[llvm-branch-commits] [llvm] [LV] Use VPReductionRecipe for partial reductions (PR #146073)

[Florian Hahn via llvm-branch-commits]

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@@ -2744,6 +2702,12 @@ class VPSingleDefBundleRecipe : public VPSingleDefRecipe {
     /// vector operands, performing a reduction.add on the result, and adding
     /// the scalar result to a chain.
     MulAccumulateReduction,
+    /// Represent an inloop multiply-accumulate reduction, multiplying the
+    /// extended vector operands, negating the multiplication, performing a
+    /// reduction.add
+    /// on the result, and adding
+    /// the scalar result to a chain.
+    ExtNegatedMulAccumulateReduction,
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fhahn wrote:

Given that `VPPartialReductionRecipe` is already a sub-class of `VPReductionRecipe`, I think it should be possible to first add support for partial reductions to bundle/expression recipes, without also merging `VPPartialReductionRecipe`. This would simplify the patches and clearly separate the functional from the non-functional changes/refactorings.

It looks like most of the code for supporting partial reductions already needs to explicitly check for partial reductions, so hopefully such a split wouldn't complicate thinga


https://github.com/llvm/llvm-project/pull/146073