nir: Modernize the out-of-SSA pass

The out-of-SSA pass was one of the first passes written when getting SSA
up-and-going (for obvious reasons).  As such, it came before a lot of the
nifty SSA-based helpers were introduced.  This commit modernizes it so that
we're no longer doing nearly as much manual banging on use/def sets.

Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
1 file changed