This tool checks for a subset of C in which ranges variables reside.
This needs ply
Annotate some variables in your C-Code with a range like this:
int x; /*[4-5]*/
Run "./crf.py" or "./crf.py filename.c". The output will have every assignement annotated with the range of the expression on the right. At the same time the maximum ranges for the variable on the left are tracked and printed at the end of the output.