[llvm] [VPlan] Impl VPlan-based pattern match for ExtendedRed and MulAccRed (NFCI) (PR #113903)

[Alexey Bataev via llvm-commits]

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@@ -1867,9 +1957,173 @@ void VPlanTransforms::convertToConcreteRecipes(VPlan &Plan) {
       PhiR->replaceAllUsesWith(ScalarR);
       PhiR->eraseFromParent();
     }
+    for (VPRecipeBase &R : make_early_inc_range(*VPBB)) {
+      if (!isa<VPExtendedReductionRecipe, VPMulAccumulateReductionRecipe>(&R))
+        continue;
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alexey-bataev wrote:

This check can be dropped

https://github.com/llvm/llvm-project/pull/113903