Also fixed a small bug related to how we handle arguments. We were not
clearing the state of the argument when we saw a potential decrement of
the argument.
<rdar://problem/17013194>
Swift SVN r18706
GlobalARCSequenceDataflow. Add in the code to implement the bottom up
dataflow, but don't wire it up. Pass in the refactored top down dataflow
to the old pairing pass so we still give correct results.
The next step is to change the pairing analysis to use both the bottom
up and top down dataflow passes.
rdar://16965332
Swift SVN r18551
