diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp index 41d4a4820bf..d10fa06f0c2 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp @@ -538,7 +538,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, LHSKnownZero, LHSKnownOne, Depth + 1) || ShrinkDemandedConstant(I, 1, DemandedFromOps) || SimplifyDemandedBits(I->getOperandUse(1), DemandedFromOps, - LHSKnownZero, LHSKnownOne, Depth + 1)) { + RHSKnownZero, RHSKnownOne, Depth + 1)) { // Disable the nsw and nuw flags here: We can no longer guarantee that // we won't wrap after simplification. Removing the nsw/nuw flags is // legal here because the top bit is not demanded. @@ -549,9 +549,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, } } - // Otherwise just hand the add/sub off to computeKnownBits to fill in - // the known zeros and ones. - computeKnownBits(V, KnownZero, KnownOne, Depth, CxtI); + // Otherwise compute the known bits using the RHS/LHS known bits. + bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap(); + computeKnownBitsForAddSub(V, NSW, KnownZero, KnownOne, LHSKnownZero, + LHSKnownOne, RHSKnownZero, RHSKnownOne); break; } case Instruction::Shl: |
