diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils/SimplifyIndVar.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp index 51fda1c..7faf291 100644 --- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp @@ -108,6 +108,7 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand) Value *IVSrc = nullptr; const unsigned OperIdx = 0; const SCEV *FoldedExpr = nullptr; + bool MustDropExactFlag = false; switch (UseInst->getOpcode()) { default: return nullptr; @@ -140,6 +141,11 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand) APInt::getOneBitSet(BitWidth, D->getZExtValue())); } FoldedExpr = SE->getUDivExpr(SE->getSCEV(IVSrc), SE->getSCEV(D)); + // We might have 'exact' flag set at this point which will no longer be + // correct after we make the replacement. + if (UseInst->isExact() && + SE->getSCEV(IVSrc) != SE->getMulExpr(FoldedExpr, SE->getSCEV(D))) + MustDropExactFlag = true; } // We have something that might fold it's operand. Compare SCEVs. if (!SE->isSCEVable(UseInst->getType())) @@ -155,6 +161,9 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand) UseInst->setOperand(OperIdx, IVSrc); assert(SE->getSCEV(UseInst) == FoldedExpr && "bad SCEV with folded oper"); + if (MustDropExactFlag) + UseInst->dropPoisonGeneratingFlags(); + ++NumElimOperand; Changed = true; if (IVOperand->use_empty()) |