[llvm] [LV] Reuse VPReplicateRecipe to handle scalar stores in exit block. (PR #106342)

[Mel Chen via llvm-commits]

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@@ -8948,12 +8957,22 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
         Operands = {OpRange.begin(), OpRange.end()};
       }
 
-      // Invariant stores inside loop will be deleted and a single store
-      // with the final reduction value will be added to the exit block
+      // The stores with invariant address inside the loop will be deleted, and
+      // in the exit block, a uniform store recipe will be created for the final
+      // invariant store of the reduction.
       StoreInst *SI;
       if ((SI = dyn_cast<StoreInst>(&I)) &&
-          Legal->isInvariantAddressOfReduction(SI->getPointerOperand()))
+          Legal->isInvariantAddressOfReduction(SI->getPointerOperand())) {
+        // Only create recipe for the final invariant store of the reduction.
+        if (!Legal->isInvariantStoreOfReduction(SI))
+          continue;
+        auto *Recipe = new VPReplicateRecipe(
+            SI, RecipeBuilder.mapToVPValues(Instr->operands()),
+            true /* IsUniform */);
+        RecipeBuilder.setRecipe(SI, Recipe);
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Mel-Chen wrote:

Thank you for your suggestion :) 
It has been removed. After confirm, I think it is not needed, as there is no use case for it at the moment.

https://github.com/llvm/llvm-project/pull/106342