An Alternative to SAT-Based Approaches for Bit-Vectors [chapter]

Sébastien Bardin, Philippe Herrmann, Florian Perroud
2010 Lecture Notes in Computer Science  
The theory BV of bit-vectors, i.e. fixed-size arrays of bits equipped with standard low-level machine instructions, is becoming very popular in formal verification. Standard solvers for this theory are based on a bit-level encoding into propositional logic and SAT-based resolution techniques. In this paper, we investigate an alternative approach based on a word-level encoding into bounded arithmetic and Constraint Logic Programming (CLP) resolution techniques. We define an original CLP
more » ... (domains and propagators) dedicated to bitvector constraints. This framework is implemented in a prototype and thorough experimental studies have been conducted. The new approach is shown to perform much better than standard CLP-based approaches, and to considerably reduce the gap with the best SAT-based BV solvers. ⋆ Work partially funded by Agence Nationale de la Recherche (grant ANR-08-SEGI-006). considerably lowering the gap with state-of-the-art SAT-based approaches. Moreover, the CLP(N ≤M BV )-based approach scales better than the SAT-based approach with the size of bit-vector variables, and is superior on non-linear arithmetic problems. Outline. The rest of the paper is structured as follows. Section 2 describes the relevant background on BV and CLP, Sections 4 and 5 presents dedicated propagators and domains, Section 6 presents experimental results and benchmarks. Section 7 discusses related work and Section 8 provides a conclusion.
doi:10.1007/978-3-642-12002-2_7 fatcat:3g32qdzo35hzxhhgad6hcwt4fe