Efficiently Solving Bit-Vector Problems Using Model Checkers

Bit-precise reasoning is essential in many applications of Satisfiability Modulo Theories (SMT). Most approaches for solving quantifier-free fixed-size bit-vector logics (QF BV) rely on bit-blasting. In previous work, we have shown that bit-blasting is not polynomial in general [19], and later proposed QF BV 1, a class of bit-vector problems that is PSpace-complete [15]. In this paper, we give examples of how to create (polynomial) SMV specifications out of QF BV 1 formulas. We then use various model checkers to solve those problems and give detailed experimental results. Our results show that BDDbased model checkers outperform current SMT solvers by several orders of magnitude on our benchmarks. Unrolling and using SAT-based model checking turns out to be the same as bit-blasting and gives worse results. In addition to this, our approach allows us to easily generate new challenging benchmarks for SMT solvers as well as for model checkers.