[Bug c/50009] New: [4.7 Regression] Segmentation fault in tree_nop_conversion

[Bug c/50009] New: [4.7 Regression] Segmentation fault in tree_nop_conversion

[d.g.gorbachev at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50009

           Summary: [4.7 Regression] Segmentation fault in
                    tree_nop_conversion
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: d.g.gorbachev@gmail.com
            Target: i686-pc-mingw32


Created attachment 24937
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24937
Backtrace

Testcase:

struct S {
  short a;
  short b[];
} __attribute__((packed));

[Bug target/50009] [4.7 Regression] Segmentation fault in tree_nop_conversion

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50009

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.08.08 09:57:48
          Component|c                           |target
   Target Milestone|---                         |4.7.0
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-08 09:57:48 UTC ---
It seems that the stor-layout code assumes fields have complete types - they
do not, in case of flexible trailing array members.

  if (targetm.ms_bitfield_layout_p (rli->t))
    {
      /* Here, the alignment of the underlying type of a bitfield can
         affect the alignment of a record; even a zero-sized field
         can do this.  The alignment should be to the alignment of
         the type, except that for zero-size bitfields this only
         applies if there was an immediately prior, nonzero-size
         bitfield.  (That's the way it is, experimentally.) */
      if ((!is_bitfield && !DECL_PACKED (field))
          || (!integer_zerop (DECL_SIZE (field))

now, the STRIP_NOPS in integer_zerop is odd as well.

[Bug target/50009] [4.7 Regression] Segmentation fault in tree_nop_conversion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50009

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |jakub at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-08-18 10:24:10 UTC ---
Created attachment 25051
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25051
gcc47-pr50009.patch

Untested fix.

[Bug target/50009] [4.7 Regression] Segmentation fault in tree_nop_conversion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50009

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-08-18 14:29:14 UTC ---
Author: jakub
Date: Thu Aug 18 14:29:10 2011
New Revision: 177860

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=177860
Log:
    PR target/50009
    * stor-layout.c (update_alignment_for_field): Don't ICE on
    packed flexible array members if ms_bitfield_layout_p.

    * gcc.c-torture/compile/pr50009.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr50009.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/stor-layout.c
    trunk/gcc/testsuite/ChangeLog

[Bug target/50009] [4.7 Regression] Segmentation fault in tree_nop_conversion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50009

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-08-18 14:31:49 UTC ---
Fixed.