Improving Automatic Complexity Analysis of Integer Programs

Abstract: In earlier work, we developed an approach for automatic complexity analysis of integer programs, based on an alternating modular inference of upper runtime and size bounds for program parts. In this paper, we show how recent techniques to improve automated termination analysis of integer programs (like the generation of multiphase-linear ranking functions and control-flow refinement) can be integrated into our approach for the inference of runtime bounds. The power of the resulting approach is demonstrated by an extensive experimental evaluation with our new re-implementation of the corresponding tool KoAT.