[llvm] [InstCombine] Simplify `(X / C0) * C1 + (X % C0) * C2` to `(X / C0) * (C1 - C2 * C0) + X * C2` (PR #76285)

[Nikita Popov via llvm-commits]

nikic wrote:

As it took me a while to get it: The core of the transform is that `x % c` is `x - x / c * c` (https://alive2.llvm.org/ce/z/I8CBWy).

https://github.com/llvm/llvm-project/pull/76285