C32SAT: Checking C Expressions

Abstract. C32SAT is a tool for checking C expressions. It can check whether a given C expression can be satisfied, is tautological, or always defined according to the ISO C99 standard. C32SAT can be used to detect nonportable expressions where program behavior depends on the compiler. Our contribution consists of C32SAT’s functional representation and the way it handles undefined values. Under-approximation is used as optimization.

Local two-level And-Inverter Graph minimization without blowup

Abstract. And-Inverter Graphs (AIGs) are an efficient and scalable representation for boolean formulas and circuits. We present a maximal set of rules for local two-level optimization of AIGs. This set consists of rules which can be applied before node creation greedily without affecting structural sharing negatively. We implemented these techniques in the AIG library of our tool SMV2QBF and report on experimental results in the context of SAT based model checking.

Exploring Predictability of SAT/SMT Solvers

This paper seeks to explore the predictability of SAT and SMT solvers in response to different kinds of changes to benchmarks. We consider both semantics-preserving and possibly semantics-modifying transformations, and provide preliminary data about solver predictability. We also propose carrying learned theory lemmas over from an original run to runs on similar benchmarks, and show the benefits of this idea as a heuristic for improving predictability of SMT solvers.