[llvm] [VPlan] Also duplicated scalar-steps when it enables sinking scalars. (PR #136021)

[via llvm-commits]

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@@ -163,18 +163,25 @@ static bool sinkScalarOperands(VPlan &Plan) {
       if (UI->getParent() == SinkTo)
         return true;
       NeedsDuplicating = UI->onlyFirstLaneUsed(SinkCandidate);
-      // We only know how to duplicate VPRecipeRecipes for now.
-      return NeedsDuplicating && isa<VPReplicateRecipe>(SinkCandidate);
+      // We only know how to duplicate VPRecipeRecipes and
+      // VPScalarIVStepsRecipes for now.
+      return NeedsDuplicating &&
+             isa<VPReplicateRecipe, VPScalarIVStepsRecipe>(SinkCandidate);
     };
     if (!all_of(SinkCandidate->users(), CanSinkWithUser))
       continue;
 
     if (NeedsDuplicating) {
       if (ScalarVFOnly)
         continue;
-      Instruction *I = SinkCandidate->getUnderlyingInstr();
-      auto *Clone = new VPReplicateRecipe(I, SinkCandidate->operands(), true);
-      // TODO: add ".cloned" suffix to name of Clone's VPValue.
+      VPSingleDefRecipe *Clone;
+      if (isa<VPReplicateRecipe>(SinkCandidate)) {
+        Instruction *I = SinkCandidate->getUnderlyingInstr();
+        Clone = new VPReplicateRecipe(I, SinkCandidate->operands(), true);
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ayalz wrote:

(Also independent) Could SinkCandidate->clone() also work for VPReplicateRecipe?
```


https://github.com/llvm/llvm-project/pull/136021