Revisiting Assumptions Ordering in CAR-Based Model Checking

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Bibliographic Details
Title: Revisiting Assumptions Ordering in CAR-Based Model Checking
Authors: Yibo Dong, Yu Chen, Jianwen Li, Geguang Pu, Ofer Strichman
Source: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems. 44:4032-4037
Publication Status: Preprint
Publisher Information: Institute of Electrical and Electronics Engineers (IEEE), 2025.
Publication Year: 2025
Subject Terms: FOS: Computer and information sciences, Computer Science - Logic in Computer Science, Logic in Computer Science (cs.LO)
Description: Model checking is an automatic formal verification technique that is widely used in hardware verification. The state-of-the-art complete model-checking techniques, based on IC3/PDR and its general variant CAR, are based on computing symbolically sets of under - and over-approximating state sets (called frames) with multiple calls to a SAT solver. The performance of those techniques is sensitive to the order of the assumptions with which the SAT solver is invoked, because it affects the unsatisfiable cores - which the solver emits when the formula is unsatisfiable - that crucially affect the search process. This observation was previously published in [15], where two partial assumption ordering strategies, intersection and rotation were suggested (partial in the sense that they determine the order of only a subset of the literals). In this paper we extend and improve these strategies based on an analysis of the reason for their effectiveness. We prove that intersection is effective because of what we call locality of the cores, and our improved strategy is based on this observation. We conclude our paper with an extensive empirical evaluation of the various ordering techniques. One of our strategies, Hybrid-CAR, which switches between strategies at runtime, not only outperforms other, fixed ordering strategies, but also outperforms other state-of-the-art bug-finding algorithms such as ABC-BMC.
Document Type: Article
ISSN: 1937-4151
0278-0070
DOI: 10.1109/tcad.2025.3551658
DOI: 10.48550/arxiv.2411.00026
Access URL: http://arxiv.org/abs/2411.00026
Rights: IEEE Copyright
CC 0
Accession Number: edsair.doi.dedup.....af499be340eb26688228f53ed988e42f
Database: OpenAIRE
Description
Abstract:Model checking is an automatic formal verification technique that is widely used in hardware verification. The state-of-the-art complete model-checking techniques, based on IC3/PDR and its general variant CAR, are based on computing symbolically sets of under - and over-approximating state sets (called frames) with multiple calls to a SAT solver. The performance of those techniques is sensitive to the order of the assumptions with which the SAT solver is invoked, because it affects the unsatisfiable cores - which the solver emits when the formula is unsatisfiable - that crucially affect the search process. This observation was previously published in [15], where two partial assumption ordering strategies, intersection and rotation were suggested (partial in the sense that they determine the order of only a subset of the literals). In this paper we extend and improve these strategies based on an analysis of the reason for their effectiveness. We prove that intersection is effective because of what we call locality of the cores, and our improved strategy is based on this observation. We conclude our paper with an extensive empirical evaluation of the various ordering techniques. One of our strategies, Hybrid-CAR, which switches between strategies at runtime, not only outperforms other, fixed ordering strategies, but also outperforms other state-of-the-art bug-finding algorithms such as ABC-BMC.
ISSN:19374151
02780070
DOI:10.1109/tcad.2025.3551658