[llvm] [LoopIdiomVectorize] Recognize and transform minidx pattern (PR #144987)

[David Sherwood via llvm-commits]

david-arm wrote:

> Please note, this patch offers 4x speedup for the pattern.

I do believe this to be true, but equally I think you also have to accept the risk of a 4x slowdown once this is finally supported in GVN as the patterns will no longer match. If this PR does go ahead, then it might be a good idea first to add similar tests in GVN. That way you have a chance at getting an early warning that the work is going ahead.

https://github.com/llvm/llvm-project/pull/144987