Analysis is call-site independent, that is, all calls of a procedure are considered simultaneously. First, all the actual parameter values from the call sites are evaluated and collected at the formal parameters and then the procedure constant propagation is performed.
Analysis is performed for a given file without processing other PL/I files that could be called from the file being analyzed. ‘NonConst’ means that the variable obtains no value and so will not be substituted. Moreover, since it has no value, other variables may not be resolved as well.