On Thu, Dec 06, 2018 at 08:02:43PM +0100, Thomas Koenig wrote:
> >>> PR fortran/88139
> >>> * dump-parse-tree.c (write_proc): Alternate return.
> >> I dissent with this patch. The introduced error is meaningless and, as
> >> mentioned by comment #3 in the PR, avoiding the ICE in dump-parse-tree
> >> is not directly the issue. The code should be rejected in parsing. In
> >> gcc-8.1 the invalid code is accepted (without an ICE) even without the
> >> -fc-prototypes flag: I haven't finished building the compiler with
> >> your changes yet to see whether that is still true afterwards, but at
> >> least the test case doesn't try this, so I strongly suspect the patch
> >> is incomplete to fix the PR.
> >
> > Comment #3 does not contain a patch to fix the problem elsewhere.
>
> I know :-)
>
> > In F2003, 15.2.6 "Interoperability of procedures and procedure interfaces",
> > I cannot find a prohibition on an alternate return in a subroutine
> > interface with BIND(C).
>
> I also does not allow this, and does not offer a valid interpretation
> of what it should mean.
>
> If it has a meaning, it should be translatable into something prescribed
> by the standard with -fc-prototypes.
>
> I have assigned the error to myself, so I will not forget to fix
> it before the gcc 9 release.
>
I have asked on c.l.f. It seems NAG rejects alternate return
mixed with bind(c). FortranFan provided a complete testcase:
subroutine foo(*) bind(C, name='f')
end subroutine foo
program p
interface
subroutine bar(*) bind(C, name='f')
end subroutine bar
end interface
call bar( *10 )
print *, "Return following 'bar' invocation: jumping to 20"
go to 20
10 print *, "THIS IS UNEXPECTED: Alternate return to 10 after bar"
20 continue
stop
end program p
NAG rejects it. Intel, PGI, and gfortran accept it.
--
Steve
