[Bug fortran/34545] ICE when compiling Fortran 95 code

[kargl at gcc dot gnu dot org]

------- Comment #8 from kargl at gcc dot gnu dot org  2007-12-26 22:07 -------
(In reply to comment #7)
> Maybe this should best be described as:
> "ICE when function returns array of values to dynamically allocated array"
> If the LHS is a 'statically allocated' array, the function returns array of
> values without problem.  If the LHS is a dynamically allocated array,
> attempting to assign the array of values from the functions causes an ICE.

Well, no.  A better description probably involves the use of stack
memory for a function result gets trashed when you return from
the function.

I can assure that gfortran can assign array function results to
allocated memory.  You appear to have stumbled on a bug.

> 
> So gfortran fails to implement an essential feature of Fortran 95.
>

This statement is in rather poor taste, and is an example of why I
quit working on gfortran.  But, thanks for the bug report.

> Workaround is to call a subroutine and have the array of values
> returned in the argument list.

One can also learn to do proper memory management.

module kmeans_aux
  implicit none
  contains
    function get_nfirst( ) result(fnres)
      use const_mod, only: mp
      use blk1_mod, only: numclusters
      implicit none
!      real(mp) :: fnres(numbcluster)   ! This uses the stack instead of heap.
      real(mp), allocatable :: fnres(:) ! Properly manage heap memory
      if (allocated(fnres) .eqv. .true.) deallocate(fnres)
      allocate(fnres(numclusters))
      fnres = 1
    end function get_nfirst
end module kmeans_aux


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34545