[Bug middle-end/48124] [4.5/4.6 Regression] likely wrong code bug

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48124

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |NEW
      Known to work|                            |4.7.1
         AssignedTo|rguenth at gcc dot gnu.org  |unassigned at gcc dot
                   |                            |gnu.org
            Summary|[4.5/4.6/4.7 Regression]    |[4.5/4.6 Regression] likely
                   |likely wrong code bug       |wrong code bug

--- Comment #30 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-04 08:43:32 UTC ---
Author: rguenth
Date: Mon Jun  4 08:43:23 2012
New Revision: 188167

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=188167
Log:
2012-06-04  Richard Guenther  <rguenther@suse.de>
    Eric Botcazou  <ebotcazou@adacore.com>

    Backport from mainline
    2012-04-03  Eric Botcazou  <ebotcazou@adacore.com>

        * expr.c (get_bit_range): Add OFFSET parameter and adjust BITPOS.
        Change type of BITOFFSET to signed.  Make sure the lower bound of
        the computed range is non-negative by adjusting OFFSET and BITPOS.
        (expand_assignment): Adjust call to get_bit_range.

    2012-03-27  Eric Botcazou  <ebotcazou@adacore.com>

        * expr.c (get_bit_range): Return the null range if the enclosing record
        is part of a larger bit field.

    2012-03-20  Richard Guenther  <rguenther@suse.de>

        * stor-layout.c (finish_bitfield_representative): Fallback
        to conservative maximum size if the padding up to the next
        field cannot be computed as a constant.
        (finish_bitfield_layout): If we cannot compute the distance
        between the start of the bitfield representative and the
        bitfield member start a new representative.
        * expr.c (get_bit_range): The distance between the start of
        the bitfield representative and the bitfield member is zero
        if the field offsets are not constants.

    2012-03-16  Richard Guenther  <rguenther@suse.de>

        * stor-layout.c (finish_bitfield_representative): Fall back
        to the conservative maximum size if we cannot compute the
        size of the tail padding.

    2012-03-14  Richard Guenther  <rguenther@suse.de>

    * tree.h (DECL_BIT_FIELD_REPRESENTATIVE): New define.
    * stor-layout.c (start_bitfield_representative): New function.
    (finish_bitfield_representative): Likewise.
    (finish_bitfield_layout): Likewise.
    (finish_record_layout): Call finish_bitfield_layout.
    * tree.c (free_lang_data_in_decl): Only free DECL_QUALIFIER
    for QUAL_UNION_TYPE fields.
    * tree-streamer-in.c (lto_input_ts_field_decl_tree_pointers):
    Stream DECL_BIT_FIELD_REPRESENTATIVE.
    * tree-streamer-out.c (write_ts_field_decl_tree_pointers): Likewise.

    PR middle-end/52080
    PR middle-end/52097
    PR middle-end/48124
    * expr.c (get_bit_range): Unconditionally extract bitrange
    from DECL_BIT_FIELD_REPRESENTATIVE.
    (expand_assignment): Adjust call to get_bit_range.

    * gcc.dg/torture/pr48124-1.c: New testcase.
    * gcc.dg/torture/pr48124-2.c: Likewise.
    * gcc.dg/torture/pr48124-3.c: Likewise.
    * gcc.dg/torture/pr48124-4.c: Likewise.
    * gnat.dg/pack16.adb: Likewise.
    * gnat.dg/pack16_pkg.ads: Likewise.
    * gnat.dg/pack17.adb: Likewise.
    * gnat.dg/specs/pack7.ads: Likewise.
    * gnat.dg/specs/pack8.ads: Likewise.
    * gnat.dg/specs/pack8_pkg.ads: Likewise.

Added:
    branches/gcc-4_7-branch/gcc/testsuite/gcc.dg/torture/pr48124-1.c
    branches/gcc-4_7-branch/gcc/testsuite/gcc.dg/torture/pr48124-2.c
    branches/gcc-4_7-branch/gcc/testsuite/gcc.dg/torture/pr48124-3.c
    branches/gcc-4_7-branch/gcc/testsuite/gcc.dg/torture/pr48124-4.c
    branches/gcc-4_7-branch/gcc/testsuite/gnat.dg/pack16.adb
    branches/gcc-4_7-branch/gcc/testsuite/gnat.dg/pack16_pkg.ads
    branches/gcc-4_7-branch/gcc/testsuite/gnat.dg/pack17.adb
    branches/gcc-4_7-branch/gcc/testsuite/gnat.dg/specs/pack7.ads
    branches/gcc-4_7-branch/gcc/testsuite/gnat.dg/specs/pack8.ads
    branches/gcc-4_7-branch/gcc/testsuite/gnat.dg/specs/pack8_pkg.ads
Modified:
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/expr.c
    branches/gcc-4_7-branch/gcc/stor-layout.c
    branches/gcc-4_7-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_7-branch/gcc/tree-streamer-in.c
    branches/gcc-4_7-branch/gcc/tree-streamer-out.c
    branches/gcc-4_7-branch/gcc/tree.c
    branches/gcc-4_7-branch/gcc/tree.h

--- Comment #31 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-04 08:44:51 UTC ---
Fixed on the 4.7 branch, too.  Not applicable as is to older branches.