R-tubound: Loop bounds for WCET analysis. We describe the structure and the usage of a new software tool, called r-TuBound, for deriving symbolic loop iteration bounds in the worst-case execution time (WCET) analysis of programs. r-TuBound implements algorithms for pattern-based recurrence solving and program flow refinement, and it was successfully tested on a wide range of examples. The purpose of this article is to illustrate what r-TuBound can do and how it can be used to derive the WCET of programs.