To implement GPRPair "properly", we need to be able to shuffle scalars around
the register file. That means we need explicit copy/swap instructions that RA
can generate them. Add some.
Swap is split in a really sketchy way, because of the 1 instruction = 1 dest
requirement. Hopefully that requirement is lifted in the future and then this
goes away.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Alyssa Rosenzweig
04c2cb5feb