Bernhard Steffen

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We present a bit-vector algorithm for the <italic>optimal</italic> and <italic>economical</italic> placement of computations within flow graphs, which is as <italic>efficient</italic> as standard uni-directional analyses. The point of our algorithm is the <italic>decomposition</italic> of the bi-directional structure of the known placement algorithms into a(More)
An implementation-oriented algorithm for <italic>lazy code motion</italic> is presented that minimizes the number of computations in programs while suppressing any unnecessary code motion in order to avoid superfluous register pressure. In particular, this variant of the original algorithm for lazy code motion works on flowgraphs whose nodes are basic(More)
12a. DISTRIBUTION / AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE 13. ABSTRACT (Maximum 200 words) We introduce three models of probabilistic processes, namely, reactive, generative and stratified. These models are investigated within the context of PCCS, an extension of Milner's SCCS in which each summand of a process summation expression is guarded by a(More)
The Concurrency Workbench is an automated tool for analyzing networks of finite-state processes expressed in Milner's Calculus of Communicating Systems. Its key feature is its breadth: a variety of different verification methods, including equivalence checking, preorder checking, and model checking, are supported for several different process semantics. One(More)
We present an interprocedural generalization of the well-known (intraprocedural) Coincidence Theorem of Kam and Ullman, which provides a suucient condition for the equivalence of the meet over all paths (MOP) solution and the maximal xed point (MFP) solution to a data ow analysis problem. This generalization covers arbitrary imperative programs with(More)
We develop a model-checking algorithm for a logic that permits propositions to be deened using greatest and least xed points of mutually recursive systems of equations. This logic is as expressive as the alternation-free fragment of the modal mu-calculus identiied by Emerson and Lei, and it may therefore be used to encode a number of temporal logics and(More)
In this paper, we present the LearnLib, a library of tools for automata learning, which is explicitly designed for the systematic experimental analysis of the profile of available learning algorithms and corresponding optimizations. Its modular structure allows users to configure their own tailored learning scenarios, which exploit specific properties of(More)
In this paper we present the LearnLib, a library for automata learning and experimentation. Its modular structure allows users to configure their tailored learning scenarios, which exploit specific properties of the envisioned applications. As has been shown earlier, exploiting application-specific structural features enables optimizations that may lead to(More)