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

[Florian Hahn via llvm-commits]

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@@ -155,6 +155,8 @@ bool VPRecipeBase::mayHaveSideEffects() const {
   case VPBlendSC:
   case VPReductionEVLSC:
   case VPReductionSC:
+  case VPExtendedReductionSC:
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fhahn wrote:

Should also be added to `mayReadFromMemory`  and `mayWriteToMemory` for completeness?

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