diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp')
-rw-r--r-- | llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp | 64 |
1 files changed, 1 insertions, 63 deletions
diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp index 34597e6..58dbac0 100644 --- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp +++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp @@ -1363,68 +1363,6 @@ Value *SCEVExpander::expandCodeFor(const SCEV *SH, Type *Ty) { return V; } -static bool -canReuseInstruction(ScalarEvolution &SE, const SCEV *S, Instruction *I, - SmallVectorImpl<Instruction *> &DropPoisonGeneratingInsts) { - // If the instruction cannot be poison, it's always safe to reuse. - if (programUndefinedIfPoison(I)) - return true; - - // Otherwise, it is possible that I is more poisonous that S. Collect the - // poison-contributors of S, and then check whether I has any additional - // poison-contributors. Poison that is contributed through poison-generating - // flags is handled by dropping those flags instead. - SmallPtrSet<const Value *, 8> PoisonVals; - SE.getPoisonGeneratingValues(PoisonVals, S); - - SmallVector<Value *> Worklist; - SmallPtrSet<Value *, 8> Visited; - Worklist.push_back(I); - while (!Worklist.empty()) { - Value *V = Worklist.pop_back_val(); - if (!Visited.insert(V).second) - continue; - - // Avoid walking large instruction graphs. - if (Visited.size() > 16) - return false; - - // Either the value can't be poison, or the S would also be poison if it - // is. - if (PoisonVals.contains(V) || isGuaranteedNotToBePoison(V)) - continue; - - auto *I = dyn_cast<Instruction>(V); - if (!I) - return false; - - // Disjoint or instructions are interpreted as adds by SCEV. However, we - // can't replace an arbitrary add with disjoint or, even if we drop the - // flag. We would need to convert the or into an add. - if (auto *PDI = dyn_cast<PossiblyDisjointInst>(I)) - if (PDI->isDisjoint()) - return false; - - // FIXME: Ignore vscale, even though it technically could be poison. Do this - // because SCEV currently assumes it can't be poison. Remove this special - // case once we proper model when vscale can be poison. - if (auto *II = dyn_cast<IntrinsicInst>(I); - II && II->getIntrinsicID() == Intrinsic::vscale) - continue; - - if (canCreatePoison(cast<Operator>(I), /*ConsiderFlagsAndMetadata*/ false)) - return false; - - // If the instruction can't create poison, we can recurse to its operands. - if (I->hasPoisonGeneratingFlagsOrMetadata()) - DropPoisonGeneratingInsts.push_back(I); - - for (Value *Op : I->operands()) - Worklist.push_back(Op); - } - return true; -} - Value *SCEVExpander::FindValueInExprValueMap( const SCEV *S, const Instruction *InsertPt, SmallVectorImpl<Instruction *> &DropPoisonGeneratingInsts) { @@ -1452,7 +1390,7 @@ Value *SCEVExpander::FindValueInExprValueMap( continue; // Make sure reusing the instruction is poison-safe. - if (canReuseInstruction(SE, S, EntInst, DropPoisonGeneratingInsts)) + if (SE.canReuseInstruction(S, EntInst, DropPoisonGeneratingInsts)) return V; DropPoisonGeneratingInsts.clear(); } |