we should detect "dead code" which is code that writes variables that are never used
and then successively remove them
if a variable is set, then only used by expressions going into variables that are never used
then that variable is also a "Dead" variable. and can be replaced with a NOP
we should detect "dead code" which is code that writes variables that are never used
and then successively remove them
if a variable is set, then only used by expressions going into variables that are never used
then that variable is also a "Dead" variable. and can be replaced with a NOP