1. A non-transitory computer-readable medium storing computer-executable instructions for execution by a processor, the computer-readable medium including one or more instructions for: determining that one or more variables, associated with a model in a graphical modeling environment, are used in one or more timer-related operations contained in the model; identifying a timer in the model based on the one or more variables being used in the one or more timer-related operations: rewriting the timer into a form that is usable for testing or analysis of the model, the rewriting including incorporating one or more notations into the model that identify the one or more timer-related operations; identifying a plurality of update operations associated with the timer; combining the identified plurality of update operations into a number of update operations that is fewer than a number of the identified plurality of update operations; and storing the rewritten timer in a memory.