caf033b142
UGPRs in warp instructions are treated more like cbufs than GPRs. You're only allowed to have one and it has to share space with the possible cbuf or immediate. This means we need to treat them as a "not a register" case for warp instructions but as a register for uniform instructions. Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29591>