Data-Flow Based Detection of Loop Bounds

To calculate the WCET of a program, safe upper bounds on the number of loop iterations for all loops in the program are needed. As the manual annotation of all loops with such bounds is difficult and time consuming, the WCET analyzer aiT originally developed by Saarland University and AbsInt GmbH uses static analysis to determine the needed bounds as far as possible. This paper describes a novel data-flow based analysis for aiT to calculate the needed loop bounds on the assembler level. The new method is compared with a pattern based loop analysis already in use by this tool