[llvm] [LV][EVL] Generate negative strided load/store for reversed load/store (PR #123608)

[Pengcheng Wang via llvm-commits]

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@@ -2670,14 +2665,13 @@ InstructionCost VPWidenLoadEVLRecipe::computeCost(ElementCount VF,
       getLoadStoreAlignment(const_cast<Instruction *>(&Ingredient));
   unsigned AS =
       getLoadStoreAddressSpace(const_cast<Instruction *>(&Ingredient));
-  InstructionCost Cost = Ctx.TTI.getMaskedMemoryOpCost(
-      Ingredient.getOpcode(), Ty, Alignment, AS, Ctx.CostKind);
   if (!Reverse)
-    return Cost;
+    return Ctx.TTI.getMaskedMemoryOpCost(Ingredient.getOpcode(), Ty, Alignment,
+                                         AS, Ctx.CostKind);
 
-  return Cost + Ctx.TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
-                                       cast<VectorType>(Ty), {}, Ctx.CostKind,
-                                       0);
+  return Ctx.TTI.getStridedMemoryOpCost(Ingredient.getOpcode(), Ty,
+                                        getAddr()->getUnderlyingValue(), false,
+                                        Alignment, Ctx.CostKind);
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wangpc-pp wrote:

Then the cost of VPlan will be invalid and we emit a marker?

https://github.com/llvm/llvm-project/pull/123608