[llvm] [InstCombine] ptrmask of gep for dynamic pointer aligment (PR #80002)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Ideally this would not be inside the `ptrmask` handling, but rather a separate `GetElementPtr` case in the switch. The simplification would then be based on the `DemandedMask`. But I guess we can start like this.

https://github.com/llvm/llvm-project/pull/80002