[llvm] [VPlan] Get Addr computation cost with scalar type if it is uniform for gather/scatter. (PR #150371)

[Luke Lau via llvm-commits]

================
@@ -3099,9 +3099,18 @@ InstructionCost VPWidenMemoryRecipe::computeCost(ElementCount VF,
     const Value *Ptr = getLoadStorePointerOperand(&Ingredient);
     assert(!Reverse &&
            "Inconsecutive memory access should not have the order.");
-    return Ctx.TTI.getAddressComputationCost(Ty) +
-           Ctx.TTI.getGatherScatterOpCost(Opcode, Ty, Ptr, IsMasked, Alignment,
-                                          Ctx.CostKind, &Ingredient);
+    InstructionCost Cost = 0;
+
+    // If the address value is uniform across all lane, then the address can be
+    // calculated with scalar type and broacast.
----------------
lukel97 wrote:

```suggestion
    // If the address value is uniform across all lanes, then the address can be
    // calculated with scalar type and broadcast.
```

https://github.com/llvm/llvm-project/pull/150371