[flang-commits] [llvm] [flang] [clang-tools-extra] [clang] [compiler-rt] [VPlan] Replace VPRecipeOrVPValue with VP2VP recipe simplification. (PR #76090)

[Florian Hahn via flang-commits]

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@@ -806,6 +806,38 @@ static unsigned getOpcodeForRecipe(VPRecipeBase &R) {
 
 /// Try to simplify recipe \p R.
 static void simplifyRecipe(VPRecipeBase &R, VPTypeAnalysis &TypeInfo) {
+  // Try to remove redundant blend recipes.
+  if (auto *Blend = dyn_cast<VPBlendRecipe>(&R)) {
+    if (Blend->getNumIncomingValues() == 1) {
+      Blend->replaceAllUsesWith(Blend->getIncomingValue(0));
+      Blend->eraseFromParent();
+      return;
+    }
+
+    bool AllEqual = true;
+    for (unsigned I = 1; I != Blend->getNumIncomingValues(); ++I)
+      AllEqual &= Blend->getIncomingValue(0) == Blend->getIncomingValue(I);
+    if (AllEqual) {
+      Blend->replaceAllUsesWith(Blend->getIncomingValue(0));
+      Blend->eraseFromParent();
+      return;
+    }
+    if (Blend->getNumIncomingValues() != 2)
+      return;
+    auto IsInLoopReduction = [](VPValue *VPV) {
+      auto *PhiR = dyn_cast<VPReductionPHIRecipe>(VPV);
+      return PhiR && PhiR->isInLoop();
+    };
+    if (IsInLoopReduction(Blend->getIncomingValue(0))) {
+      Blend->replaceAllUsesWith(Blend->getIncomingValue(1));
+      Blend->eraseFromParent();
+    } else if (IsInLoopReduction(Blend->getIncomingValue(1))) {
+      Blend->replaceAllUsesWith(Blend->getIncomingValue(0));
+      Blend->eraseFromParent();
+    }
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fhahn wrote:

Moved as suggested, thanks!

https://github.com/llvm/llvm-project/pull/76090