We should try the generated matchers before the manual selection. This
means the patterns are now handling the common cases, but the manual
selection code is not yet dead. It's still handling the non-s32/s64
cases (like v2s16 and v2s32). Currently tablegen doesn't have a nice
way to have a single pattern that covers multiple types.
The other 3-op patterns should also be theoretically handled, but
currently there's a bug in the inferred pattern complexity.
I'm not sure what the error handling strategy should be for potential
constant bus violations. I think the correct strategy is to never
produce mixed SGPR and VGPR operands in a typical VOP instruction,
which will trivially avoid them. However, it's possible to still have
hand written MIR (or erroneously transformed code) with these
operands. When these fold, the restriction will be violated. We
currently don't have any verifiers for reg bank legality. For now,
just ignore the restriction.
It might be worth triggering a DAG fallback on verifier error.