Approximate Reachability for Dead Code Elimination in Esterel ⋆

Abstract. Esterel is an imperative synchronous programming language for the design of reactive systems. Esterel ⋆ extends Esterel with a noninstantaneous jump instruction (compatible with concurrency, preemption, etc.) so as to enable powerful source-to-source program transformations, amenable to formal verification. In this work, we propose an approximate reachability algorithm for Esterel ⋆ and use its output to remove dead code. We prove the correctness of our techniques.