diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp index f8b57eeb388..936daa828a5 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp @@ -1592,8 +1592,11 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts, simplifyAndSetOp(I, 0, DemandedElts, UndefElts); simplifyAndSetOp(I, 1, DemandedElts, UndefElts2); - // TODO: If this is a potentially poison-producing instruction, we need - // to drop the wrapping/exact flags? + // Any change to an instruction with potential poison must clear those flags + // because we can not guarantee those constraints now. Other analysis may + // determine that it is safe to re-apply the flags. + if (MadeChange) + BO->dropPoisonGeneratingFlags(); // Output elements are undefined if both are undefined. Consider things // like undef & 0. The result is known zero, not undef. |
