[llvm] [APInt][NFC] Add branch hints to APInt single-word (PR #219437)

[Steffen Larsen via llvm-commits]

steffenlarsen wrote:

Thanks for trying out the alternative solution, @MaskRay! I've added `LLVM_(UN)LIKELY` to both APInt.cpp and some missed cases in APInt.h, including ternary expressions which might benefit from it as well. I'm gathering the performance differences with the newest set of additions.

https://github.com/llvm/llvm-project/pull/219437