[LICM] Preserve Disjoint flag on OR when hoisting.

Update hoistBOAssociation to preserve Disjoint flags on the newly
created instructions if both ORs are disjoint.

Fixes #139625.

Author: fhahn

llvm/lib/Transforms/Scalar/LICM.cpp

@@ -2877,6 +2877,12 @@ static bool hoistBOAssociation(Instruction &I, Loop &L,
     if (auto *I = dyn_cast<Instruction>(Inv))
       I->setFastMathFlags(Intersect);
     NewBO->setFastMathFlags(Intersect);
+  } else if (Opcode == Instruction::Or) {
+    bool Disjoint = cast<PossiblyDisjointInst>(BO)->isDisjoint() &&
+                    cast<PossiblyDisjointInst>(BO0)->isDisjoint();
+    if (auto *I = dyn_cast<PossiblyDisjointInst>(Inv))
+      I->setIsDisjoint(Disjoint);
+    cast<PossiblyDisjointInst>(NewBO)->setIsDisjoint(Disjoint);
   }
 
   BO->replaceAllUsesWith(NewBO);

llvm/test/Transforms/LICM/hoist-binop.ll

@@ -727,11 +727,11 @@ loop:
 define void @or_all_disjoint(i64 %c1, i64 %c2) {
 ; CHECK-LABEL: @or_all_disjoint(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[INVARIANT_OP:%.*]] = or i64 [[C1:%.*]], [[C2:%.*]]
+; CHECK-NEXT:    [[INVARIANT_OP:%.*]] = or disjoint i64 [[C1:%.*]], [[C2:%.*]]
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
 ; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INDEX_NEXT_REASS:%.*]], [[LOOP]] ]
-; CHECK-NEXT:    [[INDEX_NEXT_REASS]] = or i64 [[INDEX]], [[INVARIANT_OP]]
+; CHECK-NEXT:    [[INDEX_NEXT_REASS]] = or disjoint i64 [[INDEX]], [[INVARIANT_OP]]
 ; CHECK-NEXT:    br label [[LOOP]]
 ;
 entry: