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

topperc · topperc · commit ff8e0c372bd5 · 2023-12-05T10:37:18.000-08:00
diff --git 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());
     }

Original file line number	Diff line number	Diff line change
`@@ -315,6 +315,7 @@ Value InstCombinerImpl::SimplifyDemandedUseBits(Value V, APInt DemandedMask,`
`315`	`315`	`if (DemandedMask.isSubsetOf(RHSKnown.Zero \| LHSKnown.Zero)) {`
`316`	`316`	`Instruction *Or =`
`317`	`317`	`BinaryOperator::CreateOr(I->getOperand(0), I->getOperand(1));`
	`318`	`+ cast<PossiblyDisjointInst>(Or)->setIsDisjoint(true);`
`318`	`319`	`Or->takeName(I);`
`319`	`320`	`return InsertNewInstWith(Or, I->getIterator());`
`320`	`321`	`}`