[llvm] [InstCombine] fold icmp with add/sub instructions having the same operands (PR #143241)

[Acthinks Yang via llvm-commits]

Acthinks wrote:

> Please see https://llvm.org/docs/InstCombineContributorGuide.html.
> 
> Can you please attach alive2 proofs? For example your equality condition looks too strict, it needs either nuw or nsw, not both: https://alive2.llvm.org/ce/z/krSOPt

https://alive2.llvm.org/ce/z/xBZ7Bk Add alive2 proofs at nikic 



https://github.com/llvm/llvm-project/pull/143241