This ensures that if we have a bunch of passes in a row which modify the CFG, we
do not continually rebuild the post order, while at the same time preserving the
property of multiple passes which do not touch the CFG sharing the same post
order, reverse post order rather than recomputing them.
rdar://17654239
Swift SVN r19913
The induction variable analysis derives from the SCC visitor CRTP-style
and uses it to drive analysis to find the IVs of a function.
The current definition of induction variable is very weak, but enough to
use for very basic bounds-check elimination.
This is not quite ready for real use. There is an assert that I've
commented out that is firing but should not be, and that will require
some more investigation.
Swift SVN r19845
See rdar://16676020 for details.
r17101 tries to solve r16761933 by checking non-direct recursions in
the call graph. We are in discussion of solving it in a different way.
Todo: figure out why r17101 causes a preformance regression.
Swift SVN r17265
