[llvm] KnownBits: refine KnownBits::srem for high-bits (PR #109121)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

I'm not sure if you can use assume in the tgt for verification, maybe try something like this: https://alive2.llvm.org/ce/z/Ugh-Dq

https://github.com/llvm/llvm-project/pull/109121