[llvm] [KnownBits] Add fast path for udiv by pow2 and overloads for shift ops by constant (PR #189779)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

I'm not sure the new overloads really make sense if they don't actually have an optimized implementation anymore.

https://github.com/llvm/llvm-project/pull/189779