replaced by retain release code motion. This code has been disabled for sometime now.
This should bring the retain release code motion into a close. The retain release
code motion pipeline looks like this. There could be some minor cleanups after this though.
1. We perform a global data flow for retain release code motion in RRCM (RetainReleaseCodeMotion)
2. We perform a local form of retain release code motion in SILCodeMotion. This is more
for cases which can not be handled in RRCM. e.g. sinking into a switch is more efficiently
done in a local form, the retain is not needed on the None block. Release on SILArgument needs
to be split to incoming values, this can not be done in RRCM and other cases.
3. We do not perform code motion in ASO, only elimination which are very important.
Some modifications to test cases, they look different, but functionally the same.
RRCM has this canonicalization effect, i.e. it uses the rc root, instead of
the SSA value the retain/release is currently using. As a result some test cases need
to be modified.
I also removed some test cases that do not make sense anymore and lot of duplicate test
cases between earlycodemotion.sil and latecodemotion.sil. These tests cases only have retains
and should be used to test early code motion.
(Headers first)
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.
