[llvm] [SLP] Limit second pass to register VF in vectorizeNonVectorizableInsts. (PR #222755)

[Koleman Nix via llvm-commits]

kolemannix wrote:

@fhahn Hello, new to the project! I maintain a frontend (github.com/kolemannix/k1) which saw regressions after upgrading (33s to 182s), came to fix this and found it done! With your fix applied my repro goes from 5.7s to 0.30s.

Would you mind adding to 23.x? Do I understand the process correctly that, once the milestone is added, the comment `/cherry-pick dc6825047c 33578bd669 f77ec64870` would open the PR to 23.x?

https://github.com/llvm/llvm-project/pull/222755