[llvm] [GISel][AArch64][AMDGPU][RISCV] Canonicalize (sub X, C) -> (add X, -C) (PR #114309)

[David Green via llvm-commits]

davemgreen wrote:

Feel free to recommit if you want and we can work through the fallbacks as we find them. We shouldn't consider those to be breaking behaviour at the moment, they happen in too many places. Or that it's on you to fix them.

https://github.com/llvm/llvm-project/pull/114309