diff options
Diffstat (limited to 'lib/Analysis/ScalarEvolutionExpander.cpp')
-rw-r--r-- | lib/Analysis/ScalarEvolutionExpander.cpp | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp index 86f714b930d0..3ceda677ba61 100644 --- a/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/lib/Analysis/ScalarEvolutionExpander.cpp @@ -187,8 +187,21 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, // generated code. if (isa<DbgInfoIntrinsic>(IP)) ScanLimit++; + + // Conservatively, do not use any instruction which has any of wrap/exact + // flags installed. + // TODO: Instead of simply disable poison instructions we can be clever + // here and match SCEV to this instruction. + auto canGeneratePoison = [](Instruction *I) { + if (isa<OverflowingBinaryOperator>(I) && + (I->hasNoSignedWrap() || I->hasNoUnsignedWrap())) + return true; + if (isa<PossiblyExactOperator>(I) && I->isExact()) + return true; + return false; + }; if (IP->getOpcode() == (unsigned)Opcode && IP->getOperand(0) == LHS && - IP->getOperand(1) == RHS) + IP->getOperand(1) == RHS && !canGeneratePoison(&*IP)) return &*IP; if (IP == BlockBegin) break; } |