[llvm] [VPlan] Support VPReverseVectorPointer in DataWithEVL vectorization (PR #113667)

[Mel Chen via llvm-commits]

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@@ -1462,15 +1462,22 @@ static void transformRecipestoEVLRecipes(VPlan &Plan, VPValue &EVL) {
         assert(OrigMask && "Unmasked recipe when folding tail");
         return HeaderMask == OrigMask ? nullptr : OrigMask;
       };
+      auto SetEVLForReversePointer = [&EVL](VPValue *V) -> void {
+        if (auto R =
+                dyn_cast<VPReverseVectorPointerRecipe>(V->getDefiningRecipe()))
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Mel-Chen wrote:

Is it possible for V->getDefiningRecipe() to return nullptr?

https://github.com/llvm/llvm-project/pull/113667