[llvm] [VPlan] Introduce ComputeReductionResult VPInstruction opcode. (PR #70253)

[via llvm-commits]

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@@ -7640,6 +7463,42 @@ SCEV2ValueTy LoopVectorizationPlanner::executePlan(
 
   BestVPlan.execute(&State);
 
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ayalz wrote:

Worth commenting, something like
`// 2.5 Collect reduction resume values.`
?

Worth outlining?

https://github.com/llvm/llvm-project/pull/70253