Speculative SAT Modulo SAT

V. K. Hari Govind*, Isabel Garcia-Contreras, Sharon Shoham, Arie Gurfinkel

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

State-of-the-art model-checking algorithms like IC3/PDR are based on uni-directional modular SAT solving for finding and/or blocking counterexamples. Modular SAT-solvers divide a SAT-query into multiple sub-queries, each solved by a separate SAT-solver (called a module), and propagate information (lemmas, proof obligations, blocked clauses, etc.) between modules. While modular solving is key to IC3/PDR, it is obviously not as effective as monolithic solving, especially when individual sub-queries are harder to solve than the combined query. This is partially addressed in SAT modulo SAT (SMS) by propagating unit literals back and forth between the modules and using information from one module to simplify the sub-query in another module as soon as possible (i.e., before the satisfiability of any sub-query is established). However, bi-directionality of SMS is limited because of the strict order between decisions and propagation – only one module is allowed to make decisions, until its sub-query is SAT. In this paper, we propose a generalization of SMS, called specSMS, that speculates decisions between modules. This makes it bi-directional – decisions are made in multiple modules, and learned clauses are exchanged in both directions. We further extend DRUP proofs and interpolation, these are useful in model checking, to specSMS. We have implemented specSMS in Z3 and empirically validate it on a series of benchmarks that are provably hard for SMS.

Original languageEnglish
Title of host publicationTools and Algorithms for the Construction and Analysis of Systems - 30th International Conference, TACAS 2024, Held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2024, Proceedings
EditorsBernd Finkbeiner, Laura Kovács
PublisherSpringer Science and Business Media Deutschland GmbH
Pages43-60
Number of pages18
ISBN (Print)9783031572456
DOIs
StatePublished - 2024
Event30th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2024, which was held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2024 - Luxembourg City, Luxembourg
Duration: 6 Apr 202411 Apr 2024

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume14570 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference30th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2024, which was held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2024
Country/TerritoryLuxembourg
CityLuxembourg City
Period6/04/2411/04/24

Funding

FundersFunder number
MathWorks Inc
Microsoft Research
Natural Sciences and Engineering Research Council of Canada
European Research Council
University of Waterloo
Horizon 2020 Framework Programme759102-SVIS
Horizon 2020 Framework Programme
Israel Science Foundation2117/23
Israel Science Foundation

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