[llvm] [InstCombine] Optimize sub(sext(add(x, y)), sext(add(x, z))). (PR #144174)

[Slava Zakharin via llvm-commits]

vzakhari wrote:

Hi @nikic, does this change looks good to you? As I understand, I have to get your approval as the code owner.

https://github.com/llvm/llvm-project/pull/144174