[llvm] [VPlan] Simplify commutative logical ops (PR #156345)

[Ramkumar Ramachandra via llvm-commits]

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@@ -1107,6 +1092,26 @@ static void simplifyRecipe(VPRecipeBase &R, VPTypeAnalysis &TypeInfo) {
     return Def->replaceAllUsesWith(
         Builder.createLogicalAnd(X, Builder.createOr(Y, Z)));
 
+  // OR x, 1 -> 1
+  if (match(Def, m_c_BinaryOr(m_VPValue(X), m_AllOnes())))
+    return Def->replaceAllUsesWith(Def->getOperand(Def->getOperand(0) == X));
+
+  // OR x, 0 -> x
+  if (match(Def, m_c_BinaryOr(m_VPValue(X), m_ZeroInt())))
+    return Def->replaceAllUsesWith(X);
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artagnon wrote:

This simplification is necessary to avoid undoing the work you just landed: the test dead-ops-cost regresses without this simplification.

https://github.com/llvm/llvm-project/pull/156345