[Bug other/53285] New: libibiberty's md5.c builds with warnings with 4.7 and trunk

[Bug other/53285] New: libibiberty's md5.c builds with warnings with 4.7 and trunk

[doko at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53285

             Bug #: 53285
           Summary: libibiberty's md5.c builds with warnings with 4.7 and
                    trunk
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: doko@gcc.gnu.org


when libibiberty's md5.c is built using 4.7 or trunk on x86-linux, the
following warning is emitted:

md5.c: In function 'md5_finish_ctx':
md5.c:119:2: error: dereferencing type-punned pointer will break
strict-aliasing rules [-Werror=strict-aliasing]
  *(md5_uint32 *) & ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3);
  ^
md5.c:120:2: error: dereferencing type-punned pointer will break
strict-aliasing rules [-Werror=strict-aliasing]
  *(md5_uint32 *) & ctx->buffer[bytes + pad + 4] =
  ^

afaics this is the only warning emitted when building libiberty when built with
4.7 or trunk.

[Bug other/53285] libibiberty's md5.c builds with warnings with 4.7 and trunk

[doko at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53285

--- Comment #1 from Matthias Klose <doko at gcc dot gnu.org> 2012-05-28 04:38:50 UTC ---
Created attachment 27511
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27511
patch taken from glibc

the md5.c copy in glibc was fixed with the attached patch

[Bug other/53285] libibiberty's md5.c builds with warnings with 4.7 and trunk

[doko at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53285

--- Comment #2 from Matthias Klose <doko at gcc dot gnu.org> 2012-05-28 06:42:37 UTC ---
the patch is incomplete.

the patch from glibc is found at
http://sourceware.org/git/?p=glibc.git;a=patch;h=7dc6bd90c569c49807462b0740b18e32fab4d8b7

using anonymous unions which cannot be used for stage1. The original patch is
http://sourceware.org/ml/libc-alpha/2011-07/msg00085.html

A third approach from gnulib is pointed out in
http://sourceware.org/ml/libc-alpha/2011-07/msg00093.html

[Bug other/53285] libibiberty's md5.c builds with warnings with 4.7 and trunk

[ktietz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53285

--- Comment #3 from Kai Tietz <ktietz at gcc dot gnu.org> 2013-01-31 08:14:32 UTC ---
Author: ktietz
Date: Thu Jan 31 08:14:27 2013
New Revision: 195601

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=195601
Log:
    Merged from trunk.
    PR other/53285
    * md5.c (md5_finish_ctx): Declare swap_bytes.  Assign SWAP() output
    to swap_bytes, and then call memcpy to move it to ctx->buffer.


Modified:
    branches/gcc-4_7-branch/libiberty/ChangeLog
    branches/gcc-4_7-branch/libiberty/md5.c

[Bug other/53285] libibiberty's md5.c builds with warnings with 4.7 and trunk

[ktietz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53285

Kai Tietz <ktietz at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |ktietz at gcc dot gnu.org
         Resolution|                            |FIXED

--- Comment #4 from Kai Tietz <ktietz at gcc dot gnu.org> 2013-01-31 08:21:48 UTC ---
backported mainline-fix for this to 4.7.  Fixed.