Support for intrinsics cttz, ctlz, ctpop and bswap
tell sclang, using an environment var, to get Souper to print stats
Merge pull request #78 from jubitaneja/intrinsics-final

Support for intrinsics cttz, ctlz, ctpop and bswap
Rename all flags containing the substring -souper to have -souper at the start

This has bugged me for a while. It's pretty clear at this point that we
should be more consistent about this as we add more flags.
Merge pull request #83 from regehr/sclang-stats

tell sclang, using an environment var, to get Souper to print stats
A fix to issue 26

The idea is that when we build an instruction, if the instruction is a
phi-node with multiple incoming edges, we do DFS from the basic block
containing the phi-node and check if we will revisit the basic block.
If yes, we know that this phi-node is the merge point of loop iterations.
Merge branch 'issue_26' of https://github.com/chenyang78/souper into issue_26