[llvm] [LV] Vectorize selecting index of min/max element. (PR #141431)

[Florian Hahn via llvm-commits]

fhahn wrote:

> So I think it should be detected independently. Of course, a better approach would be to first identify the recurrence chain, and then determine whether it's a reduction.
> 

Yep that's a good point! I was initially planning to split off detection of the pattern separately as follow-up, but it seems better to do it to start with. I started sharing a few refactoring patches to make it simpler to create reduction phi recipes in VPlan (final one in the series is https://github.com/llvm/llvm-project/pull/142322) and will update the PR here in the next few days.



https://github.com/llvm/llvm-project/pull/141431