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

[Florian Hahn via llvm-commits]

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@@ -282,14 +283,22 @@ struct VPTransformState {
            I->second[Instance.Part][CacheIdx];
   }
 
-  /// Set the generated Value for a given VPValue and a given Part.
-  void set(VPValue *Def, Value *V, unsigned Part) {
-    if (!Data.PerPartOutput.count(Def)) {
-      DataState::PerPartValuesTy Entry(UF);
-      Data.PerPartOutput[Def] = Entry;
+  /// Set the generated vector Value for a given VPValue and a given Part, if \p
+  /// IsScalar is false. If \p IsScalar is true, set the scalar in (Part, 0).
+  void set(VPValue *Def, Value *V, unsigned Part, bool IsScalar = false) {
+    if (IsScalar) {
+      set(Def, V, VPIteration(Part, 0));
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fhahn wrote:

Done, thanks!

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