[llvm] [VPlan] Remove VPBlendRecipe and replace with select VPInstructions (PR #150369)

[Ramkumar Ramachandra via llvm-commits]

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@@ -8944,20 +8948,20 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
     // the phi until LoopExitValue. We keep track of the previous item
     // (PreviousLink) to tell which of the two operands of a Link will remain
     // scalar and which will be reduced. For minmax by select(cmp), Link will be
-    // the select instructions. Blend recipes of in-loop reduction phi's  will
+    // the select instructions. Blend selects of in-loop reduction phi's  will
     // get folded to their non-phi operand, as the reduction recipe handles the
     // condition directly.
     VPSingleDefRecipe *PreviousLink = PhiR; // Aka Worklist[0].
     for (VPSingleDefRecipe *CurrentLink : drop_begin(Worklist)) {
-      if (auto *Blend = dyn_cast<VPBlendRecipe>(CurrentLink)) {
-        assert(Blend->getNumIncomingValues() == 2 &&
-               "Blend must have 2 incoming values");
-        if (Blend->getIncomingValue(0) == PhiR) {
-          Blend->replaceAllUsesWith(Blend->getIncomingValue(1));
+      using namespace VPlanPatternMatch;
+      VPValue *T, *F;
+      if (match(CurrentLink, m_VPInstruction<Instruction::Select>(
+                                 m_VPValue(), m_VPValue(T), m_VPValue(F)))) {
+        if (T == PhiR) {
+          CurrentLink->replaceAllUsesWith(F);
         } else {
-          assert(Blend->getIncomingValue(1) == PhiR &&
-                 "PhiR must be an operand of the blend");
-          Blend->replaceAllUsesWith(Blend->getIncomingValue(0));
+          assert(F == PhiR && "PhiR must be an operand of the select");
+          CurrentLink->replaceAllUsesWith(T);
         }
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artagnon wrote:

CurrentLink->replaceAllUsesWith(T == PhiR ? F : T);

https://github.com/llvm/llvm-project/pull/150369