Why AI + ILP Is Good for WCET, but MC Is Not, Nor ILP Alone

A combination of Abstract Interpretation (AI) with Integer Linear Programming (ILP) has been successfully used to determine precise upper bounds on the execution times of real-time programs. This article gives the answer to the frequently encountered claim, “one could have done it by Model Checking!” (MC). It shows that it is the characteristic property of abstract interpretation, namely that it proves as many safety properties as it can during its fixpoint iteration, which proves AI to be applicable and successful. On the other hand, MC’s need for a specification of the safety properties to be verified makes it unsuitable for the task. ILP alone has also been used to model a processor architecture and a program whose upper bounds for execution times was to be determined. It is argued why the only ILP-only approach found in the literature has not led to success.