Since your question is about Fortran rather than g95 in particular, it
would be better to post it to comp.lang.fortran . I think two
commercial tools,
NAGWare Fortran Tools
PlusFort
can make the conversions you want. I don't of any free tools that do
so.
Allan Miller has a simple converter on his page, it is called
"to_f90.f90".
If you merely want to update your code to remove antiquated elements of
it, then there's probably so much to be done that none of the available
tools will be adequate - there's no substitute for a programmer who
understands the problem, after all. Some of the simpler conversions
can be done by the PLUSFORT/SPAG package from Polyhedron Software.
They have a free version with reduced functionality which you might
like to experiment with, but the full product is probably what you
need.
/Aria