  Parametric Worst-case execution time (WCET) analysis of a sequential program
produces a formula that represents the worst-case execution time of the
program, where parameters of the formula are user-defined parameters of the
program (as loop bounds, values of inputs or internal variables, etc).
  In this paper we propose a novel methodology to compute the parametric WCET
of a program. Unlike other algorithms in the literature, our method is not
based on Integer Linear Programming (ILP). Instead, we follow an approach based
on the notion of symbolic computation of WCET formulae. After explaining our
methodology and proving its correctness, we present a set of experiments to
compare our method against the state of the art. We show that our approach
dominates other parametric analyses, and produces results that are very close
to those produced by non-parametric ILP-based approaches, while keeping very
good computing time.
