[llvm] [AArch64] Use isKnownNonZero to optimize eligible compares to cmn (PR #96349)

[David Green via llvm-commits]

davemgreen wrote:

OK - I was just being careful as we are so close to the release and some of the issues can be subtle. I gave it a more thorough test and everything seems OK.

By "tested this and found no issue", does that include running a bootstrap and the llvm-test-suite? If so and you add a some extra test coverage then this LGTM.

https://github.com/llvm/llvm-project/pull/96349