[llvm] [SCEV] Consolidate code for proving wrap flags of controlling finite IVs (PR #101404)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM, though this doesn't really look NFC to me. The old code only handled the power of 2 case, while the new one handles any positive step. These are the same if we get the NW from the power of 2 reasoning, but we should also be able to handle additional cases in case we know NW through some other pathway and the step is not power of 2. Don't know if it's feasible to test this.

https://github.com/llvm/llvm-project/pull/101404