[llvm] [VPlan] Consistently use (Part, 0) for first lane scalar values (PR #80271)

[via llvm-commits]

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@@ -9404,7 +9403,7 @@ void VPWidenMemoryInstructionRecipe::execute(VPTransformState &State) {
           // We don't want to update the value in the map as it might be used in
           // another expression. So don't call resetVectorValue(StoredVal).
         }
-        auto *VecPtr = State.get(getAddr(), Part);
+        auto *VecPtr = State.get(getAddr(), VPIteration(Part, 0));
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ayalz wrote:

```suggestion
        auto *VecPtr = State.get(getAddr(), Part, true /* scalar */);
```

https://github.com/llvm/llvm-project/pull/80271