[llvm] [ConstraintElim] Add facts implied by llvm.abs (PR #73189)

[Alexander Shaposhnikov via llvm-commits]

alexander-shaposhnikov wrote:

p.s. clang-format doesn't seem to format "if" properly:
<img width="742" alt="Screenshot 2023-12-28 at 11 35 33 PM" src="https://github.com/llvm/llvm-project/assets/6532716/e0d9e0a5-2556-4901-bf7a-0bb5dbeb87e0">


https://github.com/llvm/llvm-project/pull/73189