Changes for GFX11:
- Clauses may not mix instructions of different types, and there are more types. For example image instructions with and without a sampler are now different types.
- The max size of a clause is explicitly documented as 63 instructions. Previously it was implicitly assumed to be 64. This is such a tiny difference that it does not seem worth making it conditional on the subtarget.
- It can be beneficial to clause stores as well as loads.
We seem to use the value twice. What if to give it a name and move the comment to where we define it?