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

[Florian Hahn via llvm-commits]

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@@ -2262,6 +2294,28 @@ class VPReductionRecipe : public VPRecipeWithIRFlags {
     setUnderlyingValue(I);
   }
 
+  /// For VPExtendedReductionRecipe.
+  /// Note that IsNonNeg flag and the debug location are for extend instruction.
----------------
fhahn wrote:

```suggestion
  /// Note that IsNonNeg flag and the debug location are from the extend.
```

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