Tutorial on World-Level Model Checking

Abstract

In SMT bit-vectors and thus word-level reasoning is common and widely used in industry. However, it took until 2019 that the hardware model checking competition started to use word-level benchmarks. Reasoning on the word-level opens up many possibilities for simplification and more powerful reasoning. In SMT we do see advantages due to operating on the word-level, even though, ultimately, bit-blasting and thus transforming the word-level problem into SAT is still the dominant and most important technique. For word-level model checking the situation is different. As the hardware model checking competition in 2019 has shown bit-level solvers are far superior (after bit-blasting the model through an SMT solver though). On the other hand word-level model checking shines for problems with memory modeled with arrays. In this tutorial we revisit the problem of word level model checking, also from a theoretical perspective, give an overview on classical and more recent approaches for word-level model checking and then discuss challenges and future work. The tutorial covered material from the following papers.