[InstCombine] Explicitly set disjoint flag when converting xor to or.

[topperc]

No description provided.

[llvmbot]

@llvm/pr-subscribers-llvm-ir

@llvm/pr-subscribers-llvm-transforms

Author: Craig Topper (topperc)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/74229.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp (+1)

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 732a3a13dacc..4f00ce661215 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -315,6 +315,7 @@ Value *InstCombinerImpl::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     if (DemandedMask.isSubsetOf(RHSKnown.Zero | LHSKnown.Zero)) {
       Instruction *Or =
           BinaryOperator::CreateOr(I->getOperand(0), I->getOperand(1));
+      cast<PossiblyDisjointInst>(Or)->setIsDisjoint(true);
       Or->takeName(I);
       return InsertNewInstWith(Or, I->getIterator());
     }

[nikic]

LGTM