[llvm] [LV] Bundle partial reductions inside VPExpressionRecipe (PR #147302)

[Sam Tebbs via llvm-commits]

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@@ -2776,25 +2776,43 @@ VPExpressionRecipe::VPExpressionRecipe(
       R->removeFromParent();
   }
 
+  // Keep track of how many instances of each recipe occur in the recipe list
+  SmallMapVector<VPSingleDefRecipe *, unsigned, 4> ExpressionRecipeCounts;
+  for (auto *R : ExpressionRecipes) {
+    auto *F = ExpressionRecipeCounts.find(R);
+    if (F == ExpressionRecipeCounts.end())
+      ExpressionRecipeCounts.insert(std::make_pair(R, 1));
+    else
+      F->second++;
+  }
+
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SamTebbs33 wrote:

This is part of the workaround to fix #156464 . I plan to break these changes out into a separate PR soon.

https://github.com/llvm/llvm-project/pull/147302