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

[Sam Tebbs via llvm-commits]

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@@ -3472,25 +3472,30 @@ tryToMatchAndCreateExtendedReduction(VPReductionRecipe *Red, VPCostContext &Ctx,
           auto *SrcVecTy = cast<VectorType>(toVectorTy(SrcTy, VF));
           TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
 
-          InstructionCost ExtRedCost;
           InstructionCost ExtCost =
               cast<VPWidenCastRecipe>(VecOp)->computeCost(VF, Ctx);
           InstructionCost RedCost = Red->computeCost(VF, Ctx);
+          InstructionCost BaseCost = ExtCost + RedCost;
 
           if (isa<VPPartialReductionRecipe>(Red)) {
             TargetTransformInfo::PartialReductionExtendKind ExtKind =
                 TargetTransformInfo::getPartialReductionExtendKind(ExtOpc);
             // FIXME: Move partial reduction creation, costing and clamping
             // here from LoopVectorize.cpp.
-            ExtRedCost = Ctx.TTI.getPartialReductionCost(
-                Opcode, SrcTy, nullptr, RedTy, VF, ExtKind,
-                llvm::TargetTransformInfo::PR_None, std::nullopt, Ctx.CostKind);
-          } else {
-            ExtRedCost = Ctx.TTI.getExtendedReductionCost(
-                Opcode, ExtOpc == Instruction::CastOps::ZExt, RedTy, SrcVecTy,
-                Red->getFastMathFlags(), CostKind);
+            InstructionCost PartialReductionCost =
+                Ctx.TTI.getPartialReductionCost(
+                    Opcode, SrcTy, nullptr, RedTy, VF, ExtKind,
+                    llvm::TargetTransformInfo::PR_None, std::nullopt,
+                    Ctx.CostKind);
+            assert(PartialReductionCost.isValid() &&
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SamTebbs33 wrote:

Done, I'll raise the new PR soon 👍  I had the assertion in this PR since it had to be removed from the other PR because of the "multiply by constant" case, which this PR introduces support for.

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