Iterated dominance frontiers are computed using the DJ Graph method in compiler.cfg.ssa.construction.tdmsc.

The renaming algorithm is based on "Practical Improvements to the Construction and Destruction of Static Single Assignment Form".

We construct pruned SSA without computing live sets, by building a dependency graph for phi instructions, marking the transitive closure of a vertex as live if it is referenced by some non-phi instruction. Thanks to Cameron Zwarich for the trick.

http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.49.9683