How to analyze large programs efficiently and informatively

Elimination of partial redundancies is a powerful optimization that has been implemented in at least three important production compilers and has inspired several simdar optimization. The global data ffow analysis that supports this family of optimization includes some bidirectional probJems. (A bidirectional problem is one in which the global inform ation at each basic block depends on both control flow predecessors and control flow successors.) This paper contributes two ways to simplify and expedite the analysis, especially for large programs.