[llvm] InstCombine: extend select-equiv to support vectors (PR #111966)

[Nikita Popov via llvm-commits]

https://github.com/nikic requested changes to this pull request.

Shufflevector is not the only lane-crossing operation, see https://github.com/llvm/llvm-project/blob/80c15c48d1fbb53478c9400e598abcbdcae0d962/llvm/lib/Analysis/InstructionSimplify.cpp#L4347-L4351 for a more accurate heuristic.

https://github.com/llvm/llvm-project/pull/111966