(re-sending with subject line tags)

Hi all,

Now that my copyright assignment is complete, I'm submitting this fix.
Test cases are included.
OK for master? I do not have write access, so someone will need to
commit this for me.

Regards,
Harris

libgfortran/ChangeLog:

    * runtime/ISO_Fortran_binding.c (CFI_establish):  fixed strides
for rank >2 arrays

gcc/testsuite/ChangeLog:

    * gfortran.dg/ISO_Fortran_binding_18.c: New test.
    * gfortran.dg/ISO_Fortran_binding_18.f90: New test.

> On Wed, Jan 13, 2021 at 2:10 PM Harris Snyder <hsnyder@structura.bio> wrote:
> >
> > Hi Tobias / all,
> >
> > Further related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93524
> > `sm` is being incorrectly computed in CFI_establish. Take a look at
> > the diff below - we are currently only using the extent of the
> > previous rank to assign `sm`, instead of all previous ranks. Have I
> > got this right, or am I missing something / does this need to be
> > handled differently? I can offer some test cases and submit a proper
> > patch if we think this solution is OK...
> >
> > Thanks,
> > Harris
> >
> > diff --git a/libgfortran/runtime/ISO_Fortran_binding.c
> > b/libgfortran/runtime/ISO_Fortran_binding.c
> > index 3746ec1c681..20833ad2025 100644
> > --- a/libgfortran/runtime/ISO_Fortran_binding.c
> > +++ b/libgfortran/runtime/ISO_Fortran_binding.c
> > @@ -391,7 +391,12 @@ int CFI_establish (CFI_cdesc_t *dv, void
> > *base_addr, CFI_attribute_t attribute,
> >           if (i == 0)
> >             dv->dim[i].sm = dv->elem_len;
> >           else
> > -           dv->dim[i].sm = (CFI_index_t)(dv->elem_len * extents[i - 1]);
> > +           {
> > +             CFI_index_t extents_product = 1;
> > +             for (int j = 0; j < i; j++)
> > +               extents_product *= extents[j];
> > +             dv->dim[i].sm = (CFI_index_t)(dv->elem_len * extents_product);
> > +           }
> >         }
> >      }