[llvm] [InstCombine] Fold `X udiv Y` to `X lshr cttz(Y)` if Y is a power of 2 (PR #121386)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw commented:

The IR diff looks good. It also eliminates some redundant `llvm.umul.with.overflow` calls :)


https://github.com/llvm/llvm-project/pull/121386