[llvm] [LV] Use VPReductionRecipe for partial reductions (PR #147513)

[Sam Tebbs via llvm-commits]

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@@ -8184,11 +8185,21 @@ VPRecipeBase *VPRecipeBuilder::tryToCreateWidenRecipe(VPSingleDefRecipe *R,
              Phi->getIncomingValueForBlock(OrigLoop->getLoopPreheader()));
 
       // If the PHI is used by a partial reduction, set the scale factor.
+      bool UseInLoopReduction = CM.isInLoopReduction(Phi);
+      bool UseOrderedReductions = CM.useOrderedReductions(RdxDesc);
       unsigned ScaleFactor =
           getScalingForReduction(RdxDesc.getLoopExitInstr()).value_or(1);
-      PhiRecipe = new VPReductionPHIRecipe(
-          Phi, RdxDesc.getRecurrenceKind(), *StartV, CM.isInLoopReduction(Phi),
-          CM.useOrderedReductions(RdxDesc), ScaleFactor);
+      RdxStyle Style(RdxNormal{});
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SamTebbs33 wrote:

It's a struct, so I think we have to use `{}`. My compiler complains at me when I use `()`: 

> warning: parentheses were disambiguated as a function declaration
> note: replace parentheses with braces to declare a variable

and

> error: assignment of function ‘llvm::RdxStyle llvm::Style(RdxNormal (*)())’

https://github.com/llvm/llvm-project/pull/147513