[llvm] [InstCombine] Fold (X + C) + (Y & ~C) to X + (Y | C) (PR #191334)

[via llvm-commits]

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@@ -1523,6 +1523,35 @@ static Instruction *foldBoxMultiply(BinaryOperator &I) {
   return nullptr;
 }
 
+static Instruction *
+foldAddWithMaskedOverwrite(BinaryOperator &Add,
+                           InstCombiner::BuilderTy &Builder) {
+  Value *LHS = Add.getOperand(0), *RHS = Add.getOperand(1);
+  Value *X, *Y;
+  const APInt *C, *Mask;
+
+  auto Match = [&](Value *AddOp, Value *AndOp) -> Instruction * {
+    if (!match(AddOp, m_c_Add(m_Value(X), m_APInt(C))) ||
+        !match(AndOp, m_c_And(m_Value(Y), m_APInt(Mask))) || *Mask != ~(*C))
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ParkHanbum wrote:

got it!

https://github.com/llvm/llvm-project/pull/191334