intel/brw, anv/hasvk: misc compiler fixes and small improvements
Just a collection of small compiler patches I've been racking up while working on other things. We've got...
- A bug fix for register coalescing with LOAD_PAYLOAD
- A bug fix for copy propagation with LOAD_PAYLOAD
- A small improvement for copy propagation with LOAD_PAYLOAD
- A fix for opt_split_sends
- A patch to make anv/hasvk passes stop relying on undefined behavior (which I plan to need in a future MR)
- Deletion of a dead compiler pass