[Bug fortran/56615] [4.6/4.7/4.8 Regression] Wrong code with TRANSFER of arrays of character with stride -1

["burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56615

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
      Known to work|                            |4.1.2, 4.3.4
           Keywords|                            |wrong-code
   Last reconfirmed|                            |2013-03-14
                 CC|                            |burnus at gcc dot gnu.org
     Ever Confirmed|0                           |1
            Summary|[4.4/4.5/4.6/4.7            |[4.6/4.7/4.8 Regression]
                   |Regression] Wrong code for  |Wrong code with TRANSFER of
                   |passing arrays of character |arrays of character with
                   |                            |stride -1
   Target Milestone|---                         |4.6.4
      Known to fail|                            |4.4.0, 4.5.3, 4.6.3, 4.7.2,
                   |                            |4.8.0

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2013-03-14 18:01:06 UTC ---
The problem seems to be the TRANSFER in:

  call cmp (a(n:1:-1), t)
...
  subroutine cmp (b, s)
    character(len=1), dimension(:), intent(in) :: b
    c = TRANSFER (b, c)



In the dump, I see code like:

__builtin_memcpy (transfer.5, parm.4.data, MAX_EXPR
<MIN_EXPR<D.1912,D.1904>,0>);


However, that assumes that parm.4.data is contiguous and walked forwardly. In
4.4, one has the same - but additionally the calls:

D.929 = _gfortran_internal_pack (&parm.4);
...
_gfortran_internal_unpack (&parm.4, D.929);