not exceed this limit before incrementing. | ||||||
| 1345 | static const SCEV *getSignedOverflowLimitForStep(const SCEV *Step, | ||||||
| 1346 | ICmpInst::Predicate *Pred, | ||||||
| 1347 | ScalarEvolution *SE) { | ||||||
| 1348 | unsigned BitWidth = SE->getTypeSizeInBits(Step->getType()); | ||||||
| 1349 | if (SE->isKnownPositive(Step)) { | ||||||
| 1350 | *Pred = ICmpInst::ICMP_SLT; | ||||||
| 1351 | return SE->getConstant(APInt::getSignedMinValue(BitWidth) - | ||||||
| 1352 | SE->getSignedRangeMax(Step)); | ||||||
| 1353 | } | ||||||
| 1354 | if (SE->isKnownNegative(Step)) { | ||||||
| 1355 | *Pred = ICmpInst::ICMP_SGT; | ||||||
| 1356 | return SE->getConstant(APInt::getSignedMaxValue(BitWidth) - | ||||||
| 1357 | SE->getSignedRangeMin(Step)); | ||||||
| 1358 | } | ||||||
| 1359 | return nullptr; | ||||||
| 1360 | } | ||||||
| 1361 | |||||||
| 1362 | // Get the limit of a recurrence such that incrementing by Step cannot cause | ||||||
| 1363 | // unsigned overflow as long as the value of the recurrence within the loop does | ||||||
| 1364 | // not exceed this limit before incrementing. | ||||||
| 1365 | static const SCEV *getUnsignedOverflowLimitForStep(const SCEV *Step, | ||||||
| 1366 | ICmpInst::Predicate *Pred, | ||||||
| 1367 | ScalarEvolution *SE) { | ||||||
| 1368 | unsigned BitWidth = SE->getTypeSizeInBits(Step->getType()); | ||||||
| 1369 | *Pred = ICmpInst::ICMP_ULT; | ||||||
| 1370 | |||||||
| 1371 | return SE->getConstant(APInt::getMinValue(BitWidth) - | ||||||
| 1372 | SE->getUnsignedRangeMax(Step)); | ||||||
| 1373 | } | ||||||
| 1374 | |||||||
| 1375 | namespace { | ||||||
| 1376 | |||||||
| 1377 | struct ExtendOpTraitsBase { | ||||||
| 1378 | typedef const SCEV *(ScalarEvolution::*GetExtendExprTy)(const SCEV *, Type *, | ||||||
| 1379 | unsigned); | ||||||
| 1380 | }; | ||||||
| 1381 | |||||||
| 1382 | // Used to make code generic over signed and unsigned overflow. | ||||||
| 1383 | template <typename ExtendOp> struct ExtendOpTraits { | ||||||
| 1384 | // Members present: | ||||||
| 1385 | // | ||||||
| 1386 | // static const SCEV::NoWrapFlags WrapType; | ||||||
| 1387 | // | ||||||
| 1388 | // static const ExtendOpTraitsBase::GetExtendExprTy GetExtendExpr; | ||||||
| 1389 | // | ||||||
| 1390 | // static const SCEV *getOverflowLimitForStep(const SCEV *Step, | ||||||
| 1391 | // ICmpInst::Predicate *Pred, | ||||||
| 1392 | // ScalarEvolution *SE); | ||||||
| 1393 | }; | ||||||
| 1394 | |||||||
| 1395 | template <> | ||||||
| 1396 | struct ExtendOpTraits<SCEVSignExtendExpr> : public ExtendOpTraitsBase { | ||||||
| 1397 | static const SCEV::NoWrapFlags WrapType = SCEV::FlagNSW; | ||||||
| 1398 | |||||||
| 1399 | static const GetExtendExprTy GetExtendExpr; | ||||||
| 1400 | |||||||
| 1401 | static const SCEV *getOverflowLimitForStep(const SCEV *Step, | ||||||
| 1402 | ICmpInst::Predicate *Pred, | ||||||
| 1403 | ScalarEvolution *SE) { | ||||||
| 1404 | return getSignedOverflowLimitForStep(Step, Pred, SE); | ||||||
| 1405 | } | ||||||
| 1406 | }; | ||||||
| 1407 | |||||||
| 1408 | const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits< | ||||||
| 1409 | SCEVSignExtendExpr>::GetExtendExpr = &ScalarEvolution::getSignExtendExpr; | ||||||
| 1410 | |||||||
| 1411 | template <> | ||||||
| 1412 | struct ExtendOpTraits<SCEVZeroExtendExpr> : public ExtendOpTraitsBase { | ||||||
| 1413 | static const SCEV::NoWrapFlags WrapType = SCEV::FlagNUW; | ||||||
| 1414 | |||||||
| 1415 | static const GetExtendExprTy GetExtendExpr; | ||||||
| 1416 | |||||||
| 1417 | static const SCEV *getOverflowLimitForStep(const SCEV *Step, | ||||||
| 1418 | ICmpInst::Predicate *Pred, | ||||||
| 1419 | ScalarEvolution *SE) { | ||||||
| 1420 | return getUnsignedOverflowLimitForStep(Step, Pred, SE); | ||||||
| 1421 | } | ||||||
| 1422 | }; | ||||||
| 1423 | |||||||
| 1424 | const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits< | ||||||
| 1425 | SCEVZeroExtendExpr>::GetExtendExpr = &ScalarEvolution::getZeroExtendExpr; | ||||||
| 1426 | |||||||
| 1427 | } // end anonymous namespace | ||||||
| 1428 | |||||||
| 1429 | // The recurrence AR has been shown to have no signed/unsigned wrap or something | ||||||
| 1430 | // close to it. Typically, if we can prove NSW/NUW for AR, then we can just as | ||||||
| 1431 | // easily prove NSW/NUW for its preincrement or postincrement sibling. This | ||||||
| 1432 | // allows normalizing a sign/zero extended AddRec as such: {sext/zext(Step + | ||||||
| 1433 | // Start),+,Step} => {(Step + sext/zext(Start),+,Step} As a result, the | ||||||
| 1434 | // expression "Step + sext/zext(PreIncAR)" is congruent with | ||||||
| 1435 | // "sext/zext(PostIncAR)" | ||||||
| 1436 | template <typename ExtendOpTy> | ||||||
| 1437 | static const SCEV *getPreStartForExtend(const SCEVAddRecExpr *AR, Type *Ty, | ||||||
| 1438 | ScalarEvolution *SE, unsigned Depth) { | ||||||
| 1439 | auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType; | ||||||
| 1440 | auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr; | ||||||
| 1441 | |||||||
| 1442 | const Loop *L = AR->getLoop(); | ||||||
| 1443 | const SCEV *Start = AR->getStart(); | ||||||
| 1444 | const SCEV *Step = AR->getStepRecurrence(*SE); | ||||||
| 1445 | |||||||
| 1446 | // Check for a simple looking step prior to loop entry. | ||||||
| 1447 | const SCEVAddExpr *SA = dyn_cast<SCEVAddExpr>(Start); | ||||||
| 1448 | if (!SA) | ||||||
| 1449 | return nullptr; | ||||||
| 1450 | |||||||
| 1451 | // Create an AddExpr for "PreStart" after subtracting Step. Full SCEV | ||||||
| 1452 | // subtraction is expensive. For this purpose, perform a quick and dirty | ||||||
| 1453 | // difference, by checking for Step in the operand list. | ||||||
| 1454 | SmallVector<const SCEV *, 4> DiffOps; | ||||||
| 1455 | for (const SCEV *Op : SA->operands()) | ||||||
| 1456 | if (Op != Step) | ||||||
| 1457 | DiffOps.push_back(Op); | ||||||
| 1458 | |||||||
| 1459 | if (DiffOps.size() == SA->getNumOperands()) | ||||||
| 1460 | return nullptr; | ||||||
| 1461 | |||||||
| 1462 | // Try to prove `WrapType` (SCEV::FlagNSW or SCEV::FlagNUW) on `PreStart` + | ||||||
| 1463 | // `Step`: | ||||||
| 1464 | |||||||
| 1465 | // 1. NSW/NUW flags on the step increment. | ||||||
| 1466 | auto PreStartFlags = | ||||||
| 1467 | ScalarEvolution::maskFlags(SA->getNoWrapFlags(), SCEV::FlagNUW); | ||||||
| 1468 | const SCEV *PreStart = SE->getAddExpr(DiffOps, PreStartFlags); | ||||||
| 1469 | const SCEVAddRecExpr *PreAR = dyn_cast<SCEVAddRecExpr>( | ||||||
| 1470 | SE->getAddRecExpr(PreStart, Step, L, SCEV::FlagAnyWrap)); | ||||||
| 1471 | |||||||
| 1472 | // "{S,+,X} is <nsw>/<nuw>" and "the backedge is taken at least once" implies | ||||||
| 1473 | // "S+X does not sign/unsign-overflow". | ||||||
| 1474 | // | ||||||
| 1475 | |||||||
| 1476 | const SCEV *BECount = SE->getBackedgeTakenCount(L); | ||||||
| 1477 | if (PreAR && PreAR->getNoWrapFlags(WrapType) && | ||||||
| 1478 | !isa<SCEVCouldNotCompute>(BECount) && SE->isKnownPositive(BECount)) | ||||||
| 1479 | return PreStart; | ||||||
| 1480 | |||||||
| 1481 | // 2. Direct overflow check on the step operation's expression. | ||||||
| 1482 | unsigned BitWidth = SE->getTypeSizeInBits(AR->getType()); | ||||||
| 1483 | Type *WideTy = IntegerType::get(SE->getContext(), BitWidth * 2); | ||||||
| 1484 | const SCEV *OperandExtendedStart = | ||||||
| 1485 | SE->getAddExpr((SE->*GetExtendExpr)(PreStart, WideTy, Depth), | ||||||
| 1486 | (SE->*GetExtendExpr)(Step, WideTy, Depth)); | ||||||
| 1487 | if ((SE->*GetExtendExpr)(Start, WideTy, Depth) == OperandExtendedStart) { | ||||||
| 1488 | if (PreAR && AR->getNoWrapFlags(WrapType)) { | ||||||
| 1489 | // If we know `AR` == {`PreStart`+`Step`,+,`Step`} is `WrapType` (FlagNSW | ||||||
| 1490 | // or FlagNUW) and that `PreStart` + `Step` is `WrapType` too, then | ||||||
| 1491 | // `PreAR` == {`PreStart`,+,`Step`} is also `WrapType`. Cache this fact. | ||||||
| 1492 | const_cast<SCEVAddRecExpr *>(PreAR)->setNoWrapFlags(WrapType); | ||||||
| 1493 | } | ||||||
| 1494 | return PreStart; | ||||||
| 1495 | } | ||||||
| 1496 | |||||||
| 1497 | // 3. Loop precondition. | ||||||
| 1498 | ICmpInst::Predicate Pred; | ||||||
| 1499 | const SCEV *OverflowLimit = | ||||||
| 1500 | ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(Step, &Pred, SE); | ||||||
| 1501 | |||||||
| 1502 | if (OverflowLimit && | ||||||
| 1503 | SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit)) | ||||||
| 1504 | return PreStart; | ||||||
| 1505 | |||||||
| 1506 | return nullptr; | ||||||
| 1507 | } | ||||||
| 1508 | |||||||
| 1509 | // Get the normalized zero or sign extended expression for this AddRec's Start. | ||||||
| 1510 | template <typename ExtendOpTy> | ||||||
| 1511 | static const SCEV *getExtendAddRecStart(const SCEVAddRecExpr *AR, Type *Ty, | ||||||
| 1512 | ScalarEvolution *SE, | ||||||
| 1513 | unsigned Depth) { | ||||||
| 1514 | auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr; | ||||||
| 1515 | |||||||
| 1516 | const SCEV *PreStart = getPreStartForExtend<ExtendOpTy>(AR, Ty, SE, Depth); | ||||||
| 1517 | if (!PreStart) | ||||||
| 1518 | return (SE->*GetExtendExpr)(AR->getStart(), Ty, Depth); | ||||||
| 1519 | |||||||
| 1520 | return SE->getAddExpr((SE->*GetExtendExpr)(AR->getStepRecurrence(*SE), Ty, | ||||||
| 1521 | Depth), | ||||||
| 1522 | (SE->*GetExtendExpr)(PreStart, Ty, Depth)); | ||||||
| 1523 | } | ||||||
| 1524 | |||||||
| 1525 | // Try to prove away overflow by looking at "nearby" add recurrences. A | ||||||
| 1526 | // motivating example for this rule: if we know `{0,+,4}` is `ult` `-1` and it | ||||||
| 1527 | // does not itself wrap then we can conclude that `{1,+,4}` is `nuw`. | ||||||
| 1528 | // | ||||||
| 1529 | // Formally: | ||||||
| 1530 | // | ||||||
| 1531 | // {S,+,X} == {S-T,+,X} + T | ||||||
| 1532 | // => Ext({S,+,X}) == Ext({S-T,+,X} + T) | ||||||
| 1533 | // | ||||||
| 1534 | // If ({S-T,+,X} + T) does not overflow ... (1) | ||||||
| 1535 | // | ||||||
| 1536 | // RHS == Ext({S-T,+,X} + T) == Ext({S-T,+,X}) + Ext(T) | ||||||
| 1537 | // | ||||||
| 1538 | // If {S-T,+,X} does not overflow ... (2) | ||||||
| 1539 | // | ||||||
| 1540 | // RHS == Ext({S-T,+,X}) + Ext(T) == {Ext(S-T),+,Ext(X)} + Ext(T) | ||||||
| 1541 | // == {Ext(S-T)+Ext(T),+,Ext(X)} | ||||||
| 1542 | // | ||||||
| 1543 | // If (S-T)+T does not overflow ... (3) | ||||||
| 1544 | // | ||||||
| 1545 | // RHS == {Ext(S-T)+Ext(T),+,Ext(X)} == {Ext(S-T+T),+,Ext(X)} | ||||||
| 1546 | // == {Ext(S),+,Ext(X)} == LHS | ||||||
| 1547 | // | ||||||
| 1548 | // Thus, if (1), (2) and (3) are true for some T, then | ||||||
| 1549 | // Ext({S,+,X}) == {Ext(S),+,Ext(X)} | ||||||
| 1550 | // | ||||||
| 1551 | // (3) is implied by (1) -- "(S-T)+T does not overflow" is simply "({S-T,+,X}+T) | ||||||
| 1552 | // does not overflow" restricted to the 0th iteration. Therefore we only need | ||||||
| 1553 | // to check for (1) and (2). | ||||||
| 1554 | // | ||||||
| 1555 | // In the current context, S is `Start`, X is `Step`, Ext is `ExtendOpTy` and T | ||||||
| 1556 | // is `Delta` (defined below). | ||||||
| 1557 | template <typename ExtendOpTy> | ||||||
| 1558 | bool ScalarEvolution::proveNoWrapByVaryingStart(const SCEV *Start, | ||||||
| 1559 | const SCEV *Step, | ||||||
| 1560 | const Loop *L) { | ||||||
| 1561 | auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType; | ||||||
| 1562 | |||||||
| 1563 | // We restrict `Start` to a constant to prevent SCEV from spending too much | ||||||
| 1564 | // time here. It is correct (but more expensive) to continue with a | ||||||
| 1565 | // non-constant `Start` and do a general SCEV subtraction to compute | ||||||
| 1566 | // `PreStart` below. | ||||||
| 1567 | const SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start); | ||||||
| 1568 | if (!StartC) | ||||||
| 1569 | return false; | ||||||
| 1570 | |||||||
| 1571 | APInt StartAI = StartC->getAPInt(); | ||||||
| 1572 | |||||||
| 1573 | for (unsigned Delta : {-2, -1, 1, 2}) { | ||||||
| 1574 | const SCEV *PreStart = getConstant(StartAI - Delta); | ||||||
| 1575 | |||||||
| 1576 | FoldingSetNodeID ID; | ||||||
| 1577 | ID.AddInteger(scAddRecExpr); | ||||||
| 1578 | ID.AddPointer(PreStart); | ||||||
| 1579 | ID.AddPointer(Step); | ||||||
| 1580 | ID.AddPointer(L); | ||||||
| 1581 | void *IP = nullptr; | ||||||
| 1582 | const auto *PreAR = | ||||||
| 1583 | static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
| 1584 | |||||||
| 1585 | // Give up if we don't already have the add recurrence we need because | ||||||
| 1586 | // actually constructing an add recurrence is relatively expensive. | ||||||
| 1587 | if (PreAR && PreAR->getNoWrapFlags(WrapType)) { // proves (2) | ||||||
| 1588 | const SCEV *DeltaS = getConstant(StartC->getType(), Delta); | ||||||
| 1589 | ICmpInst::Predicate Pred = ICmpInst::BAD_ICMP_PREDICATE; | ||||||
| 1590 | const SCEV *Limit = ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep( | ||||||
| 1591 | DeltaS, &Pred, this); | ||||||
| 1592 | if (Limit && isKnownPredicate(Pred, PreAR, Limit)) // proves (1) | ||||||
| 1593 | return true; | ||||||
| 1594 | } | ||||||
| 1595 | } | ||||||
| 1596 | |||||||
| 1597 | return false; | ||||||
| 1598 | } | ||||||
| 1599 | |||||||
| 1600 | // Finds an integer D for an expression (C + x + y + ...) such that the top | ||||||
| 1601 | // level addition in (D + (C - D + x + y + ...)) would not wrap (signed or | ||||||
| 1602 | // unsigned) and the number of trailing zeros of (C - D + x + y + ...) is | ||||||
| 1603 | // maximized, where C is the \p ConstantTerm, x, y, ... are arbitrary SCEVs, and | ||||||
| 1604 | // the (C + x + y + ...) expression is \p WholeAddExpr. | ||||||
| 1605 | static APInt extractConstantWithoutWrapping(ScalarEvolution &SE, | ||||||
| 1606 | const SCEVConstant *ConstantTerm, | ||||||
| 1607 | const SCEVAddExpr *WholeAddExpr) { | ||||||
| 1608 | const APInt C = ConstantTerm->getAPInt(); | ||||||
| 1609 | const unsigned BitWidth = C.getBitWidth(); | ||||||
| 1610 | // Find number of trailing zeros of (x + y + ...) w/o the C first: | ||||||
| 1611 | uint32_t TZ = BitWidth; | ||||||
| 1612 | for (unsigned I = 1, E = WholeAddExpr->getNumOperands(); I < E && TZ; ++I) | ||||||
| 1613 | TZ = std::min(TZ, SE.GetMinTrailingZeros(WholeAddExpr->getOperand(I))); | ||||||
| 1614 | if (TZ) { | ||||||
| 1615 | // Set D to be as many least significant bits of C as possible while still | ||||||
| 1616 | // guaranteeing that adding D to (C - D + x + y + ...) won't cause a wrap: | ||||||
| 1617 | return TZ < BitWidth ? C.trunc(TZ).zext(BitWidth) : C; | ||||||
| 1618 | } | ||||||
| 1619 | return APInt(BitWidth, 0); | ||||||
| 1620 | } | ||||||
| 1621 | |||||||
| 1622 | // Finds an integer D for an affine AddRec expression {C,+,x} such that the top | ||||||
| 1623 | // level addition in (D + {C-D,+,x}) would not wrap (signed or unsigned) and the | ||||||
| 1624 | // number of trailing zeros of (C - D + x * n) is maximized, where C is the \p | ||||||
| 1625 | // ConstantStart, x is an arbitrary \p Step, and n is the loop trip count. | ||||||
| 1626 | static APInt extractConstantWithoutWrapping(ScalarEvolution &SE, | ||||||
| 1627 | const APInt &ConstantStart, | ||||||
| 1628 | const SCEV *Step) { | ||||||
| 1629 | const unsigned BitWidth = ConstantStart.getBitWidth(); | ||||||
| 1630 | const uint32_t TZ = SE.GetMinTrailingZeros(Step); | ||||||
| 1631 | if (TZ) | ||||||
| 1632 | return TZ < BitWidth ? ConstantStart.trunc(TZ).zext(BitWidth) | ||||||
| 1633 | : ConstantStart; | ||||||
| 1634 | return APInt(BitWidth, 0); | ||||||
| 1635 | } | ||||||
| 1636 | |||||||
| 1637 | const SCEV * | ||||||
| 1638 | ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) { | ||||||
| 1639 | assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1640, __PRETTY_FUNCTION__)) | ||||||
| 1640 | "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1640, __PRETTY_FUNCTION__)); | ||||||
| 1641 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1642, __PRETTY_FUNCTION__)) | ||||||
| 1642 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1642, __PRETTY_FUNCTION__)); | ||||||
| 1643 | Ty = getEffectiveSCEVType(Ty); | ||||||
| 1644 | |||||||
| 1645 | // Fold if the operand is constant. | ||||||
| 1646 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
| 1647 | return getConstant( | ||||||
| 1648 | cast<ConstantInt>(ConstantExpr::getZExt(SC->getValue(), Ty))); | ||||||
| 1649 | |||||||
| 1650 | // zext(zext(x)) --> zext(x) | ||||||
| 1651 | if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op)) | ||||||
| 1652 | return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1); | ||||||
| 1653 | |||||||
| 1654 | // Before doing any expensive analysis, check to see if we've already | ||||||
| 1655 | // computed a SCEV for this Op and Ty. | ||||||
| 1656 | FoldingSetNodeID ID; | ||||||
| 1657 | ID.AddInteger(scZeroExtend); | ||||||
| 1658 | ID.AddPointer(Op); | ||||||
| 1659 | ID.AddPointer(Ty); | ||||||
| 1660 | void *IP = nullptr; | ||||||
| 1661 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
| 1662 | if (Depth > MaxCastDepth) { | ||||||
| 1663 | SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator), | ||||||
| 1664 | Op, Ty); | ||||||
| 1665 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 1666 | addToLoopUseLists(S); | ||||||
| 1667 | return S; | ||||||
| 1668 | } | ||||||
| 1669 | |||||||
| 1670 | // zext(trunc(x)) --> zext(x) or x or trunc(x) | ||||||
| 1671 | if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) { | ||||||
| 1672 | // It's possible the bits taken off by the truncate were all zero bits. If | ||||||
| 1673 | // so, we should be able to simplify this further. | ||||||
| 1674 | const SCEV *X = ST->getOperand(); | ||||||
| 1675 | ConstantRange CR = getUnsignedRange(X); | ||||||
| 1676 | unsigned TruncBits = getTypeSizeInBits(ST->getType()); | ||||||
| 1677 | unsigned NewBits = getTypeSizeInBits(Ty); | ||||||
| 1678 | if (CR.truncate(TruncBits).zeroExtend(NewBits).contains( | ||||||
| 1679 | CR.zextOrTrunc(NewBits))) | ||||||
| 1680 | return getTruncateOrZeroExtend(X, Ty, Depth); | ||||||
| 1681 | } | ||||||
| 1682 | |||||||
| 1683 | // If the input value is a chrec scev, and we can prove that the value | ||||||
| 1684 | // did not overflow the old, smaller, value, we can zero extend all of the | ||||||
| 1685 | // operands (often constants). This allows analysis of something like | ||||||
| 1686 | // this: for (unsigned char X = 0; X < 100; ++X) { int Y = X; } | ||||||
| 1687 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) | ||||||
| 1688 | if (AR->isAffine()) { | ||||||
| 1689 | const SCEV *Start = AR->getStart(); | ||||||
| 1690 | const SCEV *Step = AR->getStepRecurrence(*this); | ||||||
| 1691 | unsigned BitWidth = getTypeSizeInBits(AR->getType()); | ||||||
| 1692 | const Loop *L = AR->getLoop(); | ||||||
| 1693 | |||||||
| 1694 | if (!AR->hasNoUnsignedWrap()) { | ||||||
| 1695 | auto NewFlags = proveNoWrapViaConstantRanges(AR); | ||||||
| 1696 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags); | ||||||
| 1697 | } | ||||||
| 1698 | |||||||
| 1699 | // If we have special knowledge that this addrec won't overflow, | ||||||
| 1700 | // we don't need to do any further analysis. | ||||||
| 1701 | if (AR->hasNoUnsignedWrap()) | ||||||
| 1702 | return getAddRecExpr( | ||||||
| 1703 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
| 1704 | getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
| 1705 | |||||||
| 1706 | // Check whether the backedge-taken count is SCEVCouldNotCompute. | ||||||
| 1707 | // Note that this serves two purposes: It filters out loops that are | ||||||
| 1708 | // simply not analyzable, and it covers the case where this code is | ||||||
| 1709 | // being called from within backedge-taken count analysis, such that | ||||||
| 1710 | // attempting to ask for the backedge-taken count would likely result | ||||||
| 1711 | // in infinite recursion. In the later case, the analysis code will | ||||||
| 1712 | // cope with a conservative value, and it will take care to purge | ||||||
| 1713 | // that value once it has finished. | ||||||
| 1714 | const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L); | ||||||
| 1715 | if (!isa<SCEVCouldNotCompute>(MaxBECount)) { | ||||||
| 1716 | // Manually compute the final value for AR, checking for | ||||||
| 1717 | // overflow. | ||||||
| 1718 | |||||||
| 1719 | // Check whether the backedge-taken count can be losslessly casted to | ||||||
| 1720 | // the addrec's type. The count is always unsigned. | ||||||
| 1721 | const SCEV *CastedMaxBECount = | ||||||
| 1722 | getTruncateOrZeroExtend(MaxBECount, Start->getType(), Depth); | ||||||
| 1723 | const SCEV *RecastedMaxBECount = getTruncateOrZeroExtend( | ||||||
| 1724 | CastedMaxBECount, MaxBECount->getType(), Depth); | ||||||
| 1725 | if (MaxBECount == RecastedMaxBECount) { | ||||||
| 1726 | Type *WideTy = IntegerType::get(getContext(), BitWidth * 2); | ||||||
| 1727 | // Check whether Start+Step*MaxBECount has no unsigned overflow. | ||||||
| 1728 | const SCEV *ZMul = getMulExpr(CastedMaxBECount, Step, | ||||||
| 1729 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 1730 | const SCEV *ZAdd = getZeroExtendExpr(getAddExpr(Start, ZMul, | ||||||
| 1731 | SCEV::FlagAnyWrap, | ||||||
| 1732 | Depth + 1), | ||||||
| 1733 | WideTy, Depth + 1); | ||||||
| 1734 | const SCEV *WideStart = getZeroExtendExpr(Start, WideTy, Depth + 1); | ||||||
| 1735 | const SCEV *WideMaxBECount = | ||||||
| 1736 | getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1); | ||||||
| 1737 | const SCEV *OperandExtendedAdd = | ||||||
| 1738 | getAddExpr(WideStart, | ||||||
| 1739 | getMulExpr(WideMaxBECount, | ||||||
| 1740 | getZeroExtendExpr(Step, WideTy, Depth + 1), | ||||||
| 1741 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
| 1742 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 1743 | if (ZAdd == OperandExtendedAdd) { | ||||||
| 1744 | // Cache knowledge of AR NUW, which is propagated to this AddRec. | ||||||
| 1745 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW); | ||||||
| 1746 | // Return the expression with the addrec on the outside. | ||||||
| 1747 | return getAddRecExpr( | ||||||
| 1748 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
| 1749 | Depth + 1), | ||||||
| 1750 | getZeroExtendExpr(Step, Ty, Depth + 1), L, | ||||||
| 1751 | AR->getNoWrapFlags()); | ||||||
| 1752 | } | ||||||
| 1753 | // Similar to above, only this time treat the step value as signed. | ||||||
| 1754 | // This covers loops that count down. | ||||||
| 1755 | OperandExtendedAdd = | ||||||
| 1756 | getAddExpr(WideStart, | ||||||
| 1757 | getMulExpr(WideMaxBECount, | ||||||
| 1758 | getSignExtendExpr(Step, WideTy, Depth + 1), | ||||||
| 1759 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
| 1760 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 1761 | if (ZAdd == OperandExtendedAdd) { | ||||||
| 1762 | // Cache knowledge of AR NW, which is propagated to this AddRec. | ||||||
| 1763 | // Negative step causes unsigned wrap, but it still can't self-wrap. | ||||||
| 1764 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW); | ||||||
| 1765 | // Return the expression with the addrec on the outside. | ||||||
| 1766 | return getAddRecExpr( | ||||||
| 1767 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
| 1768 | Depth + 1), | ||||||
| 1769 | getSignExtendExpr(Step, Ty, Depth + 1), L, | ||||||
| 1770 | AR->getNoWrapFlags()); | ||||||
| 1771 | } | ||||||
| 1772 | } | ||||||
| 1773 | } | ||||||
| 1774 | |||||||
| 1775 | // Normally, in the cases we can prove no-overflow via a | ||||||
| 1776 | // backedge guarding condition, we can also compute a backedge | ||||||
| 1777 | // taken count for the loop. The exceptions are assumptions and | ||||||
| 1778 | // guards present in the loop -- SCEV is not great at exploiting | ||||||
| 1779 | // these to compute max backedge taken counts, but can still use | ||||||
| 1780 | // these to prove lack of overflow. Use this fact to avoid | ||||||
| 1781 | // doing extra work that may not pay off. | ||||||
| 1782 | if (!isa<SCEVCouldNotCompute>(MaxBECount) || HasGuards || | ||||||
| 1783 | !AC.assumptions().empty()) { | ||||||
| 1784 | // If the backedge is guarded by a comparison with the pre-inc | ||||||
| 1785 | // value the addrec is safe. Also, if the entry is guarded by | ||||||
| 1786 | // a comparison with the start value and the backedge is | ||||||
| 1787 | // guarded by a comparison with the post-inc value, the addrec | ||||||
| 1788 | // is safe. | ||||||
| 1789 | if (isKnownPositive(Step)) { | ||||||
| 1790 | const SCEV *N = getConstant(APInt::getMinValue(BitWidth) - | ||||||
| 1791 | getUnsignedRangeMax(Step)); | ||||||
| 1792 | if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT, AR, N) || | ||||||
| 1793 | isKnownOnEveryIteration(ICmpInst::ICMP_ULT, AR, N)) { | ||||||
| 1794 | // Cache knowledge of AR NUW, which is propagated to this | ||||||
| 1795 | // AddRec. | ||||||
| 1796 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW); | ||||||
| 1797 | // Return the expression with the addrec on the outside. | ||||||
| 1798 | return getAddRecExpr( | ||||||
| 1799 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
| 1800 | Depth + 1), | ||||||
| 1801 | getZeroExtendExpr(Step, Ty, Depth + 1), L, | ||||||
| 1802 | AR->getNoWrapFlags()); | ||||||
| 1803 | } | ||||||
| 1804 | } else if (isKnownNegative(Step)) { | ||||||
| 1805 | const SCEV *N = getConstant(APInt::getMaxValue(BitWidth) - | ||||||
| 1806 | getSignedRangeMin(Step)); | ||||||
| 1807 | if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT, AR, N) || | ||||||
| 1808 | isKnownOnEveryIteration(ICmpInst::ICMP_UGT, AR, N)) { | ||||||
| 1809 | // Cache knowledge of AR NW, which is propagated to this | ||||||
| 1810 | // AddRec. Negative step causes unsigned wrap, but it | ||||||
| 1811 | // still can't self-wrap. | ||||||
| 1812 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW); | ||||||
| 1813 | // Return the expression with the addrec on the outside. | ||||||
| 1814 | return getAddRecExpr( | ||||||
| 1815 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, | ||||||
| 1816 | Depth + 1), | ||||||
| 1817 | getSignExtendExpr(Step, Ty, Depth + 1), L, | ||||||
| 1818 | AR->getNoWrapFlags()); | ||||||
| 1819 | } | ||||||
| 1820 | } | ||||||
| 1821 | } | ||||||
| 1822 | |||||||
| 1823 | // zext({C,+,Step}) --> (zext(D) + zext({C-D,+,Step}))<nuw><nsw> | ||||||
| 1824 | // if D + (C - D + Step * n) could be proven to not unsigned wrap | ||||||
| 1825 | // where D maximizes the number of trailing zeros of (C - D + Step * n) | ||||||
| 1826 | if (const auto *SC = dyn_cast<SCEVConstant>(Start)) { | ||||||
| 1827 | const APInt &C = SC->getAPInt(); | ||||||
| 1828 | const APInt &D = extractConstantWithoutWrapping(*this, C, Step); | ||||||
| 1829 | if (D != 0) { | ||||||
| 1830 | const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth); | ||||||
| 1831 | const SCEV *SResidual = | ||||||
| 1832 | getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags()); | ||||||
| 1833 | const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1); | ||||||
| 1834 | return getAddExpr(SZExtD, SZExtR, | ||||||
| 1835 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
| 1836 | Depth + 1); | ||||||
| 1837 | } | ||||||
| 1838 | } | ||||||
| 1839 | |||||||
| 1840 | if (proveNoWrapByVaryingStart<SCEVZeroExtendExpr>(Start, Step, L)) { | ||||||
| 1841 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW); | ||||||
| 1842 | return getAddRecExpr( | ||||||
| 1843 | getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
| 1844 | getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
| 1845 | } | ||||||
| 1846 | } | ||||||
| 1847 | |||||||
| 1848 | // zext(A % B) --> zext(A) % zext(B) | ||||||
| 1849 | { | ||||||
| 1850 | const SCEV *LHS; | ||||||
| 1851 | const SCEV *RHS; | ||||||
| 1852 | if (matchURem(Op, LHS, RHS)) | ||||||
| 1853 | return getURemExpr(getZeroExtendExpr(LHS, Ty, Depth + 1), | ||||||
| 1854 | getZeroExtendExpr(RHS, Ty, Depth + 1)); | ||||||
| 1855 | } | ||||||
| 1856 | |||||||
| 1857 | // zext(A / B) --> zext(A) / zext(B). | ||||||
| 1858 | if (auto *Div = dyn_cast<SCEVUDivExpr>(Op)) | ||||||
| 1859 | return getUDivExpr(getZeroExtendExpr(Div->getLHS(), Ty, Depth + 1), | ||||||
| 1860 | getZeroExtendExpr(Div->getRHS(), Ty, Depth + 1)); | ||||||
| 1861 | |||||||
| 1862 | if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) { | ||||||
| 1863 | // zext((A + B + ...)<nuw>) --> (zext(A) + zext(B) + ...)<nuw> | ||||||
| 1864 | if (SA->hasNoUnsignedWrap()) { | ||||||
| 1865 | // If the addition does not unsign overflow then we can, by definition, | ||||||
| 1866 | // commute the zero extension with the addition operation. | ||||||
| 1867 | SmallVector<const SCEV *, 4> Ops; | ||||||
| 1868 | for (const auto *Op : SA->operands()) | ||||||
| 1869 | Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1)); | ||||||
| 1870 | return getAddExpr(Ops, SCEV::FlagNUW, Depth + 1); | ||||||
| 1871 | } | ||||||
| 1872 | |||||||
| 1873 | // zext(C + x + y + ...) --> (zext(D) + zext((C - D) + x + y + ...)) | ||||||
| 1874 | // if D + (C - D + x + y + ...) could be proven to not unsigned wrap | ||||||
| 1875 | // where D maximizes the number of trailing zeros of (C - D + x + y + ...) | ||||||
| 1876 | // | ||||||
| 1877 | // Often address arithmetics contain expressions like | ||||||
| 1878 | // (zext (add (shl X, C1), C2)), for instance, (zext (5 + (4 * X))). | ||||||
| 1879 | // This transformation is useful while proving that such expressions are | ||||||
| 1880 | // equal or differ by a small constant amount, see LoadStoreVectorizer pass. | ||||||
| 1881 | if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) { | ||||||
| 1882 | const APInt &D = extractConstantWithoutWrapping(*this, SC, SA); | ||||||
| 1883 | if (D != 0) { | ||||||
| 1884 | const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth); | ||||||
| 1885 | const SCEV *SResidual = | ||||||
| 1886 | getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth); | ||||||
| 1887 | const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1); | ||||||
| 1888 | return getAddExpr(SZExtD, SZExtR, | ||||||
| 1889 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
| 1890 | Depth + 1); | ||||||
| 1891 | } | ||||||
| 1892 | } | ||||||
| 1893 | } | ||||||
| 1894 | |||||||
| 1895 | if (auto *SM = dyn_cast<SCEVMulExpr>(Op)) { | ||||||
| 1896 | // zext((A * B * ...)<nuw>) --> (zext(A) * zext(B) * ...)<nuw> | ||||||
| 1897 | if (SM->hasNoUnsignedWrap()) { | ||||||
| 1898 | // If the multiply does not unsign overflow then we can, by definition, | ||||||
| 1899 | // commute the zero extension with the multiply operation. | ||||||
| 1900 | SmallVector<const SCEV *, 4> Ops; | ||||||
| 1901 | for (const auto *Op : SM->operands()) | ||||||
| 1902 | Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1)); | ||||||
| 1903 | return getMulExpr(Ops, SCEV::FlagNUW, Depth + 1); | ||||||
| 1904 | } | ||||||
| 1905 | |||||||
| 1906 | // zext(2^K * (trunc X to iN)) to iM -> | ||||||
| 1907 | // 2^K * (zext(trunc X to i{N-K}) to iM)<nuw> | ||||||
| 1908 | // | ||||||
| 1909 | // Proof: | ||||||
| 1910 | // | ||||||
| 1911 | // zext(2^K * (trunc X to iN)) to iM | ||||||
| 1912 | // = zext((trunc X to iN) << K) to iM | ||||||
| 1913 | // = zext((trunc X to i{N-K}) << K)<nuw> to iM | ||||||
| 1914 | // (because shl removes the top K bits) | ||||||
| 1915 | // = zext((2^K * (trunc X to i{N-K}))<nuw>) to iM | ||||||
| 1916 | // = (2^K * (zext(trunc X to i{N-K}) to iM))<nuw>. | ||||||
| 1917 | // | ||||||
| 1918 | if (SM->getNumOperands() == 2) | ||||||
| 1919 | if (auto *MulLHS = dyn_cast<SCEVConstant>(SM->getOperand(0))) | ||||||
| 1920 | if (MulLHS->getAPInt().isPowerOf2()) | ||||||
| 1921 | if (auto *TruncRHS = dyn_cast<SCEVTruncateExpr>(SM->getOperand(1))) { | ||||||
| 1922 | int NewTruncBits = getTypeSizeInBits(TruncRHS->getType()) - | ||||||
| 1923 | MulLHS->getAPInt().logBase2(); | ||||||
| 1924 | Type *NewTruncTy = IntegerType::get(getContext(), NewTruncBits); | ||||||
| 1925 | return getMulExpr( | ||||||
| 1926 | getZeroExtendExpr(MulLHS, Ty), | ||||||
| 1927 | getZeroExtendExpr( | ||||||
| 1928 | getTruncateExpr(TruncRHS->getOperand(), NewTruncTy), Ty), | ||||||
| 1929 | SCEV::FlagNUW, Depth + 1); | ||||||
| 1930 | } | ||||||
| 1931 | } | ||||||
| 1932 | |||||||
| 1933 | // The cast wasn't folded; create an explicit cast node. | ||||||
| 1934 | // Recompute the insert position, as it may have been invalidated. | ||||||
| 1935 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
| 1936 | SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator), | ||||||
| 1937 | Op, Ty); | ||||||
| 1938 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 1939 | addToLoopUseLists(S); | ||||||
| 1940 | return S; | ||||||
| 1941 | } | ||||||
| 1942 | |||||||
| 1943 | const SCEV * | ||||||
| 1944 | ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) { | ||||||
| 1945 | assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1946, __PRETTY_FUNCTION__)) | ||||||
| 1946 | "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1946, __PRETTY_FUNCTION__)); | ||||||
| 1947 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1948, __PRETTY_FUNCTION__)) | ||||||
| 1948 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 1948, __PRETTY_FUNCTION__)); | ||||||
| 1949 | Ty = getEffectiveSCEVType(Ty); | ||||||
| 1950 | |||||||
| 1951 | // Fold if the operand is constant. | ||||||
| 1952 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
| 1953 | return getConstant( | ||||||
| 1954 | cast<ConstantInt>(ConstantExpr::getSExt(SC->getValue(), Ty))); | ||||||
| 1955 | |||||||
| 1956 | // sext(sext(x)) --> sext(x) | ||||||
| 1957 | if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op)) | ||||||
| 1958 | return getSignExtendExpr(SS->getOperand(), Ty, Depth + 1); | ||||||
| 1959 | |||||||
| 1960 | // sext(zext(x)) --> zext(x) | ||||||
| 1961 | if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op)) | ||||||
| 1962 | return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1); | ||||||
| 1963 | |||||||
| 1964 | // Before doing any expensive analysis, check to see if we've already | ||||||
| 1965 | // computed a SCEV for this Op and Ty. | ||||||
| 1966 | FoldingSetNodeID ID; | ||||||
| 1967 | ID.AddInteger(scSignExtend); | ||||||
| 1968 | ID.AddPointer(Op); | ||||||
| 1969 | ID.AddPointer(Ty); | ||||||
| 1970 | void *IP = nullptr; | ||||||
| 1971 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
| 1972 | // Limit recursion depth. | ||||||
| 1973 | if (Depth > MaxCastDepth) { | ||||||
| 1974 | SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator), | ||||||
| 1975 | Op, Ty); | ||||||
| 1976 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 1977 | addToLoopUseLists(S); | ||||||
| 1978 | return S; | ||||||
| 1979 | } | ||||||
| 1980 | |||||||
| 1981 | // sext(trunc(x)) --> sext(x) or x or trunc(x) | ||||||
| 1982 | if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) { | ||||||
| 1983 | // It's possible the bits taken off by the truncate were all sign bits. If | ||||||
| 1984 | // so, we should be able to simplify this further. | ||||||
| 1985 | const SCEV *X = ST->getOperand(); | ||||||
| 1986 | ConstantRange CR = getSignedRange(X); | ||||||
| 1987 | unsigned TruncBits = getTypeSizeInBits(ST->getType()); | ||||||
| 1988 | unsigned NewBits = getTypeSizeInBits(Ty); | ||||||
| 1989 | if (CR.truncate(TruncBits).signExtend(NewBits).contains( | ||||||
| 1990 | CR.sextOrTrunc(NewBits))) | ||||||
| 1991 | return getTruncateOrSignExtend(X, Ty, Depth); | ||||||
| 1992 | } | ||||||
| 1993 | |||||||
| 1994 | if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) { | ||||||
| 1995 | // sext((A + B + ...)<nsw>) --> (sext(A) + sext(B) + ...)<nsw> | ||||||
| 1996 | if (SA->hasNoSignedWrap()) { | ||||||
| 1997 | // If the addition does not sign overflow then we can, by definition, | ||||||
| 1998 | // commute the sign extension with the addition operation. | ||||||
| 1999 | SmallVector<const SCEV *, 4> Ops; | ||||||
| 2000 | for (const auto *Op : SA->operands()) | ||||||
| 2001 | Ops.push_back(getSignExtendExpr(Op, Ty, Depth + 1)); | ||||||
| 2002 | return getAddExpr(Ops, SCEV::FlagNSW, Depth + 1); | ||||||
| 2003 | } | ||||||
| 2004 | |||||||
| 2005 | // sext(C + x + y + ...) --> (sext(D) + sext((C - D) + x + y + ...)) | ||||||
| 2006 | // if D + (C - D + x + y + ...) could be proven to not signed wrap | ||||||
| 2007 | // where D maximizes the number of trailing zeros of (C - D + x + y + ...) | ||||||
| 2008 | // | ||||||
| 2009 | // For instance, this will bring two seemingly different expressions: | ||||||
| 2010 | // 1 + sext(5 + 20 * %x + 24 * %y) and | ||||||
| 2011 | // sext(6 + 20 * %x + 24 * %y) | ||||||
| 2012 | // to the same form: | ||||||
| 2013 | // 2 + sext(4 + 20 * %x + 24 * %y) | ||||||
| 2014 | if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) { | ||||||
| 2015 | const APInt &D = extractConstantWithoutWrapping(*this, SC, SA); | ||||||
| 2016 | if (D != 0) { | ||||||
| 2017 | const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth); | ||||||
| 2018 | const SCEV *SResidual = | ||||||
| 2019 | getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth); | ||||||
| 2020 | const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1); | ||||||
| 2021 | return getAddExpr(SSExtD, SSExtR, | ||||||
| 2022 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
| 2023 | Depth + 1); | ||||||
| 2024 | } | ||||||
| 2025 | } | ||||||
| 2026 | } | ||||||
| 2027 | // If the input value is a chrec scev, and we can prove that the value | ||||||
| 2028 | // did not overflow the old, smaller, value, we can sign extend all of the | ||||||
| 2029 | // operands (often constants). This allows analysis of something like | ||||||
| 2030 | // this: for (signed char X = 0; X < 100; ++X) { int Y = X; } | ||||||
| 2031 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) | ||||||
| 2032 | if (AR->isAffine()) { | ||||||
| 2033 | const SCEV *Start = AR->getStart(); | ||||||
| 2034 | const SCEV *Step = AR->getStepRecurrence(*this); | ||||||
| 2035 | unsigned BitWidth = getTypeSizeInBits(AR->getType()); | ||||||
| 2036 | const Loop *L = AR->getLoop(); | ||||||
| 2037 | |||||||
| 2038 | if (!AR->hasNoSignedWrap()) { | ||||||
| 2039 | auto NewFlags = proveNoWrapViaConstantRanges(AR); | ||||||
| 2040 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(NewFlags); | ||||||
| 2041 | } | ||||||
| 2042 | |||||||
| 2043 | // If we have special knowledge that this addrec won't overflow, | ||||||
| 2044 | // we don't need to do any further analysis. | ||||||
| 2045 | if (AR->hasNoSignedWrap()) | ||||||
| 2046 | return getAddRecExpr( | ||||||
| 2047 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
| 2048 | getSignExtendExpr(Step, Ty, Depth + 1), L, SCEV::FlagNSW); | ||||||
| 2049 | |||||||
| 2050 | // Check whether the backedge-taken count is SCEVCouldNotCompute. | ||||||
| 2051 | // Note that this serves two purposes: It filters out loops that are | ||||||
| 2052 | // simply not analyzable, and it covers the case where this code is | ||||||
| 2053 | // being called from within backedge-taken count analysis, such that | ||||||
| 2054 | // attempting to ask for the backedge-taken count would likely result | ||||||
| 2055 | // in infinite recursion. In the later case, the analysis code will | ||||||
| 2056 | // cope with a conservative value, and it will take care to purge | ||||||
| 2057 | // that value once it has finished. | ||||||
| 2058 | const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L); | ||||||
| 2059 | if (!isa<SCEVCouldNotCompute>(MaxBECount)) { | ||||||
| 2060 | // Manually compute the final value for AR, checking for | ||||||
| 2061 | // overflow. | ||||||
| 2062 | |||||||
| 2063 | // Check whether the backedge-taken count can be losslessly casted to | ||||||
| 2064 | // the addrec's type. The count is always unsigned. | ||||||
| 2065 | const SCEV *CastedMaxBECount = | ||||||
| 2066 | getTruncateOrZeroExtend(MaxBECount, Start->getType(), Depth); | ||||||
| 2067 | const SCEV *RecastedMaxBECount = getTruncateOrZeroExtend( | ||||||
| 2068 | CastedMaxBECount, MaxBECount->getType(), Depth); | ||||||
| 2069 | if (MaxBECount == RecastedMaxBECount) { | ||||||
| 2070 | Type *WideTy = IntegerType::get(getContext(), BitWidth * 2); | ||||||
| 2071 | // Check whether Start+Step*MaxBECount has no signed overflow. | ||||||
| 2072 | const SCEV *SMul = getMulExpr(CastedMaxBECount, Step, | ||||||
| 2073 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2074 | const SCEV *SAdd = getSignExtendExpr(getAddExpr(Start, SMul, | ||||||
| 2075 | SCEV::FlagAnyWrap, | ||||||
| 2076 | Depth + 1), | ||||||
| 2077 | WideTy, Depth + 1); | ||||||
| 2078 | const SCEV *WideStart = getSignExtendExpr(Start, WideTy, Depth + 1); | ||||||
| 2079 | const SCEV *WideMaxBECount = | ||||||
| 2080 | getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1); | ||||||
| 2081 | const SCEV *OperandExtendedAdd = | ||||||
| 2082 | getAddExpr(WideStart, | ||||||
| 2083 | getMulExpr(WideMaxBECount, | ||||||
| 2084 | getSignExtendExpr(Step, WideTy, Depth + 1), | ||||||
| 2085 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
| 2086 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2087 | if (SAdd == OperandExtendedAdd) { | ||||||
| 2088 | // Cache knowledge of AR NSW, which is propagated to this AddRec. | ||||||
| 2089 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW); | ||||||
| 2090 | // Return the expression with the addrec on the outside. | ||||||
| 2091 | return getAddRecExpr( | ||||||
| 2092 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, | ||||||
| 2093 | Depth + 1), | ||||||
| 2094 | getSignExtendExpr(Step, Ty, Depth + 1), L, | ||||||
| 2095 | AR->getNoWrapFlags()); | ||||||
| 2096 | } | ||||||
| 2097 | // Similar to above, only this time treat the step value as unsigned. | ||||||
| 2098 | // This covers loops that count up with an unsigned step. | ||||||
| 2099 | OperandExtendedAdd = | ||||||
| 2100 | getAddExpr(WideStart, | ||||||
| 2101 | getMulExpr(WideMaxBECount, | ||||||
| 2102 | getZeroExtendExpr(Step, WideTy, Depth + 1), | ||||||
| 2103 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
| 2104 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2105 | if (SAdd == OperandExtendedAdd) { | ||||||
| 2106 | // If AR wraps around then | ||||||
| 2107 | // | ||||||
| 2108 | // abs(Step) * MaxBECount > unsigned-max(AR->getType()) | ||||||
| 2109 | // => SAdd != OperandExtendedAdd | ||||||
| 2110 | // | ||||||
| 2111 | // Thus (AR is not NW => SAdd != OperandExtendedAdd) <=> | ||||||
| 2112 | // (SAdd == OperandExtendedAdd => AR is NW) | ||||||
| 2113 | |||||||
| 2114 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW); | ||||||
| 2115 | |||||||
| 2116 | // Return the expression with the addrec on the outside. | ||||||
| 2117 | return getAddRecExpr( | ||||||
| 2118 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, | ||||||
| 2119 | Depth + 1), | ||||||
| 2120 | getZeroExtendExpr(Step, Ty, Depth + 1), L, | ||||||
| 2121 | AR->getNoWrapFlags()); | ||||||
| 2122 | } | ||||||
| 2123 | } | ||||||
| 2124 | } | ||||||
| 2125 | |||||||
| 2126 | // Normally, in the cases we can prove no-overflow via a | ||||||
| 2127 | // backedge guarding condition, we can also compute a backedge | ||||||
| 2128 | // taken count for the loop. The exceptions are assumptions and | ||||||
| 2129 | // guards present in the loop -- SCEV is not great at exploiting | ||||||
| 2130 | // these to compute max backedge taken counts, but can still use | ||||||
| 2131 | // these to prove lack of overflow. Use this fact to avoid | ||||||
| 2132 | // doing extra work that may not pay off. | ||||||
| 2133 | |||||||
| 2134 | if (!isa<SCEVCouldNotCompute>(MaxBECount) || HasGuards || | ||||||
| 2135 | !AC.assumptions().empty()) { | ||||||
| 2136 | // If the backedge is guarded by a comparison with the pre-inc | ||||||
| 2137 | // value the addrec is safe. Also, if the entry is guarded by | ||||||
| 2138 | // a comparison with the start value and the backedge is | ||||||
| 2139 | // guarded by a comparison with the post-inc value, the addrec | ||||||
| 2140 | // is safe. | ||||||
| 2141 | ICmpInst::Predicate Pred; | ||||||
| 2142 | const SCEV *OverflowLimit = | ||||||
| 2143 | getSignedOverflowLimitForStep(Step, &Pred, this); | ||||||
| 2144 | if (OverflowLimit && | ||||||
| 2145 | (isLoopBackedgeGuardedByCond(L, Pred, AR, OverflowLimit) || | ||||||
| 2146 | isKnownOnEveryIteration(Pred, AR, OverflowLimit))) { | ||||||
| 2147 | // Cache knowledge of AR NSW, then propagate NSW to the wide AddRec. | ||||||
| 2148 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW); | ||||||
| 2149 | return getAddRecExpr( | ||||||
| 2150 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
| 2151 | getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
| 2152 | } | ||||||
| 2153 | } | ||||||
| 2154 | |||||||
| 2155 | // sext({C,+,Step}) --> (sext(D) + sext({C-D,+,Step}))<nuw><nsw> | ||||||
| 2156 | // if D + (C - D + Step * n) could be proven to not signed wrap | ||||||
| 2157 | // where D maximizes the number of trailing zeros of (C - D + Step * n) | ||||||
| 2158 | if (const auto *SC = dyn_cast<SCEVConstant>(Start)) { | ||||||
| 2159 | const APInt &C = SC->getAPInt(); | ||||||
| 2160 | const APInt &D = extractConstantWithoutWrapping(*this, C, Step); | ||||||
| 2161 | if (D != 0) { | ||||||
| 2162 | const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth); | ||||||
| 2163 | const SCEV *SResidual = | ||||||
| 2164 | getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags()); | ||||||
| 2165 | const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1); | ||||||
| 2166 | return getAddExpr(SSExtD, SSExtR, | ||||||
| 2167 | (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW), | ||||||
| 2168 | Depth + 1); | ||||||
| 2169 | } | ||||||
| 2170 | } | ||||||
| 2171 | |||||||
| 2172 | if (proveNoWrapByVaryingStart<SCEVSignExtendExpr>(Start, Step, L)) { | ||||||
| 2173 | const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW); | ||||||
| 2174 | return getAddRecExpr( | ||||||
| 2175 | getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1), | ||||||
| 2176 | getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags()); | ||||||
| 2177 | } | ||||||
| 2178 | } | ||||||
| 2179 | |||||||
| 2180 | // If the input value is provably positive and we could not simplify | ||||||
| 2181 | // away the sext build a zext instead. | ||||||
| 2182 | if (isKnownNonNegative(Op)) | ||||||
| 2183 | return getZeroExtendExpr(Op, Ty, Depth + 1); | ||||||
| 2184 | |||||||
| 2185 | // The cast wasn't folded; create an explicit cast node. | ||||||
| 2186 | // Recompute the insert position, as it may have been invalidated. | ||||||
| 2187 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
| 2188 | SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator), | ||||||
| 2189 | Op, Ty); | ||||||
| 2190 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 2191 | addToLoopUseLists(S); | ||||||
| 2192 | return S; | ||||||
| 2193 | } | ||||||
| 2194 | |||||||
| 2195 | /// getAnyExtendExpr - Return a SCEV for the given operand extended with | ||||||
| 2196 | /// unspecified bits out to the given type. | ||||||
| 2197 | const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op, | ||||||
| 2198 | Type *Ty) { | ||||||
| 2199 | assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2200, __PRETTY_FUNCTION__)) | ||||||
| 2200 | "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits( Ty) && "This is not an extending conversion!") ? static_cast <void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2200, __PRETTY_FUNCTION__)); | ||||||
| 2201 | assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2202, __PRETTY_FUNCTION__)) | ||||||
| 2202 | "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2202, __PRETTY_FUNCTION__)); | ||||||
| 2203 | Ty = getEffectiveSCEVType(Ty); | ||||||
| 2204 | |||||||
| 2205 | // Sign-extend negative constants. | ||||||
| 2206 | if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) | ||||||
| 2207 | if (SC->getAPInt().isNegative()) | ||||||
| 2208 | return getSignExtendExpr(Op, Ty); | ||||||
| 2209 | |||||||
| 2210 | // Peel off a truncate cast. | ||||||
| 2211 | if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Op)) { | ||||||
| 2212 | const SCEV *NewOp = T->getOperand(); | ||||||
| 2213 | if (getTypeSizeInBits(NewOp->getType()) < getTypeSizeInBits(Ty)) | ||||||
| 2214 | return getAnyExtendExpr(NewOp, Ty); | ||||||
| 2215 | return getTruncateOrNoop(NewOp, Ty); | ||||||
| 2216 | } | ||||||
| 2217 | |||||||
| 2218 | // Next try a zext cast. If the cast is folded, use it. | ||||||
| 2219 | const SCEV *ZExt = getZeroExtendExpr(Op, Ty); | ||||||
| 2220 | if (!isa<SCEVZeroExtendExpr>(ZExt)) | ||||||
| 2221 | return ZExt; | ||||||
| 2222 | |||||||
| 2223 | // Next try a sext cast. If the cast is folded, use it. | ||||||
| 2224 | const SCEV *SExt = getSignExtendExpr(Op, Ty); | ||||||
| 2225 | if (!isa<SCEVSignExtendExpr>(SExt)) | ||||||
| 2226 | return SExt; | ||||||
| 2227 | |||||||
| 2228 | // Force the cast to be folded into the operands of an addrec. | ||||||
| 2229 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) { | ||||||
| 2230 | SmallVector<const SCEV *, 4> Ops; | ||||||
| 2231 | for (const SCEV *Op : AR->operands()) | ||||||
| 2232 | Ops.push_back(getAnyExtendExpr(Op, Ty)); | ||||||
| 2233 | return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagNW); | ||||||
| 2234 | } | ||||||
| 2235 | |||||||
| 2236 | // If the expression is obviously signed, use the sext cast value. | ||||||
| 2237 | if (isa<SCEVSMaxExpr>(Op)) | ||||||
| 2238 | return SExt; | ||||||
| 2239 | |||||||
| 2240 | // Absent any other information, use the zext cast value. | ||||||
| 2241 | return ZExt; | ||||||
| 2242 | } | ||||||
| 2243 | |||||||
| 2244 | /// Process the given Ops list, which is a list of operands to be added under | ||||||
| 2245 | /// the given scale, update the given map. This is a helper function for | ||||||
| 2246 | /// getAddRecExpr. As an example of what it does, given a sequence of operands | ||||||
| 2247 | /// that would form an add expression like this: | ||||||
| 2248 | /// | ||||||
| 2249 | /// m + n + 13 + (A * (o + p + (B * (q + m + 29)))) + r + (-1 * r) | ||||||
| 2250 | /// | ||||||
| 2251 | /// where A and B are constants, update the map with these values: | ||||||
| 2252 | /// | ||||||
| 2253 | /// (m, 1+A*B), (n, 1), (o, A), (p, A), (q, A*B), (r, 0) | ||||||
| 2254 | /// | ||||||
| 2255 | /// and add 13 + A*B*29 to AccumulatedConstant. | ||||||
| 2256 | /// This will allow getAddRecExpr to produce this: | ||||||
| 2257 | /// | ||||||
| 2258 | /// 13+A*B*29 + n + (m * (1+A*B)) + ((o + p) * A) + (q * A*B) | ||||||
| 2259 | /// | ||||||
| 2260 | /// This form often exposes folding opportunities that are hidden in | ||||||
| 2261 | /// the original operand list. | ||||||
| 2262 | /// | ||||||
| 2263 | /// Return true iff it appears that any interesting folding opportunities | ||||||
| 2264 | /// may be exposed. This helps getAddRecExpr short-circuit extra work in | ||||||
| 2265 | /// the common case where no interesting opportunities are present, and | ||||||
| 2266 | /// is also used as a check to avoid infinite recursion. | ||||||
| 2267 | static bool | ||||||
| 2268 | CollectAddOperandsWithScales(DenseMap<const SCEV *, APInt> &M, | ||||||
| 2269 | SmallVectorImpl<const SCEV *> &NewOps, | ||||||
| 2270 | APInt &AccumulatedConstant, | ||||||
| 2271 | const SCEV *const *Ops, size_t NumOperands, | ||||||
| 2272 | const APInt &Scale, | ||||||
| 2273 | ScalarEvolution &SE) { | ||||||
| 2274 | bool Interesting = false; | ||||||
| 2275 | |||||||
| 2276 | // Iterate over the add operands. They are sorted, with constants first. | ||||||
| 2277 | unsigned i = 0; | ||||||
| 2278 | while (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) { | ||||||
| 2279 | ++i; | ||||||
| 2280 | // Pull a buried constant out to the outside. | ||||||
| 2281 | if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero()) | ||||||
| 2282 | Interesting = true; | ||||||
| 2283 | AccumulatedConstant += Scale * C->getAPInt(); | ||||||
| 2284 | } | ||||||
| 2285 | |||||||
| 2286 | // Next comes everything else. We're especially interested in multiplies | ||||||
| 2287 | // here, but they're in the middle, so just visit the rest with one loop. | ||||||
| 2288 | for (; i != NumOperands; ++i) { | ||||||
| 2289 | const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[i]); | ||||||
| 2290 | if (Mul && isa<SCEVConstant>(Mul->getOperand(0))) { | ||||||
| 2291 | APInt NewScale = | ||||||
| 2292 | Scale * cast<SCEVConstant>(Mul->getOperand(0))->getAPInt(); | ||||||
| 2293 | if (Mul->getNumOperands() == 2 && isa<SCEVAddExpr>(Mul->getOperand(1))) { | ||||||
| 2294 | // A multiplication of a constant with another add; recurse. | ||||||
| 2295 | const SCEVAddExpr *Add = cast<SCEVAddExpr>(Mul->getOperand(1)); | ||||||
| 2296 | Interesting |= | ||||||
| 2297 | CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant, | ||||||
| 2298 | Add->op_begin(), Add->getNumOperands(), | ||||||
| 2299 | NewScale, SE); | ||||||
| 2300 | } else { | ||||||
| 2301 | // A multiplication of a constant with some other value. Update | ||||||
| 2302 | // the map. | ||||||
| 2303 | SmallVector<const SCEV *, 4> MulOps(Mul->op_begin()+1, Mul->op_end()); | ||||||
| 2304 | const SCEV *Key = SE.getMulExpr(MulOps); | ||||||
| 2305 | auto Pair = M.insert({Key, NewScale}); | ||||||
| 2306 | if (Pair.second) { | ||||||
| 2307 | NewOps.push_back(Pair.first->first); | ||||||
| 2308 | } else { | ||||||
| 2309 | Pair.first->second += NewScale; | ||||||
| 2310 | // The map already had an entry for this value, which may indicate | ||||||
| 2311 | // a folding opportunity. | ||||||
| 2312 | Interesting = true; | ||||||
| 2313 | } | ||||||
| 2314 | } | ||||||
| 2315 | } else { | ||||||
| 2316 | // An ordinary operand. Update the map. | ||||||
| 2317 | std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair = | ||||||
| 2318 | M.insert({Ops[i], Scale}); | ||||||
| 2319 | if (Pair.second) { | ||||||
| 2320 | NewOps.push_back(Pair.first->first); | ||||||
| 2321 | } else { | ||||||
| 2322 | Pair.first->second += Scale; | ||||||
| 2323 | // The map already had an entry for this value, which may indicate | ||||||
| 2324 | // a folding opportunity. | ||||||
| 2325 | Interesting = true; | ||||||
| 2326 | } | ||||||
| 2327 | } | ||||||
| 2328 | } | ||||||
| 2329 | |||||||
| 2330 | return Interesting; | ||||||
| 2331 | } | ||||||
| 2332 | |||||||
| 2333 | // We're trying to construct a SCEV of type `Type' with `Ops' as operands and | ||||||
| 2334 | // `OldFlags' as can't-wrap behavior. Infer a more aggressive set of | ||||||
| 2335 | // can't-overflow flags for the operation if possible. | ||||||
| 2336 | static SCEV::NoWrapFlags | ||||||
| 2337 | StrengthenNoWrapFlags(ScalarEvolution *SE, SCEVTypes Type, | ||||||
| 2338 | const ArrayRef<const SCEV *> Ops, | ||||||
| 2339 | SCEV::NoWrapFlags Flags) { | ||||||
| 2340 | using namespace std::placeholders; | ||||||
| 2341 | |||||||
| 2342 | using OBO = OverflowingBinaryOperator; | ||||||
| 2343 | |||||||
| 2344 | bool CanAnalyze = | ||||||
| 2345 | Type == scAddExpr || Type == scAddRecExpr || Type == scMulExpr; | ||||||
| 2346 | (void)CanAnalyze; | ||||||
| 2347 | assert(CanAnalyze && "don't call from other places!")((CanAnalyze && "don't call from other places!") ? static_cast <void> (0) : __assert_fail ("CanAnalyze && \"don't call from other places!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2347, __PRETTY_FUNCTION__)); | ||||||
| 2348 | |||||||
| 2349 | int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW; | ||||||
| 2350 | SCEV::NoWrapFlags SignOrUnsignWrap = | ||||||
| 2351 | ScalarEvolution::maskFlags(Flags, SignOrUnsignMask); | ||||||
| 2352 | |||||||
| 2353 | // If FlagNSW is true and all the operands are non-negative, infer FlagNUW. | ||||||
| 2354 | auto IsKnownNonNegative = [&](const SCEV *S) { | ||||||
| 2355 | return SE->isKnownNonNegative(S); | ||||||
| 2356 | }; | ||||||
| 2357 | |||||||
| 2358 | if (SignOrUnsignWrap == SCEV::FlagNSW && all_of(Ops, IsKnownNonNegative)) | ||||||
| 2359 | Flags = | ||||||
| 2360 | ScalarEvolution::setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask); | ||||||
| 2361 | |||||||
| 2362 | SignOrUnsignWrap = ScalarEvolution::maskFlags(Flags, SignOrUnsignMask); | ||||||
| 2363 | |||||||
| 2364 | if (SignOrUnsignWrap != SignOrUnsignMask && | ||||||
| 2365 | (Type == scAddExpr || Type == scMulExpr) && Ops.size() == 2 && | ||||||
| 2366 | isa<SCEVConstant>(Ops[0])) { | ||||||
| 2367 | |||||||
| 2368 | auto Opcode = [&] { | ||||||
| 2369 | switch (Type) { | ||||||
| 2370 | case scAddExpr: | ||||||
| 2371 | return Instruction::Add; | ||||||
| 2372 | case scMulExpr: | ||||||
| 2373 | return Instruction::Mul; | ||||||
| 2374 | default: | ||||||
| 2375 | llvm_unreachable("Unexpected SCEV op.")::llvm::llvm_unreachable_internal("Unexpected SCEV op.", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2375); | ||||||
| 2376 | } | ||||||
| 2377 | }(); | ||||||
| 2378 | |||||||
| 2379 | const APInt &C = cast<SCEVConstant>(Ops[0])->getAPInt(); | ||||||
| 2380 | |||||||
| 2381 | // (A <opcode> C) --> (A <opcode> C)<nsw> if the op doesn't sign overflow. | ||||||
| 2382 | if (!(SignOrUnsignWrap & SCEV::FlagNSW)) { | ||||||
| 2383 | auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
| 2384 | Opcode, C, OBO::NoSignedWrap); | ||||||
| 2385 | if (NSWRegion.contains(SE->getSignedRange(Ops[1]))) | ||||||
| 2386 | Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW); | ||||||
| 2387 | } | ||||||
| 2388 | |||||||
| 2389 | // (A <opcode> C) --> (A <opcode> C)<nuw> if the op doesn't unsign overflow. | ||||||
| 2390 | if (!(SignOrUnsignWrap & SCEV::FlagNUW)) { | ||||||
| 2391 | auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
| 2392 | Opcode, C, OBO::NoUnsignedWrap); | ||||||
| 2393 | if (NUWRegion.contains(SE->getUnsignedRange(Ops[1]))) | ||||||
| 2394 | Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW); | ||||||
| 2395 | } | ||||||
| 2396 | } | ||||||
| 2397 | |||||||
| 2398 | return Flags; | ||||||
| 2399 | } | ||||||
| 2400 | |||||||
| 2401 | bool ScalarEvolution::isAvailableAtLoopEntry(const SCEV *S, const Loop *L) { | ||||||
| 2402 | return isLoopInvariant(S, L) && properlyDominates(S, L->getHeader()); | ||||||
| 2403 | } | ||||||
| 2404 | |||||||
| 2405 | /// Get a canonical add expression, or something simpler if possible. | ||||||
| 2406 | const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops, | ||||||
| 2407 | SCEV::NoWrapFlags Flags, | ||||||
| 2408 | unsigned Depth) { | ||||||
| 2409 | assert(!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) &&((!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && "only nuw or nsw allowed" ) ? static_cast<void> (0) : __assert_fail ("!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2410, __PRETTY_FUNCTION__)) | ||||||
| 2410 | "only nuw or nsw allowed")((!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && "only nuw or nsw allowed" ) ? static_cast<void> (0) : __assert_fail ("!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2410, __PRETTY_FUNCTION__)); | ||||||
| 2411 | assert(!Ops.empty() && "Cannot get empty add!")((!Ops.empty() && "Cannot get empty add!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty add!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2411, __PRETTY_FUNCTION__)); | ||||||
| 2412 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 2413 | #ifndef NDEBUG | ||||||
| 2414 | Type *ETy = getEffectiveSCEVType(Ops[0]->getType()); | ||||||
| 2415 | for (unsigned i = 1, e = Ops.size(); i != e; ++i) | ||||||
| 2416 | assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVAddExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVAddExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2417, __PRETTY_FUNCTION__)) | ||||||
| 2417 | "SCEVAddExpr operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVAddExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVAddExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2417, __PRETTY_FUNCTION__)); | ||||||
| 2418 | #endif | ||||||
| 2419 | |||||||
| 2420 | // Sort by complexity, this groups all similar expression types together. | ||||||
| 2421 | GroupByComplexity(Ops, &LI, DT); | ||||||
| 2422 | |||||||
| 2423 | Flags = StrengthenNoWrapFlags(this, scAddExpr, Ops, Flags); | ||||||
| 2424 | |||||||
| 2425 | // If there are any constants, fold them together. | ||||||
| 2426 | unsigned Idx = 0; | ||||||
| 2427 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) { | ||||||
| 2428 | ++Idx; | ||||||
| 2429 | assert(Idx < Ops.size())((Idx < Ops.size()) ? static_cast<void> (0) : __assert_fail ("Idx < Ops.size()", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2429, __PRETTY_FUNCTION__)); | ||||||
| 2430 | while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) { | ||||||
| 2431 | // We found two constants, fold them together! | ||||||
| 2432 | Ops[0] = getConstant(LHSC->getAPInt() + RHSC->getAPInt()); | ||||||
| 2433 | if (Ops.size() == 2) return Ops[0]; | ||||||
| 2434 | Ops.erase(Ops.begin()+1); // Erase the folded element | ||||||
| 2435 | LHSC = cast<SCEVConstant>(Ops[0]); | ||||||
| 2436 | } | ||||||
| 2437 | |||||||
| 2438 | // If we are left with a constant zero being added, strip it off. | ||||||
| 2439 | if (LHSC->getValue()->isZero()) { | ||||||
| 2440 | Ops.erase(Ops.begin()); | ||||||
| 2441 | --Idx; | ||||||
| 2442 | } | ||||||
| 2443 | |||||||
| 2444 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 2445 | } | ||||||
| 2446 | |||||||
| 2447 | // Limit recursion calls depth. | ||||||
| 2448 | if (Depth > MaxArithDepth || hasHugeExpression(Ops)) | ||||||
| 2449 | return getOrCreateAddExpr(Ops, Flags); | ||||||
| 2450 | |||||||
| 2451 | // Okay, check to see if the same value occurs in the operand list more than | ||||||
| 2452 | // once. If so, merge them together into an multiply expression. Since we | ||||||
| 2453 | // sorted the list, these values are required to be adjacent. | ||||||
| 2454 | Type *Ty = Ops[0]->getType(); | ||||||
| 2455 | bool FoundMatch = false; | ||||||
| 2456 | for (unsigned i = 0, e = Ops.size(); i != e-1; ++i) | ||||||
| 2457 | if (Ops[i] == Ops[i+1]) { // X + Y + Y --> X + Y*2 | ||||||
| 2458 | // Scan ahead to count how many equal operands there are. | ||||||
| 2459 | unsigned Count = 2; | ||||||
| 2460 | while (i+Count != e && Ops[i+Count] == Ops[i]) | ||||||
| 2461 | ++Count; | ||||||
| 2462 | // Merge the values into a multiply. | ||||||
| 2463 | const SCEV *Scale = getConstant(Ty, Count); | ||||||
| 2464 | const SCEV *Mul = getMulExpr(Scale, Ops[i], SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2465 | if (Ops.size() == Count) | ||||||
| 2466 | return Mul; | ||||||
| 2467 | Ops[i] = Mul; | ||||||
| 2468 | Ops.erase(Ops.begin()+i+1, Ops.begin()+i+Count); | ||||||
| 2469 | --i; e -= Count - 1; | ||||||
| 2470 | FoundMatch = true; | ||||||
| 2471 | } | ||||||
| 2472 | if (FoundMatch) | ||||||
| 2473 | return getAddExpr(Ops, Flags, Depth + 1); | ||||||
| 2474 | |||||||
| 2475 | // Check for truncates. If all the operands are truncated from the same | ||||||
| 2476 | // type, see if factoring out the truncate would permit the result to be | ||||||
| 2477 | // folded. eg., n*trunc(x) + m*trunc(y) --> trunc(trunc(m)*x + trunc(n)*y) | ||||||
| 2478 | // if the contents of the resulting outer trunc fold to something simple. | ||||||
| 2479 | auto FindTruncSrcType = [&]() -> Type * { | ||||||
| 2480 | // We're ultimately looking to fold an addrec of truncs and muls of only | ||||||
| 2481 | // constants and truncs, so if we find any other types of SCEV | ||||||
| 2482 | // as operands of the addrec then we bail and return nullptr here. | ||||||
| 2483 | // Otherwise, we return the type of the operand of a trunc that we find. | ||||||
| 2484 | if (auto *T = dyn_cast<SCEVTruncateExpr>(Ops[Idx])) | ||||||
| 2485 | return T->getOperand()->getType(); | ||||||
| 2486 | if (const auto *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) { | ||||||
| 2487 | const auto *LastOp = Mul->getOperand(Mul->getNumOperands() - 1); | ||||||
| 2488 | if (const auto *T = dyn_cast<SCEVTruncateExpr>(LastOp)) | ||||||
| 2489 | return T->getOperand()->getType(); | ||||||
| 2490 | } | ||||||
| 2491 | return nullptr; | ||||||
| 2492 | }; | ||||||
| 2493 | if (auto *SrcType = FindTruncSrcType()) { | ||||||
| 2494 | SmallVector<const SCEV *, 8> LargeOps; | ||||||
| 2495 | bool Ok = true; | ||||||
| 2496 | // Check all the operands to see if they can be represented in the | ||||||
| 2497 | // source type of the truncate. | ||||||
| 2498 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) { | ||||||
| 2499 | if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Ops[i])) { | ||||||
| 2500 | if (T->getOperand()->getType() != SrcType) { | ||||||
| 2501 | Ok = false; | ||||||
| 2502 | break; | ||||||
| 2503 | } | ||||||
| 2504 | LargeOps.push_back(T->getOperand()); | ||||||
| 2505 | } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) { | ||||||
| 2506 | LargeOps.push_back(getAnyExtendExpr(C, SrcType)); | ||||||
| 2507 | } else if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Ops[i])) { | ||||||
| 2508 | SmallVector<const SCEV *, 8> LargeMulOps; | ||||||
| 2509 | for (unsigned j = 0, f = M->getNumOperands(); j != f && Ok; ++j) { | ||||||
| 2510 | if (const SCEVTruncateExpr *T = | ||||||
| 2511 | dyn_cast<SCEVTruncateExpr>(M->getOperand(j))) { | ||||||
| 2512 | if (T->getOperand()->getType() != SrcType) { | ||||||
| 2513 | Ok = false; | ||||||
| 2514 | break; | ||||||
| 2515 | } | ||||||
| 2516 | LargeMulOps.push_back(T->getOperand()); | ||||||
| 2517 | } else if (const auto *C = dyn_cast<SCEVConstant>(M->getOperand(j))) { | ||||||
| 2518 | LargeMulOps.push_back(getAnyExtendExpr(C, SrcType)); | ||||||
| 2519 | } else { | ||||||
| 2520 | Ok = false; | ||||||
| 2521 | break; | ||||||
| 2522 | } | ||||||
| 2523 | } | ||||||
| 2524 | if (Ok) | ||||||
| 2525 | LargeOps.push_back(getMulExpr(LargeMulOps, SCEV::FlagAnyWrap, Depth + 1)); | ||||||
| 2526 | } else { | ||||||
| 2527 | Ok = false; | ||||||
| 2528 | break; | ||||||
| 2529 | } | ||||||
| 2530 | } | ||||||
| 2531 | if (Ok) { | ||||||
| 2532 | // Evaluate the expression in the larger type. | ||||||
| 2533 | const SCEV *Fold = getAddExpr(LargeOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2534 | // If it folds to something simple, use it. Otherwise, don't. | ||||||
| 2535 | if (isa<SCEVConstant>(Fold) || isa<SCEVUnknown>(Fold)) | ||||||
| 2536 | return getTruncateExpr(Fold, Ty); | ||||||
| 2537 | } | ||||||
| 2538 | } | ||||||
| 2539 | |||||||
| 2540 | // Skip past any other cast SCEVs. | ||||||
| 2541 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddExpr) | ||||||
| 2542 | ++Idx; | ||||||
| 2543 | |||||||
| 2544 | // If there are add operands they would be next. | ||||||
| 2545 | if (Idx < Ops.size()) { | ||||||
| 2546 | bool DeletedAdd = false; | ||||||
| 2547 | while (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[Idx])) { | ||||||
| 2548 | if (Ops.size() > AddOpsInlineThreshold || | ||||||
| 2549 | Add->getNumOperands() > AddOpsInlineThreshold) | ||||||
| 2550 | break; | ||||||
| 2551 | // If we have an add, expand the add operands onto the end of the operands | ||||||
| 2552 | // list. | ||||||
| 2553 | Ops.erase(Ops.begin()+Idx); | ||||||
| 2554 | Ops.append(Add->op_begin(), Add->op_end()); | ||||||
| 2555 | DeletedAdd = true; | ||||||
| 2556 | } | ||||||
| 2557 | |||||||
| 2558 | // If we deleted at least one add, we added operands to the end of the list, | ||||||
| 2559 | // and they are not necessarily sorted. Recurse to resort and resimplify | ||||||
| 2560 | // any operands we just acquired. | ||||||
| 2561 | if (DeletedAdd) | ||||||
| 2562 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2563 | } | ||||||
| 2564 | |||||||
| 2565 | // Skip over the add expression until we get to a multiply. | ||||||
| 2566 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr) | ||||||
| 2567 | ++Idx; | ||||||
| 2568 | |||||||
| 2569 | // Check to see if there are any folding opportunities present with | ||||||
| 2570 | // operands multiplied by constant values. | ||||||
| 2571 | if (Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx])) { | ||||||
| 2572 | uint64_t BitWidth = getTypeSizeInBits(Ty); | ||||||
| 2573 | DenseMap<const SCEV *, APInt> M; | ||||||
| 2574 | SmallVector<const SCEV *, 8> NewOps; | ||||||
| 2575 | APInt AccumulatedConstant(BitWidth, 0); | ||||||
| 2576 | if (CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant, | ||||||
| 2577 | Ops.data(), Ops.size(), | ||||||
| 2578 | APInt(BitWidth, 1), *this)) { | ||||||
| 2579 | struct APIntCompare { | ||||||
| 2580 | bool operator()(const APInt &LHS, const APInt &RHS) const { | ||||||
| 2581 | return LHS.ult(RHS); | ||||||
| 2582 | } | ||||||
| 2583 | }; | ||||||
| 2584 | |||||||
| 2585 | // Some interesting folding opportunity is present, so its worthwhile to | ||||||
| 2586 | // re-generate the operands list. Group the operands by constant scale, | ||||||
| 2587 | // to avoid multiplying by the same constant scale multiple times. | ||||||
| 2588 | std::map<APInt, SmallVector<const SCEV *, 4>, APIntCompare> MulOpLists; | ||||||
| 2589 | for (const SCEV *NewOp : NewOps) | ||||||
| 2590 | MulOpLists[M.find(NewOp)->second].push_back(NewOp); | ||||||
| 2591 | // Re-generate the operands list. | ||||||
| 2592 | Ops.clear(); | ||||||
| 2593 | if (AccumulatedConstant != 0) | ||||||
| 2594 | Ops.push_back(getConstant(AccumulatedConstant)); | ||||||
| 2595 | for (auto &MulOp : MulOpLists) | ||||||
| 2596 | if (MulOp.first != 0) | ||||||
| 2597 | Ops.push_back(getMulExpr( | ||||||
| 2598 | getConstant(MulOp.first), | ||||||
| 2599 | getAddExpr(MulOp.second, SCEV::FlagAnyWrap, Depth + 1), | ||||||
| 2600 | SCEV::FlagAnyWrap, Depth + 1)); | ||||||
| 2601 | if (Ops.empty()) | ||||||
| 2602 | return getZero(Ty); | ||||||
| 2603 | if (Ops.size() == 1) | ||||||
| 2604 | return Ops[0]; | ||||||
| 2605 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2606 | } | ||||||
| 2607 | } | ||||||
| 2608 | |||||||
| 2609 | // If we are adding something to a multiply expression, make sure the | ||||||
| 2610 | // something is not already an operand of the multiply. If so, merge it into | ||||||
| 2611 | // the multiply. | ||||||
| 2612 | for (; Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx]); ++Idx) { | ||||||
| 2613 | const SCEVMulExpr *Mul = cast<SCEVMulExpr>(Ops[Idx]); | ||||||
| 2614 | for (unsigned MulOp = 0, e = Mul->getNumOperands(); MulOp != e; ++MulOp) { | ||||||
| 2615 | const SCEV *MulOpSCEV = Mul->getOperand(MulOp); | ||||||
| 2616 | if (isa<SCEVConstant>(MulOpSCEV)) | ||||||
| 2617 | continue; | ||||||
| 2618 | for (unsigned AddOp = 0, e = Ops.size(); AddOp != e; ++AddOp) | ||||||
| 2619 | if (MulOpSCEV == Ops[AddOp]) { | ||||||
| 2620 | // Fold W + X + (X * Y * Z) --> W + (X * ((Y*Z)+1)) | ||||||
| 2621 | const SCEV *InnerMul = Mul->getOperand(MulOp == 0); | ||||||
| 2622 | if (Mul->getNumOperands() != 2) { | ||||||
| 2623 | // If the multiply has more than two operands, we must get the | ||||||
| 2624 | // Y*Z term. | ||||||
| 2625 | SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(), | ||||||
| 2626 | Mul->op_begin()+MulOp); | ||||||
| 2627 | MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end()); | ||||||
| 2628 | InnerMul = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2629 | } | ||||||
| 2630 | SmallVector<const SCEV *, 2> TwoOps = {getOne(Ty), InnerMul}; | ||||||
| 2631 | const SCEV *AddOne = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2632 | const SCEV *OuterMul = getMulExpr(AddOne, MulOpSCEV, | ||||||
| 2633 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2634 | if (Ops.size() == 2) return OuterMul; | ||||||
| 2635 | if (AddOp < Idx) { | ||||||
| 2636 | Ops.erase(Ops.begin()+AddOp); | ||||||
| 2637 | Ops.erase(Ops.begin()+Idx-1); | ||||||
| 2638 | } else { | ||||||
| 2639 | Ops.erase(Ops.begin()+Idx); | ||||||
| 2640 | Ops.erase(Ops.begin()+AddOp-1); | ||||||
| 2641 | } | ||||||
| 2642 | Ops.push_back(OuterMul); | ||||||
| 2643 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2644 | } | ||||||
| 2645 | |||||||
| 2646 | // Check this multiply against other multiplies being added together. | ||||||
| 2647 | for (unsigned OtherMulIdx = Idx+1; | ||||||
| 2648 | OtherMulIdx < Ops.size() && isa<SCEVMulExpr>(Ops[OtherMulIdx]); | ||||||
| 2649 | ++OtherMulIdx) { | ||||||
| 2650 | const SCEVMulExpr *OtherMul = cast<SCEVMulExpr>(Ops[OtherMulIdx]); | ||||||
| 2651 | // If MulOp occurs in OtherMul, we can fold the two multiplies | ||||||
| 2652 | // together. | ||||||
| 2653 | for (unsigned OMulOp = 0, e = OtherMul->getNumOperands(); | ||||||
| 2654 | OMulOp != e; ++OMulOp) | ||||||
| 2655 | if (OtherMul->getOperand(OMulOp) == MulOpSCEV) { | ||||||
| 2656 | // Fold X + (A*B*C) + (A*D*E) --> X + (A*(B*C+D*E)) | ||||||
| 2657 | const SCEV *InnerMul1 = Mul->getOperand(MulOp == 0); | ||||||
| 2658 | if (Mul->getNumOperands() != 2) { | ||||||
| 2659 | SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(), | ||||||
| 2660 | Mul->op_begin()+MulOp); | ||||||
| 2661 | MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end()); | ||||||
| 2662 | InnerMul1 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2663 | } | ||||||
| 2664 | const SCEV *InnerMul2 = OtherMul->getOperand(OMulOp == 0); | ||||||
| 2665 | if (OtherMul->getNumOperands() != 2) { | ||||||
| 2666 | SmallVector<const SCEV *, 4> MulOps(OtherMul->op_begin(), | ||||||
| 2667 | OtherMul->op_begin()+OMulOp); | ||||||
| 2668 | MulOps.append(OtherMul->op_begin()+OMulOp+1, OtherMul->op_end()); | ||||||
| 2669 | InnerMul2 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2670 | } | ||||||
| 2671 | SmallVector<const SCEV *, 2> TwoOps = {InnerMul1, InnerMul2}; | ||||||
| 2672 | const SCEV *InnerMulSum = | ||||||
| 2673 | getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2674 | const SCEV *OuterMul = getMulExpr(MulOpSCEV, InnerMulSum, | ||||||
| 2675 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2676 | if (Ops.size() == 2) return OuterMul; | ||||||
| 2677 | Ops.erase(Ops.begin()+Idx); | ||||||
| 2678 | Ops.erase(Ops.begin()+OtherMulIdx-1); | ||||||
| 2679 | Ops.push_back(OuterMul); | ||||||
| 2680 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2681 | } | ||||||
| 2682 | } | ||||||
| 2683 | } | ||||||
| 2684 | } | ||||||
| 2685 | |||||||
| 2686 | // If there are any add recurrences in the operands list, see if any other | ||||||
| 2687 | // added values are loop invariant. If so, we can fold them into the | ||||||
| 2688 | // recurrence. | ||||||
| 2689 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr) | ||||||
| 2690 | ++Idx; | ||||||
| 2691 | |||||||
| 2692 | // Scan over all recurrences, trying to fold loop invariants into them. | ||||||
| 2693 | for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) { | ||||||
| 2694 | // Scan all of the other operands to this add and add them to the vector if | ||||||
| 2695 | // they are loop invariant w.r.t. the recurrence. | ||||||
| 2696 | SmallVector<const SCEV *, 8> LIOps; | ||||||
| 2697 | const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]); | ||||||
| 2698 | const Loop *AddRecLoop = AddRec->getLoop(); | ||||||
| 2699 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
| 2700 | if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) { | ||||||
| 2701 | LIOps.push_back(Ops[i]); | ||||||
| 2702 | Ops.erase(Ops.begin()+i); | ||||||
| 2703 | --i; --e; | ||||||
| 2704 | } | ||||||
| 2705 | |||||||
| 2706 | // If we found some loop invariants, fold them into the recurrence. | ||||||
| 2707 | if (!LIOps.empty()) { | ||||||
| 2708 | // NLI + LI + {Start,+,Step} --> NLI + {LI+Start,+,Step} | ||||||
| 2709 | LIOps.push_back(AddRec->getStart()); | ||||||
| 2710 | |||||||
| 2711 | SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(), | ||||||
| 2712 | AddRec->op_end()); | ||||||
| 2713 | // This follows from the fact that the no-wrap flags on the outer add | ||||||
| 2714 | // expression are applicable on the 0th iteration, when the add recurrence | ||||||
| 2715 | // will be equal to its start value. | ||||||
| 2716 | AddRecOps[0] = getAddExpr(LIOps, Flags, Depth + 1); | ||||||
| 2717 | |||||||
| 2718 | // Build the new addrec. Propagate the NUW and NSW flags if both the | ||||||
| 2719 | // outer add and the inner addrec are guaranteed to have no overflow. | ||||||
| 2720 | // Always propagate NW. | ||||||
| 2721 | Flags = AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW)); | ||||||
| 2722 | const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, Flags); | ||||||
| 2723 | |||||||
| 2724 | // If all of the other operands were loop invariant, we are done. | ||||||
| 2725 | if (Ops.size() == 1) return NewRec; | ||||||
| 2726 | |||||||
| 2727 | // Otherwise, add the folded AddRec by the non-invariant parts. | ||||||
| 2728 | for (unsigned i = 0;; ++i) | ||||||
| 2729 | if (Ops[i] == AddRec) { | ||||||
| 2730 | Ops[i] = NewRec; | ||||||
| 2731 | break; | ||||||
| 2732 | } | ||||||
| 2733 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2734 | } | ||||||
| 2735 | |||||||
| 2736 | // Okay, if there weren't any loop invariants to be folded, check to see if | ||||||
| 2737 | // there are multiple AddRec's with the same loop induction variable being | ||||||
| 2738 | // added together. If so, we can fold them. | ||||||
| 2739 | for (unsigned OtherIdx = Idx+1; | ||||||
| 2740 | OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
| 2741 | ++OtherIdx) { | ||||||
| 2742 | // We expect the AddRecExpr's to be sorted in reverse dominance order, | ||||||
| 2743 | // so that the 1st found AddRecExpr is dominated by all others. | ||||||
| 2744 | assert(DT.dominates(((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2747, __PRETTY_FUNCTION__)) | ||||||
| 2745 | cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(),((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2747, __PRETTY_FUNCTION__)) | ||||||
| 2746 | AddRec->getLoop()->getHeader()) &&((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2747, __PRETTY_FUNCTION__)) | ||||||
| 2747 | "AddRecExprs are not sorted in reverse dominance order?")((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])-> getLoop()->getHeader(), AddRec->getLoop()->getHeader ()) && "AddRecExprs are not sorted in reverse dominance order?" ) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2747, __PRETTY_FUNCTION__)); | ||||||
| 2748 | if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) { | ||||||
| 2749 | // Other + {A,+,B}<L> + {C,+,D}<L> --> Other + {A+C,+,B+D}<L> | ||||||
| 2750 | SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(), | ||||||
| 2751 | AddRec->op_end()); | ||||||
| 2752 | for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
| 2753 | ++OtherIdx) { | ||||||
| 2754 | const auto *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
| 2755 | if (OtherAddRec->getLoop() == AddRecLoop) { | ||||||
| 2756 | for (unsigned i = 0, e = OtherAddRec->getNumOperands(); | ||||||
| 2757 | i != e; ++i) { | ||||||
| 2758 | if (i >= AddRecOps.size()) { | ||||||
| 2759 | AddRecOps.append(OtherAddRec->op_begin()+i, | ||||||
| 2760 | OtherAddRec->op_end()); | ||||||
| 2761 | break; | ||||||
| 2762 | } | ||||||
| 2763 | SmallVector<const SCEV *, 2> TwoOps = { | ||||||
| 2764 | AddRecOps[i], OtherAddRec->getOperand(i)}; | ||||||
| 2765 | AddRecOps[i] = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2766 | } | ||||||
| 2767 | Ops.erase(Ops.begin() + OtherIdx); --OtherIdx; | ||||||
| 2768 | } | ||||||
| 2769 | } | ||||||
| 2770 | // Step size has changed, so we cannot guarantee no self-wraparound. | ||||||
| 2771 | Ops[Idx] = getAddRecExpr(AddRecOps, AddRecLoop, SCEV::FlagAnyWrap); | ||||||
| 2772 | return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2773 | } | ||||||
| 2774 | } | ||||||
| 2775 | |||||||
| 2776 | // Otherwise couldn't fold anything into this recurrence. Move onto the | ||||||
| 2777 | // next one. | ||||||
| 2778 | } | ||||||
| 2779 | |||||||
| 2780 | // Okay, it looks like we really DO need an add expr. Check to see if we | ||||||
| 2781 | // already have one, otherwise create a new one. | ||||||
| 2782 | return getOrCreateAddExpr(Ops, Flags); | ||||||
| 2783 | } | ||||||
| 2784 | |||||||
| 2785 | const SCEV * | ||||||
| 2786 | ScalarEvolution::getOrCreateAddExpr(ArrayRef<const SCEV *> Ops, | ||||||
| 2787 | SCEV::NoWrapFlags Flags) { | ||||||
| 2788 | FoldingSetNodeID ID; | ||||||
| 2789 | ID.AddInteger(scAddExpr); | ||||||
| 2790 | for (const SCEV *Op : Ops) | ||||||
| 2791 | ID.AddPointer(Op); | ||||||
| 2792 | void *IP = nullptr; | ||||||
| 2793 | SCEVAddExpr *S = | ||||||
| 2794 | static_cast<SCEVAddExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
| 2795 | if (!S) { | ||||||
| 2796 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
| 2797 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
| 2798 | S = new (SCEVAllocator) | ||||||
| 2799 | SCEVAddExpr(ID.Intern(SCEVAllocator), O, Ops.size()); | ||||||
| 2800 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 2801 | addToLoopUseLists(S); | ||||||
| 2802 | } | ||||||
| 2803 | S->setNoWrapFlags(Flags); | ||||||
| 2804 | return S; | ||||||
| 2805 | } | ||||||
| 2806 | |||||||
| 2807 | const SCEV * | ||||||
| 2808 | ScalarEvolution::getOrCreateAddRecExpr(ArrayRef<const SCEV *> Ops, | ||||||
| 2809 | const Loop *L, SCEV::NoWrapFlags Flags) { | ||||||
| 2810 | FoldingSetNodeID ID; | ||||||
| 2811 | ID.AddInteger(scAddRecExpr); | ||||||
| 2812 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
| 2813 | ID.AddPointer(Ops[i]); | ||||||
| 2814 | ID.AddPointer(L); | ||||||
| 2815 | void *IP = nullptr; | ||||||
| 2816 | SCEVAddRecExpr *S = | ||||||
| 2817 | static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
| 2818 | if (!S) { | ||||||
| 2819 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
| 2820 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
| 2821 | S = new (SCEVAllocator) | ||||||
| 2822 | SCEVAddRecExpr(ID.Intern(SCEVAllocator), O, Ops.size(), L); | ||||||
| 2823 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 2824 | addToLoopUseLists(S); | ||||||
| 2825 | } | ||||||
| 2826 | S->setNoWrapFlags(Flags); | ||||||
| 2827 | return S; | ||||||
| 2828 | } | ||||||
| 2829 | |||||||
| 2830 | const SCEV * | ||||||
| 2831 | ScalarEvolution::getOrCreateMulExpr(ArrayRef<const SCEV *> Ops, | ||||||
| 2832 | SCEV::NoWrapFlags Flags) { | ||||||
| 2833 | FoldingSetNodeID ID; | ||||||
| 2834 | ID.AddInteger(scMulExpr); | ||||||
| 2835 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
| 2836 | ID.AddPointer(Ops[i]); | ||||||
| 2837 | void *IP = nullptr; | ||||||
| 2838 | SCEVMulExpr *S = | ||||||
| 2839 | static_cast<SCEVMulExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP)); | ||||||
| 2840 | if (!S) { | ||||||
| 2841 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
| 2842 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
| 2843 | S = new (SCEVAllocator) SCEVMulExpr(ID.Intern(SCEVAllocator), | ||||||
| 2844 | O, Ops.size()); | ||||||
| 2845 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 2846 | addToLoopUseLists(S); | ||||||
| 2847 | } | ||||||
| 2848 | S->setNoWrapFlags(Flags); | ||||||
| 2849 | return S; | ||||||
| 2850 | } | ||||||
| 2851 | |||||||
| 2852 | static uint64_t umul_ov(uint64_t i, uint64_t j, bool &Overflow) { | ||||||
| 2853 | uint64_t k = i*j; | ||||||
| 2854 | if (j > 1 && k / j != i) Overflow = true; | ||||||
| 2855 | return k; | ||||||
| 2856 | } | ||||||
| 2857 | |||||||
| 2858 | /// Compute the result of "n choose k", the binomial coefficient. If an | ||||||
| 2859 | /// intermediate computation overflows, Overflow will be set and the return will | ||||||
| 2860 | /// be garbage. Overflow is not cleared on absence of overflow. | ||||||
| 2861 | static uint64_t Choose(uint64_t n, uint64_t k, bool &Overflow) { | ||||||
| 2862 | // We use the multiplicative formula: | ||||||
| 2863 | // n(n-1)(n-2)...(n-(k-1)) / k(k-1)(k-2)...1 . | ||||||
| 2864 | // At each iteration, we take the n-th term of the numeral and divide by the | ||||||
| 2865 | // (k-n)th term of the denominator. This division will always produce an | ||||||
| 2866 | // integral result, and helps reduce the chance of overflow in the | ||||||
| 2867 | // intermediate computations. However, we can still overflow even when the | ||||||
| 2868 | // final result would fit. | ||||||
| 2869 | |||||||
| 2870 | if (n == 0 || n == k) return 1; | ||||||
| 2871 | if (k > n) return 0; | ||||||
| 2872 | |||||||
| 2873 | if (k > n/2) | ||||||
| 2874 | k = n-k; | ||||||
| 2875 | |||||||
| 2876 | uint64_t r = 1; | ||||||
| 2877 | for (uint64_t i = 1; i <= k; ++i) { | ||||||
| 2878 | r = umul_ov(r, n-(i-1), Overflow); | ||||||
| 2879 | r /= i; | ||||||
| 2880 | } | ||||||
| 2881 | return r; | ||||||
| 2882 | } | ||||||
| 2883 | |||||||
| 2884 | /// Determine if any of the operands in this SCEV are a constant or if | ||||||
| 2885 | /// any of the add or multiply expressions in this SCEV contain a constant. | ||||||
| 2886 | static bool containsConstantInAddMulChain(const SCEV *StartExpr) { | ||||||
| 2887 | struct FindConstantInAddMulChain { | ||||||
| 2888 | bool FoundConstant = false; | ||||||
| 2889 | |||||||
| 2890 | bool follow(const SCEV *S) { | ||||||
| 2891 | FoundConstant |= isa<SCEVConstant>(S); | ||||||
| 2892 | return isa<SCEVAddExpr>(S) || isa<SCEVMulExpr>(S); | ||||||
| 2893 | } | ||||||
| 2894 | |||||||
| 2895 | bool isDone() const { | ||||||
| 2896 | return FoundConstant; | ||||||
| 2897 | } | ||||||
| 2898 | }; | ||||||
| 2899 | |||||||
| 2900 | FindConstantInAddMulChain F; | ||||||
| 2901 | SCEVTraversal<FindConstantInAddMulChain> ST(F); | ||||||
| 2902 | ST.visitAll(StartExpr); | ||||||
| 2903 | return F.FoundConstant; | ||||||
| 2904 | } | ||||||
| 2905 | |||||||
| 2906 | /// Get a canonical multiply expression, or something simpler if possible. | ||||||
| 2907 | const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops, | ||||||
| 2908 | SCEV::NoWrapFlags Flags, | ||||||
| 2909 | unsigned Depth) { | ||||||
| 2910 | assert(Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) &&((Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && "only nuw or nsw allowed") ? static_cast<void> (0) : __assert_fail ("Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2911, __PRETTY_FUNCTION__)) | ||||||
| 2911 | "only nuw or nsw allowed")((Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && "only nuw or nsw allowed") ? static_cast<void> (0) : __assert_fail ("Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) && \"only nuw or nsw allowed\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2911, __PRETTY_FUNCTION__)); | ||||||
| 2912 | assert(!Ops.empty() && "Cannot get empty mul!")((!Ops.empty() && "Cannot get empty mul!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty mul!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2912, __PRETTY_FUNCTION__)); | ||||||
| 2913 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 2914 | #ifndef NDEBUG | ||||||
| 2915 | Type *ETy = getEffectiveSCEVType(Ops[0]->getType()); | ||||||
| 2916 | for (unsigned i = 1, e = Ops.size(); i != e; ++i) | ||||||
| 2917 | assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVMulExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVMulExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2918, __PRETTY_FUNCTION__)) | ||||||
| 2918 | "SCEVMulExpr operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "SCEVMulExpr operand types don't match!") ? static_cast<void > (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVMulExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 2918, __PRETTY_FUNCTION__)); | ||||||
| 2919 | #endif | ||||||
| 2920 | |||||||
| 2921 | // Sort by complexity, this groups all similar expression types together. | ||||||
| 2922 | GroupByComplexity(Ops, &LI, DT); | ||||||
| 2923 | |||||||
| 2924 | Flags = StrengthenNoWrapFlags(this, scMulExpr, Ops, Flags); | ||||||
| 2925 | |||||||
| 2926 | // Limit recursion calls depth. | ||||||
| 2927 | if (Depth > MaxArithDepth || hasHugeExpression(Ops)) | ||||||
| 2928 | return getOrCreateMulExpr(Ops, Flags); | ||||||
| 2929 | |||||||
| 2930 | // If there are any constants, fold them together. | ||||||
| 2931 | unsigned Idx = 0; | ||||||
| 2932 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) { | ||||||
| 2933 | |||||||
| 2934 | if (Ops.size() == 2) | ||||||
| 2935 | // C1*(C2+V) -> C1*C2 + C1*V | ||||||
| 2936 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) | ||||||
| 2937 | // If any of Add's ops are Adds or Muls with a constant, apply this | ||||||
| 2938 | // transformation as well. | ||||||
| 2939 | // | ||||||
| 2940 | // TODO: There are some cases where this transformation is not | ||||||
| 2941 | // profitable; for example, Add = (C0 + X) * Y + Z. Maybe the scope of | ||||||
| 2942 | // this transformation should be narrowed down. | ||||||
| 2943 | if (Add->getNumOperands() == 2 && containsConstantInAddMulChain(Add)) | ||||||
| 2944 | return getAddExpr(getMulExpr(LHSC, Add->getOperand(0), | ||||||
| 2945 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
| 2946 | getMulExpr(LHSC, Add->getOperand(1), | ||||||
| 2947 | SCEV::FlagAnyWrap, Depth + 1), | ||||||
| 2948 | SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2949 | |||||||
| 2950 | ++Idx; | ||||||
| 2951 | while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) { | ||||||
| 2952 | // We found two constants, fold them together! | ||||||
| 2953 | ConstantInt *Fold = | ||||||
| 2954 | ConstantInt::get(getContext(), LHSC->getAPInt() * RHSC->getAPInt()); | ||||||
| 2955 | Ops[0] = getConstant(Fold); | ||||||
| 2956 | Ops.erase(Ops.begin()+1); // Erase the folded element | ||||||
| 2957 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 2958 | LHSC = cast<SCEVConstant>(Ops[0]); | ||||||
| 2959 | } | ||||||
| 2960 | |||||||
| 2961 | // If we are left with a constant one being multiplied, strip it off. | ||||||
| 2962 | if (cast<SCEVConstant>(Ops[0])->getValue()->isOne()) { | ||||||
| 2963 | Ops.erase(Ops.begin()); | ||||||
| 2964 | --Idx; | ||||||
| 2965 | } else if (cast<SCEVConstant>(Ops[0])->getValue()->isZero()) { | ||||||
| 2966 | // If we have a multiply of zero, it will always be zero. | ||||||
| 2967 | return Ops[0]; | ||||||
| 2968 | } else if (Ops[0]->isAllOnesValue()) { | ||||||
| 2969 | // If we have a mul by -1 of an add, try distributing the -1 among the | ||||||
| 2970 | // add operands. | ||||||
| 2971 | if (Ops.size() == 2) { | ||||||
| 2972 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) { | ||||||
| 2973 | SmallVector<const SCEV *, 4> NewOps; | ||||||
| 2974 | bool AnyFolded = false; | ||||||
| 2975 | for (const SCEV *AddOp : Add->operands()) { | ||||||
| 2976 | const SCEV *Mul = getMulExpr(Ops[0], AddOp, SCEV::FlagAnyWrap, | ||||||
| 2977 | Depth + 1); | ||||||
| 2978 | if (!isa<SCEVMulExpr>(Mul)) AnyFolded = true; | ||||||
| 2979 | NewOps.push_back(Mul); | ||||||
| 2980 | } | ||||||
| 2981 | if (AnyFolded) | ||||||
| 2982 | return getAddExpr(NewOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 2983 | } else if (const auto *AddRec = dyn_cast<SCEVAddRecExpr>(Ops[1])) { | ||||||
| 2984 | // Negation preserves a recurrence's no self-wrap property. | ||||||
| 2985 | SmallVector<const SCEV *, 4> Operands; | ||||||
| 2986 | for (const SCEV *AddRecOp : AddRec->operands()) | ||||||
| 2987 | Operands.push_back(getMulExpr(Ops[0], AddRecOp, SCEV::FlagAnyWrap, | ||||||
| 2988 | Depth + 1)); | ||||||
| 2989 | |||||||
| 2990 | return getAddRecExpr(Operands, AddRec->getLoop(), | ||||||
| 2991 | AddRec->getNoWrapFlags(SCEV::FlagNW)); | ||||||
| 2992 | } | ||||||
| 2993 | } | ||||||
| 2994 | } | ||||||
| 2995 | |||||||
| 2996 | if (Ops.size() == 1) | ||||||
| 2997 | return Ops[0]; | ||||||
| 2998 | } | ||||||
| 2999 | |||||||
| 3000 | // Skip over the add expression until we get to a multiply. | ||||||
| 3001 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr) | ||||||
| 3002 | ++Idx; | ||||||
| 3003 | |||||||
| 3004 | // If there are mul operands inline them all into this expression. | ||||||
| 3005 | if (Idx < Ops.size()) { | ||||||
| 3006 | bool DeletedMul = false; | ||||||
| 3007 | while (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) { | ||||||
| 3008 | if (Ops.size() > MulOpsInlineThreshold) | ||||||
| 3009 | break; | ||||||
| 3010 | // If we have an mul, expand the mul operands onto the end of the | ||||||
| 3011 | // operands list. | ||||||
| 3012 | Ops.erase(Ops.begin()+Idx); | ||||||
| 3013 | Ops.append(Mul->op_begin(), Mul->op_end()); | ||||||
| 3014 | DeletedMul = true; | ||||||
| 3015 | } | ||||||
| 3016 | |||||||
| 3017 | // If we deleted at least one mul, we added operands to the end of the | ||||||
| 3018 | // list, and they are not necessarily sorted. Recurse to resort and | ||||||
| 3019 | // resimplify any operands we just acquired. | ||||||
| 3020 | if (DeletedMul) | ||||||
| 3021 | return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 3022 | } | ||||||
| 3023 | |||||||
| 3024 | // If there are any add recurrences in the operands list, see if any other | ||||||
| 3025 | // added values are loop invariant. If so, we can fold them into the | ||||||
| 3026 | // recurrence. | ||||||
| 3027 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr) | ||||||
| 3028 | ++Idx; | ||||||
| 3029 | |||||||
| 3030 | // Scan over all recurrences, trying to fold loop invariants into them. | ||||||
| 3031 | for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) { | ||||||
| 3032 | // Scan all of the other operands to this mul and add them to the vector | ||||||
| 3033 | // if they are loop invariant w.r.t. the recurrence. | ||||||
| 3034 | SmallVector<const SCEV *, 8> LIOps; | ||||||
| 3035 | const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]); | ||||||
| 3036 | const Loop *AddRecLoop = AddRec->getLoop(); | ||||||
| 3037 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
| 3038 | if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) { | ||||||
| 3039 | LIOps.push_back(Ops[i]); | ||||||
| 3040 | Ops.erase(Ops.begin()+i); | ||||||
| 3041 | --i; --e; | ||||||
| 3042 | } | ||||||
| 3043 | |||||||
| 3044 | // If we found some loop invariants, fold them into the recurrence. | ||||||
| 3045 | if (!LIOps.empty()) { | ||||||
| 3046 | // NLI * LI * {Start,+,Step} --> NLI * {LI*Start,+,LI*Step} | ||||||
| 3047 | SmallVector<const SCEV *, 4> NewOps; | ||||||
| 3048 | NewOps.reserve(AddRec->getNumOperands()); | ||||||
| 3049 | const SCEV *Scale = getMulExpr(LIOps, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 3050 | for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) | ||||||
| 3051 | NewOps.push_back(getMulExpr(Scale, AddRec->getOperand(i), | ||||||
| 3052 | SCEV::FlagAnyWrap, Depth + 1)); | ||||||
| 3053 | |||||||
| 3054 | // Build the new addrec. Propagate the NUW and NSW flags if both the | ||||||
| 3055 | // outer mul and the inner addrec are guaranteed to have no overflow. | ||||||
| 3056 | // | ||||||
| 3057 | // No self-wrap cannot be guaranteed after changing the step size, but | ||||||
| 3058 | // will be inferred if either NUW or NSW is true. | ||||||
| 3059 | Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW)); | ||||||
| 3060 | const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags); | ||||||
| 3061 | |||||||
| 3062 | // If all of the other operands were loop invariant, we are done. | ||||||
| 3063 | if (Ops.size() == 1) return NewRec; | ||||||
| 3064 | |||||||
| 3065 | // Otherwise, multiply the folded AddRec by the non-invariant parts. | ||||||
| 3066 | for (unsigned i = 0;; ++i) | ||||||
| 3067 | if (Ops[i] == AddRec) { | ||||||
| 3068 | Ops[i] = NewRec; | ||||||
| 3069 | break; | ||||||
| 3070 | } | ||||||
| 3071 | return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 3072 | } | ||||||
| 3073 | |||||||
| 3074 | // Okay, if there weren't any loop invariants to be folded, check to see | ||||||
| 3075 | // if there are multiple AddRec's with the same loop induction variable | ||||||
| 3076 | // being multiplied together. If so, we can fold them. | ||||||
| 3077 | |||||||
| 3078 | // {A1,+,A2,+,...,+,An}<L> * {B1,+,B2,+,...,+,Bn}<L> | ||||||
| 3079 | // = {x=1 in [ sum y=x..2x [ sum z=max(y-x, y-n)..min(x,n) [ | ||||||
| 3080 | // choose(x, 2x)*choose(2x-y, x-z)*A_{y-z}*B_z | ||||||
| 3081 | // ]]],+,...up to x=2n}. | ||||||
| 3082 | // Note that the arguments to choose() are always integers with values | ||||||
| 3083 | // known at compile time, never SCEV objects. | ||||||
| 3084 | // | ||||||
| 3085 | // The implementation avoids pointless extra computations when the two | ||||||
| 3086 | // addrec's are of different length (mathematically, it's equivalent to | ||||||
| 3087 | // an infinite stream of zeros on the right). | ||||||
| 3088 | bool OpsModified = false; | ||||||
| 3089 | for (unsigned OtherIdx = Idx+1; | ||||||
| 3090 | OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
| 3091 | ++OtherIdx) { | ||||||
| 3092 | const SCEVAddRecExpr *OtherAddRec = | ||||||
| 3093 | dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]); | ||||||
| 3094 | if (!OtherAddRec || OtherAddRec->getLoop() != AddRecLoop) | ||||||
| 3095 | continue; | ||||||
| 3096 | |||||||
| 3097 | // Limit max number of arguments to avoid creation of unreasonably big | ||||||
| 3098 | // SCEVAddRecs with very complex operands. | ||||||
| 3099 | if (AddRec->getNumOperands() + OtherAddRec->getNumOperands() - 1 > | ||||||
| 3100 | MaxAddRecSize || isHugeExpression(AddRec) || | ||||||
| 3101 | isHugeExpression(OtherAddRec)) | ||||||
| 3102 | continue; | ||||||
| 3103 | |||||||
| 3104 | bool Overflow = false; | ||||||
| 3105 | Type *Ty = AddRec->getType(); | ||||||
| 3106 | bool LargerThan64Bits = getTypeSizeInBits(Ty) > 64; | ||||||
| 3107 | SmallVector<const SCEV*, 7> AddRecOps; | ||||||
| 3108 | for (int x = 0, xe = AddRec->getNumOperands() + | ||||||
| 3109 | OtherAddRec->getNumOperands() - 1; x != xe && !Overflow; ++x) { | ||||||
| 3110 | SmallVector <const SCEV *, 7> SumOps; | ||||||
| 3111 | for (int y = x, ye = 2*x+1; y != ye && !Overflow; ++y) { | ||||||
| 3112 | uint64_t Coeff1 = Choose(x, 2*x - y, Overflow); | ||||||
| 3113 | for (int z = std::max(y-x, y-(int)AddRec->getNumOperands()+1), | ||||||
| 3114 | ze = std::min(x+1, (int)OtherAddRec->getNumOperands()); | ||||||
| 3115 | z < ze && !Overflow; ++z) { | ||||||
| 3116 | uint64_t Coeff2 = Choose(2*x - y, x-z, Overflow); | ||||||
| 3117 | uint64_t Coeff; | ||||||
| 3118 | if (LargerThan64Bits) | ||||||
| 3119 | Coeff = umul_ov(Coeff1, Coeff2, Overflow); | ||||||
| 3120 | else | ||||||
| 3121 | Coeff = Coeff1*Coeff2; | ||||||
| 3122 | const SCEV *CoeffTerm = getConstant(Ty, Coeff); | ||||||
| 3123 | const SCEV *Term1 = AddRec->getOperand(y-z); | ||||||
| 3124 | const SCEV *Term2 = OtherAddRec->getOperand(z); | ||||||
| 3125 | SumOps.push_back(getMulExpr(CoeffTerm, Term1, Term2, | ||||||
| 3126 | SCEV::FlagAnyWrap, Depth + 1)); | ||||||
| 3127 | } | ||||||
| 3128 | } | ||||||
| 3129 | if (SumOps.empty()) | ||||||
| 3130 | SumOps.push_back(getZero(Ty)); | ||||||
| 3131 | AddRecOps.push_back(getAddExpr(SumOps, SCEV::FlagAnyWrap, Depth + 1)); | ||||||
| 3132 | } | ||||||
| 3133 | if (!Overflow) { | ||||||
| 3134 | const SCEV *NewAddRec = getAddRecExpr(AddRecOps, AddRecLoop, | ||||||
| 3135 | SCEV::FlagAnyWrap); | ||||||
| 3136 | if (Ops.size() == 2) return NewAddRec; | ||||||
| 3137 | Ops[Idx] = NewAddRec; | ||||||
| 3138 | Ops.erase(Ops.begin() + OtherIdx); --OtherIdx; | ||||||
| 3139 | OpsModified = true; | ||||||
| 3140 | AddRec = dyn_cast<SCEVAddRecExpr>(NewAddRec); | ||||||
| 3141 | if (!AddRec) | ||||||
| 3142 | break; | ||||||
| 3143 | } | ||||||
| 3144 | } | ||||||
| 3145 | if (OpsModified) | ||||||
| 3146 | return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1); | ||||||
| 3147 | |||||||
| 3148 | // Otherwise couldn't fold anything into this recurrence. Move onto the | ||||||
| 3149 | // next one. | ||||||
| 3150 | } | ||||||
| 3151 | |||||||
| 3152 | // Okay, it looks like we really DO need an mul expr. Check to see if we | ||||||
| 3153 | // already have one, otherwise create a new one. | ||||||
| 3154 | return getOrCreateMulExpr(Ops, Flags); | ||||||
| 3155 | } | ||||||
| 3156 | |||||||
| 3157 | /// Represents an unsigned remainder expression based on unsigned division. | ||||||
| 3158 | const SCEV *ScalarEvolution::getURemExpr(const SCEV *LHS, | ||||||
| 3159 | const SCEV *RHS) { | ||||||
| 3160 | assert(getEffectiveSCEVType(LHS->getType()) ==((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVURemExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3162, __PRETTY_FUNCTION__)) | ||||||
| 3161 | getEffectiveSCEVType(RHS->getType()) &&((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVURemExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3162, __PRETTY_FUNCTION__)) | ||||||
| 3162 | "SCEVURemExpr operand types don't match!")((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVURemExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3162, __PRETTY_FUNCTION__)); | ||||||
| 3163 | |||||||
| 3164 | // Short-circuit easy cases | ||||||
| 3165 | if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) { | ||||||
| 3166 | // If constant is one, the result is trivial | ||||||
| 3167 | if (RHSC->getValue()->isOne()) | ||||||
| 3168 | return getZero(LHS->getType()); // X urem 1 --> 0 | ||||||
| 3169 | |||||||
| 3170 | // If constant is a power of two, fold into a zext(trunc(LHS)). | ||||||
| 3171 | if (RHSC->getAPInt().isPowerOf2()) { | ||||||
| 3172 | Type *FullTy = LHS->getType(); | ||||||
| 3173 | Type *TruncTy = | ||||||
| 3174 | IntegerType::get(getContext(), RHSC->getAPInt().logBase2()); | ||||||
| 3175 | return getZeroExtendExpr(getTruncateExpr(LHS, TruncTy), FullTy); | ||||||
| 3176 | } | ||||||
| 3177 | } | ||||||
| 3178 | |||||||
| 3179 | // Fallback to %a == %x urem %y == %x -<nuw> ((%x udiv %y) *<nuw> %y) | ||||||
| 3180 | const SCEV *UDiv = getUDivExpr(LHS, RHS); | ||||||
| 3181 | const SCEV *Mult = getMulExpr(UDiv, RHS, SCEV::FlagNUW); | ||||||
| 3182 | return getMinusSCEV(LHS, Mult, SCEV::FlagNUW); | ||||||
| 3183 | } | ||||||
| 3184 | |||||||
| 3185 | /// Get a canonical unsigned division expression, or something simpler if | ||||||
| 3186 | /// possible. | ||||||
| 3187 | const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS, | ||||||
| 3188 | const SCEV *RHS) { | ||||||
| 3189 | assert(getEffectiveSCEVType(LHS->getType()) ==((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVUDivExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3191, __PRETTY_FUNCTION__)) | ||||||
| 3190 | getEffectiveSCEVType(RHS->getType()) &&((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVUDivExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3191, __PRETTY_FUNCTION__)) | ||||||
| 3191 | "SCEVUDivExpr operand types don't match!")((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType (RHS->getType()) && "SCEVUDivExpr operand types don't match!" ) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3191, __PRETTY_FUNCTION__)); | ||||||
| 3192 | |||||||
| 3193 | if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) { | ||||||
| 3194 | if (RHSC->getValue()->isOne()) | ||||||
| 3195 | return LHS; // X udiv 1 --> x | ||||||
| 3196 | // If the denominator is zero, the result of the udiv is undefined. Don't | ||||||
| 3197 | // try to analyze it, because the resolution chosen here may differ from | ||||||
| 3198 | // the resolution chosen in other parts of the compiler. | ||||||
| 3199 | if (!RHSC->getValue()->isZero()) { | ||||||
| 3200 | // Determine if the division can be folded into the operands of | ||||||
| 3201 | // its operands. | ||||||
| 3202 | // TODO: Generalize this to non-constants by using known-bits information. | ||||||
| 3203 | Type *Ty = LHS->getType(); | ||||||
| 3204 | unsigned LZ = RHSC->getAPInt().countLeadingZeros(); | ||||||
| 3205 | unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ - 1; | ||||||
| 3206 | // For non-power-of-two values, effectively round the value up to the | ||||||
| 3207 | // nearest power of two. | ||||||
| 3208 | if (!RHSC->getAPInt().isPowerOf2()) | ||||||
| 3209 | ++MaxShiftAmt; | ||||||
| 3210 | IntegerType *ExtTy = | ||||||
| 3211 | IntegerType::get(getContext(), getTypeSizeInBits(Ty) + MaxShiftAmt); | ||||||
| 3212 | if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS)) | ||||||
| 3213 | if (const SCEVConstant *Step = | ||||||
| 3214 | dyn_cast<SCEVConstant>(AR->getStepRecurrence(*this))) { | ||||||
| 3215 | // {X,+,N}/C --> {X/C,+,N/C} if safe and N/C can be folded. | ||||||
| 3216 | const APInt &StepInt = Step->getAPInt(); | ||||||
| 3217 | const APInt &DivInt = RHSC->getAPInt(); | ||||||
| 3218 | if (!StepInt.urem(DivInt) && | ||||||
| 3219 | getZeroExtendExpr(AR, ExtTy) == | ||||||
| 3220 | getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy), | ||||||
| 3221 | getZeroExtendExpr(Step, ExtTy), | ||||||
| 3222 | AR->getLoop(), SCEV::FlagAnyWrap)) { | ||||||
| 3223 | SmallVector<const SCEV *, 4> Operands; | ||||||
| 3224 | for (const SCEV *Op : AR->operands()) | ||||||
| 3225 | Operands.push_back(getUDivExpr(Op, RHS)); | ||||||
| 3226 | return getAddRecExpr(Operands, AR->getLoop(), SCEV::FlagNW); | ||||||
| 3227 | } | ||||||
| 3228 | /// Get a canonical UDivExpr for a recurrence. | ||||||
| 3229 | /// {X,+,N}/C => {Y,+,N}/C where Y=X-(X%N). Safe when C%N=0. | ||||||
| 3230 | // We can currently only fold X%N if X is constant. | ||||||
| 3231 | const SCEVConstant *StartC = dyn_cast<SCEVConstant>(AR->getStart()); | ||||||
| 3232 | if (StartC && !DivInt.urem(StepInt) && | ||||||
| 3233 | getZeroExtendExpr(AR, ExtTy) == | ||||||
| 3234 | getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy), | ||||||
| 3235 | getZeroExtendExpr(Step, ExtTy), | ||||||
| 3236 | AR->getLoop(), SCEV::FlagAnyWrap)) { | ||||||
| 3237 | const APInt &StartInt = StartC->getAPInt(); | ||||||
| 3238 | const APInt &StartRem = StartInt.urem(StepInt); | ||||||
| 3239 | if (StartRem != 0) | ||||||
| 3240 | LHS = getAddRecExpr(getConstant(StartInt - StartRem), Step, | ||||||
| 3241 | AR->getLoop(), SCEV::FlagNW); | ||||||
| 3242 | } | ||||||
| 3243 | } | ||||||
| 3244 | // (A*B)/C --> A*(B/C) if safe and B/C can be folded. | ||||||
| 3245 | if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(LHS)) { | ||||||
| 3246 | SmallVector<const SCEV *, 4> Operands; | ||||||
| 3247 | for (const SCEV *Op : M->operands()) | ||||||
| 3248 | Operands.push_back(getZeroExtendExpr(Op, ExtTy)); | ||||||
| 3249 | if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands)) | ||||||
| 3250 | // Find an operand that's safely divisible. | ||||||
| 3251 | for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) { | ||||||
| 3252 | const SCEV *Op = M->getOperand(i); | ||||||
| 3253 | const SCEV *Div = getUDivExpr(Op, RHSC); | ||||||
| 3254 | if (!isa<SCEVUDivExpr>(Div) && getMulExpr(Div, RHSC) == Op) { | ||||||
| 3255 | Operands = SmallVector<const SCEV *, 4>(M->op_begin(), | ||||||
| 3256 | M->op_end()); | ||||||
| 3257 | Operands[i] = Div; | ||||||
| 3258 | return getMulExpr(Operands); | ||||||
| 3259 | } | ||||||
| 3260 | } | ||||||
| 3261 | } | ||||||
| 3262 | |||||||
| 3263 | // (A/B)/C --> A/(B*C) if safe and B*C can be folded. | ||||||
| 3264 | if (const SCEVUDivExpr *OtherDiv = dyn_cast<SCEVUDivExpr>(LHS)) { | ||||||
| 3265 | if (auto *DivisorConstant = | ||||||
| 3266 | dyn_cast<SCEVConstant>(OtherDiv->getRHS())) { | ||||||
| 3267 | bool Overflow = false; | ||||||
| 3268 | APInt NewRHS = | ||||||
| 3269 | DivisorConstant->getAPInt().umul_ov(RHSC->getAPInt(), Overflow); | ||||||
| 3270 | if (Overflow) { | ||||||
| 3271 | return getConstant(RHSC->getType(), 0, false); | ||||||
| 3272 | } | ||||||
| 3273 | return getUDivExpr(OtherDiv->getLHS(), getConstant(NewRHS)); | ||||||
| 3274 | } | ||||||
| 3275 | } | ||||||
| 3276 | |||||||
| 3277 | // (A+B)/C --> (A/C + B/C) if safe and A/C and B/C can be folded. | ||||||
| 3278 | if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(LHS)) { | ||||||
| 3279 | SmallVector<const SCEV *, 4> Operands; | ||||||
| 3280 | for (const SCEV *Op : A->operands()) | ||||||
| 3281 | Operands.push_back(getZeroExtendExpr(Op, ExtTy)); | ||||||
| 3282 | if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) { | ||||||
| 3283 | Operands.clear(); | ||||||
| 3284 | for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) { | ||||||
| 3285 | const SCEV *Op = getUDivExpr(A->getOperand(i), RHS); | ||||||
| 3286 | if (isa<SCEVUDivExpr>(Op) || | ||||||
| 3287 | getMulExpr(Op, RHS) != A->getOperand(i)) | ||||||
| 3288 | break; | ||||||
| 3289 | Operands.push_back(Op); | ||||||
| 3290 | } | ||||||
| 3291 | if (Operands.size() == A->getNumOperands()) | ||||||
| 3292 | return getAddExpr(Operands); | ||||||
| 3293 | } | ||||||
| 3294 | } | ||||||
| 3295 | |||||||
| 3296 | // Fold if both operands are constant. | ||||||
| 3297 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) { | ||||||
| 3298 | Constant *LHSCV = LHSC->getValue(); | ||||||
| 3299 | Constant *RHSCV = RHSC->getValue(); | ||||||
| 3300 | return getConstant(cast<ConstantInt>(ConstantExpr::getUDiv(LHSCV, | ||||||
| 3301 | RHSCV))); | ||||||
| 3302 | } | ||||||
| 3303 | } | ||||||
| 3304 | } | ||||||
| 3305 | |||||||
| 3306 | FoldingSetNodeID ID; | ||||||
| 3307 | ID.AddInteger(scUDivExpr); | ||||||
| 3308 | ID.AddPointer(LHS); | ||||||
| 3309 | ID.AddPointer(RHS); | ||||||
| 3310 | void *IP = nullptr; | ||||||
| 3311 | if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; | ||||||
| 3312 | SCEV *S = new (SCEVAllocator) SCEVUDivExpr(ID.Intern(SCEVAllocator), | ||||||
| 3313 | LHS, RHS); | ||||||
| 3314 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 3315 | addToLoopUseLists(S); | ||||||
| 3316 | return S; | ||||||
| 3317 | } | ||||||
| 3318 | |||||||
| 3319 | static const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) { | ||||||
| 3320 | APInt A = C1->getAPInt().abs(); | ||||||
| 3321 | APInt B = C2->getAPInt().abs(); | ||||||
| 3322 | uint32_t ABW = A.getBitWidth(); | ||||||
| 3323 | uint32_t BBW = B.getBitWidth(); | ||||||
| 3324 | |||||||
| 3325 | if (ABW > BBW) | ||||||
| 3326 | B = B.zext(ABW); | ||||||
| 3327 | else if (ABW < BBW) | ||||||
| 3328 | A = A.zext(BBW); | ||||||
| 3329 | |||||||
| 3330 | return APIntOps::GreatestCommonDivisor(std::move(A), std::move(B)); | ||||||
| 3331 | } | ||||||
| 3332 | |||||||
| 3333 | /// Get a canonical unsigned division expression, or something simpler if | ||||||
| 3334 | /// possible. There is no representation for an exact udiv in SCEV IR, but we | ||||||
| 3335 | /// can attempt to remove factors from the LHS and RHS. We can't do this when | ||||||
| 3336 | /// it's not exact because the udiv may be clearing bits. | ||||||
| 3337 | const SCEV *ScalarEvolution::getUDivExactExpr(const SCEV *LHS, | ||||||
| 3338 | const SCEV *RHS) { | ||||||
| 3339 | // TODO: we could try to find factors in all sorts of things, but for now we | ||||||
| 3340 | // just deal with u/exact (multiply, constant). See SCEVDivision towards the | ||||||
| 3341 | // end of this file for inspiration. | ||||||
| 3342 | |||||||
| 3343 | const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS); | ||||||
| 3344 | if (!Mul || !Mul->hasNoUnsignedWrap()) | ||||||
| 3345 | return getUDivExpr(LHS, RHS); | ||||||
| 3346 | |||||||
| 3347 | if (const SCEVConstant *RHSCst = dyn_cast<SCEVConstant>(RHS)) { | ||||||
| 3348 | // If the mulexpr multiplies by a constant, then that constant must be the | ||||||
| 3349 | // first element of the mulexpr. | ||||||
| 3350 | if (const auto *LHSCst = dyn_cast<SCEVConstant>(Mul->getOperand(0))) { | ||||||
| 3351 | if (LHSCst == RHSCst) { | ||||||
| 3352 | SmallVector<const SCEV *, 2> Operands; | ||||||
| 3353 | Operands.append(Mul->op_begin() + 1, Mul->op_end()); | ||||||
| 3354 | return getMulExpr(Operands); | ||||||
| 3355 | } | ||||||
| 3356 | |||||||
| 3357 | // We can't just assume that LHSCst divides RHSCst cleanly, it could be | ||||||
| 3358 | // that there's a factor provided by one of the other terms. We need to | ||||||
| 3359 | // check. | ||||||
| 3360 | APInt Factor = gcd(LHSCst, RHSCst); | ||||||
| 3361 | if (!Factor.isIntN(1)) { | ||||||
| 3362 | LHSCst = | ||||||
| 3363 | cast<SCEVConstant>(getConstant(LHSCst->getAPInt().udiv(Factor))); | ||||||
| 3364 | RHSCst = | ||||||
| 3365 | cast<SCEVConstant>(getConstant(RHSCst->getAPInt().udiv(Factor))); | ||||||
| 3366 | SmallVector<const SCEV *, 2> Operands; | ||||||
| 3367 | Operands.push_back(LHSCst); | ||||||
| 3368 | Operands.append(Mul->op_begin() + 1, Mul->op_end()); | ||||||
| 3369 | LHS = getMulExpr(Operands); | ||||||
| 3370 | RHS = RHSCst; | ||||||
| 3371 | Mul = dyn_cast<SCEVMulExpr>(LHS); | ||||||
| 3372 | if (!Mul) | ||||||
| 3373 | return getUDivExactExpr(LHS, RHS); | ||||||
| 3374 | } | ||||||
| 3375 | } | ||||||
| 3376 | } | ||||||
| 3377 | |||||||
| 3378 | for (int i = 0, e = Mul->getNumOperands(); i != e; ++i) { | ||||||
| 3379 | if (Mul->getOperand(i) == RHS) { | ||||||
| 3380 | SmallVector<const SCEV *, 2> Operands; | ||||||
| 3381 | Operands.append(Mul->op_begin(), Mul->op_begin() + i); | ||||||
| 3382 | Operands.append(Mul->op_begin() + i + 1, Mul->op_end()); | ||||||
| 3383 | return getMulExpr(Operands); | ||||||
| 3384 | } | ||||||
| 3385 | } | ||||||
| 3386 | |||||||
| 3387 | return getUDivExpr(LHS, RHS); | ||||||
| 3388 | } | ||||||
| 3389 | |||||||
| 3390 | /// Get an add recurrence expression for the specified loop. Simplify the | ||||||
| 3391 | /// expression as much as possible. | ||||||
| 3392 | const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start, const SCEV *Step, | ||||||
| 3393 | const Loop *L, | ||||||
| 3394 | SCEV::NoWrapFlags Flags) { | ||||||
| 3395 | SmallVector<const SCEV *, 4> Operands; | ||||||
| 3396 | Operands.push_back(Start); | ||||||
| 3397 | if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step)) | ||||||
| 3398 | if (StepChrec->getLoop() == L) { | ||||||
| 3399 | Operands.append(StepChrec->op_begin(), StepChrec->op_end()); | ||||||
| 3400 | return getAddRecExpr(Operands, L, maskFlags(Flags, SCEV::FlagNW)); | ||||||
| 3401 | } | ||||||
| 3402 | |||||||
| 3403 | Operands.push_back(Step); | ||||||
| 3404 | return getAddRecExpr(Operands, L, Flags); | ||||||
| 3405 | } | ||||||
| 3406 | |||||||
| 3407 | /// Get an add recurrence expression for the specified loop. Simplify the | ||||||
| 3408 | /// expression as much as possible. | ||||||
| 3409 | const SCEV * | ||||||
| 3410 | ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands, | ||||||
| 3411 | const Loop *L, SCEV::NoWrapFlags Flags) { | ||||||
| 3412 | if (Operands.size() == 1) return Operands[0]; | ||||||
| 3413 | #ifndef NDEBUG | ||||||
| 3414 | Type *ETy = getEffectiveSCEVType(Operands[0]->getType()); | ||||||
| 3415 | for (unsigned i = 1, e = Operands.size(); i != e; ++i) | ||||||
| 3416 | assert(getEffectiveSCEVType(Operands[i]->getType()) == ETy &&((getEffectiveSCEVType(Operands[i]->getType()) == ETy && "SCEVAddRecExpr operand types don't match!") ? static_cast< void> (0) : __assert_fail ("getEffectiveSCEVType(Operands[i]->getType()) == ETy && \"SCEVAddRecExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3417, __PRETTY_FUNCTION__)) | ||||||
| 3417 | "SCEVAddRecExpr operand types don't match!")((getEffectiveSCEVType(Operands[i]->getType()) == ETy && "SCEVAddRecExpr operand types don't match!") ? static_cast< void> (0) : __assert_fail ("getEffectiveSCEVType(Operands[i]->getType()) == ETy && \"SCEVAddRecExpr operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3417, __PRETTY_FUNCTION__)); | ||||||
| 3418 | for (unsigned i = 0, e = Operands.size(); i != e; ++i) | ||||||
| 3419 | assert(isLoopInvariant(Operands[i], L) &&((isLoopInvariant(Operands[i], L) && "SCEVAddRecExpr operand is not loop-invariant!" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Operands[i], L) && \"SCEVAddRecExpr operand is not loop-invariant!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3420, __PRETTY_FUNCTION__)) | ||||||
| 3420 | "SCEVAddRecExpr operand is not loop-invariant!")((isLoopInvariant(Operands[i], L) && "SCEVAddRecExpr operand is not loop-invariant!" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Operands[i], L) && \"SCEVAddRecExpr operand is not loop-invariant!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3420, __PRETTY_FUNCTION__)); | ||||||
| 3421 | #endif | ||||||
| 3422 | |||||||
| 3423 | if (Operands.back()->isZero()) { | ||||||
| 3424 | Operands.pop_back(); | ||||||
| 3425 | return getAddRecExpr(Operands, L, SCEV::FlagAnyWrap); // {X,+,0} --> X | ||||||
| 3426 | } | ||||||
| 3427 | |||||||
| 3428 | // It's tempting to want to call getConstantMaxBackedgeTakenCount count here and | ||||||
| 3429 | // use that information to infer NUW and NSW flags. However, computing a | ||||||
| 3430 | // BE count requires calling getAddRecExpr, so we may not yet have a | ||||||
| 3431 | // meaningful BE count at this point (and if we don't, we'd be stuck | ||||||
| 3432 | // with a SCEVCouldNotCompute as the cached BE count). | ||||||
| 3433 | |||||||
| 3434 | Flags = StrengthenNoWrapFlags(this, scAddRecExpr, Operands, Flags); | ||||||
| 3435 | |||||||
| 3436 | // Canonicalize nested AddRecs in by nesting them in order of loop depth. | ||||||
| 3437 | if (const SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) { | ||||||
| 3438 | const Loop *NestedLoop = NestedAR->getLoop(); | ||||||
| 3439 | if (L->contains(NestedLoop) | ||||||
| 3440 | ? (L->getLoopDepth() < NestedLoop->getLoopDepth()) | ||||||
| 3441 | : (!NestedLoop->contains(L) && | ||||||
| 3442 | DT.dominates(L->getHeader(), NestedLoop->getHeader()))) { | ||||||
| 3443 | SmallVector<const SCEV *, 4> NestedOperands(NestedAR->op_begin(), | ||||||
| 3444 | NestedAR->op_end()); | ||||||
| 3445 | Operands[0] = NestedAR->getStart(); | ||||||
| 3446 | // AddRecs require their operands be loop-invariant with respect to their | ||||||
| 3447 | // loops. Don't perform this transformation if it would break this | ||||||
| 3448 | // requirement. | ||||||
| 3449 | bool AllInvariant = all_of( | ||||||
| 3450 | Operands, [&](const SCEV *Op) { return isLoopInvariant(Op, L); }); | ||||||
| 3451 | |||||||
| 3452 | if (AllInvariant) { | ||||||
| 3453 | // Create a recurrence for the outer loop with the same step size. | ||||||
| 3454 | // | ||||||
| 3455 | // The outer recurrence keeps its NW flag but only keeps NUW/NSW if the | ||||||
| 3456 | // inner recurrence has the same property. | ||||||
| 3457 | SCEV::NoWrapFlags OuterFlags = | ||||||
| 3458 | maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags()); | ||||||
| 3459 | |||||||
| 3460 | NestedOperands[0] = getAddRecExpr(Operands, L, OuterFlags); | ||||||
| 3461 | AllInvariant = all_of(NestedOperands, [&](const SCEV *Op) { | ||||||
| 3462 | return isLoopInvariant(Op, NestedLoop); | ||||||
| 3463 | }); | ||||||
| 3464 | |||||||
| 3465 | if (AllInvariant) { | ||||||
| 3466 | // Ok, both add recurrences are valid after the transformation. | ||||||
| 3467 | // | ||||||
| 3468 | // The inner recurrence keeps its NW flag but only keeps NUW/NSW if | ||||||
| 3469 | // the outer recurrence has the same property. | ||||||
| 3470 | SCEV::NoWrapFlags InnerFlags = | ||||||
| 3471 | maskFlags(NestedAR->getNoWrapFlags(), SCEV::FlagNW | Flags); | ||||||
| 3472 | return getAddRecExpr(NestedOperands, NestedLoop, InnerFlags); | ||||||
| 3473 | } | ||||||
| 3474 | } | ||||||
| 3475 | // Reset Operands to its original state. | ||||||
| 3476 | Operands[0] = NestedAR; | ||||||
| 3477 | } | ||||||
| 3478 | } | ||||||
| 3479 | |||||||
| 3480 | // Okay, it looks like we really DO need an addrec expr. Check to see if we | ||||||
| 3481 | // already have one, otherwise create a new one. | ||||||
| 3482 | return getOrCreateAddRecExpr(Operands, L, Flags); | ||||||
| 3483 | } | ||||||
| 3484 | |||||||
| 3485 | const SCEV * | ||||||
| 3486 | ScalarEvolution::getGEPExpr(GEPOperator *GEP, | ||||||
| 3487 | const SmallVectorImpl<const SCEV *> &IndexExprs) { | ||||||
| 3488 | const SCEV *BaseExpr = getSCEV(GEP->getPointerOperand()); | ||||||
| 3489 | // getSCEV(Base)->getType() has the same address space as Base->getType() | ||||||
| 3490 | // because SCEV::getType() preserves the address space. | ||||||
| 3491 | Type *IntPtrTy = getEffectiveSCEVType(BaseExpr->getType()); | ||||||
| 3492 | // FIXME(PR23527): Don't blindly transfer the inbounds flag from the GEP | ||||||
| 3493 | // instruction to its SCEV, because the Instruction may be guarded by control | ||||||
| 3494 | // flow and the no-overflow bits may not be valid for the expression in any | ||||||
| 3495 | // context. This can be fixed similarly to how these flags are handled for | ||||||
| 3496 | // adds. | ||||||
| 3497 | SCEV::NoWrapFlags Wrap = GEP->isInBounds() ? SCEV::FlagNSW | ||||||
| 3498 | : SCEV::FlagAnyWrap; | ||||||
| 3499 | |||||||
| 3500 | const SCEV *TotalOffset = getZero(IntPtrTy); | ||||||
| 3501 | // The array size is unimportant. The first thing we do on CurTy is getting | ||||||
| 3502 | // its element type. | ||||||
| 3503 | Type *CurTy = ArrayType::get(GEP->getSourceElementType(), 0); | ||||||
| 3504 | for (const SCEV *IndexExpr : IndexExprs) { | ||||||
| 3505 | // Compute the (potentially symbolic) offset in bytes for this index. | ||||||
| 3506 | if (StructType *STy = dyn_cast<StructType>(CurTy)) { | ||||||
| 3507 | // For a struct, add the member offset. | ||||||
| 3508 | ConstantInt *Index = cast<SCEVConstant>(IndexExpr)->getValue(); | ||||||
| 3509 | unsigned FieldNo = Index->getZExtValue(); | ||||||
| 3510 | const SCEV *FieldOffset = getOffsetOfExpr(IntPtrTy, STy, FieldNo); | ||||||
| 3511 | |||||||
| 3512 | // Add the field offset to the running total offset. | ||||||
| 3513 | TotalOffset = getAddExpr(TotalOffset, FieldOffset); | ||||||
| 3514 | |||||||
| 3515 | // Update CurTy to the type of the field at Index. | ||||||
| 3516 | CurTy = STy->getTypeAtIndex(Index); | ||||||
| 3517 | } else { | ||||||
| 3518 | // Update CurTy to its element type. | ||||||
| 3519 | CurTy = cast<SequentialType>(CurTy)->getElementType(); | ||||||
| 3520 | // For an array, add the element offset, explicitly scaled. | ||||||
| 3521 | const SCEV *ElementSize = getSizeOfExpr(IntPtrTy, CurTy); | ||||||
| 3522 | // Getelementptr indices are signed. | ||||||
| 3523 | IndexExpr = getTruncateOrSignExtend(IndexExpr, IntPtrTy); | ||||||
| 3524 | |||||||
| 3525 | // Multiply the index by the element size to compute the element offset. | ||||||
| 3526 | const SCEV *LocalOffset = getMulExpr(IndexExpr, ElementSize, Wrap); | ||||||
| 3527 | |||||||
| 3528 | // Add the element offset to the running total offset. | ||||||
| 3529 | TotalOffset = getAddExpr(TotalOffset, LocalOffset); | ||||||
| 3530 | } | ||||||
| 3531 | } | ||||||
| 3532 | |||||||
| 3533 | // Add the total offset from all the GEP indices to the base. | ||||||
| 3534 | return getAddExpr(BaseExpr, TotalOffset, Wrap); | ||||||
| 3535 | } | ||||||
| 3536 | |||||||
| 3537 | std::tuple<const SCEV *, FoldingSetNodeID, void *> | ||||||
| 3538 | ScalarEvolution::findExistingSCEVInCache(int SCEVType, | ||||||
| 3539 | ArrayRef<const SCEV *> Ops) { | ||||||
| 3540 | FoldingSetNodeID ID; | ||||||
| 3541 | void *IP = nullptr; | ||||||
| 3542 | ID.AddInteger(SCEVType); | ||||||
| 3543 | for (unsigned i = 0, e = Ops.size(); i != e; ++i) | ||||||
| 3544 | ID.AddPointer(Ops[i]); | ||||||
| 3545 | return std::tuple<const SCEV *, FoldingSetNodeID, void *>( | ||||||
| 3546 | UniqueSCEVs.FindNodeOrInsertPos(ID, IP), std::move(ID), IP); | ||||||
| 3547 | } | ||||||
| 3548 | |||||||
| 3549 | const SCEV *ScalarEvolution::getMinMaxExpr(unsigned Kind, | ||||||
| 3550 | SmallVectorImpl<const SCEV *> &Ops) { | ||||||
| 3551 | assert(!Ops.empty() && "Cannot get empty (u|s)(min|max)!")((!Ops.empty() && "Cannot get empty (u|s)(min|max)!") ? static_cast<void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty (u|s)(min|max)!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3551, __PRETTY_FUNCTION__)); | ||||||
| 3552 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 3553 | #ifndef NDEBUG | ||||||
| 3554 | Type *ETy = getEffectiveSCEVType(Ops[0]->getType()); | ||||||
| 3555 | for (unsigned i = 1, e = Ops.size(); i != e; ++i) | ||||||
| 3556 | assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "Operand types don't match!") ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"Operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3557, __PRETTY_FUNCTION__)) | ||||||
| 3557 | "Operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy && "Operand types don't match!") ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"Operand types don't match!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3557, __PRETTY_FUNCTION__)); | ||||||
| 3558 | #endif | ||||||
| 3559 | |||||||
| 3560 | bool IsSigned = Kind == scSMaxExpr || Kind == scSMinExpr; | ||||||
| 3561 | bool IsMax = Kind == scSMaxExpr || Kind == scUMaxExpr; | ||||||
| 3562 | |||||||
| 3563 | // Sort by complexity, this groups all similar expression types together. | ||||||
| 3564 | GroupByComplexity(Ops, &LI, DT); | ||||||
| 3565 | |||||||
| 3566 | // Check if we have created the same expression before. | ||||||
| 3567 | if (const SCEV *S = std::get<0>(findExistingSCEVInCache(Kind, Ops))) { | ||||||
| 3568 | return S; | ||||||
| 3569 | } | ||||||
| 3570 | |||||||
| 3571 | // If there are any constants, fold them together. | ||||||
| 3572 | unsigned Idx = 0; | ||||||
| 3573 | if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) { | ||||||
| 3574 | ++Idx; | ||||||
| 3575 | assert(Idx < Ops.size())((Idx < Ops.size()) ? static_cast<void> (0) : __assert_fail ("Idx < Ops.size()", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3575, __PRETTY_FUNCTION__)); | ||||||
| 3576 | auto FoldOp = [&](const APInt &LHS, const APInt &RHS) { | ||||||
| 3577 | if (Kind == scSMaxExpr) | ||||||
| 3578 | return APIntOps::smax(LHS, RHS); | ||||||
| 3579 | else if (Kind == scSMinExpr) | ||||||
| 3580 | return APIntOps::smin(LHS, RHS); | ||||||
| 3581 | else if (Kind == scUMaxExpr) | ||||||
| 3582 | return APIntOps::umax(LHS, RHS); | ||||||
| 3583 | else if (Kind == scUMinExpr) | ||||||
| 3584 | return APIntOps::umin(LHS, RHS); | ||||||
| 3585 | llvm_unreachable("Unknown SCEV min/max opcode")::llvm::llvm_unreachable_internal("Unknown SCEV min/max opcode" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3585); | ||||||
| 3586 | }; | ||||||
| 3587 | |||||||
| 3588 | while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) { | ||||||
| 3589 | // We found two constants, fold them together! | ||||||
| 3590 | ConstantInt *Fold = ConstantInt::get( | ||||||
| 3591 | getContext(), FoldOp(LHSC->getAPInt(), RHSC->getAPInt())); | ||||||
| 3592 | Ops[0] = getConstant(Fold); | ||||||
| 3593 | Ops.erase(Ops.begin()+1); // Erase the folded element | ||||||
| 3594 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 3595 | LHSC = cast<SCEVConstant>(Ops[0]); | ||||||
| 3596 | } | ||||||
| 3597 | |||||||
| 3598 | bool IsMinV = LHSC->getValue()->isMinValue(IsSigned); | ||||||
| 3599 | bool IsMaxV = LHSC->getValue()->isMaxValue(IsSigned); | ||||||
| 3600 | |||||||
| 3601 | if (IsMax ? IsMinV : IsMaxV) { | ||||||
| 3602 | // If we are left with a constant minimum(/maximum)-int, strip it off. | ||||||
| 3603 | Ops.erase(Ops.begin()); | ||||||
| 3604 | --Idx; | ||||||
| 3605 | } else if (IsMax ? IsMaxV : IsMinV) { | ||||||
| 3606 | // If we have a max(/min) with a constant maximum(/minimum)-int, | ||||||
| 3607 | // it will always be the extremum. | ||||||
| 3608 | return LHSC; | ||||||
| 3609 | } | ||||||
| 3610 | |||||||
| 3611 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 3612 | } | ||||||
| 3613 | |||||||
| 3614 | // Find the first operation of the same kind | ||||||
| 3615 | while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < Kind) | ||||||
| 3616 | ++Idx; | ||||||
| 3617 | |||||||
| 3618 | // Check to see if one of the operands is of the same kind. If so, expand its | ||||||
| 3619 | // operands onto our operand list, and recurse to simplify. | ||||||
| 3620 | if (Idx < Ops.size()) { | ||||||
| 3621 | bool DeletedAny = false; | ||||||
| 3622 | while (Ops[Idx]->getSCEVType() == Kind) { | ||||||
| 3623 | const SCEVMinMaxExpr *SMME = cast<SCEVMinMaxExpr>(Ops[Idx]); | ||||||
| 3624 | Ops.erase(Ops.begin()+Idx); | ||||||
| 3625 | Ops.append(SMME->op_begin(), SMME->op_end()); | ||||||
| 3626 | DeletedAny = true; | ||||||
| 3627 | } | ||||||
| 3628 | |||||||
| 3629 | if (DeletedAny) | ||||||
| 3630 | return getMinMaxExpr(Kind, Ops); | ||||||
| 3631 | } | ||||||
| 3632 | |||||||
| 3633 | // Okay, check to see if the same value occurs in the operand list twice. If | ||||||
| 3634 | // so, delete one. Since we sorted the list, these values are required to | ||||||
| 3635 | // be adjacent. | ||||||
| 3636 | llvm::CmpInst::Predicate GEPred = | ||||||
| 3637 | IsSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; | ||||||
| 3638 | llvm::CmpInst::Predicate LEPred = | ||||||
| 3639 | IsSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; | ||||||
| 3640 | llvm::CmpInst::Predicate FirstPred = IsMax ? GEPred : LEPred; | ||||||
| 3641 | llvm::CmpInst::Predicate SecondPred = IsMax ? LEPred : GEPred; | ||||||
| 3642 | for (unsigned i = 0, e = Ops.size() - 1; i != e; ++i) { | ||||||
| 3643 | if (Ops[i] == Ops[i + 1] || | ||||||
| 3644 | isKnownViaNonRecursiveReasoning(FirstPred, Ops[i], Ops[i + 1])) { | ||||||
| 3645 | // X op Y op Y --> X op Y | ||||||
| 3646 | // X op Y --> X, if we know X, Y are ordered appropriately | ||||||
| 3647 | Ops.erase(Ops.begin() + i + 1, Ops.begin() + i + 2); | ||||||
| 3648 | --i; | ||||||
| 3649 | --e; | ||||||
| 3650 | } else if (isKnownViaNonRecursiveReasoning(SecondPred, Ops[i], | ||||||
| 3651 | Ops[i + 1])) { | ||||||
| 3652 | // X op Y --> Y, if we know X, Y are ordered appropriately | ||||||
| 3653 | Ops.erase(Ops.begin() + i, Ops.begin() + i + 1); | ||||||
| 3654 | --i; | ||||||
| 3655 | --e; | ||||||
| 3656 | } | ||||||
| 3657 | } | ||||||
| 3658 | |||||||
| 3659 | if (Ops.size() == 1) return Ops[0]; | ||||||
| 3660 | |||||||
| 3661 | assert(!Ops.empty() && "Reduced smax down to nothing!")((!Ops.empty() && "Reduced smax down to nothing!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"Reduced smax down to nothing!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3661, __PRETTY_FUNCTION__)); | ||||||
| 3662 | |||||||
| 3663 | // Okay, it looks like we really DO need an expr. Check to see if we | ||||||
| 3664 | // already have one, otherwise create a new one. | ||||||
| 3665 | const SCEV *ExistingSCEV; | ||||||
| 3666 | FoldingSetNodeID ID; | ||||||
| 3667 | void *IP; | ||||||
| 3668 | std::tie(ExistingSCEV, ID, IP) = findExistingSCEVInCache(Kind, Ops); | ||||||
| 3669 | if (ExistingSCEV) | ||||||
| 3670 | return ExistingSCEV; | ||||||
| 3671 | const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size()); | ||||||
| 3672 | std::uninitialized_copy(Ops.begin(), Ops.end(), O); | ||||||
| 3673 | SCEV *S = new (SCEVAllocator) SCEVMinMaxExpr( | ||||||
| 3674 | ID.Intern(SCEVAllocator), static_cast<SCEVTypes>(Kind), O, Ops.size()); | ||||||
| 3675 | |||||||
| 3676 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 3677 | addToLoopUseLists(S); | ||||||
| 3678 | return S; | ||||||
| 3679 | } | ||||||
| 3680 | |||||||
| 3681 | const SCEV *ScalarEvolution::getSMaxExpr(const SCEV *LHS, const SCEV *RHS) { | ||||||
| 3682 | SmallVector<const SCEV *, 2> Ops = {LHS, RHS}; | ||||||
| 3683 | return getSMaxExpr(Ops); | ||||||
| 3684 | } | ||||||
| 3685 | |||||||
| 3686 | const SCEV *ScalarEvolution::getSMaxExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
| 3687 | return getMinMaxExpr(scSMaxExpr, Ops); | ||||||
| 3688 | } | ||||||
| 3689 | |||||||
| 3690 | const SCEV *ScalarEvolution::getUMaxExpr(const SCEV *LHS, const SCEV *RHS) { | ||||||
| 3691 | SmallVector<const SCEV *, 2> Ops = {LHS, RHS}; | ||||||
| 3692 | return getUMaxExpr(Ops); | ||||||
| 3693 | } | ||||||
| 3694 | |||||||
| 3695 | const SCEV *ScalarEvolution::getUMaxExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
| 3696 | return getMinMaxExpr(scUMaxExpr, Ops); | ||||||
| 3697 | } | ||||||
| 3698 | |||||||
| 3699 | const SCEV *ScalarEvolution::getSMinExpr(const SCEV *LHS, | ||||||
| 3700 | const SCEV *RHS) { | ||||||
| 3701 | SmallVector<const SCEV *, 2> Ops = { LHS, RHS }; | ||||||
| 3702 | return getSMinExpr(Ops); | ||||||
| 3703 | } | ||||||
| 3704 | |||||||
| 3705 | const SCEV *ScalarEvolution::getSMinExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
| 3706 | return getMinMaxExpr(scSMinExpr, Ops); | ||||||
| 3707 | } | ||||||
| 3708 | |||||||
| 3709 | const SCEV *ScalarEvolution::getUMinExpr(const SCEV *LHS, | ||||||
| 3710 | const SCEV *RHS) { | ||||||
| 3711 | SmallVector<const SCEV *, 2> Ops = { LHS, RHS }; | ||||||
| 3712 | return getUMinExpr(Ops); | ||||||
| 3713 | } | ||||||
| 3714 | |||||||
| 3715 | const SCEV *ScalarEvolution::getUMinExpr(SmallVectorImpl<const SCEV *> &Ops) { | ||||||
| 3716 | return getMinMaxExpr(scUMinExpr, Ops); | ||||||
| 3717 | } | ||||||
| 3718 | |||||||
| 3719 | const SCEV *ScalarEvolution::getSizeOfExpr(Type *IntTy, Type *AllocTy) { | ||||||
| 3720 | // We can bypass creating a target-independent | ||||||
| 3721 | // constant expression and then folding it back into a ConstantInt. | ||||||
| 3722 | // This is just a compile-time optimization. | ||||||
| 3723 | return getConstant(IntTy, getDataLayout().getTypeAllocSize(AllocTy)); | ||||||
| 3724 | } | ||||||
| 3725 | |||||||
| 3726 | const SCEV *ScalarEvolution::getOffsetOfExpr(Type *IntTy, | ||||||
| 3727 | StructType *STy, | ||||||
| 3728 | unsigned FieldNo) { | ||||||
| 3729 | // We can bypass creating a target-independent | ||||||
| 3730 | // constant expression and then folding it back into a ConstantInt. | ||||||
| 3731 | // This is just a compile-time optimization. | ||||||
| 3732 | return getConstant( | ||||||
| 3733 | IntTy, getDataLayout().getStructLayout(STy)->getElementOffset(FieldNo)); | ||||||
| 3734 | } | ||||||
| 3735 | |||||||
| 3736 | const SCEV *ScalarEvolution::getUnknown(Value *V) { | ||||||
| 3737 | // Don't attempt to do anything other than create a SCEVUnknown object | ||||||
| 3738 | // here. createSCEV only calls getUnknown after checking for all other | ||||||
| 3739 | // interesting possibilities, and any other code that calls getUnknown | ||||||
| 3740 | // is doing so in order to hide a value from SCEV canonicalization. | ||||||
| 3741 | |||||||
| 3742 | FoldingSetNodeID ID; | ||||||
| 3743 | ID.AddInteger(scUnknown); | ||||||
| 3744 | ID.AddPointer(V); | ||||||
| 3745 | void *IP = nullptr; | ||||||
| 3746 | if (SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) { | ||||||
| 3747 | assert(cast<SCEVUnknown>(S)->getValue() == V &&((cast<SCEVUnknown>(S)->getValue() == V && "Stale SCEVUnknown in uniquing map!" ) ? static_cast<void> (0) : __assert_fail ("cast<SCEVUnknown>(S)->getValue() == V && \"Stale SCEVUnknown in uniquing map!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3748, __PRETTY_FUNCTION__)) | ||||||
| 3748 | "Stale SCEVUnknown in uniquing map!")((cast<SCEVUnknown>(S)->getValue() == V && "Stale SCEVUnknown in uniquing map!" ) ? static_cast<void> (0) : __assert_fail ("cast<SCEVUnknown>(S)->getValue() == V && \"Stale SCEVUnknown in uniquing map!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3748, __PRETTY_FUNCTION__)); | ||||||
| 3749 | return S; | ||||||
| 3750 | } | ||||||
| 3751 | SCEV *S = new (SCEVAllocator) SCEVUnknown(ID.Intern(SCEVAllocator), V, this, | ||||||
| 3752 | FirstUnknown); | ||||||
| 3753 | FirstUnknown = cast<SCEVUnknown>(S); | ||||||
| 3754 | UniqueSCEVs.InsertNode(S, IP); | ||||||
| 3755 | return S; | ||||||
| 3756 | } | ||||||
| 3757 | |||||||
| 3758 | //===----------------------------------------------------------------------===// | ||||||
| 3759 | // Basic SCEV Analysis and PHI Idiom Recognition Code | ||||||
| 3760 | // | ||||||
| 3761 | |||||||
| 3762 | /// Test if values of the given type are analyzable within the SCEV | ||||||
| 3763 | /// framework. This primarily includes integer types, and it can optionally | ||||||
| 3764 | /// include pointer types if the ScalarEvolution class has access to | ||||||
| 3765 | /// target-specific information. | ||||||
| 3766 | bool ScalarEvolution::isSCEVable(Type *Ty) const { | ||||||
| 3767 | // Integers and pointers are always SCEVable. | ||||||
| 3768 | return Ty->isIntOrPtrTy(); | ||||||
| 3769 | } | ||||||
| 3770 | |||||||
| 3771 | /// Return the size in bits of the specified type, for which isSCEVable must | ||||||
| 3772 | /// return true. | ||||||
| 3773 | uint64_t ScalarEvolution::getTypeSizeInBits(Type *Ty) const { | ||||||
| 3774 | assert(isSCEVable(Ty) && "Type is not SCEVable!")((isSCEVable(Ty) && "Type is not SCEVable!") ? static_cast <void> (0) : __assert_fail ("isSCEVable(Ty) && \"Type is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3774, __PRETTY_FUNCTION__)); | ||||||
| 3775 | if (Ty->isPointerTy()) | ||||||
| 3776 | return getDataLayout().getIndexTypeSizeInBits(Ty); | ||||||
| 3777 | return getDataLayout().getTypeSizeInBits(Ty); | ||||||
| 3778 | } | ||||||
| 3779 | |||||||
| 3780 | /// Return a type with the same bitwidth as the given type and which represents | ||||||
| 3781 | /// how SCEV will treat the given type, for which isSCEVable must return | ||||||
| 3782 | /// true. For pointer types, this is the pointer-sized integer type. | ||||||
| 3783 | Type *ScalarEvolution::getEffectiveSCEVType(Type *Ty) const { | ||||||
| 3784 | assert(isSCEVable(Ty) && "Type is not SCEVable!")((isSCEVable(Ty) && "Type is not SCEVable!") ? static_cast <void> (0) : __assert_fail ("isSCEVable(Ty) && \"Type is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3784, __PRETTY_FUNCTION__)); | ||||||
| 3785 | |||||||
| 3786 | if (Ty->isIntegerTy()) | ||||||
| 3787 | return Ty; | ||||||
| 3788 | |||||||
| 3789 | // The only other support type is pointer. | ||||||
| 3790 | assert(Ty->isPointerTy() && "Unexpected non-pointer non-integer type!")((Ty->isPointerTy() && "Unexpected non-pointer non-integer type!" ) ? static_cast<void> (0) : __assert_fail ("Ty->isPointerTy() && \"Unexpected non-pointer non-integer type!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3790, __PRETTY_FUNCTION__)); | ||||||
| 3791 | return getDataLayout().getIntPtrType(Ty); | ||||||
| 3792 | } | ||||||
| 3793 | |||||||
| 3794 | Type *ScalarEvolution::getWiderType(Type *T1, Type *T2) const { | ||||||
| 3795 | return getTypeSizeInBits(T1) >= getTypeSizeInBits(T2) ? T1 : T2; | ||||||
| 3796 | } | ||||||
| 3797 | |||||||
| 3798 | const SCEV *ScalarEvolution::getCouldNotCompute() { | ||||||
| 3799 | return CouldNotCompute.get(); | ||||||
| 3800 | } | ||||||
| 3801 | |||||||
| 3802 | bool ScalarEvolution::checkValidity(const SCEV *S) const { | ||||||
| 3803 | bool ContainsNulls = SCEVExprContains(S, [](const SCEV *S) { | ||||||
| 3804 | auto *SU = dyn_cast<SCEVUnknown>(S); | ||||||
| 3805 | return SU && SU->getValue() == nullptr; | ||||||
| 3806 | }); | ||||||
| 3807 | |||||||
| 3808 | return !ContainsNulls; | ||||||
| 3809 | } | ||||||
| 3810 | |||||||
| 3811 | bool ScalarEvolution::containsAddRecurrence(const SCEV *S) { | ||||||
| 3812 | HasRecMapType::iterator I = HasRecMap.find(S); | ||||||
| 3813 | if (I != HasRecMap.end()) | ||||||
| 3814 | return I->second; | ||||||
| 3815 | |||||||
| 3816 | bool FoundAddRec = SCEVExprContains(S, isa<SCEVAddRecExpr, const SCEV *>); | ||||||
| 3817 | HasRecMap.insert({S, FoundAddRec}); | ||||||
| 3818 | return FoundAddRec; | ||||||
| 3819 | } | ||||||
| 3820 | |||||||
| 3821 | /// Try to split a SCEVAddExpr into a pair of {SCEV, ConstantInt}. | ||||||
| 3822 | /// If \p S is a SCEVAddExpr and is composed of a sub SCEV S' and an | ||||||
| 3823 | /// offset I, then return {S', I}, else return {\p S, nullptr}. | ||||||
| 3824 | static std::pair<const SCEV *, ConstantInt *> splitAddExpr(const SCEV *S) { | ||||||
| 3825 | const auto *Add = dyn_cast<SCEVAddExpr>(S); | ||||||
| 3826 | if (!Add) | ||||||
| 3827 | return {S, nullptr}; | ||||||
| 3828 | |||||||
| 3829 | if (Add->getNumOperands() != 2) | ||||||
| 3830 | return {S, nullptr}; | ||||||
| 3831 | |||||||
| 3832 | auto *ConstOp = dyn_cast<SCEVConstant>(Add->getOperand(0)); | ||||||
| 3833 | if (!ConstOp) | ||||||
| 3834 | return {S, nullptr}; | ||||||
| 3835 | |||||||
| 3836 | return {Add->getOperand(1), ConstOp->getValue()}; | ||||||
| 3837 | } | ||||||
| 3838 | |||||||
| 3839 | /// Return the ValueOffsetPair set for \p S. \p S can be represented | ||||||
| 3840 | /// by the value and offset from any ValueOffsetPair in the set. | ||||||
| 3841 | SetVector<ScalarEvolution::ValueOffsetPair> * | ||||||
| 3842 | ScalarEvolution::getSCEVValues(const SCEV *S) { | ||||||
| 3843 | ExprValueMapType::iterator SI = ExprValueMap.find_as(S); | ||||||
| 3844 | if (SI == ExprValueMap.end()) | ||||||
| 3845 | return nullptr; | ||||||
| 3846 | #ifndef NDEBUG | ||||||
| 3847 | if (VerifySCEVMap) { | ||||||
| 3848 | // Check there is no dangling Value in the set returned. | ||||||
| 3849 | for (const auto &VE : SI->second) | ||||||
| 3850 | assert(ValueExprMap.count(VE.first))((ValueExprMap.count(VE.first)) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.count(VE.first)", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3850, __PRETTY_FUNCTION__)); | ||||||
| 3851 | } | ||||||
| 3852 | #endif | ||||||
| 3853 | return &SI->second; | ||||||
| 3854 | } | ||||||
| 3855 | |||||||
| 3856 | /// Erase Value from ValueExprMap and ExprValueMap. ValueExprMap.erase(V) | ||||||
| 3857 | /// cannot be used separately. eraseValueFromMap should be used to remove | ||||||
| 3858 | /// V from ValueExprMap and ExprValueMap at the same time. | ||||||
| 3859 | void ScalarEvolution::eraseValueFromMap(Value *V) { | ||||||
| 3860 | ValueExprMapType::iterator I = ValueExprMap.find_as(V); | ||||||
| 3861 | if (I != ValueExprMap.end()) { | ||||||
| 3862 | const SCEV *S = I->second; | ||||||
| 3863 | // Remove {V, 0} from the set of ExprValueMap[S] | ||||||
| 3864 | if (SetVector<ValueOffsetPair> *SV = getSCEVValues(S)) | ||||||
| 3865 | SV->remove({V, nullptr}); | ||||||
| 3866 | |||||||
| 3867 | // Remove {V, Offset} from the set of ExprValueMap[Stripped] | ||||||
| 3868 | const SCEV *Stripped; | ||||||
| 3869 | ConstantInt *Offset; | ||||||
| 3870 | std::tie(Stripped, Offset) = splitAddExpr(S); | ||||||
| 3871 | if (Offset != nullptr) { | ||||||
| 3872 | if (SetVector<ValueOffsetPair> *SV = getSCEVValues(Stripped)) | ||||||
| 3873 | SV->remove({V, Offset}); | ||||||
| 3874 | } | ||||||
| 3875 | ValueExprMap.erase(V); | ||||||
| 3876 | } | ||||||
| 3877 | } | ||||||
| 3878 | |||||||
| 3879 | /// Check whether value has nuw/nsw/exact set but SCEV does not. | ||||||
| 3880 | /// TODO: In reality it is better to check the poison recursively | ||||||
| 3881 | /// but this is better than nothing. | ||||||
| 3882 | static bool SCEVLostPoisonFlags(const SCEV *S, const Value *V) { | ||||||
| 3883 | if (auto *I = dyn_cast<Instruction>(V)) { | ||||||
| 3884 | if (isa<OverflowingBinaryOperator>(I)) { | ||||||
| 3885 | if (auto *NS = dyn_cast<SCEVNAryExpr>(S)) { | ||||||
| 3886 | if (I->hasNoSignedWrap() && !NS->hasNoSignedWrap()) | ||||||
| 3887 | return true; | ||||||
| 3888 | if (I->hasNoUnsignedWrap() && !NS->hasNoUnsignedWrap()) | ||||||
| 3889 | return true; | ||||||
| 3890 | } | ||||||
| 3891 | } else if (isa<PossiblyExactOperator>(I) && I->isExact()) | ||||||
| 3892 | return true; | ||||||
| 3893 | } | ||||||
| 3894 | return false; | ||||||
| 3895 | } | ||||||
| 3896 | |||||||
| 3897 | /// Return an existing SCEV if it exists, otherwise analyze the expression and | ||||||
| 3898 | /// create a new one. | ||||||
| 3899 | const SCEV *ScalarEvolution::getSCEV(Value *V) { | ||||||
| 3900 | assert(isSCEVable(V->getType()) && "Value is not SCEVable!")((isSCEVable(V->getType()) && "Value is not SCEVable!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(V->getType()) && \"Value is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3900, __PRETTY_FUNCTION__)); | ||||||
| 3901 | |||||||
| 3902 | const SCEV *S = getExistingSCEV(V); | ||||||
| 3903 | if (S == nullptr) { | ||||||
| 3904 | S = createSCEV(V); | ||||||
| 3905 | // During PHI resolution, it is possible to create two SCEVs for the same | ||||||
| 3906 | // V, so it is needed to double check whether V->S is inserted into | ||||||
| 3907 | // ValueExprMap before insert S->{V, 0} into ExprValueMap. | ||||||
| 3908 | std::pair<ValueExprMapType::iterator, bool> Pair = | ||||||
| 3909 | ValueExprMap.insert({SCEVCallbackVH(V, this), S}); | ||||||
| 3910 | if (Pair.second && !SCEVLostPoisonFlags(S, V)) { | ||||||
| 3911 | ExprValueMap[S].insert({V, nullptr}); | ||||||
| 3912 | |||||||
| 3913 | // If S == Stripped + Offset, add Stripped -> {V, Offset} into | ||||||
| 3914 | // ExprValueMap. | ||||||
| 3915 | const SCEV *Stripped = S; | ||||||
| 3916 | ConstantInt *Offset = nullptr; | ||||||
| 3917 | std::tie(Stripped, Offset) = splitAddExpr(S); | ||||||
| 3918 | // If stripped is SCEVUnknown, don't bother to save | ||||||
| 3919 | // Stripped -> {V, offset}. It doesn't simplify and sometimes even | ||||||
| 3920 | // increase the complexity of the expansion code. | ||||||
| 3921 | // If V is GetElementPtrInst, don't save Stripped -> {V, offset} | ||||||
| 3922 | // because it may generate add/sub instead of GEP in SCEV expansion. | ||||||
| 3923 | if (Offset != nullptr && !isa<SCEVUnknown>(Stripped) && | ||||||
| 3924 | !isa<GetElementPtrInst>(V)) | ||||||
| 3925 | ExprValueMap[Stripped].insert({V, Offset}); | ||||||
| 3926 | } | ||||||
| 3927 | } | ||||||
| 3928 | return S; | ||||||
| 3929 | } | ||||||
| 3930 | |||||||
| 3931 | const SCEV *ScalarEvolution::getExistingSCEV(Value *V) { | ||||||
| 3932 | assert(isSCEVable(V->getType()) && "Value is not SCEVable!")((isSCEVable(V->getType()) && "Value is not SCEVable!" ) ? static_cast<void> (0) : __assert_fail ("isSCEVable(V->getType()) && \"Value is not SCEVable!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 3932, __PRETTY_FUNCTION__)); | ||||||
| 3933 | |||||||
| 3934 | ValueExprMapType::iterator I = ValueExprMap.find_as(V); | ||||||
| 3935 | if (I != ValueExprMap.end()) { | ||||||
| 3936 | const SCEV *S = I->second; | ||||||
| 3937 | if (checkValidity(S)) | ||||||
| 3938 | return S; | ||||||
| 3939 | eraseValueFromMap(V); | ||||||
| 3940 | forgetMemoizedResults(S); | ||||||
| 3941 | } | ||||||
| 3942 | return nullptr; | ||||||
| 3943 | } | ||||||
| 3944 | |||||||
| 3945 | /// Return a SCEV corresponding to -V = -1*V | ||||||
| 3946 | const SCEV *ScalarEvolution::getNegativeSCEV(const SCEV *V, | ||||||
| 3947 | SCEV::NoWrapFlags Flags) { | ||||||
| 3948 | if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V)) | ||||||
| 3949 | return getConstant( | ||||||
| 3950 | cast<ConstantInt>(ConstantExpr::getNeg(VC->getValue()))); | ||||||
| 3951 | |||||||
| 3952 | Type *Ty = V->getType(); | ||||||
| 3953 | Ty = getEffectiveSCEVType(Ty); | ||||||
| 3954 | return getMulExpr( | ||||||
| 3955 | V, getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))), Flags); | ||||||
| 3956 | } | ||||||
| 3957 | |||||||
| 3958 | /// If Expr computes ~A, return A else return nullptr | ||||||
| 3959 | static const SCEV *MatchNotExpr(const SCEV *Expr) { | ||||||
| 3960 | const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Expr); | ||||||
| 3961 | if (!Add || Add->getNumOperands() != 2 || | ||||||
| 3962 | !Add->getOperand(0)->isAllOnesValue()) | ||||||
| 3963 | return nullptr; | ||||||
| 3964 | |||||||
| 3965 | const SCEVMulExpr *AddRHS = dyn_cast<SCEVMulExpr>(Add->getOperand(1)); | ||||||
| 3966 | if (!AddRHS || AddRHS->getNumOperands() != 2 || | ||||||
| 3967 | !AddRHS->getOperand(0)->isAllOnesValue()) | ||||||
| 3968 | return nullptr; | ||||||
| 3969 | |||||||
| 3970 | return AddRHS->getOperand(1); | ||||||
| 3971 | } | ||||||
| 3972 | |||||||
| 3973 | /// Return a SCEV corresponding to ~V = -1-V | ||||||
| 3974 | const SCEV *ScalarEvolution::getNotSCEV(const SCEV *V) { | ||||||
| 3975 | if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V)) | ||||||
| 3976 | return getConstant( | ||||||
| 3977 | cast<ConstantInt>(ConstantExpr::getNot(VC->getValue()))); | ||||||
| 3978 | |||||||
| 3979 | // Fold ~(u|s)(min|max)(~x, ~y) to (u|s)(max|min)(x, y) | ||||||
| 3980 | if (const SCEVMinMaxExpr *MME = dyn_cast<SCEVMinMaxExpr>(V)) { | ||||||
| 3981 | auto MatchMinMaxNegation = [&](const SCEVMinMaxExpr *MME) { | ||||||
| 3982 | SmallVector<const SCEV *, 2> MatchedOperands; | ||||||
| 3983 | for (const SCEV *Operand : MME->operands()) { | ||||||
| 3984 | const SCEV *Matched = MatchNotExpr(Operand); | ||||||
| 3985 | if (!Matched) | ||||||
| 3986 | return (const SCEV *)nullptr; | ||||||
| 3987 | MatchedOperands.push_back(Matched); | ||||||
| 3988 | } | ||||||
| 3989 | return getMinMaxExpr( | ||||||
| 3990 | SCEVMinMaxExpr::negate(static_cast<SCEVTypes>(MME->getSCEVType())), | ||||||
| 3991 | MatchedOperands); | ||||||
| 3992 | }; | ||||||
| 3993 | if (const SCEV *Replaced = MatchMinMaxNegation(MME)) | ||||||
| 3994 | return Replaced; | ||||||
| 3995 | } | ||||||
| 3996 | |||||||
| 3997 | Type *Ty = V->getType(); | ||||||
| 3998 | Ty = getEffectiveSCEVType(Ty); | ||||||
| 3999 | const SCEV *AllOnes = | ||||||
| 4000 | getConstant(cast<ConstantInt>(Constant::getAllOnesValue(Ty))); | ||||||
| 4001 | return getMinusSCEV(AllOnes, V); | ||||||
| 4002 | } | ||||||
| 4003 | |||||||
| 4004 | const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS, | ||||||
| 4005 | SCEV::NoWrapFlags Flags, | ||||||
| 4006 | unsigned Depth) { | ||||||
| 4007 | // Fast path: X - X --> 0. | ||||||
| 4008 | if (LHS == RHS) | ||||||
| 4009 | return getZero(LHS->getType()); | ||||||
| 4010 | |||||||
| 4011 | // We represent LHS - RHS as LHS + (-1)*RHS. This transformation | ||||||
| 4012 | // makes it so that we cannot make much use of NUW. | ||||||
| 4013 | auto AddFlags = SCEV::FlagAnyWrap; | ||||||
| 4014 | const bool RHSIsNotMinSigned = | ||||||
| 4015 | !getSignedRangeMin(RHS).isMinSignedValue(); | ||||||
| 4016 | if (maskFlags(Flags, SCEV::FlagNSW) == SCEV::FlagNSW) { | ||||||
| 4017 | // Let M be the minimum representable signed value. Then (-1)*RHS | ||||||
| 4018 | // signed-wraps if and only if RHS is M. That can happen even for | ||||||
| 4019 | // a NSW subtraction because e.g. (-1)*M signed-wraps even though | ||||||
| 4020 | // -1 - M does not. So to transfer NSW from LHS - RHS to LHS + | ||||||
| 4021 | // (-1)*RHS, we need to prove that RHS != M. | ||||||
| 4022 | // | ||||||
| 4023 | // If LHS is non-negative and we know that LHS - RHS does not | ||||||
| 4024 | // signed-wrap, then RHS cannot be M. So we can rule out signed-wrap | ||||||
| 4025 | // either by proving that RHS > M or that LHS >= 0. | ||||||
| 4026 | if (RHSIsNotMinSigned || isKnownNonNegative(LHS)) { | ||||||
| 4027 | AddFlags = SCEV::FlagNSW; | ||||||
| 4028 | } | ||||||
| 4029 | } | ||||||
| 4030 | |||||||
| 4031 | // FIXME: Find a correct way to transfer NSW to (-1)*M when LHS - | ||||||
| 4032 | // RHS is NSW and LHS >= 0. | ||||||
| 4033 | // | ||||||
| 4034 | // The difficulty here is that the NSW flag may have been proven | ||||||
| 4035 | // relative to a loop that is to be found in a recurrence in LHS and | ||||||
| 4036 | // not in RHS. Applying NSW to (-1)*M may then let the NSW have a | ||||||
| 4037 | // larger scope than intended. | ||||||
| 4038 | auto NegFlags = RHSIsNotMinSigned ? SCEV::FlagNSW : SCEV::FlagAnyWrap; | ||||||
| 4039 | |||||||
| 4040 | return getAddExpr(LHS, getNegativeSCEV(RHS, NegFlags), AddFlags, Depth); | ||||||
| 4041 | } | ||||||
| 4042 | |||||||
| 4043 | const SCEV *ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V, Type *Ty, | ||||||
| 4044 | unsigned Depth) { | ||||||
| 4045 | Type *SrcTy = V->getType(); | ||||||
| 4046 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4047, __PRETTY_FUNCTION__)) | ||||||
| 4047 | "Cannot truncate or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4047, __PRETTY_FUNCTION__)); | ||||||
| 4048 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
| 4049 | return V; // No conversion | ||||||
| 4050 | if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty)) | ||||||
| 4051 | return getTruncateExpr(V, Ty, Depth); | ||||||
| 4052 | return getZeroExtendExpr(V, Ty, Depth); | ||||||
| 4053 | } | ||||||
| 4054 | |||||||
| 4055 | const SCEV *ScalarEvolution::getTruncateOrSignExtend(const SCEV *V, Type *Ty, | ||||||
| 4056 | unsigned Depth) { | ||||||
| 4057 | Type *SrcTy = V->getType(); | ||||||
| 4058 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4059, __PRETTY_FUNCTION__)) | ||||||
| 4059 | "Cannot truncate or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or zero extend with non-integer arguments!" ) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4059, __PRETTY_FUNCTION__)); | ||||||
| 4060 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
| 4061 | return V; // No conversion | ||||||
| 4062 | if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty)) | ||||||
| 4063 | return getTruncateExpr(V, Ty, Depth); | ||||||
| 4064 | return getSignExtendExpr(V, Ty, Depth); | ||||||
| 4065 | } | ||||||
| 4066 | |||||||
| 4067 | const SCEV * | ||||||
| 4068 | ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, Type *Ty) { | ||||||
| 4069 | Type *SrcTy = V->getType(); | ||||||
| 4070 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or zero extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4071, __PRETTY_FUNCTION__)) | ||||||
| 4071 | "Cannot noop or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or zero extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or zero extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4071, __PRETTY_FUNCTION__)); | ||||||
| 4072 | assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrZeroExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrZeroExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4073, __PRETTY_FUNCTION__)) | ||||||
| 4073 | "getNoopOrZeroExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrZeroExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrZeroExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4073, __PRETTY_FUNCTION__)); | ||||||
| 4074 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
| 4075 | return V; // No conversion | ||||||
| 4076 | return getZeroExtendExpr(V, Ty); | ||||||
| 4077 | } | ||||||
| 4078 | |||||||
| 4079 | const SCEV * | ||||||
| 4080 | ScalarEvolution::getNoopOrSignExtend(const SCEV *V, Type *Ty) { | ||||||
| 4081 | Type *SrcTy = V->getType(); | ||||||
| 4082 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or sign extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or sign extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4083, __PRETTY_FUNCTION__)) | ||||||
| 4083 | "Cannot noop or sign extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or sign extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or sign extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4083, __PRETTY_FUNCTION__)); | ||||||
| 4084 | assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrSignExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrSignExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4085, __PRETTY_FUNCTION__)) | ||||||
| 4085 | "getNoopOrSignExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrSignExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrSignExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4085, __PRETTY_FUNCTION__)); | ||||||
| 4086 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
| 4087 | return V; // No conversion | ||||||
| 4088 | return getSignExtendExpr(V, Ty); | ||||||
| 4089 | } | ||||||
| 4090 | |||||||
| 4091 | const SCEV * | ||||||
| 4092 | ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, Type *Ty) { | ||||||
| 4093 | Type *SrcTy = V->getType(); | ||||||
| 4094 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or any extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or any extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4095, __PRETTY_FUNCTION__)) | ||||||
| 4095 | "Cannot noop or any extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot noop or any extend with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or any extend with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4095, __PRETTY_FUNCTION__)); | ||||||
| 4096 | assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrAnyExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrAnyExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4097, __PRETTY_FUNCTION__)) | ||||||
| 4097 | "getNoopOrAnyExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && "getNoopOrAnyExtend cannot truncate!") ? static_cast<void > (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrAnyExtend cannot truncate!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4097, __PRETTY_FUNCTION__)); | ||||||
| 4098 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
| 4099 | return V; // No conversion | ||||||
| 4100 | return getAnyExtendExpr(V, Ty); | ||||||
| 4101 | } | ||||||
| 4102 | |||||||
| 4103 | const SCEV * | ||||||
| 4104 | ScalarEvolution::getTruncateOrNoop(const SCEV *V, Type *Ty) { | ||||||
| 4105 | Type *SrcTy = V->getType(); | ||||||
| 4106 | assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or noop with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or noop with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4107, __PRETTY_FUNCTION__)) | ||||||
| 4107 | "Cannot truncate or noop with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && "Cannot truncate or noop with non-integer arguments!") ? static_cast <void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or noop with non-integer arguments!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4107, __PRETTY_FUNCTION__)); | ||||||
| 4108 | assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && "getTruncateOrNoop cannot extend!") ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && \"getTruncateOrNoop cannot extend!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4109, __PRETTY_FUNCTION__)) | ||||||
| 4109 | "getTruncateOrNoop cannot extend!")((getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && "getTruncateOrNoop cannot extend!") ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && \"getTruncateOrNoop cannot extend!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4109, __PRETTY_FUNCTION__)); | ||||||
| 4110 | if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty)) | ||||||
| 4111 | return V; // No conversion | ||||||
| 4112 | return getTruncateExpr(V, Ty); | ||||||
| 4113 | } | ||||||
| 4114 | |||||||
| 4115 | const SCEV *ScalarEvolution::getUMaxFromMismatchedTypes(const SCEV *LHS, | ||||||
| 4116 | const SCEV *RHS) { | ||||||
| 4117 | const SCEV *PromotedLHS = LHS; | ||||||
| 4118 | const SCEV *PromotedRHS = RHS; | ||||||
| 4119 | |||||||
| 4120 | if (getTypeSizeInBits(LHS->getType()) > getTypeSizeInBits(RHS->getType())) | ||||||
| 4121 | PromotedRHS = getZeroExtendExpr(RHS, LHS->getType()); | ||||||
| 4122 | else | ||||||
| 4123 | PromotedLHS = getNoopOrZeroExtend(LHS, RHS->getType()); | ||||||
| 4124 | |||||||
| 4125 | return getUMaxExpr(PromotedLHS, PromotedRHS); | ||||||
| 4126 | } | ||||||
| 4127 | |||||||
| 4128 | const SCEV *ScalarEvolution::getUMinFromMismatchedTypes(const SCEV *LHS, | ||||||
| 4129 | const SCEV *RHS) { | ||||||
| 4130 | SmallVector<const SCEV *, 2> Ops = { LHS, RHS }; | ||||||
| 4131 | return getUMinFromMismatchedTypes(Ops); | ||||||
| 4132 | } | ||||||
| 4133 | |||||||
| 4134 | const SCEV *ScalarEvolution::getUMinFromMismatchedTypes( | ||||||
| 4135 | SmallVectorImpl<const SCEV *> &Ops) { | ||||||
| 4136 | assert(!Ops.empty() && "At least one operand must be!")((!Ops.empty() && "At least one operand must be!") ? static_cast <void> (0) : __assert_fail ("!Ops.empty() && \"At least one operand must be!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4136, __PRETTY_FUNCTION__)); | ||||||
| 4137 | // Trivial case. | ||||||
| 4138 | if (Ops.size() == 1) | ||||||
| 4139 | return Ops[0]; | ||||||
| 4140 | |||||||
| 4141 | // Find the max type first. | ||||||
| 4142 | Type *MaxType = nullptr; | ||||||
| 4143 | for (auto *S : Ops) | ||||||
| 4144 | if (MaxType) | ||||||
| 4145 | MaxType = getWiderType(MaxType, S->getType()); | ||||||
| 4146 | else | ||||||
| 4147 | MaxType = S->getType(); | ||||||
| 4148 | |||||||
| 4149 | // Extend all ops to max type. | ||||||
| 4150 | SmallVector<const SCEV *, 2> PromotedOps; | ||||||
| 4151 | for (auto *S : Ops) | ||||||
| 4152 | PromotedOps.push_back(getNoopOrZeroExtend(S, MaxType)); | ||||||
| 4153 | |||||||
| 4154 | // Generate umin. | ||||||
| 4155 | return getUMinExpr(PromotedOps); | ||||||
| 4156 | } | ||||||
| 4157 | |||||||
| 4158 | const SCEV *ScalarEvolution::getPointerBase(const SCEV *V) { | ||||||
| 4159 | // A pointer operand may evaluate to a nonpointer expression, such as null. | ||||||
| 4160 | if (!V->getType()->isPointerTy()) | ||||||
| 4161 | return V; | ||||||
| 4162 | |||||||
| 4163 | if (const SCEVCastExpr *Cast = dyn_cast<SCEVCastExpr>(V)) { | ||||||
| 4164 | return getPointerBase(Cast->getOperand()); | ||||||
| 4165 | } else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) { | ||||||
| 4166 | const SCEV *PtrOp = nullptr; | ||||||
| 4167 | for (const SCEV *NAryOp : NAry->operands()) { | ||||||
| 4168 | if (NAryOp->getType()->isPointerTy()) { | ||||||
| 4169 | // Cannot find the base of an expression with multiple pointer operands. | ||||||
| 4170 | if (PtrOp) | ||||||
| 4171 | return V; | ||||||
| 4172 | PtrOp = NAryOp; | ||||||
| 4173 | } | ||||||
| 4174 | } | ||||||
| 4175 | if (!PtrOp) | ||||||
| 4176 | return V; | ||||||
| 4177 | return getPointerBase(PtrOp); | ||||||
| 4178 | } | ||||||
| 4179 | return V; | ||||||
| 4180 | } | ||||||
| 4181 | |||||||
| 4182 | /// Push users of the given Instruction onto the given Worklist. | ||||||
| 4183 | static void | ||||||
| 4184 | PushDefUseChildren(Instruction *I, | ||||||
| 4185 | SmallVectorImpl<Instruction *> &Worklist) { | ||||||
| 4186 | // Push the def-use children onto the Worklist stack. | ||||||
| 4187 | for (User *U : I->users()) | ||||||
| 4188 | Worklist.push_back(cast<Instruction>(U)); | ||||||
| 4189 | } | ||||||
| 4190 | |||||||
| 4191 | void ScalarEvolution::forgetSymbolicName(Instruction *PN, const SCEV *SymName) { | ||||||
| 4192 | SmallVector<Instruction *, 16> Worklist; | ||||||
| 4193 | PushDefUseChildren(PN, Worklist); | ||||||
| 4194 | |||||||
| 4195 | SmallPtrSet<Instruction *, 8> Visited; | ||||||
| 4196 | Visited.insert(PN); | ||||||
| 4197 | while (!Worklist.empty()) { | ||||||
| 4198 | Instruction *I = Worklist.pop_back_val(); | ||||||
| 4199 | if (!Visited.insert(I).second) | ||||||
| 4200 | continue; | ||||||
| 4201 | |||||||
| 4202 | auto It = ValueExprMap.find_as(static_cast<Value *>(I)); | ||||||
| 4203 | if (It != ValueExprMap.end()) { | ||||||
| 4204 | const SCEV *Old = It->second; | ||||||
| 4205 | |||||||
| 4206 | // Short-circuit the def-use traversal if the symbolic name | ||||||
| 4207 | // ceases to appear in expressions. | ||||||
| 4208 | if (Old != SymName && !hasOperand(Old, SymName)) | ||||||
| 4209 | continue; | ||||||
| 4210 | |||||||
| 4211 | // SCEVUnknown for a PHI either means that it has an unrecognized | ||||||
| 4212 | // structure, it's a PHI that's in the progress of being computed | ||||||
| 4213 | // by createNodeForPHI, or it's a single-value PHI. In the first case, | ||||||
| 4214 | // additional loop trip count information isn't going to change anything. | ||||||
| 4215 | // In the second case, createNodeForPHI will perform the necessary | ||||||
| 4216 | // updates on its own when it gets to that point. In the third, we do | ||||||
| 4217 | // want to forget the SCEVUnknown. | ||||||
| 4218 | if (!isa<PHINode>(I) || | ||||||
| 4219 | !isa<SCEVUnknown>(Old) || | ||||||
| 4220 | (I != PN && Old == SymName)) { | ||||||
| 4221 | eraseValueFromMap(It->first); | ||||||
| 4222 | forgetMemoizedResults(Old); | ||||||
| 4223 | } | ||||||
| 4224 | } | ||||||
| 4225 | |||||||
| 4226 | PushDefUseChildren(I, Worklist); | ||||||
| 4227 | } | ||||||
| 4228 | } | ||||||
| 4229 | |||||||
| 4230 | namespace { | ||||||
| 4231 | |||||||
| 4232 | /// Takes SCEV S and Loop L. For each AddRec sub-expression, use its start | ||||||
| 4233 | /// expression in case its Loop is L. If it is not L then | ||||||
| 4234 | /// if IgnoreOtherLoops is true then use AddRec itself | ||||||
| 4235 | /// otherwise rewrite cannot be done. | ||||||
| 4236 | /// If SCEV contains non-invariant unknown SCEV rewrite cannot be done. | ||||||
| 4237 | class SCEVInitRewriter : public SCEVRewriteVisitor<SCEVInitRewriter> { | ||||||
| 4238 | public: | ||||||
| 4239 | static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE, | ||||||
| 4240 | bool IgnoreOtherLoops = true) { | ||||||
| 4241 | SCEVInitRewriter Rewriter(L, SE); | ||||||
| 4242 | const SCEV *Result = Rewriter.visit(S); | ||||||
| 4243 | if (Rewriter.hasSeenLoopVariantSCEVUnknown()) | ||||||
| 4244 | return SE.getCouldNotCompute(); | ||||||
| 4245 | return Rewriter.hasSeenOtherLoops() && !IgnoreOtherLoops | ||||||
| 4246 | ? SE.getCouldNotCompute() | ||||||
| 4247 | : Result; | ||||||
| 4248 | } | ||||||
| 4249 | |||||||
| 4250 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
| 4251 | if (!SE.isLoopInvariant(Expr, L)) | ||||||
| 4252 | SeenLoopVariantSCEVUnknown = true; | ||||||
| 4253 | return Expr; | ||||||
| 4254 | } | ||||||
| 4255 | |||||||
| 4256 | const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { | ||||||
| 4257 | // Only re-write AddRecExprs for this loop. | ||||||
| 4258 | if (Expr->getLoop() == L) | ||||||
| 4259 | return Expr->getStart(); | ||||||
| 4260 | SeenOtherLoops = true; | ||||||
| 4261 | return Expr; | ||||||
| 4262 | } | ||||||
| 4263 | |||||||
| 4264 | bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; } | ||||||
| 4265 | |||||||
| 4266 | bool hasSeenOtherLoops() { return SeenOtherLoops; } | ||||||
| 4267 | |||||||
| 4268 | private: | ||||||
| 4269 | explicit SCEVInitRewriter(const Loop *L, ScalarEvolution &SE) | ||||||
| 4270 | : SCEVRewriteVisitor(SE), L(L) {} | ||||||
| 4271 | |||||||
| 4272 | const Loop *L; | ||||||
| 4273 | bool SeenLoopVariantSCEVUnknown = false; | ||||||
| 4274 | bool SeenOtherLoops = false; | ||||||
| 4275 | }; | ||||||
| 4276 | |||||||
| 4277 | /// Takes SCEV S and Loop L. For each AddRec sub-expression, use its post | ||||||
| 4278 | /// increment expression in case its Loop is L. If it is not L then | ||||||
| 4279 | /// use AddRec itself. | ||||||
| 4280 | /// If SCEV contains non-invariant unknown SCEV rewrite cannot be done. | ||||||
| 4281 | class SCEVPostIncRewriter : public SCEVRewriteVisitor<SCEVPostIncRewriter> { | ||||||
| 4282 | public: | ||||||
| 4283 | static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE) { | ||||||
| 4284 | SCEVPostIncRewriter Rewriter(L, SE); | ||||||
| 4285 | const SCEV *Result = Rewriter.visit(S); | ||||||
| 4286 | return Rewriter.hasSeenLoopVariantSCEVUnknown() | ||||||
| 4287 | ? SE.getCouldNotCompute() | ||||||
| 4288 | : Result; | ||||||
| 4289 | } | ||||||
| 4290 | |||||||
| 4291 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
| 4292 | if (!SE.isLoopInvariant(Expr, L)) | ||||||
| 4293 | SeenLoopVariantSCEVUnknown = true; | ||||||
| 4294 | return Expr; | ||||||
| 4295 | } | ||||||
| 4296 | |||||||
| 4297 | const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { | ||||||
| 4298 | // Only re-write AddRecExprs for this loop. | ||||||
| 4299 | if (Expr->getLoop() == L) | ||||||
| 4300 | return Expr->getPostIncExpr(SE); | ||||||
| 4301 | SeenOtherLoops = true; | ||||||
| 4302 | return Expr; | ||||||
| 4303 | } | ||||||
| 4304 | |||||||
| 4305 | bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; } | ||||||
| 4306 | |||||||
| 4307 | bool hasSeenOtherLoops() { return SeenOtherLoops; } | ||||||
| 4308 | |||||||
| 4309 | private: | ||||||
| 4310 | explicit SCEVPostIncRewriter(const Loop *L, ScalarEvolution &SE) | ||||||
| 4311 | : SCEVRewriteVisitor(SE), L(L) {} | ||||||
| 4312 | |||||||
| 4313 | const Loop *L; | ||||||
| 4314 | bool SeenLoopVariantSCEVUnknown = false; | ||||||
| 4315 | bool SeenOtherLoops = false; | ||||||
| 4316 | }; | ||||||
| 4317 | |||||||
| 4318 | /// This class evaluates the compare condition by matching it against the | ||||||
| 4319 | /// condition of loop latch. If there is a match we assume a true value | ||||||
| 4320 | /// for the condition while building SCEV nodes. | ||||||
| 4321 | class SCEVBackedgeConditionFolder | ||||||
| 4322 | : public SCEVRewriteVisitor<SCEVBackedgeConditionFolder> { | ||||||
| 4323 | public: | ||||||
| 4324 | static const SCEV *rewrite(const SCEV *S, const Loop *L, | ||||||
| 4325 | ScalarEvolution &SE) { | ||||||
| 4326 | bool IsPosBECond = false; | ||||||
| 4327 | Value *BECond = nullptr; | ||||||
| 4328 | if (BasicBlock *Latch = L->getLoopLatch()) { | ||||||
| 4329 | BranchInst *BI = dyn_cast<BranchInst>(Latch->getTerminator()); | ||||||
| 4330 | if (BI && BI->isConditional()) { | ||||||
| 4331 | assert(BI->getSuccessor(0) != BI->getSuccessor(1) &&((BI->getSuccessor(0) != BI->getSuccessor(1) && "Both outgoing branches should not target same header!") ? static_cast <void> (0) : __assert_fail ("BI->getSuccessor(0) != BI->getSuccessor(1) && \"Both outgoing branches should not target same header!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4332, __PRETTY_FUNCTION__)) | ||||||
| 4332 | "Both outgoing branches should not target same header!")((BI->getSuccessor(0) != BI->getSuccessor(1) && "Both outgoing branches should not target same header!") ? static_cast <void> (0) : __assert_fail ("BI->getSuccessor(0) != BI->getSuccessor(1) && \"Both outgoing branches should not target same header!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4332, __PRETTY_FUNCTION__)); | ||||||
| 4333 | BECond = BI->getCondition(); | ||||||
| 4334 | IsPosBECond = BI->getSuccessor(0) == L->getHeader(); | ||||||
| 4335 | } else { | ||||||
| 4336 | return S; | ||||||
| 4337 | } | ||||||
| 4338 | } | ||||||
| 4339 | SCEVBackedgeConditionFolder Rewriter(L, BECond, IsPosBECond, SE); | ||||||
| 4340 | return Rewriter.visit(S); | ||||||
| 4341 | } | ||||||
| 4342 | |||||||
| 4343 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
| 4344 | const SCEV *Result = Expr; | ||||||
| 4345 | bool InvariantF = SE.isLoopInvariant(Expr, L); | ||||||
| 4346 | |||||||
| 4347 | if (!InvariantF) { | ||||||
| 4348 | Instruction *I = cast<Instruction>(Expr->getValue()); | ||||||
| 4349 | switch (I->getOpcode()) { | ||||||
| 4350 | case Instruction::Select: { | ||||||
| 4351 | SelectInst *SI = cast<SelectInst>(I); | ||||||
| 4352 | Optional<const SCEV *> Res = | ||||||
| 4353 | compareWithBackedgeCondition(SI->getCondition()); | ||||||
| 4354 | if (Res.hasValue()) { | ||||||
| 4355 | bool IsOne = cast<SCEVConstant>(Res.getValue())->getValue()->isOne(); | ||||||
| 4356 | Result = SE.getSCEV(IsOne ? SI->getTrueValue() : SI->getFalseValue()); | ||||||
| 4357 | } | ||||||
| 4358 | break; | ||||||
| 4359 | } | ||||||
| 4360 | default: { | ||||||
| 4361 | Optional<const SCEV *> Res = compareWithBackedgeCondition(I); | ||||||
| 4362 | if (Res.hasValue()) | ||||||
| 4363 | Result = Res.getValue(); | ||||||
| 4364 | break; | ||||||
| 4365 | } | ||||||
| 4366 | } | ||||||
| 4367 | } | ||||||
| 4368 | return Result; | ||||||
| 4369 | } | ||||||
| 4370 | |||||||
| 4371 | private: | ||||||
| 4372 | explicit SCEVBackedgeConditionFolder(const Loop *L, Value *BECond, | ||||||
| 4373 | bool IsPosBECond, ScalarEvolution &SE) | ||||||
| 4374 | : SCEVRewriteVisitor(SE), L(L), BackedgeCond(BECond), | ||||||
| 4375 | IsPositiveBECond(IsPosBECond) {} | ||||||
| 4376 | |||||||
| 4377 | Optional<const SCEV *> compareWithBackedgeCondition(Value *IC); | ||||||
| 4378 | |||||||
| 4379 | const Loop *L; | ||||||
| 4380 | /// Loop back condition. | ||||||
| 4381 | Value *BackedgeCond = nullptr; | ||||||
| 4382 | /// Set to true if loop back is on positive branch condition. | ||||||
| 4383 | bool IsPositiveBECond; | ||||||
| 4384 | }; | ||||||
| 4385 | |||||||
| 4386 | Optional<const SCEV *> | ||||||
| 4387 | SCEVBackedgeConditionFolder::compareWithBackedgeCondition(Value *IC) { | ||||||
| 4388 | |||||||
| 4389 | // If value matches the backedge condition for loop latch, | ||||||
| 4390 | // then return a constant evolution node based on loopback | ||||||
| 4391 | // branch taken. | ||||||
| 4392 | if (BackedgeCond == IC) | ||||||
| 4393 | return IsPositiveBECond ? SE.getOne(Type::getInt1Ty(SE.getContext())) | ||||||
| 4394 | : SE.getZero(Type::getInt1Ty(SE.getContext())); | ||||||
| 4395 | return None; | ||||||
| 4396 | } | ||||||
| 4397 | |||||||
| 4398 | class SCEVShiftRewriter : public SCEVRewriteVisitor<SCEVShiftRewriter> { | ||||||
| 4399 | public: | ||||||
| 4400 | static const SCEV *rewrite(const SCEV *S, const Loop *L, | ||||||
| 4401 | ScalarEvolution &SE) { | ||||||
| 4402 | SCEVShiftRewriter Rewriter(L, SE); | ||||||
| 4403 | const SCEV *Result = Rewriter.visit(S); | ||||||
| 4404 | return Rewriter.isValid() ? Result : SE.getCouldNotCompute(); | ||||||
| 4405 | } | ||||||
| 4406 | |||||||
| 4407 | const SCEV *visitUnknown(const SCEVUnknown *Expr) { | ||||||
| 4408 | // Only allow AddRecExprs for this loop. | ||||||
| 4409 | if (!SE.isLoopInvariant(Expr, L)) | ||||||
| 4410 | Valid = false; | ||||||
| 4411 | return Expr; | ||||||
| 4412 | } | ||||||
| 4413 | |||||||
| 4414 | const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { | ||||||
| 4415 | if (Expr->getLoop() == L && Expr->isAffine()) | ||||||
| 4416 | return SE.getMinusSCEV(Expr, Expr->getStepRecurrence(SE)); | ||||||
| 4417 | Valid = false; | ||||||
| 4418 | return Expr; | ||||||
| 4419 | } | ||||||
| 4420 | |||||||
| 4421 | bool isValid() { return Valid; } | ||||||
| 4422 | |||||||
| 4423 | private: | ||||||
| 4424 | explicit SCEVShiftRewriter(const Loop *L, ScalarEvolution &SE) | ||||||
| 4425 | : SCEVRewriteVisitor(SE), L(L) {} | ||||||
| 4426 | |||||||
| 4427 | const Loop *L; | ||||||
| 4428 | bool Valid = true; | ||||||
| 4429 | }; | ||||||
| 4430 | |||||||
| 4431 | } // end anonymous namespace | ||||||
| 4432 | |||||||
| 4433 | SCEV::NoWrapFlags | ||||||
| 4434 | ScalarEvolution::proveNoWrapViaConstantRanges(const SCEVAddRecExpr *AR) { | ||||||
| 4435 | if (!AR->isAffine()) | ||||||
| 4436 | return SCEV::FlagAnyWrap; | ||||||
| 4437 | |||||||
| 4438 | using OBO = OverflowingBinaryOperator; | ||||||
| 4439 | |||||||
| 4440 | SCEV::NoWrapFlags Result = SCEV::FlagAnyWrap; | ||||||
| 4441 | |||||||
| 4442 | if (!AR->hasNoSignedWrap()) { | ||||||
| 4443 | ConstantRange AddRecRange = getSignedRange(AR); | ||||||
| 4444 | ConstantRange IncRange = getSignedRange(AR->getStepRecurrence(*this)); | ||||||
| 4445 | |||||||
| 4446 | auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
| 4447 | Instruction::Add, IncRange, OBO::NoSignedWrap); | ||||||
| 4448 | if (NSWRegion.contains(AddRecRange)) | ||||||
| 4449 | Result = ScalarEvolution::setFlags(Result, SCEV::FlagNSW); | ||||||
| 4450 | } | ||||||
| 4451 | |||||||
| 4452 | if (!AR->hasNoUnsignedWrap()) { | ||||||
| 4453 | ConstantRange AddRecRange = getUnsignedRange(AR); | ||||||
| 4454 | ConstantRange IncRange = getUnsignedRange(AR->getStepRecurrence(*this)); | ||||||
| 4455 | |||||||
| 4456 | auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion( | ||||||
| 4457 | Instruction::Add, IncRange, OBO::NoUnsignedWrap); | ||||||
| 4458 | if (NUWRegion.contains(AddRecRange)) | ||||||
| 4459 | Result = ScalarEvolution::setFlags(Result, SCEV::FlagNUW); | ||||||
| 4460 | } | ||||||
| 4461 | |||||||
| 4462 | return Result; | ||||||
| 4463 | } | ||||||
| 4464 | |||||||
| 4465 | namespace { | ||||||
| 4466 | |||||||
| 4467 | /// Represents an abstract binary operation. This may exist as a | ||||||
| 4468 | /// normal instruction or constant expression, or may have been | ||||||
| 4469 | /// derived from an expression tree. | ||||||
| 4470 | struct BinaryOp { | ||||||
| 4471 | unsigned Opcode; | ||||||
| 4472 | Value *LHS; | ||||||
| 4473 | Value *RHS; | ||||||
| 4474 | bool IsNSW = false; | ||||||
| 4475 | bool IsNUW = false; | ||||||
| 4476 | |||||||
| 4477 | /// Op is set if this BinaryOp corresponds to a concrete LLVM instruction or | ||||||
| 4478 | /// constant expression. | ||||||
| 4479 | Operator *Op = nullptr; | ||||||
| 4480 | |||||||
| 4481 | explicit BinaryOp(Operator *Op) | ||||||
| 4482 | : Opcode(Op->getOpcode()), LHS(Op->getOperand(0)), RHS(Op->getOperand(1)), | ||||||
| 4483 | Op(Op) { | ||||||
| 4484 | if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(Op)) { | ||||||
| 4485 | IsNSW = OBO->hasNoSignedWrap(); | ||||||
| 4486 | IsNUW = OBO->hasNoUnsignedWrap(); | ||||||
| 4487 | } | ||||||
| 4488 | } | ||||||
| 4489 | |||||||
| 4490 | explicit BinaryOp(unsigned Opcode, Value *LHS, Value *RHS, bool IsNSW = false, | ||||||
| 4491 | bool IsNUW = false) | ||||||
| 4492 | : Opcode(Opcode), LHS(LHS), RHS(RHS), IsNSW(IsNSW), IsNUW(IsNUW) {} | ||||||
| 4493 | }; | ||||||
| 4494 | |||||||
| 4495 | } // end anonymous namespace | ||||||
| 4496 | |||||||
| 4497 | /// Try to map \p V into a BinaryOp, and return \c None on failure. | ||||||
| 4498 | static Optional<BinaryOp> MatchBinaryOp(Value *V, DominatorTree &DT) { | ||||||
| 4499 | auto *Op = dyn_cast<Operator>(V); | ||||||
| 4500 | if (!Op
| ||||||
| 4501 | return None; | ||||||
| 4502 | |||||||
| 4503 | // Implementation detail: all the cleverness here should happen without | ||||||
| 4504 | // creating new SCEV expressions -- our caller knowns tricks to avoid creating | ||||||
| 4505 | // SCEV expressions when possible, and we should not break that. | ||||||
| 4506 | |||||||
| 4507 | switch (Op->getOpcode()) { | ||||||
| 4508 | case Instruction::Add: | ||||||
| 4509 | case Instruction::Sub: | ||||||
| 4510 | case Instruction::Mul: | ||||||
| 4511 | case Instruction::UDiv: | ||||||
| 4512 | case Instruction::URem: | ||||||
| 4513 | case Instruction::And: | ||||||
| 4514 | case Instruction::Or: | ||||||
| 4515 | case Instruction::AShr: | ||||||
| 4516 | case Instruction::Shl: | ||||||
| 4517 | return BinaryOp(Op); | ||||||
| 4518 | |||||||
| 4519 | case Instruction::Xor: | ||||||
| 4520 | if (auto *RHSC = dyn_cast<ConstantInt>(Op->getOperand(1))) | ||||||
| 4521 | // If the RHS of the xor is a signmask, then this is just an add. | ||||||
| 4522 | // Instcombine turns add of signmask into xor as a strength reduction step. | ||||||
| 4523 | if (RHSC->getValue().isSignMask()) | ||||||
| 4524 | return BinaryOp(Instruction::Add, Op->getOperand(0), Op->getOperand(1)); | ||||||
| 4525 | return BinaryOp(Op); | ||||||
| 4526 | |||||||
| 4527 | case Instruction::LShr: | ||||||
| 4528 | // Turn logical shift right of a constant into a unsigned divide. | ||||||
| 4529 | if (ConstantInt *SA = dyn_cast<ConstantInt>(Op->getOperand(1))) { | ||||||
| 4530 | uint32_t BitWidth = cast<IntegerType>(Op->getType())->getBitWidth(); | ||||||
| 4531 | |||||||
| 4532 | // If the shift count is not less than the bitwidth, the result of | ||||||
| 4533 | // the shift is undefined. Don't try to analyze it, because the | ||||||
| 4534 | // resolution chosen here may differ from the resolution chosen in | ||||||
| 4535 | // other parts of the compiler. | ||||||
| 4536 | if (SA->getValue().ult(BitWidth)) { | ||||||
| 4537 | Constant *X = | ||||||
| 4538 | ConstantInt::get(SA->getContext(), | ||||||
| 4539 | APInt::getOneBitSet(BitWidth, SA->getZExtValue())); | ||||||
| 4540 | return BinaryOp(Instruction::UDiv, Op->getOperand(0), X); | ||||||
| 4541 | } | ||||||
| 4542 | } | ||||||
| 4543 | return BinaryOp(Op); | ||||||
| 4544 | |||||||
| 4545 | case Instruction::ExtractValue: { | ||||||
| 4546 | auto *EVI = cast<ExtractValueInst>(Op); | ||||||
| 4547 | if (EVI->getNumIndices() != 1 || EVI->getIndices()[0] != 0) | ||||||
| 4548 | break; | ||||||
| 4549 | |||||||
| 4550 | auto *WO = dyn_cast<WithOverflowInst>(EVI->getAggregateOperand()); | ||||||
| 4551 | if (!WO) | ||||||
| 4552 | break; | ||||||
| 4553 | |||||||
| 4554 | Instruction::BinaryOps BinOp = WO->getBinaryOp(); | ||||||
| 4555 | bool Signed = WO->isSigned(); | ||||||
| 4556 | // TODO: Should add nuw/nsw flags for mul as well. | ||||||
| 4557 | if (BinOp == Instruction::Mul || !isOverflowIntrinsicNoWrap(WO, DT)) | ||||||
| 4558 | return BinaryOp(BinOp, WO->getLHS(), WO->getRHS()); | ||||||
| 4559 | |||||||
| 4560 | // Now that we know that all uses of the arithmetic-result component of | ||||||
| 4561 | // CI are guarded by the overflow check, we can go ahead and pretend | ||||||
| 4562 | // that the arithmetic is non-overflowing. | ||||||
| 4563 | return BinaryOp(BinOp, WO->getLHS(), WO->getRHS(), | ||||||
| 4564 | /* IsNSW = */ Signed, /* IsNUW = */ !Signed); | ||||||
| 4565 | } | ||||||
| 4566 | |||||||
| 4567 | default: | ||||||
| 4568 | break; | ||||||
| 4569 | } | ||||||
| 4570 | |||||||
| 4571 | return None; | ||||||
| 4572 | } | ||||||
| 4573 | |||||||
| 4574 | /// Helper function to createAddRecFromPHIWithCasts. We have a phi | ||||||
| 4575 | /// node whose symbolic (unknown) SCEV is \p SymbolicPHI, which is updated via | ||||||
| 4576 | /// the loop backedge by a SCEVAddExpr, possibly also with a few casts on the | ||||||
| 4577 | /// way. This function checks if \p Op, an operand of this SCEVAddExpr, | ||||||
| 4578 | /// follows one of the following patterns: | ||||||
| 4579 | /// Op == (SExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) | ||||||
| 4580 | /// Op == (ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) | ||||||
| 4581 | /// If the SCEV expression of \p Op conforms with one of the expected patterns | ||||||
| 4582 | /// we return the type of the truncation operation, and indicate whether the | ||||||
| 4583 | /// truncated type should be treated as signed/unsigned by setting | ||||||
| 4584 | /// \p Signed to true/false, respectively. | ||||||
| 4585 | static Type *isSimpleCastedPHI(const SCEV *Op, const SCEVUnknown *SymbolicPHI, | ||||||
| 4586 | bool &Signed, ScalarEvolution &SE) { | ||||||
| 4587 | // The case where Op == SymbolicPHI (that is, with no type conversions on | ||||||
| 4588 | // the way) is handled by the regular add recurrence creating logic and | ||||||
| 4589 | // would have already been triggered in createAddRecForPHI. Reaching it here | ||||||
| 4590 | // means that createAddRecFromPHI had failed for this PHI before (e.g., | ||||||
| 4591 | // because one of the other operands of the SCEVAddExpr updating this PHI is | ||||||
| 4592 | // not invariant). | ||||||
| 4593 | // | ||||||
| 4594 | // Here we look for the case where Op = (ext(trunc(SymbolicPHI))), and in | ||||||
| 4595 | // this case predicates that allow us to prove that Op == SymbolicPHI will | ||||||
| 4596 | // be added. | ||||||
| 4597 | if (Op == SymbolicPHI) | ||||||
| 4598 | return nullptr; | ||||||
| 4599 | |||||||
| 4600 | unsigned SourceBits = SE.getTypeSizeInBits(SymbolicPHI->getType()); | ||||||
| 4601 | unsigned NewBits = SE.getTypeSizeInBits(Op->getType()); | ||||||
| 4602 | if (SourceBits != NewBits) | ||||||
| 4603 | return nullptr; | ||||||
| 4604 | |||||||
| 4605 | const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(Op); | ||||||
| 4606 | const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(Op); | ||||||
| 4607 | if (!SExt && !ZExt) | ||||||
| 4608 | return nullptr; | ||||||
| 4609 | const SCEVTruncateExpr *Trunc = | ||||||
| 4610 | SExt ? dyn_cast<SCEVTruncateExpr>(SExt->getOperand()) | ||||||
| 4611 | : dyn_cast<SCEVTruncateExpr>(ZExt->getOperand()); | ||||||
| 4612 | if (!Trunc) | ||||||
| 4613 | return nullptr; | ||||||
| 4614 | const SCEV *X = Trunc->getOperand(); | ||||||
| 4615 | if (X != SymbolicPHI) | ||||||
| 4616 | return nullptr; | ||||||
| 4617 | Signed = SExt != nullptr; | ||||||
| 4618 | return Trunc->getType(); | ||||||
| 4619 | } | ||||||
| 4620 | |||||||
| 4621 | static const Loop *isIntegerLoopHeaderPHI(const PHINode *PN, LoopInfo &LI) { | ||||||
| 4622 | if (!PN->getType()->isIntegerTy()) | ||||||
| 4623 | return nullptr; | ||||||
| 4624 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
| 4625 | if (!L || L->getHeader() != PN->getParent()) | ||||||
| 4626 | return nullptr; | ||||||
| 4627 | return L; | ||||||
| 4628 | } | ||||||
| 4629 | |||||||
| 4630 | // Analyze \p SymbolicPHI, a SCEV expression of a phi node, and check if the | ||||||
| 4631 | // computation that updates the phi follows the following pattern: | ||||||
| 4632 | // (SExt/ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) + InvariantAccum | ||||||
| 4633 | // which correspond to a phi->trunc->sext/zext->add->phi update chain. | ||||||
| 4634 | // If so, try to see if it can be rewritten as an AddRecExpr under some | ||||||
| 4635 | // Predicates. If successful, return them as a pair. Also cache the results | ||||||
| 4636 | // of the analysis. | ||||||
| 4637 | // | ||||||
| 4638 | // Example usage scenario: | ||||||
| 4639 | // Say the Rewriter is called for the following SCEV: | ||||||
| 4640 | // 8 * ((sext i32 (trunc i64 %X to i32) to i64) + %Step) | ||||||
| 4641 | // where: | ||||||
| 4642 | // %X = phi i64 (%Start, %BEValue) | ||||||
| 4643 | // It will visitMul->visitAdd->visitSExt->visitTrunc->visitUnknown(%X), | ||||||
| 4644 | // and call this function with %SymbolicPHI = %X. | ||||||
| 4645 | // | ||||||
| 4646 | // The analysis will find that the value coming around the backedge has | ||||||
| 4647 | // the following SCEV: | ||||||
| 4648 | // BEValue = ((sext i32 (trunc i64 %X to i32) to i64) + %Step) | ||||||
| 4649 | // Upon concluding that this matches the desired pattern, the function | ||||||
| 4650 | // will return the pair {NewAddRec, SmallPredsVec} where: | ||||||
| 4651 | // NewAddRec = {%Start,+,%Step} | ||||||
| 4652 | // SmallPredsVec = {P1, P2, P3} as follows: | ||||||
| 4653 | // P1(WrapPred): AR: {trunc(%Start),+,(trunc %Step)}<nsw> Flags: <nssw> | ||||||
| 4654 | // P2(EqualPred): %Start == (sext i32 (trunc i64 %Start to i32) to i64) | ||||||
| 4655 | // P3(EqualPred): %Step == (sext i32 (trunc i64 %Step to i32) to i64) | ||||||
| 4656 | // The returned pair means that SymbolicPHI can be rewritten into NewAddRec | ||||||
| 4657 | // under the predicates {P1,P2,P3}. | ||||||
| 4658 | // This predicated rewrite will be cached in PredicatedSCEVRewrites: | ||||||
| 4659 | // PredicatedSCEVRewrites[{%X,L}] = {NewAddRec, {P1,P2,P3)} | ||||||
| 4660 | // | ||||||
| 4661 | // TODO's: | ||||||
| 4662 | // | ||||||
| 4663 | // 1) Extend the Induction descriptor to also support inductions that involve | ||||||
| 4664 | // casts: When needed (namely, when we are called in the context of the | ||||||
| 4665 | // vectorizer induction analysis), a Set of cast instructions will be | ||||||
| 4666 | // populated by this method, and provided back to isInductionPHI. This is | ||||||
| 4667 | // needed to allow the vectorizer to properly record them to be ignored by | ||||||
| 4668 | // the cost model and to avoid vectorizing them (otherwise these casts, | ||||||
| 4669 | // which are redundant under the runtime overflow checks, will be | ||||||
| 4670 | // vectorized, which can be costly). | ||||||
| 4671 | // | ||||||
| 4672 | // 2) Support additional induction/PHISCEV patterns: We also want to support | ||||||
| 4673 | // inductions where the sext-trunc / zext-trunc operations (partly) occur | ||||||
| 4674 | // after the induction update operation (the induction increment): | ||||||
| 4675 | // | ||||||
| 4676 | // (Trunc iy (SExt/ZExt ix (%SymbolicPHI + InvariantAccum) to iy) to ix) | ||||||
| 4677 | // which correspond to a phi->add->trunc->sext/zext->phi update chain. | ||||||
| 4678 | // | ||||||
| 4679 | // (Trunc iy ((SExt/ZExt ix (%SymbolicPhi) to iy) + InvariantAccum) to ix) | ||||||
| 4680 | // which correspond to a phi->trunc->add->sext/zext->phi update chain. | ||||||
| 4681 | // | ||||||
| 4682 | // 3) Outline common code with createAddRecFromPHI to avoid duplication. | ||||||
| 4683 | Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>> | ||||||
| 4684 | ScalarEvolution::createAddRecFromPHIWithCastsImpl(const SCEVUnknown *SymbolicPHI) { | ||||||
| 4685 | SmallVector<const SCEVPredicate *, 3> Predicates; | ||||||
| 4686 | |||||||
| 4687 | // *** Part1: Analyze if we have a phi-with-cast pattern for which we can | ||||||
| 4688 | // return an AddRec expression under some predicate. | ||||||
| 4689 | |||||||
| 4690 | auto *PN = cast<PHINode>(SymbolicPHI->getValue()); | ||||||
| 4691 | const Loop *L = isIntegerLoopHeaderPHI(PN, LI); | ||||||
| 4692 | assert(L && "Expecting an integer loop header phi")((L && "Expecting an integer loop header phi") ? static_cast <void> (0) : __assert_fail ("L && \"Expecting an integer loop header phi\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4692, __PRETTY_FUNCTION__)); | ||||||
| 4693 | |||||||
| 4694 | // The loop may have multiple entrances or multiple exits; we can analyze | ||||||
| 4695 | // this phi as an addrec if it has a unique entry value and a unique | ||||||
| 4696 | // backedge value. | ||||||
| 4697 | Value *BEValueV = nullptr, *StartValueV = nullptr; | ||||||
| 4698 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { | ||||||
| 4699 | Value *V = PN->getIncomingValue(i); | ||||||
| 4700 | if (L->contains(PN->getIncomingBlock(i))) { | ||||||
| 4701 | if (!BEValueV) { | ||||||
| 4702 | BEValueV = V; | ||||||
| 4703 | } else if (BEValueV != V) { | ||||||
| 4704 | BEValueV = nullptr; | ||||||
| 4705 | break; | ||||||
| 4706 | } | ||||||
| 4707 | } else if (!StartValueV) { | ||||||
| 4708 | StartValueV = V; | ||||||
| 4709 | } else if (StartValueV != V) { | ||||||
| 4710 | StartValueV = nullptr; | ||||||
| 4711 | break; | ||||||
| 4712 | } | ||||||
| 4713 | } | ||||||
| 4714 | if (!BEValueV || !StartValueV) | ||||||
| 4715 | return None; | ||||||
| 4716 | |||||||
| 4717 | const SCEV *BEValue = getSCEV(BEValueV); | ||||||
| 4718 | |||||||
| 4719 | // If the value coming around the backedge is an add with the symbolic | ||||||
| 4720 | // value we just inserted, possibly with casts that we can ignore under | ||||||
| 4721 | // an appropriate runtime guard, then we found a simple induction variable! | ||||||
| 4722 | const auto *Add = dyn_cast<SCEVAddExpr>(BEValue); | ||||||
| 4723 | if (!Add) | ||||||
| 4724 | return None; | ||||||
| 4725 | |||||||
| 4726 | // If there is a single occurrence of the symbolic value, possibly | ||||||
| 4727 | // casted, replace it with a recurrence. | ||||||
| 4728 | unsigned FoundIndex = Add->getNumOperands(); | ||||||
| 4729 | Type *TruncTy = nullptr; | ||||||
| 4730 | bool Signed; | ||||||
| 4731 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
| 4732 | if ((TruncTy = | ||||||
| 4733 | isSimpleCastedPHI(Add->getOperand(i), SymbolicPHI, Signed, *this))) | ||||||
| 4734 | if (FoundIndex == e) { | ||||||
| 4735 | FoundIndex = i; | ||||||
| 4736 | break; | ||||||
| 4737 | } | ||||||
| 4738 | |||||||
| 4739 | if (FoundIndex == Add->getNumOperands()) | ||||||
| 4740 | return None; | ||||||
| 4741 | |||||||
| 4742 | // Create an add with everything but the specified operand. | ||||||
| 4743 | SmallVector<const SCEV *, 8> Ops; | ||||||
| 4744 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
| 4745 | if (i != FoundIndex) | ||||||
| 4746 | Ops.push_back(Add->getOperand(i)); | ||||||
| 4747 | const SCEV *Accum = getAddExpr(Ops); | ||||||
| 4748 | |||||||
| 4749 | // The runtime checks will not be valid if the step amount is | ||||||
| 4750 | // varying inside the loop. | ||||||
| 4751 | if (!isLoopInvariant(Accum, L)) | ||||||
| 4752 | return None; | ||||||
| 4753 | |||||||
| 4754 | // *** Part2: Create the predicates | ||||||
| 4755 | |||||||
| 4756 | // Analysis was successful: we have a phi-with-cast pattern for which we | ||||||
| 4757 | // can return an AddRec expression under the following predicates: | ||||||
| 4758 | // | ||||||
| 4759 | // P1: A Wrap predicate that guarantees that Trunc(Start) + i*Trunc(Accum) | ||||||
| 4760 | // fits within the truncated type (does not overflow) for i = 0 to n-1. | ||||||
| 4761 | // P2: An Equal predicate that guarantees that | ||||||
| 4762 | // Start = (Ext ix (Trunc iy (Start) to ix) to iy) | ||||||
| 4763 | // P3: An Equal predicate that guarantees that | ||||||
| 4764 | // Accum = (Ext ix (Trunc iy (Accum) to ix) to iy) | ||||||
| 4765 | // | ||||||
| 4766 | // As we next prove, the above predicates guarantee that: | ||||||
| 4767 | // Start + i*Accum = (Ext ix (Trunc iy ( Start + i*Accum ) to ix) to iy) | ||||||
| 4768 | // | ||||||
| 4769 | // | ||||||
| 4770 | // More formally, we want to prove that: | ||||||
| 4771 | // Expr(i+1) = Start + (i+1) * Accum | ||||||
| 4772 | // = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum | ||||||
| 4773 | // | ||||||
| 4774 | // Given that: | ||||||
| 4775 | // 1) Expr(0) = Start | ||||||
| 4776 | // 2) Expr(1) = Start + Accum | ||||||
| 4777 | // = (Ext ix (Trunc iy (Start) to ix) to iy) + Accum :: from P2 | ||||||
| 4778 | // 3) Induction hypothesis (step i): | ||||||
| 4779 | // Expr(i) = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum | ||||||
| 4780 | // | ||||||
| 4781 | // Proof: | ||||||
| 4782 | // Expr(i+1) = | ||||||
| 4783 | // = Start + (i+1)*Accum | ||||||
| 4784 | // = (Start + i*Accum) + Accum | ||||||
| 4785 | // = Expr(i) + Accum | ||||||
| 4786 | // = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum + Accum | ||||||
| 4787 | // :: from step i | ||||||
| 4788 | // | ||||||
| 4789 | // = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy) + Accum + Accum | ||||||
| 4790 | // | ||||||
| 4791 | // = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy) | ||||||
| 4792 | // + (Ext ix (Trunc iy (Accum) to ix) to iy) | ||||||
| 4793 | // + Accum :: from P3 | ||||||
| 4794 | // | ||||||
| 4795 | // = (Ext ix (Trunc iy ((Start + (i-1)*Accum) + Accum) to ix) to iy) | ||||||
| 4796 | // + Accum :: from P1: Ext(x)+Ext(y)=>Ext(x+y) | ||||||
| 4797 | // | ||||||
| 4798 | // = (Ext ix (Trunc iy (Start + i*Accum) to ix) to iy) + Accum | ||||||
| 4799 | // = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum | ||||||
| 4800 | // | ||||||
| 4801 | // By induction, the same applies to all iterations 1<=i<n: | ||||||
| 4802 | // | ||||||
| 4803 | |||||||
| 4804 | // Create a truncated addrec for which we will add a no overflow check (P1). | ||||||
| 4805 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
| 4806 | const SCEV *PHISCEV = | ||||||
| 4807 | getAddRecExpr(getTruncateExpr(StartVal, TruncTy), | ||||||
| 4808 | getTruncateExpr(Accum, TruncTy), L, SCEV::FlagAnyWrap); | ||||||
| 4809 | |||||||
| 4810 | // PHISCEV can be either a SCEVConstant or a SCEVAddRecExpr. | ||||||
| 4811 | // ex: If truncated Accum is 0 and StartVal is a constant, then PHISCEV | ||||||
| 4812 | // will be constant. | ||||||
| 4813 | // | ||||||
| 4814 | // If PHISCEV is a constant, then P1 degenerates into P2 or P3, so we don't | ||||||
| 4815 | // add P1. | ||||||
| 4816 | if (const auto *AR = dyn_cast<SCEVAddRecExpr>(PHISCEV)) { | ||||||
| 4817 | SCEVWrapPredicate::IncrementWrapFlags AddedFlags = | ||||||
| 4818 | Signed ? SCEVWrapPredicate::IncrementNSSW | ||||||
| 4819 | : SCEVWrapPredicate::IncrementNUSW; | ||||||
| 4820 | const SCEVPredicate *AddRecPred = getWrapPredicate(AR, AddedFlags); | ||||||
| 4821 | Predicates.push_back(AddRecPred); | ||||||
| 4822 | } | ||||||
| 4823 | |||||||
| 4824 | // Create the Equal Predicates P2,P3: | ||||||
| 4825 | |||||||
| 4826 | // It is possible that the predicates P2 and/or P3 are computable at | ||||||
| 4827 | // compile time due to StartVal and/or Accum being constants. | ||||||
| 4828 | // If either one is, then we can check that now and escape if either P2 | ||||||
| 4829 | // or P3 is false. | ||||||
| 4830 | |||||||
| 4831 | // Construct the extended SCEV: (Ext ix (Trunc iy (Expr) to ix) to iy) | ||||||
| 4832 | // for each of StartVal and Accum | ||||||
| 4833 | auto getExtendedExpr = [&](const SCEV *Expr, | ||||||
| 4834 | bool CreateSignExtend) -> const SCEV * { | ||||||
| 4835 | assert(isLoopInvariant(Expr, L) && "Expr is expected to be invariant")((isLoopInvariant(Expr, L) && "Expr is expected to be invariant" ) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Expr, L) && \"Expr is expected to be invariant\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4835, __PRETTY_FUNCTION__)); | ||||||
| 4836 | const SCEV *TruncatedExpr = getTruncateExpr(Expr, TruncTy); | ||||||
| 4837 | const SCEV *ExtendedExpr = | ||||||
| 4838 | CreateSignExtend ? getSignExtendExpr(TruncatedExpr, Expr->getType()) | ||||||
| 4839 | : getZeroExtendExpr(TruncatedExpr, Expr->getType()); | ||||||
| 4840 | return ExtendedExpr; | ||||||
| 4841 | }; | ||||||
| 4842 | |||||||
| 4843 | // Given: | ||||||
| 4844 | // ExtendedExpr = (Ext ix (Trunc iy (Expr) to ix) to iy | ||||||
| 4845 | // = getExtendedExpr(Expr) | ||||||
| 4846 | // Determine whether the predicate P: Expr == ExtendedExpr | ||||||
| 4847 | // is known to be false at compile time | ||||||
| 4848 | auto PredIsKnownFalse = [&](const SCEV *Expr, | ||||||
| 4849 | const SCEV *ExtendedExpr) -> bool { | ||||||
| 4850 | return Expr != ExtendedExpr && | ||||||
| 4851 | isKnownPredicate(ICmpInst::ICMP_NE, Expr, ExtendedExpr); | ||||||
| 4852 | }; | ||||||
| 4853 | |||||||
| 4854 | const SCEV *StartExtended = getExtendedExpr(StartVal, Signed); | ||||||
| 4855 | if (PredIsKnownFalse(StartVal, StartExtended)) { | ||||||
| 4856 | LLVM_DEBUG(dbgs() << "P2 is compile-time false\n";)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "P2 is compile-time false\n" ;; } } while (false); | ||||||
| 4857 | return None; | ||||||
| 4858 | } | ||||||
| 4859 | |||||||
| 4860 | // The Step is always Signed (because the overflow checks are either | ||||||
| 4861 | // NSSW or NUSW) | ||||||
| 4862 | const SCEV *AccumExtended = getExtendedExpr(Accum, /*CreateSignExtend=*/true); | ||||||
| 4863 | if (PredIsKnownFalse(Accum, AccumExtended)) { | ||||||
| 4864 | LLVM_DEBUG(dbgs() << "P3 is compile-time false\n";)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "P3 is compile-time false\n" ;; } } while (false); | ||||||
| 4865 | return None; | ||||||
| 4866 | } | ||||||
| 4867 | |||||||
| 4868 | auto AppendPredicate = [&](const SCEV *Expr, | ||||||
| 4869 | const SCEV *ExtendedExpr) -> void { | ||||||
| 4870 | if (Expr != ExtendedExpr && | ||||||
| 4871 | !isKnownPredicate(ICmpInst::ICMP_EQ, Expr, ExtendedExpr)) { | ||||||
| 4872 | const SCEVPredicate *Pred = getEqualPredicate(Expr, ExtendedExpr); | ||||||
| 4873 | LLVM_DEBUG(dbgs() << "Added Predicate: " << *Pred)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("scalar-evolution")) { dbgs() << "Added Predicate: " << *Pred; } } while (false); | ||||||
| 4874 | Predicates.push_back(Pred); | ||||||
| 4875 | } | ||||||
| 4876 | }; | ||||||
| 4877 | |||||||
| 4878 | AppendPredicate(StartVal, StartExtended); | ||||||
| 4879 | AppendPredicate(Accum, AccumExtended); | ||||||
| 4880 | |||||||
| 4881 | // *** Part3: Predicates are ready. Now go ahead and create the new addrec in | ||||||
| 4882 | // which the casts had been folded away. The caller can rewrite SymbolicPHI | ||||||
| 4883 | // into NewAR if it will also add the runtime overflow checks specified in | ||||||
| 4884 | // Predicates. | ||||||
| 4885 | auto *NewAR = getAddRecExpr(StartVal, Accum, L, SCEV::FlagAnyWrap); | ||||||
| 4886 | |||||||
| 4887 | std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> PredRewrite = | ||||||
| 4888 | std::make_pair(NewAR, Predicates); | ||||||
| 4889 | // Remember the result of the analysis for this SCEV at this locayyytion. | ||||||
| 4890 | PredicatedSCEVRewrites[{SymbolicPHI, L}] = PredRewrite; | ||||||
| 4891 | return PredRewrite; | ||||||
| 4892 | } | ||||||
| 4893 | |||||||
| 4894 | Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>> | ||||||
| 4895 | ScalarEvolution::createAddRecFromPHIWithCasts(const SCEVUnknown *SymbolicPHI) { | ||||||
| 4896 | auto *PN = cast<PHINode>(SymbolicPHI->getValue()); | ||||||
| 4897 | const Loop *L = isIntegerLoopHeaderPHI(PN, LI); | ||||||
| 4898 | if (!L) | ||||||
| 4899 | return None; | ||||||
| 4900 | |||||||
| 4901 | // Check to see if we already analyzed this PHI. | ||||||
| 4902 | auto I = PredicatedSCEVRewrites.find({SymbolicPHI, L}); | ||||||
| 4903 | if (I != PredicatedSCEVRewrites.end()) { | ||||||
| 4904 | std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> Rewrite = | ||||||
| 4905 | I->second; | ||||||
| 4906 | // Analysis was done before and failed to create an AddRec: | ||||||
| 4907 | if (Rewrite.first == SymbolicPHI) | ||||||
| 4908 | return None; | ||||||
| 4909 | // Analysis was done before and succeeded to create an AddRec under | ||||||
| 4910 | // a predicate: | ||||||
| 4911 | assert(isa<SCEVAddRecExpr>(Rewrite.first) && "Expected an AddRec")((isa<SCEVAddRecExpr>(Rewrite.first) && "Expected an AddRec" ) ? static_cast<void> (0) : __assert_fail ("isa<SCEVAddRecExpr>(Rewrite.first) && \"Expected an AddRec\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4911, __PRETTY_FUNCTION__)); | ||||||
| 4912 | assert(!(Rewrite.second).empty() && "Expected to find Predicates")((!(Rewrite.second).empty() && "Expected to find Predicates" ) ? static_cast<void> (0) : __assert_fail ("!(Rewrite.second).empty() && \"Expected to find Predicates\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4912, __PRETTY_FUNCTION__)); | ||||||
| 4913 | return Rewrite; | ||||||
| 4914 | } | ||||||
| 4915 | |||||||
| 4916 | Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>> | ||||||
| 4917 | Rewrite = createAddRecFromPHIWithCastsImpl(SymbolicPHI); | ||||||
| 4918 | |||||||
| 4919 | // Record in the cache that the analysis failed | ||||||
| 4920 | if (!Rewrite) { | ||||||
| 4921 | SmallVector<const SCEVPredicate *, 3> Predicates; | ||||||
| 4922 | PredicatedSCEVRewrites[{SymbolicPHI, L}] = {SymbolicPHI, Predicates}; | ||||||
| 4923 | return None; | ||||||
| 4924 | } | ||||||
| 4925 | |||||||
| 4926 | return Rewrite; | ||||||
| 4927 | } | ||||||
| 4928 | |||||||
| 4929 | // FIXME: This utility is currently required because the Rewriter currently | ||||||
| 4930 | // does not rewrite this expression: | ||||||
| 4931 | // {0, +, (sext ix (trunc iy to ix) to iy)} | ||||||
| 4932 | // into {0, +, %step}, | ||||||
| 4933 | // even when the following Equal predicate exists: | ||||||
| 4934 | // "%step == (sext ix (trunc iy to ix) to iy)". | ||||||
| 4935 | bool PredicatedScalarEvolution::areAddRecsEqualWithPreds( | ||||||
| 4936 | const SCEVAddRecExpr *AR1, const SCEVAddRecExpr *AR2) const { | ||||||
| 4937 | if (AR1 == AR2) | ||||||
| 4938 | return true; | ||||||
| 4939 | |||||||
| 4940 | auto areExprsEqual = [&](const SCEV *Expr1, const SCEV *Expr2) -> bool { | ||||||
| 4941 | if (Expr1 != Expr2 && !Preds.implies(SE.getEqualPredicate(Expr1, Expr2)) && | ||||||
| 4942 | !Preds.implies(SE.getEqualPredicate(Expr2, Expr1))) | ||||||
| 4943 | return false; | ||||||
| 4944 | return true; | ||||||
| 4945 | }; | ||||||
| 4946 | |||||||
| 4947 | if (!areExprsEqual(AR1->getStart(), AR2->getStart()) || | ||||||
| 4948 | !areExprsEqual(AR1->getStepRecurrence(SE), AR2->getStepRecurrence(SE))) | ||||||
| 4949 | return false; | ||||||
| 4950 | return true; | ||||||
| 4951 | } | ||||||
| 4952 | |||||||
| 4953 | /// A helper function for createAddRecFromPHI to handle simple cases. | ||||||
| 4954 | /// | ||||||
| 4955 | /// This function tries to find an AddRec expression for the simplest (yet most | ||||||
| 4956 | /// common) cases: PN = PHI(Start, OP(Self, LoopInvariant)). | ||||||
| 4957 | /// If it fails, createAddRecFromPHI will use a more general, but slow, | ||||||
| 4958 | /// technique for finding the AddRec expression. | ||||||
| 4959 | const SCEV *ScalarEvolution::createSimpleAffineAddRec(PHINode *PN, | ||||||
| 4960 | Value *BEValueV, | ||||||
| 4961 | Value *StartValueV) { | ||||||
| 4962 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
| 4963 | assert(L && L->getHeader() == PN->getParent())((L && L->getHeader() == PN->getParent()) ? static_cast <void> (0) : __assert_fail ("L && L->getHeader() == PN->getParent()" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4963, __PRETTY_FUNCTION__)); | ||||||
| 4964 | assert(BEValueV && StartValueV)((BEValueV && StartValueV) ? static_cast<void> ( 0) : __assert_fail ("BEValueV && StartValueV", "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 4964, __PRETTY_FUNCTION__)); | ||||||
| 4965 | |||||||
| 4966 | auto BO = MatchBinaryOp(BEValueV, DT); | ||||||
| 4967 | if (!BO) | ||||||
| 4968 | return nullptr; | ||||||
| 4969 | |||||||
| 4970 | if (BO->Opcode != Instruction::Add) | ||||||
| 4971 | return nullptr; | ||||||
| 4972 | |||||||
| 4973 | const SCEV *Accum = nullptr; | ||||||
| 4974 | if (BO->LHS == PN && L->isLoopInvariant(BO->RHS)) | ||||||
| 4975 | Accum = getSCEV(BO->RHS); | ||||||
| 4976 | else if (BO->RHS == PN && L->isLoopInvariant(BO->LHS)) | ||||||
| 4977 | Accum = getSCEV(BO->LHS); | ||||||
| 4978 | |||||||
| 4979 | if (!Accum) | ||||||
| 4980 | return nullptr; | ||||||
| 4981 | |||||||
| 4982 | SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | ||||||
| 4983 | if (BO->IsNUW) | ||||||
| 4984 | Flags = setFlags(Flags, SCEV::FlagNUW); | ||||||
| 4985 | if (BO->IsNSW) | ||||||
| 4986 | Flags = setFlags(Flags, SCEV::FlagNSW); | ||||||
| 4987 | |||||||
| 4988 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
| 4989 | const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags); | ||||||
| 4990 | |||||||
| 4991 | ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV; | ||||||
| 4992 | |||||||
| 4993 | // We can add Flags to the post-inc expression only if we | ||||||
| 4994 | // know that it is *undefined behavior* for BEValueV to | ||||||
| 4995 | // overflow. | ||||||
| 4996 | if (auto *BEInst = dyn_cast<Instruction>(BEValueV)) | ||||||
| 4997 | if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L)) | ||||||
| 4998 | (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags); | ||||||
| 4999 | |||||||
| 5000 | return PHISCEV; | ||||||
| 5001 | } | ||||||
| 5002 | |||||||
| 5003 | const SCEV *ScalarEvolution::createAddRecFromPHI(PHINode *PN) { | ||||||
| 5004 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
| 5005 | if (!L || L->getHeader() != PN->getParent()) | ||||||
| 5006 | return nullptr; | ||||||
| 5007 | |||||||
| 5008 | // The loop may have multiple entrances or multiple exits; we can analyze | ||||||
| 5009 | // this phi as an addrec if it has a unique entry value and a unique | ||||||
| 5010 | // backedge value. | ||||||
| 5011 | Value *BEValueV = nullptr, *StartValueV = nullptr; | ||||||
| 5012 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { | ||||||
| 5013 | Value *V = PN->getIncomingValue(i); | ||||||
| 5014 | if (L->contains(PN->getIncomingBlock(i))) { | ||||||
| 5015 | if (!BEValueV) { | ||||||
| 5016 | BEValueV = V; | ||||||
| 5017 | } else if (BEValueV != V) { | ||||||
| 5018 | BEValueV = nullptr; | ||||||
| 5019 | break; | ||||||
| 5020 | } | ||||||
| 5021 | } else if (!StartValueV) { | ||||||
| 5022 | StartValueV = V; | ||||||
| 5023 | } else if (StartValueV != V) { | ||||||
| 5024 | StartValueV = nullptr; | ||||||
| 5025 | break; | ||||||
| 5026 | } | ||||||
| 5027 | } | ||||||
| 5028 | if (!BEValueV || !StartValueV) | ||||||
| 5029 | return nullptr; | ||||||
| 5030 | |||||||
| 5031 | assert(ValueExprMap.find_as(PN) == ValueExprMap.end() &&((ValueExprMap.find_as(PN) == ValueExprMap.end() && "PHI node already processed?" ) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.find_as(PN) == ValueExprMap.end() && \"PHI node already processed?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5032, __PRETTY_FUNCTION__)) | ||||||
| 5032 | "PHI node already processed?")((ValueExprMap.find_as(PN) == ValueExprMap.end() && "PHI node already processed?" ) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.find_as(PN) == ValueExprMap.end() && \"PHI node already processed?\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5032, __PRETTY_FUNCTION__)); | ||||||
| 5033 | |||||||
| 5034 | // First, try to find AddRec expression without creating a fictituos symbolic | ||||||
| 5035 | // value for PN. | ||||||
| 5036 | if (auto *S = createSimpleAffineAddRec(PN, BEValueV, StartValueV)) | ||||||
| 5037 | return S; | ||||||
| 5038 | |||||||
| 5039 | // Handle PHI node value symbolically. | ||||||
| 5040 | const SCEV *SymbolicName = getUnknown(PN); | ||||||
| 5041 | ValueExprMap.insert({SCEVCallbackVH(PN, this), SymbolicName}); | ||||||
| 5042 | |||||||
| 5043 | // Using this symbolic name for the PHI, analyze the value coming around | ||||||
| 5044 | // the back-edge. | ||||||
| 5045 | const SCEV *BEValue = getSCEV(BEValueV); | ||||||
| 5046 | |||||||
| 5047 | // NOTE: If BEValue is loop invariant, we know that the PHI node just | ||||||
| 5048 | // has a special value for the first iteration of the loop. | ||||||
| 5049 | |||||||
| 5050 | // If the value coming around the backedge is an add with the symbolic | ||||||
| 5051 | // value we just inserted, then we found a simple induction variable! | ||||||
| 5052 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) { | ||||||
| 5053 | // If there is a single occurrence of the symbolic value, replace it | ||||||
| 5054 | // with a recurrence. | ||||||
| 5055 | unsigned FoundIndex = Add->getNumOperands(); | ||||||
| 5056 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
| 5057 | if (Add->getOperand(i) == SymbolicName) | ||||||
| 5058 | if (FoundIndex == e) { | ||||||
| 5059 | FoundIndex = i; | ||||||
| 5060 | break; | ||||||
| 5061 | } | ||||||
| 5062 | |||||||
| 5063 | if (FoundIndex != Add->getNumOperands()) { | ||||||
| 5064 | // Create an add with everything but the specified operand. | ||||||
| 5065 | SmallVector<const SCEV *, 8> Ops; | ||||||
| 5066 | for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i) | ||||||
| 5067 | if (i != FoundIndex) | ||||||
| 5068 | Ops.push_back(SCEVBackedgeConditionFolder::rewrite(Add->getOperand(i), | ||||||
| 5069 | L, *this)); | ||||||
| 5070 | const SCEV *Accum = getAddExpr(Ops); | ||||||
| 5071 | |||||||
| 5072 | // This is not a valid addrec if the step amount is varying each | ||||||
| 5073 | // loop iteration, but is not itself an addrec in this loop. | ||||||
| 5074 | if (isLoopInvariant(Accum, L) || | ||||||
| 5075 | (isa<SCEVAddRecExpr>(Accum) && | ||||||
| 5076 | cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) { | ||||||
| 5077 | SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | ||||||
| 5078 | |||||||
| 5079 | if (auto BO = MatchBinaryOp(BEValueV, DT)) { | ||||||
| 5080 | if (BO->Opcode == Instruction::Add && BO->LHS == PN) { | ||||||
| 5081 | if (BO->IsNUW) | ||||||
| 5082 | Flags = setFlags(Flags, SCEV::FlagNUW); | ||||||
| 5083 | if (BO->IsNSW) | ||||||
| 5084 | Flags = setFlags(Flags, SCEV::FlagNSW); | ||||||
| 5085 | } | ||||||
| 5086 | } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(BEValueV)) { | ||||||
| 5087 | // If the increment is an inbounds GEP, then we know the address | ||||||
| 5088 | // space cannot be wrapped around. We cannot make any guarantee | ||||||
| 5089 | // about signed or unsigned overflow because pointers are | ||||||
| 5090 | // unsigned but we may have a negative index from the base | ||||||
| 5091 | // pointer. We can guarantee that no unsigned wrap occurs if the | ||||||
| 5092 | // indices form a positive value. | ||||||
| 5093 | if (GEP->isInBounds() && GEP->getOperand(0) == PN) { | ||||||
| 5094 | Flags = setFlags(Flags, SCEV::FlagNW); | ||||||
| 5095 | |||||||
| 5096 | const SCEV *Ptr = getSCEV(GEP->getPointerOperand()); | ||||||
| 5097 | if (isKnownPositive(getMinusSCEV(getSCEV(GEP), Ptr))) | ||||||
| 5098 | Flags = setFlags(Flags, SCEV::FlagNUW); | ||||||
| 5099 | } | ||||||
| 5100 | |||||||
| 5101 | // We cannot transfer nuw and nsw flags from subtraction | ||||||
| 5102 | // operations -- sub nuw X, Y is not the same as add nuw X, -Y | ||||||
| 5103 | // for instance. | ||||||
| 5104 | } | ||||||
| 5105 | |||||||
| 5106 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
| 5107 | const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags); | ||||||
| 5108 | |||||||
| 5109 | // Okay, for the entire analysis of this edge we assumed the PHI | ||||||
| 5110 | // to be symbolic. We now need to go back and purge all of the | ||||||
| 5111 | // entries for the scalars that use the symbolic expression. | ||||||
| 5112 | forgetSymbolicName(PN, SymbolicName); | ||||||
| 5113 | ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV; | ||||||
| 5114 | |||||||
| 5115 | // We can add Flags to the post-inc expression only if we | ||||||
| 5116 | // know that it is *undefined behavior* for BEValueV to | ||||||
| 5117 | // overflow. | ||||||
| 5118 | if (auto *BEInst = dyn_cast<Instruction>(BEValueV)) | ||||||
| 5119 | if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L)) | ||||||
| 5120 | (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags); | ||||||
| 5121 | |||||||
| 5122 | return PHISCEV; | ||||||
| 5123 | } | ||||||
| 5124 | } | ||||||
| 5125 | } else { | ||||||
| 5126 | // Otherwise, this could be a loop like this: | ||||||
| 5127 | // i = 0; for (j = 1; ..; ++j) { .... i = j; } | ||||||
| 5128 | // In this case, j = {1,+,1} and BEValue is j. | ||||||
| 5129 | // Because the other in-value of i (0) fits the evolution of BEValue | ||||||
| 5130 | // i really is an addrec evolution. | ||||||
| 5131 | // | ||||||
| 5132 | // We can generalize this saying that i is the shifted value of BEValue | ||||||
| 5133 | // by one iteration: | ||||||
| 5134 | // PHI(f(0), f({1,+,1})) --> f({0,+,1}) | ||||||
| 5135 | const SCEV *Shifted = SCEVShiftRewriter::rewrite(BEValue, L, *this); | ||||||
| 5136 | const SCEV *Start = SCEVInitRewriter::rewrite(Shifted, L, *this, false); | ||||||
| 5137 | if (Shifted != getCouldNotCompute() && | ||||||
| 5138 | Start != getCouldNotCompute()) { | ||||||
| 5139 | const SCEV *StartVal = getSCEV(StartValueV); | ||||||
| 5140 | if (Start == StartVal) { | ||||||
| 5141 | // Okay, for the entire analysis of this edge we assumed the PHI | ||||||
| 5142 | // to be symbolic. We now need to go back and purge all of the | ||||||
| 5143 | // entries for the scalars that use the symbolic expression. | ||||||
| 5144 | forgetSymbolicName(PN, SymbolicName); | ||||||
| 5145 | ValueExprMap[SCEVCallbackVH(PN, this)] = Shifted; | ||||||
| 5146 | return Shifted; | ||||||
| 5147 | } | ||||||
| 5148 | } | ||||||
| 5149 | } | ||||||
| 5150 | |||||||
| 5151 | // Remove the temporary PHI node SCEV that has been inserted while intending | ||||||
| 5152 | // to create an AddRecExpr for this PHI node. We can not keep this temporary | ||||||
| 5153 | // as it will prevent later (possibly simpler) SCEV expressions to be added | ||||||
| 5154 | // to the ValueExprMap. | ||||||
| 5155 | eraseValueFromMap(PN); | ||||||
| 5156 | |||||||
| 5157 | return nullptr; | ||||||
| 5158 | } | ||||||
| 5159 | |||||||
| 5160 | // Checks if the SCEV S is available at BB. S is considered available at BB | ||||||
| 5161 | // if S can be materialized at BB without introducing a fault. | ||||||
| 5162 | static bool IsAvailableOnEntry(const Loop *L, DominatorTree &DT, const SCEV *S, | ||||||
| 5163 | BasicBlock *BB) { | ||||||
| 5164 | struct CheckAvailable { | ||||||
| 5165 | bool TraversalDone = false; | ||||||
| 5166 | bool Available = true; | ||||||
| 5167 | |||||||
| 5168 | const Loop *L = nullptr; // The loop BB is in (can be nullptr) | ||||||
| 5169 | BasicBlock *BB = nullptr; | ||||||
| 5170 | DominatorTree &DT; | ||||||
| 5171 | |||||||
| 5172 | CheckAvailable(const Loop *L, BasicBlock *BB, DominatorTree &DT) | ||||||
| 5173 | : L(L), BB(BB), DT(DT) {} | ||||||
| 5174 | |||||||
| 5175 | bool setUnavailable() { | ||||||
| 5176 | TraversalDone = true; | ||||||
| 5177 | Available = false; | ||||||
| 5178 | return false; | ||||||
| 5179 | } | ||||||
| 5180 | |||||||
| 5181 | bool follow(const SCEV *S) { | ||||||
| 5182 | switch (S->getSCEVType()) { | ||||||
| 5183 | case scConstant: case scTruncate: case scZeroExtend: case scSignExtend: | ||||||
| 5184 | case scAddExpr: case scMulExpr: case scUMaxExpr: case scSMaxExpr: | ||||||
| 5185 | case scUMinExpr: | ||||||
| 5186 | case scSMinExpr: | ||||||
| 5187 | // These expressions are available if their operand(s) is/are. | ||||||
| 5188 | return true; | ||||||
| 5189 | |||||||
| 5190 | case scAddRecExpr: { | ||||||
| 5191 | // We allow add recurrences that are on the loop BB is in, or some | ||||||
| 5192 | // outer loop. This guarantees availability because the value of the | ||||||
| 5193 | // add recurrence at BB is simply the "current" value of the induction | ||||||
| 5194 | // variable. We can relax this in the future; for instance an add | ||||||
| 5195 | // recurrence on a sibling dominating loop is also available at BB. | ||||||
| 5196 | const auto *ARLoop = cast<SCEVAddRecExpr>(S)->getLoop(); | ||||||
| 5197 | if (L && (ARLoop == L || ARLoop->contains(L))) | ||||||
| 5198 | return true; | ||||||
| 5199 | |||||||
| 5200 | return setUnavailable(); | ||||||
| 5201 | } | ||||||
| 5202 | |||||||
| 5203 | case scUnknown: { | ||||||
| 5204 | // For SCEVUnknown, we check for simple dominance. | ||||||
| 5205 | const auto *SU = cast<SCEVUnknown>(S); | ||||||
| 5206 | Value *V = SU->getValue(); | ||||||
| 5207 | |||||||
| 5208 | if (isa<Argument>(V)) | ||||||
| 5209 | return false; | ||||||
| 5210 | |||||||
| 5211 | if (isa<Instruction>(V) && DT.dominates(cast<Instruction>(V), BB)) | ||||||
| 5212 | return false; | ||||||
| 5213 | |||||||
| 5214 | return setUnavailable(); | ||||||
| 5215 | } | ||||||
| 5216 | |||||||
| 5217 | case scUDivExpr: | ||||||
| 5218 | case scCouldNotCompute: | ||||||
| 5219 | // We do not try to smart about these at all. | ||||||
| 5220 | return setUnavailable(); | ||||||
| 5221 | } | ||||||
| 5222 | llvm_unreachable("switch should be fully covered!")::llvm::llvm_unreachable_internal("switch should be fully covered!" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5222); | ||||||
| 5223 | } | ||||||
| 5224 | |||||||
| 5225 | bool isDone() { return TraversalDone; } | ||||||
| 5226 | }; | ||||||
| 5227 | |||||||
| 5228 | CheckAvailable CA(L, BB, DT); | ||||||
| 5229 | SCEVTraversal<CheckAvailable> ST(CA); | ||||||
| 5230 | |||||||
| 5231 | ST.visitAll(S); | ||||||
| 5232 | return CA.Available; | ||||||
| 5233 | } | ||||||
| 5234 | |||||||
| 5235 | // Try to match a control flow sequence that branches out at BI and merges back | ||||||
| 5236 | // at Merge into a "C ? LHS : RHS" select pattern. Return true on a successful | ||||||
| 5237 | // match. | ||||||
| 5238 | static bool BrPHIToSelect(DominatorTree &DT, BranchInst *BI, PHINode *Merge, | ||||||
| 5239 | Value *&C, Value *&LHS, Value *&RHS) { | ||||||
| 5240 | C = BI->getCondition(); | ||||||
| 5241 | |||||||
| 5242 | BasicBlockEdge LeftEdge(BI->getParent(), BI->getSuccessor(0)); | ||||||
| 5243 | BasicBlockEdge RightEdge(BI->getParent(), BI->getSuccessor(1)); | ||||||
| 5244 | |||||||
| 5245 | if (!LeftEdge.isSingleEdge()) | ||||||
| 5246 | return false; | ||||||
| 5247 | |||||||
| 5248 | assert(RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()")((RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()" ) ? static_cast<void> (0) : __assert_fail ("RightEdge.isSingleEdge() && \"Follows from LeftEdge.isSingleEdge()\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5248, __PRETTY_FUNCTION__)); | ||||||
| 5249 | |||||||
| 5250 | Use &LeftUse = Merge->getOperandUse(0); | ||||||
| 5251 | Use &RightUse = Merge->getOperandUse(1); | ||||||
| 5252 | |||||||
| 5253 | if (DT.dominates(LeftEdge, LeftUse) && DT.dominates(RightEdge, RightUse)) { | ||||||
| 5254 | LHS = LeftUse; | ||||||
| 5255 | RHS = RightUse; | ||||||
| 5256 | return true; | ||||||
| 5257 | } | ||||||
| 5258 | |||||||
| 5259 | if (DT.dominates(LeftEdge, RightUse) && DT.dominates(RightEdge, LeftUse)) { | ||||||
| 5260 | LHS = RightUse; | ||||||
| 5261 | RHS = LeftUse; | ||||||
| 5262 | return true; | ||||||
| 5263 | } | ||||||
| 5264 | |||||||
| 5265 | return false; | ||||||
| 5266 | } | ||||||
| 5267 | |||||||
| 5268 | const SCEV *ScalarEvolution::createNodeFromSelectLikePHI(PHINode *PN) { | ||||||
| 5269 | auto IsReachable = | ||||||
| 5270 | [&](BasicBlock *BB) { return DT.isReachableFromEntry(BB); }; | ||||||
| 5271 | if (PN->getNumIncomingValues() == 2 && all_of(PN->blocks(), IsReachable)) { | ||||||
| 5272 | const Loop *L = LI.getLoopFor(PN->getParent()); | ||||||
| 5273 | |||||||
| 5274 | // We don't want to break LCSSA, even in a SCEV expression tree. | ||||||
| 5275 | for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) | ||||||
| 5276 | if (LI.getLoopFor(PN->getIncomingBlock(i)) != L) | ||||||
| 5277 | return nullptr; | ||||||
| 5278 | |||||||
| 5279 | // Try to match | ||||||
| 5280 | // | ||||||
| 5281 | // br %cond, label %left, label %right | ||||||
| 5282 | // left: | ||||||
| 5283 | // br label %merge | ||||||
| 5284 | // right: | ||||||
| 5285 | // br label %merge | ||||||
| 5286 | // merge: | ||||||
| 5287 | // V = phi [ %x, %left ], [ %y, %right ] | ||||||
| 5288 | // | ||||||
| 5289 | // as "select %cond, %x, %y" | ||||||
| 5290 | |||||||
| 5291 | BasicBlock *IDom = DT[PN->getParent()]->getIDom()->getBlock(); | ||||||
| 5292 | assert(IDom && "At least the entry block should dominate PN")((IDom && "At least the entry block should dominate PN" ) ? static_cast<void> (0) : __assert_fail ("IDom && \"At least the entry block should dominate PN\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5292, __PRETTY_FUNCTION__)); | ||||||
| 5293 | |||||||
| 5294 | auto *BI = dyn_cast<BranchInst>(IDom->getTerminator()); | ||||||
| 5295 | Value *Cond = nullptr, *LHS = nullptr, *RHS = nullptr; | ||||||
| 5296 | |||||||
| 5297 | if (BI && BI->isConditional() && | ||||||
| 5298 | BrPHIToSelect(DT, BI, PN, Cond, LHS, RHS) && | ||||||
| 5299 | IsAvailableOnEntry(L, DT, getSCEV(LHS), PN->getParent()) && | ||||||
| 5300 | IsAvailableOnEntry(L, DT, getSCEV(RHS), PN->getParent())) | ||||||
| 5301 | return createNodeForSelectOrPHI(PN, Cond, LHS, RHS); | ||||||
| 5302 | } | ||||||
| 5303 | |||||||
| 5304 | return nullptr; | ||||||
| 5305 | } | ||||||
| 5306 | |||||||
| 5307 | const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) { | ||||||
| 5308 | if (const SCEV *S = createAddRecFromPHI(PN)) | ||||||
| 5309 | return S; | ||||||
| 5310 | |||||||
| 5311 | if (const SCEV *S = createNodeFromSelectLikePHI(PN)) | ||||||
| 5312 | return S; | ||||||
| 5313 | |||||||
| 5314 | // If the PHI has a single incoming value, follow that value, unless the | ||||||
| 5315 | // PHI's incoming blocks are in a different loop, in which case doing so | ||||||
| 5316 | // risks breaking LCSSA form. Instcombine would normally zap these, but | ||||||
| 5317 | // it doesn't have DominatorTree information, so it may miss cases. | ||||||
| 5318 | if (Value *V = SimplifyInstruction(PN, {getDataLayout(), &TLI, &DT, &AC})) | ||||||
| 5319 | if (LI.replacementPreservesLCSSAForm(PN, V)) | ||||||
| 5320 | return getSCEV(V); | ||||||
| 5321 | |||||||
| 5322 | // If it's not a loop phi, we can't handle it yet. | ||||||
| 5323 | return getUnknown(PN); | ||||||
| 5324 | } | ||||||
| 5325 | |||||||
| 5326 | const SCEV *ScalarEvolution::createNodeForSelectOrPHI(Instruction *I, | ||||||
| 5327 | Value *Cond, | ||||||
| 5328 | Value *TrueVal, | ||||||
| 5329 | Value *FalseVal) { | ||||||
| 5330 | // Handle "constant" branch or select. This can occur for instance when a | ||||||
| 5331 | // loop pass transforms an inner loop and moves on to process the outer loop. | ||||||
| 5332 | if (auto *CI = dyn_cast<ConstantInt>(Cond)) | ||||||
| 5333 | return getSCEV(CI->isOne() ? TrueVal : FalseVal); | ||||||
| 5334 | |||||||
| 5335 | // Try to match some simple smax or umax patterns. | ||||||
| 5336 | auto *ICI = dyn_cast<ICmpInst>(Cond); | ||||||
| 5337 | if (!ICI) | ||||||
| 5338 | return getUnknown(I); | ||||||
| 5339 | |||||||
| 5340 | Value *LHS = ICI->getOperand(0); | ||||||
| 5341 | Value *RHS = ICI->getOperand(1); | ||||||
| 5342 | |||||||
| 5343 | switch (ICI->getPredicate()) { | ||||||
| 5344 | case ICmpInst::ICMP_SLT: | ||||||
| 5345 | case ICmpInst::ICMP_SLE: | ||||||
| 5346 | std::swap(LHS, RHS); | ||||||
| 5347 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
| 5348 | case ICmpInst::ICMP_SGT: | ||||||
| 5349 | case ICmpInst::ICMP_SGE: | ||||||
| 5350 | // a >s b ? a+x : b+x -> smax(a, b)+x | ||||||
| 5351 | // a >s b ? b+x : a+x -> smin(a, b)+x | ||||||
| 5352 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) { | ||||||
| 5353 | const SCEV *LS = getNoopOrSignExtend(getSCEV(LHS), I->getType()); | ||||||
| 5354 | const SCEV *RS = getNoopOrSignExtend(getSCEV(RHS), I->getType()); | ||||||
| 5355 | const SCEV *LA = getSCEV(TrueVal); | ||||||
| 5356 | const SCEV *RA = getSCEV(FalseVal); | ||||||
| 5357 | const SCEV *LDiff = getMinusSCEV(LA, LS); | ||||||
| 5358 | const SCEV *RDiff = getMinusSCEV(RA, RS); | ||||||
| 5359 | if (LDiff == RDiff) | ||||||
| 5360 | return getAddExpr(getSMaxExpr(LS, RS), LDiff); | ||||||
| 5361 | LDiff = getMinusSCEV(LA, RS); | ||||||
| 5362 | RDiff = getMinusSCEV(RA, LS); | ||||||
| 5363 | if (LDiff == RDiff) | ||||||
| 5364 | return getAddExpr(getSMinExpr(LS, RS), LDiff); | ||||||
| 5365 | } | ||||||
| 5366 | break; | ||||||
| 5367 | case ICmpInst::ICMP_ULT: | ||||||
| 5368 | case ICmpInst::ICMP_ULE: | ||||||
| 5369 | std::swap(LHS, RHS); | ||||||
| 5370 | LLVM_FALLTHROUGH[[gnu::fallthrough]]; | ||||||
| 5371 | case ICmpInst::ICMP_UGT: | ||||||
| 5372 | case ICmpInst::ICMP_UGE: | ||||||
| 5373 | // a >u b ? a+x : b+x -> umax(a, b)+x | ||||||
| 5374 | // a >u b ? b+x : a+x -> umin(a, b)+x | ||||||
| 5375 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) { | ||||||
| 5376 | const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType()); | ||||||
| 5377 | const SCEV *RS = getNoopOrZeroExtend(getSCEV(RHS), I->getType()); | ||||||
| 5378 | const SCEV *LA = getSCEV(TrueVal); | ||||||
| 5379 | const SCEV *RA = getSCEV(FalseVal); | ||||||
| 5380 | const SCEV *LDiff = getMinusSCEV(LA, LS); | ||||||
| 5381 | const SCEV *RDiff = getMinusSCEV(RA, RS); | ||||||
| 5382 | if (LDiff == RDiff) | ||||||
| 5383 | return getAddExpr(getUMaxExpr(LS, RS), LDiff); | ||||||
| 5384 | LDiff = getMinusSCEV(LA, RS); | ||||||
| 5385 | RDiff = getMinusSCEV(RA, LS); | ||||||
| 5386 | if (LDiff == RDiff) | ||||||
| 5387 | return getAddExpr(getUMinExpr(LS, RS), LDiff); | ||||||
| 5388 | } | ||||||
| 5389 | break; | ||||||
| 5390 | case ICmpInst::ICMP_NE: | ||||||
| 5391 | // n != 0 ? n+x : 1+x -> umax(n, 1)+x | ||||||
| 5392 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) && | ||||||
| 5393 | isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) { | ||||||
| 5394 | const SCEV *One = getOne(I->getType()); | ||||||
| 5395 | const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType()); | ||||||
| 5396 | const SCEV *LA = getSCEV(TrueVal); | ||||||
| 5397 | const SCEV *RA = getSCEV(FalseVal); | ||||||
| 5398 | const SCEV *LDiff = getMinusSCEV(LA, LS); | ||||||
| 5399 | const SCEV *RDiff = getMinusSCEV(RA, One); | ||||||
| 5400 | if (LDiff == RDiff) | ||||||
| 5401 | return getAddExpr(getUMaxExpr(One, LS), LDiff); | ||||||
| 5402 | } | ||||||
| 5403 | break; | ||||||
| 5404 | case ICmpInst::ICMP_EQ: | ||||||
| 5405 | // n == 0 ? 1+x : n+x -> umax(n, 1)+x | ||||||
| 5406 | if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) && | ||||||
| 5407 | isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) { | ||||||
| 5408 | const SCEV *One = getOne(I->getType()); | ||||||
| 5409 | const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType()); | ||||||
| 5410 | const SCEV *LA = getSCEV(TrueVal); | ||||||
| 5411 | const SCEV *RA = getSCEV(FalseVal); | ||||||
| 5412 | const SCEV *LDiff = getMinusSCEV(LA, One); | ||||||
| 5413 | const SCEV *RDiff = getMinusSCEV(RA, LS); | ||||||
| 5414 | if (LDiff == RDiff) | ||||||
| 5415 | return getAddExpr(getUMaxExpr(One, LS), LDiff); | ||||||
| 5416 | } | ||||||
| 5417 | break; | ||||||
| 5418 | default: | ||||||
| 5419 | break; | ||||||
| 5420 | } | ||||||
| 5421 | |||||||
| 5422 | return getUnknown(I); | ||||||
| 5423 | } | ||||||
| 5424 | |||||||
| 5425 | /// Expand GEP instructions into add and multiply operations. This allows them | ||||||
| 5426 | /// to be analyzed by regular SCEV code. | ||||||
| 5427 | const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) { | ||||||
| 5428 | // Don't attempt to analyze GEPs over unsized objects. | ||||||
| 5429 | if (!GEP->getSourceElementType()->isSized()) | ||||||
| 5430 | return getUnknown(GEP); | ||||||
| 5431 | |||||||
| 5432 | SmallVector<const SCEV *, 4> IndexExprs; | ||||||
| 5433 | for (auto Index = GEP->idx_begin(); Index != GEP->idx_end(); ++Index) | ||||||
| 5434 | IndexExprs.push_back(getSCEV(*Index)); | ||||||
| 5435 | return getGEPExpr(GEP, IndexExprs); | ||||||
| 5436 | } | ||||||
| 5437 | |||||||
| 5438 | uint32_t ScalarEvolution::GetMinTrailingZerosImpl(const SCEV *S) { | ||||||
| 5439 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) | ||||||
| 5440 | return C->getAPInt().countTrailingZeros(); | ||||||
| 5441 | |||||||
| 5442 | if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S)) | ||||||
| 5443 | return std::min(GetMinTrailingZeros(T->getOperand()), | ||||||
| 5444 | (uint32_t)getTypeSizeInBits(T->getType())); | ||||||
| 5445 | |||||||
| 5446 | if (const SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) { | ||||||
| 5447 | uint32_t OpRes = GetMinTrailingZeros(E->getOperand()); | ||||||
| 5448 | return OpRes == getTypeSizeInBits(E->getOperand()->getType()) | ||||||
| 5449 | ? getTypeSizeInBits(E->getType()) | ||||||
| 5450 | : OpRes; | ||||||
| 5451 | } | ||||||
| 5452 | |||||||
| 5453 | if (const SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) { | ||||||
| 5454 | uint32_t OpRes = GetMinTrailingZeros(E->getOperand()); | ||||||
| 5455 | return OpRes == getTypeSizeInBits(E->getOperand()->getType()) | ||||||
| 5456 | ? getTypeSizeInBits(E->getType()) | ||||||
| 5457 | : OpRes; | ||||||
| 5458 | } | ||||||
| 5459 | |||||||
| 5460 | if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) { | ||||||
| 5461 | // The result is the min of all operands results. | ||||||
| 5462 | uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0)); | ||||||
| 5463 | for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
| 5464 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i))); | ||||||
| 5465 | return MinOpRes; | ||||||
| 5466 | } | ||||||
| 5467 | |||||||
| 5468 | if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) { | ||||||
| 5469 | // The result is the sum of all operands results. | ||||||
| 5470 | uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0)); | ||||||
| 5471 | uint32_t BitWidth = getTypeSizeInBits(M->getType()); | ||||||
| 5472 | for (unsigned i = 1, e = M->getNumOperands(); | ||||||
| 5473 | SumOpRes != BitWidth && i != e; ++i) | ||||||
| 5474 | SumOpRes = | ||||||
| 5475 | std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i)), BitWidth); | ||||||
| 5476 | return SumOpRes; | ||||||
| 5477 | } | ||||||
| 5478 | |||||||
| 5479 | if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) { | ||||||
| 5480 | // The result is the min of all operands results. | ||||||
| 5481 | uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0)); | ||||||
| 5482 | for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
| 5483 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i))); | ||||||
| 5484 | return MinOpRes; | ||||||
| 5485 | } | ||||||
| 5486 | |||||||
| 5487 | if (const SCEVSMaxExpr *M = dyn_cast<SCEVSMaxExpr>(S)) { | ||||||
| 5488 | // The result is the min of all operands results. | ||||||
| 5489 | uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0)); | ||||||
| 5490 | for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
| 5491 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i))); | ||||||
| 5492 | return MinOpRes; | ||||||
| 5493 | } | ||||||
| 5494 | |||||||
| 5495 | if (const SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) { | ||||||
| 5496 | // The result is the min of all operands results. | ||||||
| 5497 | uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0)); | ||||||
| 5498 | for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i) | ||||||
| 5499 | MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i))); | ||||||
| 5500 | return MinOpRes; | ||||||
| 5501 | } | ||||||
| 5502 | |||||||
| 5503 | if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { | ||||||
| 5504 | // For a SCEVUnknown, ask ValueTracking. | ||||||
| 5505 | KnownBits Known = computeKnownBits(U->getValue(), getDataLayout(), 0, &AC, nullptr, &DT); | ||||||
| 5506 | return Known.countMinTrailingZeros(); | ||||||
| 5507 | } | ||||||
| 5508 | |||||||
| 5509 | // SCEVUDivExpr | ||||||
| 5510 | return 0; | ||||||
| 5511 | } | ||||||
| 5512 | |||||||
| 5513 | uint32_t ScalarEvolution::GetMinTrailingZeros(const SCEV *S) { | ||||||
| 5514 | auto I = MinTrailingZerosCache.find(S); | ||||||
| 5515 | if (I != MinTrailingZerosCache.end()) | ||||||
| 5516 | return I->second; | ||||||
| 5517 | |||||||
| 5518 | uint32_t Result = GetMinTrailingZerosImpl(S); | ||||||
| 5519 | auto InsertPair = MinTrailingZerosCache.insert({S, Result}); | ||||||
| 5520 | assert(InsertPair.second && "Should insert a new key")((InsertPair.second && "Should insert a new key") ? static_cast <void> (0) : __assert_fail ("InsertPair.second && \"Should insert a new key\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5520, __PRETTY_FUNCTION__)); | ||||||
| 5521 | return InsertPair.first->second; | ||||||
| 5522 | } | ||||||
| 5523 | |||||||
| 5524 | /// Helper method to assign a range to V from metadata present in the IR. | ||||||
| 5525 | static Optional<ConstantRange> GetRangeFromMetadata(Value *V) { | ||||||
| 5526 | if (Instruction *I = dyn_cast<Instruction>(V)) | ||||||
| 5527 | if (MDNode *MD = I->getMetadata(LLVMContext::MD_range)) | ||||||
| 5528 | return getConstantRangeFromMetadata(*MD); | ||||||
| 5529 | |||||||
| 5530 | return None; | ||||||
| 5531 | } | ||||||
| 5532 | |||||||
| 5533 | /// Determine the range for a particular SCEV. If SignHint is | ||||||
| 5534 | /// HINT_RANGE_UNSIGNED (resp. HINT_RANGE_SIGNED) then getRange prefers ranges | ||||||
| 5535 | /// with a "cleaner" unsigned (resp. signed) representation. | ||||||
| 5536 | const ConstantRange & | ||||||
| 5537 | ScalarEvolution::getRangeRef(const SCEV *S, | ||||||
| 5538 | ScalarEvolution::RangeSignHint SignHint) { | ||||||
| 5539 | DenseMap<const SCEV *, ConstantRange> &Cache = | ||||||
| 5540 | SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED ? UnsignedRanges | ||||||
| 5541 | : SignedRanges; | ||||||
| 5542 | ConstantRange::PreferredRangeType RangeType = | ||||||
| 5543 | SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED | ||||||
| 5544 | ? ConstantRange::Unsigned : ConstantRange::Signed; | ||||||
| 5545 | |||||||
| 5546 | // See if we've computed this range already. | ||||||
| 5547 | DenseMap<const SCEV *, ConstantRange>::iterator I = Cache.find(S); | ||||||
| 5548 | if (I != Cache.end()) | ||||||
| 5549 | return I->second; | ||||||
| 5550 | |||||||
| 5551 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) | ||||||
| 5552 | return setRange(C, SignHint, ConstantRange(C->getAPInt())); | ||||||
| 5553 | |||||||
| 5554 | unsigned BitWidth = getTypeSizeInBits(S->getType()); | ||||||
| 5555 | ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true); | ||||||
| 5556 | |||||||
| 5557 | // If the value has known zeros, the maximum value will have those known zeros | ||||||
| 5558 | // as well. | ||||||
| 5559 | uint32_t TZ = GetMinTrailingZeros(S); | ||||||
| 5560 | if (TZ != 0) { | ||||||
| 5561 | if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) | ||||||
| 5562 | ConservativeResult = | ||||||
| 5563 | ConstantRange(APInt::getMinValue(BitWidth), | ||||||
| 5564 | APInt::getMaxValue(BitWidth).lshr(TZ).shl(TZ) + 1); | ||||||
| 5565 | else | ||||||
| 5566 | ConservativeResult = ConstantRange( | ||||||
| 5567 | APInt::getSignedMinValue(BitWidth), | ||||||
| 5568 | APInt::getSignedMaxValue(BitWidth).ashr(TZ).shl(TZ) + 1); | ||||||
| 5569 | } | ||||||
| 5570 | |||||||
| 5571 | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) { | ||||||
| 5572 | ConstantRange X = getRangeRef(Add->getOperand(0), SignHint); | ||||||
| 5573 | for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i) | ||||||
| 5574 | X = X.add(getRangeRef(Add->getOperand(i), SignHint)); | ||||||
| 5575 | return setRange(Add, SignHint, | ||||||
| 5576 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
| 5577 | } | ||||||
| 5578 | |||||||
| 5579 | if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) { | ||||||
| 5580 | ConstantRange X = getRangeRef(Mul->getOperand(0), SignHint); | ||||||
| 5581 | for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i) | ||||||
| 5582 | X = X.multiply(getRangeRef(Mul->getOperand(i), SignHint)); | ||||||
| 5583 | return setRange(Mul, SignHint, | ||||||
| 5584 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
| 5585 | } | ||||||
| 5586 | |||||||
| 5587 | if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) { | ||||||
| 5588 | ConstantRange X = getRangeRef(SMax->getOperand(0), SignHint); | ||||||
| 5589 | for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i) | ||||||
| 5590 | X = X.smax(getRangeRef(SMax->getOperand(i), SignHint)); | ||||||
| 5591 | return setRange(SMax, SignHint, | ||||||
| 5592 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
| 5593 | } | ||||||
| 5594 | |||||||
| 5595 | if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) { | ||||||
| 5596 | ConstantRange X = getRangeRef(UMax->getOperand(0), SignHint); | ||||||
| 5597 | for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i) | ||||||
| 5598 | X = X.umax(getRangeRef(UMax->getOperand(i), SignHint)); | ||||||
| 5599 | return setRange(UMax, SignHint, | ||||||
| 5600 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
| 5601 | } | ||||||
| 5602 | |||||||
| 5603 | if (const SCEVSMinExpr *SMin = dyn_cast<SCEVSMinExpr>(S)) { | ||||||
| 5604 | ConstantRange X = getRangeRef(SMin->getOperand(0), SignHint); | ||||||
| 5605 | for (unsigned i = 1, e = SMin->getNumOperands(); i != e; ++i) | ||||||
| 5606 | X = X.smin(getRangeRef(SMin->getOperand(i), SignHint)); | ||||||
| 5607 | return setRange(SMin, SignHint, | ||||||
| 5608 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
| 5609 | } | ||||||
| 5610 | |||||||
| 5611 | if (const SCEVUMinExpr *UMin = dyn_cast<SCEVUMinExpr>(S)) { | ||||||
| 5612 | ConstantRange X = getRangeRef(UMin->getOperand(0), SignHint); | ||||||
| 5613 | for (unsigned i = 1, e = UMin->getNumOperands(); i != e; ++i) | ||||||
| 5614 | X = X.umin(getRangeRef(UMin->getOperand(i), SignHint)); | ||||||
| 5615 | return setRange(UMin, SignHint, | ||||||
| 5616 | ConservativeResult.intersectWith(X, RangeType)); | ||||||
| 5617 | } | ||||||
| 5618 | |||||||
| 5619 | if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) { | ||||||
| 5620 | ConstantRange X = getRangeRef(UDiv->getLHS(), SignHint); | ||||||
| 5621 | ConstantRange Y = getRangeRef(UDiv->getRHS(), SignHint); | ||||||
| 5622 | return setRange(UDiv, SignHint, | ||||||
| 5623 | ConservativeResult.intersectWith(X.udiv(Y), RangeType)); | ||||||
| 5624 | } | ||||||
| 5625 | |||||||
| 5626 | if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) { | ||||||
| 5627 | ConstantRange X = getRangeRef(ZExt->getOperand(), SignHint); | ||||||
| 5628 | return setRange(ZExt, SignHint, | ||||||
| 5629 | ConservativeResult.intersectWith(X.zeroExtend(BitWidth), | ||||||
| 5630 | RangeType)); | ||||||
| 5631 | } | ||||||
| 5632 | |||||||
| 5633 | if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) { | ||||||
| 5634 | ConstantRange X = getRangeRef(SExt->getOperand(), SignHint); | ||||||
| 5635 | return setRange(SExt, SignHint, | ||||||
| 5636 | ConservativeResult.intersectWith(X.signExtend(BitWidth), | ||||||
| 5637 | RangeType)); | ||||||
| 5638 | } | ||||||
| 5639 | |||||||
| 5640 | if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) { | ||||||
| 5641 | ConstantRange X = getRangeRef(Trunc->getOperand(), SignHint); | ||||||
| 5642 | return setRange(Trunc, SignHint, | ||||||
| 5643 | ConservativeResult.intersectWith(X.truncate(BitWidth), | ||||||
| 5644 | RangeType)); | ||||||
| 5645 | } | ||||||
| 5646 | |||||||
| 5647 | if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) { | ||||||
| 5648 | // If there's no unsigned wrap, the value will never be less than its | ||||||
| 5649 | // initial value. | ||||||
| 5650 | if (AddRec->hasNoUnsignedWrap()) | ||||||
| 5651 | if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart())) | ||||||
| 5652 | if (!C->getValue()->isZero()) | ||||||
| 5653 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
| 5654 | ConstantRange(C->getAPInt(), APInt(BitWidth, 0)), RangeType); | ||||||
| 5655 | |||||||
| 5656 | // If there's no signed wrap, and all the operands have the same sign or | ||||||
| 5657 | // zero, the value won't ever change sign. | ||||||
| 5658 | if (AddRec->hasNoSignedWrap()) { | ||||||
| 5659 | bool AllNonNeg = true; | ||||||
| 5660 | bool AllNonPos = true; | ||||||
| 5661 | for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) { | ||||||
| 5662 | if (!isKnownNonNegative(AddRec->getOperand(i))) AllNonNeg = false; | ||||||
| 5663 | if (!isKnownNonPositive(AddRec->getOperand(i))) AllNonPos = false; | ||||||
| 5664 | } | ||||||
| 5665 | if (AllNonNeg) | ||||||
| 5666 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
| 5667 | ConstantRange(APInt(BitWidth, 0), | ||||||
| 5668 | APInt::getSignedMinValue(BitWidth)), RangeType); | ||||||
| 5669 | else if (AllNonPos) | ||||||
| 5670 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
| 5671 | ConstantRange(APInt::getSignedMinValue(BitWidth), | ||||||
| 5672 | APInt(BitWidth, 1)), RangeType); | ||||||
| 5673 | } | ||||||
| 5674 | |||||||
| 5675 | // TODO: non-affine addrec | ||||||
| 5676 | if (AddRec->isAffine()) { | ||||||
| 5677 | const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(AddRec->getLoop()); | ||||||
| 5678 | if (!isa<SCEVCouldNotCompute>(MaxBECount) && | ||||||
| 5679 | getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) { | ||||||
| 5680 | auto RangeFromAffine = getRangeForAffineAR( | ||||||
| 5681 | AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount, | ||||||
| 5682 | BitWidth); | ||||||
| 5683 | if (!RangeFromAffine.isFullSet()) | ||||||
| 5684 | ConservativeResult = | ||||||
| 5685 | ConservativeResult.intersectWith(RangeFromAffine, RangeType); | ||||||
| 5686 | |||||||
| 5687 | auto RangeFromFactoring = getRangeViaFactoring( | ||||||
| 5688 | AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount, | ||||||
| 5689 | BitWidth); | ||||||
| 5690 | if (!RangeFromFactoring.isFullSet()) | ||||||
| 5691 | ConservativeResult = | ||||||
| 5692 | ConservativeResult.intersectWith(RangeFromFactoring, RangeType); | ||||||
| 5693 | } | ||||||
| 5694 | } | ||||||
| 5695 | |||||||
| 5696 | return setRange(AddRec, SignHint, std::move(ConservativeResult)); | ||||||
| 5697 | } | ||||||
| 5698 | |||||||
| 5699 | if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { | ||||||
| 5700 | // Check if the IR explicitly contains !range metadata. | ||||||
| 5701 | Optional<ConstantRange> MDRange = GetRangeFromMetadata(U->getValue()); | ||||||
| 5702 | if (MDRange.hasValue()) | ||||||
| 5703 | ConservativeResult = ConservativeResult.intersectWith(MDRange.getValue(), | ||||||
| 5704 | RangeType); | ||||||
| 5705 | |||||||
| 5706 | // Split here to avoid paying the compile-time cost of calling both | ||||||
| 5707 | // computeKnownBits and ComputeNumSignBits. This restriction can be lifted | ||||||
| 5708 | // if needed. | ||||||
| 5709 | const DataLayout &DL = getDataLayout(); | ||||||
| 5710 | if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) { | ||||||
| 5711 | // For a SCEVUnknown, ask ValueTracking. | ||||||
| 5712 | KnownBits Known = computeKnownBits(U->getValue(), DL, 0, &AC, nullptr, &DT); | ||||||
| 5713 | if (Known.One != ~Known.Zero + 1) | ||||||
| 5714 | ConservativeResult = | ||||||
| 5715 | ConservativeResult.intersectWith( | ||||||
| 5716 | ConstantRange(Known.One, ~Known.Zero + 1), RangeType); | ||||||
| 5717 | } else { | ||||||
| 5718 | assert(SignHint == ScalarEvolution::HINT_RANGE_SIGNED &&((SignHint == ScalarEvolution::HINT_RANGE_SIGNED && "generalize as needed!" ) ? static_cast<void> (0) : __assert_fail ("SignHint == ScalarEvolution::HINT_RANGE_SIGNED && \"generalize as needed!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5719, __PRETTY_FUNCTION__)) | ||||||
| 5719 | "generalize as needed!")((SignHint == ScalarEvolution::HINT_RANGE_SIGNED && "generalize as needed!" ) ? static_cast<void> (0) : __assert_fail ("SignHint == ScalarEvolution::HINT_RANGE_SIGNED && \"generalize as needed!\"" , "/build/llvm-toolchain-snapshot-10~svn374877/lib/Analysis/ScalarEvolution.cpp" , 5719, __PRETTY_FUNCTION__)); | ||||||
| 5720 | unsigned NS = ComputeNumSignBits(U->getValue(), DL, 0, &AC, nullptr, &DT); | ||||||
| 5721 | if (NS > 1) | ||||||
| 5722 | ConservativeResult = ConservativeResult.intersectWith( | ||||||
| 5723 | ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1), | ||||||
| 5724 |