[Bug fortran/44582] gfortran generates wrong results due to wrong ABI in function with array return

[kargl at gcc dot gnu dot org]

------- Comment #5 from kargl at gcc dot gnu dot org  2010-06-18 19:10 -------
(In reply to comment #4)
> O.K. I doublechecked the standard. The array declared does not need to be
> initialized in this case. So the return value could be any number. However,
> this kind of implementation should fail in a certian case. I am trying to write
> a small example to prove this. I will post it later.
> 

Well, actually the array needs to be initialized, but not
by the compiler.  It is the responsibility of the programmer
to initialize his/her variables.  Techincally, your function
is invalid because

    function ddx(array)
    implicit double precision (a-h,o-z)
    double precision::          array(:,:)
    double precision::          ddx(size(array,dim=1),size(array,dim=2))

    print *, ddx(1,1)

    end function ddx

the print statement references an undefined variable.  See section
16.5.1:

  (1) An array is defined if and only if all of its elements are defined.

A careful reading of 16.5 might be useful.


-- 

kargl at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44582