[Bug fortran/44735] New: ICE on FORALL with character array pointer

[Bug fortran/44735] New: ICE on FORALL with character array pointer

[jkrahn at nc dot rr dot com]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 855 bytes --]

$ cat bug3.f90
subroutine bug
  character(len=10) :: F_string
  character(len=1), dimension(:), pointer :: p_chars
  forall (i=1:len(F_string))
    F_string(i:i) = p_chars(i)
  end forall
end subroutine bug

$ /usr/local/gfortran/bin/gfortran -c bug3.f90
bug3.f90: In function ‘bug’:
bug3.f90:1:0: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


-- 
           Summary: ICE on FORALL with character array pointer
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jkrahn at nc dot rr dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44735

[Bug fortran/44735] ICE on FORALL with character array pointer

[burnus at gcc dot gnu dot org]

------- Comment #1 from burnus at gcc dot gnu dot org  2010-07-01 06:21 -------
Confirm.

Valgrind shows:

==11328== Invalid read of size 8
==11328==    at 0x6CBB86: fold_convert_loc (fold-const.c:1856)
==11328==    by 0x58E7A3: allocate_temp_for_forall_nest_1 (trans-stmt.c:2583)
==11328==    by 0x58F394: gfc_trans_assign_need_temp (trans-stmt.c:2702)
==11328==    by 0x59284C: gfc_trans_forall_1 (trans-stmt.c:3158)
==11328==    by 0x551DFF: trans_code (trans.c:1205)

Failing is the following line in fold-const.c
  tree orig = TREE_TYPE (arg);
which is the second argument in the following line of
allocate_temp_for_forall_nest_1:
   unit = fold_convert (gfc_array_index_type, TYPE_SIZE_UNIT (type));

It is set in gfc_trans_assign_need_temp:

  if (expr1->ts.type == BT_CHARACTER && expr1->ts.u.cl->length)
    ...
  else
    type = gfc_typenode_for_spec (&expr1->ts);

For the example, expr1->ts.type == BT_CHARACTER but expr1->ts.u.cl->length ==
NULL.

The symbol itself has:
(gdb) p *expr1->symtree->n.sym->ts.u.cl->length->value.integer._mp_d
$8 = 10

And the size is given by the expression:
(gdb) p expr1->ref->u.ss.start->expr_type 
$19 = EXPR_VARIABLE


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
      Known to fail|                            |4.3.4 4.4.0 4.5.1 4.6.0
   Last reconfirmed|0000-00-00 00:00:00         |2010-07-01 06:21:38
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44735

[Bug fortran/44735] ICE on FORALL with character array pointer

[pault at gcc dot gnu dot org]

------- Comment #2 from pault at gcc dot gnu dot org  2010-08-18 18:55 -------
Created an attachment (id=21513)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21513&action=view)
The beginings of a fix

This PR is going to drive me mad!

The immediate cause is a failure to get the TYPE_SIZE_UNIT to calculate the
size of the temporary needed for the assignment.  This fixes that part of the
problem but moves the focus to the assignment itself.  Something is badly wrong
with the temporary's TREE_TYPE but I do not see what it is right now.

Let this be the record of where I got to....

Paul


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44735