Invariance of Approximate Semantics with Respect to Program Transformations

Program transformations, as used for optimization and sometimes for program development, utilize information about the program which is derived by the method of abstract interpretation within various data flow analysis frameworks. Each transformation, as it changes the program, may render the flow information derived for the original program suboptimal or even invalid with respect to the new program. Although the outdated flow information may serve well as a starting point for rederivation, it appears profitable to look for conditions where passes of many transformations may be performed without recalculating flow information each time a transformation rule is applied.