[llvm] [VPlan] Replace RdxDesc with RecurKind in VPReductionPHIRecipe (NFC). (PR #142322)

[Ramkumar Ramachandra via llvm-commits]

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@@ -9177,7 +9175,8 @@ void LoopVectorizationPlanner::adjustRecipesForReductions(
     if (!PhiR)
       continue;
 
-    const RecurrenceDescriptor &RdxDesc = PhiR->getRecurrenceDescriptor();
+    const RecurrenceDescriptor &RdxDesc = Legal->getReductionVars().lookup(
+        cast<PHINode>(PhiR->getUnderlyingInstr()));
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artagnon wrote:

Can you comment on why this is a good change? Are we planning to never use Recurrence descriptors in the future?

https://github.com/llvm/llvm-project/pull/142322