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

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

It would probably make sense to add a takeLog2 based fold for cttz as a follow up. I think that would recover the regression from https://github.com/dtcxzyw/llvm-opt-benchmark/pull/1908#discussion_r1900188252.

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