[llvm] [AMDGPU] Improved Lowering of abs(i16) and -abs(i16) (PR #165626)

[Patrick Simmons via llvm-commits]

linuxrocks123 wrote:

@arsenm also am I making the lowering "custom for i16" properly in that commit, or is there another way?  It bugged me that I had to make that function virtual to override it since I thought, if this was the right way to go, some other target probably would have made it virtual by now.

https://github.com/llvm/llvm-project/pull/165626