[llvm] [InstCombine] Remove redundant alignment assumptions. (PR #123348)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

ping :)

Rebased on current `main`, it looks as-is there's only a single case I could spot where alignment gets narrowed/regressed: https://github.com/dtcxzyw/llvm-opt-benchmark/pull/2725/files/50758450294569ef6ac6f41d50dcbc7f189257b1#diff-40a5ffbdcae402ed7681965b1723569e2cafa9ceb214ba4b248aab028c07dbda

This case and more can be further strengthed by https://github.com/llvm/llvm-project/pull/123518.

https://github.com/llvm/llvm-project/pull/123348