[llvm] [CodeGenPrepare] Folding `urem` with loop invariant value as remainder (PR #96625)

[via llvm-commits]

goldsteinn wrote:

> > Alive2 seemed unable to prove this (see:
> > https://alive2.llvm.org/ce/z/ATGDp3 which is clearly wrong but still
> > checks out...)
> 
> Can you try again with "--src-unroll=xxx --tgt-unroll=xxx"?

Ah, didn't know about that: https://alive2.llvm.org/ce/z/BsyXdJ (anything past i3/unroll of 4 was taking too long).

https://github.com/llvm/llvm-project/pull/96625