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From: "aldot at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug fortran/102043] Wrong array types used for negative stride
 accesses
Date: Sun, 14 Nov 2021 16:18:31 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102043

--- Comment #17 from Bernhard Reutner-Fischer <aldot at gcc dot gnu.org> ---
Do we want to address arrays always at position 0 (maybe to help graphite ?=
) or
would it be sufficient to just not dereference the array "before" the first
position like Mikael suggests in comment #14?

gfc_conv_expr_descriptor has this
      if (se->data_not_needed)
        gfc_conv_descriptor_data_set (&loop.pre, parm,
                                      gfc_index_zero_node);
      else
        /* Point the data pointer at the 1st element in the section.  */
        gfc_get_dataptr_offset (&loop.pre, parm, desc, base,
                                subref_array_target, expr);

      gfc_conv_descriptor_offset_set (&loop.pre, parm, offset);

where base is (for "section"-addressing) 9 for the testcase in comment #16 =
as
can be seen in Richard's initial report.=