[llvm] [ValueTracking] Compute knownbits from `(icmp upred (add/sub nuw X, Y), C)` (PR #87180)

[via llvm-commits]

goldsteinn wrote:

> Needs another rebase.
> 
> > @dtcxzyw i update with support for `sub nuw` as well.
> 
> Why?

I guess the `add nuw` mirrors the `or` case and the `sub nuw` mirrors the `and` case. I had meant to leave it as a folllowup todo but it seemed to fit well enough.



https://github.com/llvm/llvm-project/pull/87180