[llvm] [InstCombine] Add transforms for `(or/and (icmp eq/ne X,0),(icmp eq/ne X,Pow2OrZero))` (PR #94648)

[via llvm-commits]

goldsteinn wrote:

NB: this was approved by nikic a while back: https://reviews.llvm.org/D157312
There where concerns that we didn't handle `(icmp pred (x, y), x)` so well which has prompted a variety of independent patches to improve our handling of such cases.

Hopefully its time to get this in :)

https://github.com/llvm/llvm-project/pull/94648