[llvm-branch-commits] [llvm] [LV] Bundle (partial) reductions with a mul of a constant (PR #162503)

[Sander de Smalen via llvm-branch-commits]

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@@ -3597,6 +3607,32 @@ tryToMatchAndCreateMulAccumulateReduction(VPReductionRecipe *Red,
         dyn_cast_if_present<VPWidenCastRecipe>(B->getDefiningRecipe());
     auto *Mul = cast<VPWidenRecipe>(VecOp->getDefiningRecipe());
 
+    // Match reduce.add(mul(ext, const)) and convert it to
+    // reduce.add(mul(ext, ext(const)))
+    if (RecipeA && !RecipeB && B->isLiveIn()) {
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sdesmalen-arm wrote:

It would be nice if this could also work for the case handled on loop 3657 (`zext(mul(zext(a), zext(b)))` where `b` is a constant)

https://github.com/llvm/llvm-project/pull/162503