[llvm] [InstCombine] fold `sub(zext(ptrtoint), zext(ptrtoint))` (PR #115369)

[Nikolay Panchenko via llvm-commits]

npanchen wrote:

> I believe you're doing this now, which is still incorrect: https://alive2.llvm.org/ce/z/irt9qk

Argh... I misread `nusw` as `nuw + nsw` in gep.



https://github.com/llvm/llvm-project/pull/115369