[llvm] [DAGCombiner][AMDGPU] Track signedness in ByteProviders (PR #65995)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Thanks for swift responses. In general, I would think the unsigned type "wins" 

Signed or unsigned types do not exist. There are only operations which you may associate with signed or unsigned behavior 

https://github.com/llvm/llvm-project/pull/65995