From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-436977-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 14120 invoked by alias); 8 Dec 2013 00:56:26 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Received: (qmail 14091 invoked by uid 48); 8 Dec 2013 00:56:20 -0000
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/59420] arm: broken code generated (memset from newlib 2.0)
Date: Sun, 08 Dec 2013 00:56:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 4.8.2
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: pinskia at gcc dot gnu.org
X-Bugzilla-Status: RESOLVED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: bug_status component resolution
Message-ID: <bug-59420-4-CdVAleBwjx@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-59420-4@http.gcc.gnu.org/bugzilla/>
References: <bug-59420-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2013-12/txt/msg00632.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59420

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
          Component|c                           |middle-end
         Resolution|---                         |INVALID

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Richard Earnshaw from comment #2)
> You'll get more attention paid to this if you can describe why you think the
> code generated is incorrect.

The issue is there is a loop inside of memset that gets converted to a call to
memset; that is if I read the assembly code correctly.  if that is the case
then this is a bug in the newlib makefiles as they should be using
-fno-tree-loop-distribute-patterns or like what glibc does:
/* Add the compiler optimization to inhibit loop transformation to library
   calls.  This is used to avoid recursive calls in memset and memmove
   default implementations.  */
#ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
# define inhibit_loop_to_libcall \
    __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
#else
# define inhibit_loop_to_libcall
#endif

So closing as invalid, please report this to newlib.

Note the work around is not to use -O3 or use -O3
-fno-tree-loop-distribute-patterns .