Approximate logic synthesis via iterative SMT-based subcircuit rewriting
Author(s)
Type
Journal Article
Abstract
This paper presents a novel iterative approach to achieve effective and efficient approximate logic synthesis (ALS). The core idea is to perform circuit rewriting in a way that is both local, i.e., is applied piece-wise to selected subcircuits, and extensive, i.e., systematically explores the design space for good solutions. Concretely, we propose SubXPAT, a new Boolean rewriting framework which iteratively employs satisfiability modulo theories (SMT) solving to select and approximate key parts of a circuit. Selection aims at finding subcircuits that at the same time include a significant number of gates and can be efficiently approximated, which is done by searching for large convex subcircuits with a limited number of inputs and outputs. Approximation is guided by the use of a parametric template, structured as a sum of products, which allows for fine-grained control over the subcircuit characteristics. SubXPAT was implemented as an open-source tool and compared against other ALS tools implementing state-of-the-art techniques. Our experimental evaluation used a broad range of arithmetic circuits with different bit-widths and our results indicate that SubXPAT generates approximate circuits that are more area-efficient than those generated by state-of-the-art techniques in 72% of the cases.
Date Issued
2026-07-01
Date Acceptance
2025-11-08
Citation
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2026, 45 (7), pp.3224-3237
ISSN
0278-0070
Publisher
Institute of Electrical and Electronics Engineers
Start Page
3224
End Page
3237
Journal / Book Title
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Volume
45
Issue
7
Copyright Statement
Copyright © 2025 IEEE. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Date Publish Online
2025-12-01