[llvm] [AArch64] Eliminate Common SUBS by Reassociating Non-Constants (PR #123344)

[Marius Kamp via llvm-commits]

mskamp wrote:

> Thanks - it might be possible to remove the other lambda too by creating the negative constant, I'm not sure if that is worth it or not.

Good suggestion. I've adjusted the code accordingly to get rid of the remaining lambda.

> LGTM. Thanks for the follow-up. Let me know if you are happy for this version to be submitted.

In case the latest changes are fine, I'd consider this ready.

https://github.com/llvm/llvm-project/pull/123344