[llvm] [VPlan] Split VPWidenMemoryInstructionRecipe (NFCI). (PR #87411)

[via llvm-commits]

================
@@ -875,7 +875,8 @@ class VPSingleDefRecipe : public VPRecipeBase, public VPValue {
       return true;
     case VPRecipeBase::VPInterleaveSC:
     case VPRecipeBase::VPBranchOnMaskSC:
-    case VPRecipeBase::VPWidenMemoryInstructionSC:
+    case VPRecipeBase::VPWidenLoadSC:
+    case VPRecipeBase::VPWidenStoreSC:
----------------
ayalz wrote:

Another alternative may be to also consider VPWidenStoreRecipe as a Single Def recipe, with a singleton "void" Def that has no uses. Akin to LLVM. I.e., VPSingle[OrNo]DefRecipe.

https://github.com/llvm/llvm-project/pull/87411