[llvm] [InstCombine] Fold (X << Y) / (X << Z) -> (1 << Y) / (1 << Z) (PR #68863)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Thanks for your review. Here is a more direct fold. [Alive2](https://alive2.llvm.org/ce/z/_N7cxo).

Please update the PR title.


https://github.com/llvm/llvm-project/pull/68863