[Bug fortran/30450] calling subroutine with constant parameter

["milan at cmm dot ki dot si" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #3 from milan at cmm dot ki dot si  2007-01-12 18:23 -------
Subject: Re:  calling subroutine with constant parameter

>>>>> "pinskia" == pinskia at gcc dot gnu dot org <gcc-bugzilla@gcc.gnu.org> writes:

    pinskia> ------- Comment #1 from pinskia at gcc dot gnu dot org
    pinskia> 2007-01-12 17:58 ------- The only use is to change the
    pinskia> value of "1" :).

    pinskia> Gfortran is correct as this behavior is undefined as you
    pinskia> are trying to change the value of the constant 1.  in
    pinskia> Fortran all agruments are passed as reference.  This has
    pinskia> been what Fortran has done for years.

Yes but in my case the compiler should create a temporary variable and
use that in a real call to subroutine. Passing 1 to the the subroutine
is just telling the compiler I am not interested in the final value of
this parameter in the calling routine. But in some other places in the
code this valus is important. I think this is what the compilers did
in the old VAX times and I guess some other compilers do it also
now. Since gfortran/gcc is so good (within 10% of ifort, sometimes
faster sometimes slower) I lost interest in any other compiler, so I
don't have anything handy to compile this program with say ifort.

    pinskia> Oh and this is not an issue that was introduced by the
    pinskia> change over to gfortran from g77.  g77 also segfaulted on
    pinskia> your undefined code.

I couldn't remember this for sure, but I know this problem for long
time already. Only I just fixed a bug in a very old program and
couldn't beleive it is still there. I think gfortran is more picky
when something goes wrong in the program and reports an error, while
others just go on with some stupid values :-(

I am still not convinced this is not standard complying.

Milan


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30450