[Bug fortran/46007] New: wrong code for SHAPE in a scalarized loop

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46007

           Summary: wrong code for SHAPE in a scalarized loop
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org
                CC: mikael@gcc.gnu.org, arjen.markus@deltares.nl


Reported by Arjen at http://gcc.gnu.org/ml/fortran/2010-10/msg00153.html

Reduced test case:

    integer, dimension(10)             :: int1d
    integer, dimension(:), pointer     :: int1d_retrieved

    allocate(int1d_retrieved(10))
    if (any(shape(int1d_retrieved) /= shape(INT1D))) call abort()
    end

It crashes (segfault) at run time for the IF condition.

First analysis:


    struct array1_integer(kind=4) atmp.1;
    atmp.1.dtype = 265;
    atmp.1.data = 0B;
    atmp.1.offset = 0;
    D.1529 = &int1d_retrieved;
    _gfortran_shape_4 (&atmp.1, D.1529);

The problem is that the bounds are not set - but _gfortran_shape tries to acces
the lbound/ubound via:

    if (GFC_DESCRIPTOR_EXTENT(ret,0) < 1)

Additionally, it tries to set the value via:
      ret->data[n * stride] = extent > 0 ? extent : 0 ;
which fails as ret->data alias "atmp.1.data" is not allocated.


Interestingly, if one uses:
      tmp = shape(int1d_retrieved)
one has:
    integer(kind=4) A.1[1];
    atmp.0.dim[0].lbound = 0;
    atmp.0.dim[0].ubound = 0;
    atmp.0.data = (void * restrict) &A.1;
    _gfortran_shape_4 (&atmp.0, D.1525);

which works. For some reason (scalarizer?) .data is not allocated/associated
and the bounds are not set for the first test case.