GCC Bugzilla Bug 19574

The following code (from
http://home.comcast.net/~kmbtib/gfortran_bugs/REF_JVB_GFTN_005.html) fails in
the following way (on i686-mingw and powerpc-apple-darwin):

---------------------------------
module funcs
   implicit none
   contains
      function f(x)
         character(*), intent(in) :: x
         integer f(len(x))
         integer i

!         do i=1,len(x)
!           f(i) = 0
!         end do
      end function f
end module funcs

program spec_expr_test
   use funcs
   implicit none

   write(*,*) size(f('test'))
end program spec_expr_test
---------------------------------

$ gfortran reduced_spec.f90 && ./a.out 
reduced_spec.f90: In function 'f':
reduced_spec.f90:4: warning: Function does not return a value
At line 19 of file reduced_spec.f90
Fortran runtime error: Internal: Possible double free of temporary.


If you uncomment the three lines in the code above, you get a runtime segfault
(on powerpc-apple-darwin):

$ gfortran reduced_spec.f90 && ./a.out
zsh: bus error  ./a.out


I don't know if these two issues are related, but I post them both in one PR
just in case they can be debuggued altogether.

The segmentation fault seems to me to have the same source as PR19561 - 
temporaries are not being allocated/assigned properly.

This does the first wriet OK and then seg faults on the second:

! { dg-do run }
module funcs
   implicit none
   contains
      function f (x)
         character(*), intent(in) :: x
         integer f(len(x))
	 f = 0
      end function f
end module funcs
program spec_expr_test
   use funcs
   implicit none
   integer, dimension(10)  :: i
   i(1:5) = f ('test')
   write (*,*) i(1:5)
   write (*,*) f('untest')
end program spec_expr_test
! { dg-error "Segmentation fault (core dumped)" }

Confirmed.

Fixed in 4.0.1.

Reopening for now, I think I read comment # 1 wrong.

the testcase in comment #1 no longer seg faults.

(In reply to comment #5)
> the testcase in comment #1 no longer seg faults.

module funcs
   implicit none
   contains
      function f(x)
         character(*), intent(in) :: x
         integer f(len(x))
         integer i

         do i=1,len(x)
            f(i) = iachar (x(i:i))
         end do

      end function f
end module funcs

program spec_expr_test
   use funcs
   implicit none

   write(*,*) f('test')
end program spec_expr_test

now compiles and runs correctly, as does my testcase.

I will close this tonight

(In reply to comment #6)
> I will close this tonight

This never happened so I am closing it right now as fixed.