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

[Florian Hahn via llvm-commits]

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@@ -407,7 +408,7 @@ Value *VPInstruction::generateInstruction(VPTransformState &State,
   }
   case VPInstruction::ComputeReductionResult: {
     if (Part != 0)
-      return State.get(this, 0);
+      return State.get(this, VPIteration(0, 0));
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fhahn wrote:

Adjusted, thanks!

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