As there are no instructions left which produce multiple result values, this is a NFC regarding the generated SIL and generated code.
Although this commit is large, most changes are straightforward adoptions to the changes in the ValueBase and SILValue classes.
In all of the cases where this is being used, we already immediately perform an
unreachable if we find a TermKind::Invalid. So simplify the code and move it
into the conversion switch itself.
This exposed the first interesting bug found by using TermKind, in DCE we were
not properly handling switch_enum_addr and checked_cast_addr_br.
SR-335
rdar://23980060
(libraries now)
It has been generally agreed that we need to do this reorg, and now
seems like the perfect time. Some major pass reorganization is in the
works.
This does not have to be the final word on the matter. The consensus
among those working on the code is that it's much better than what we
had and a better starting point for future bike shedding.
Note that the previous organization was designed to allow separate
analysis and optimization libraries. It turns out this is an
artificial distinction and not an important goal.
