[llvm] [LoopVectorizer] Add support for partial reductions (PR #92418)

[Sam Tebbs via llvm-commits]

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@@ -331,6 +344,8 @@ class LoopVectorizationPlanner {
   /// Profitable vector factors.
   SmallVector<VectorizationFactor, 8> ProfitableVFs;
 
+  SmallVector<PartialReductionChain> PartialReductionChains;
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SamTebbs33 wrote:

It looks like this is cleaner than passing it between functions with parameters. And the functions that use it are all part of `LoopVectorizationPlanner` anyway.

https://github.com/llvm/llvm-project/pull/92418