/* A jump function for a callsite represents the values passed as actual
arguments of the callsite. There are three main types of values :
Formal - the caller's formal parameter is passed as an actual argument.
- Constant - a constant is passed as a an actual argument.
+ Constant - a constant is passed as an actual argument.
Unknown - neither of the above.
Integer and real constants are represented as CONST_IPATYPE and Fortran
constants are represented as CONST_IPATYPE_REF. */