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

[Florian Hahn via llvm-commits]

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@@ -1915,23 +1917,27 @@ class VPReductionPHIRecipe : public VPHeaderPHIRecipe {
   /// The phi is part of an ordered reduction. Requires IsInLoop to be true.
   bool IsOrdered;
 
+  /// The amount that the VF should be divided by during ::execute
+  unsigned VFScaleFactor = 1;
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fhahn wrote:

Can this be explained better?

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