[llvm] Simplify `(a % b) lt/ge (b-1)` into `(a % b) eq/ne (b-1)` (PR #72504)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Should we add tests with constant scalars only (use integer constants, and splat vectors)? for example:

Yeah, you should use `@llvm.assume` in Alive2 proof and use constants in tests.


https://github.com/llvm/llvm-project/pull/72504