[llvm] [llvm][loop-rotate] Allow forcing loop-rotation (PR #82828)

[Florian Hahn via llvm-commits]

fhahn wrote:

> @fhahn If there's no objections, I plan to land this in the afternoon. Are there any more changes you'd like to see?

FWIW I still think this would be better fixed by improve LoopIdiomRecognize to support non-rotated loops. This would benefit all users by default.

With the flag, it's not clear to me if we expect any feedback from downstream users and what we would do with the feedback.

https://github.com/llvm/llvm-project/pull/82828