Efficient symbolic analysis of programs
This paper is concerned with constructing, for each expression in a given program text, a symbolic expression whose value is equal to the value of the text expression for all executions of the program. A cover is a mapping from text expressions to such symbolic expressions. Covers can be used for constant propagation, code motion, and a variety of other program optimizations. Covers can also be used as an aid in symbolic program execution and for finding loop invariants for program verification. We describe a direct (non-iterative) algorithm for computing a cover. The cover computed by our algorithm is characterized as a minimum of a certain fixed point equation, and is in general a better cover than might be computed by iteration methods (which can compute fixed point covers which are not minimal). Our algorithm is efficient and applicable to all flow graphs. A variant of our algorithm is implemented by \textit{R. N. Kalman} and \textit{A. A. Kortesoja} [IEEE Trans. Software Eng. SE-6, 512-519 (1980)] in an optimizing compiler.
scientific article; zbMATH DE number 3974261
scientific article