Fast Computation of Strong Control Dependencies

TL;DR

This paper presents faster algorithms for computing control dependencies in programs, fixing inaccuracies in previous methods and demonstrating significant performance improvements through experimental evaluation.

Contribution

The paper introduces new, more efficient algorithms for NTSCD and DOD, correcting errors in earlier algorithms and validating their effectiveness experimentally.

Findings

New algorithms are asymptotically faster.

Original algorithms may produce incorrect results.

Experimental results show significant performance improvements.

Abstract

We introduce new algorithms for computing non-termination sensitive control dependence (NTSCD) and decisive order dependence (DOD). These relations on control flow graph vertices have many applications including program slicing and compiler optimizations. Our algorithms are asymptotically faster than the current algorithms. We also show that the original algorithms for computing NTSCD and DOD may produce incorrect results. We implemented the new as well as fixed versions of the original algorithms for the computation of NTSCD and DOD and we experimentally compare their performance and outcome. Our algorithms dramatically outperform the original ones.