[llvm] [LV] Create in-loop sub reductions (PR #147026)

[Sam Tebbs via llvm-commits]

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@@ -9144,6 +9144,14 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
             CurrentLinkI->getFastMathFlags());
         LinkVPBB->insert(FMulRecipe, CurrentLink->getIterator());
         VecOp = FMulRecipe;
+      } else if (PhiR->isInLoop() && Kind == RecurKind::Add &&
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SamTebbs33 wrote:

I don't think there is a reason so I'll experiment with adding RecurKind::Sub :+1: .

https://github.com/llvm/llvm-project/pull/147026