From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-448088-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 24933 invoked by alias); 2 Apr 2014 04:35:32 -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 24884 invoked by uid 48); 2 Apr 2014 04:35:28 -0000
From: "anton at samba dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/60737] New: rs6000 expand_block_clear uses word stores on double word pointer
Date: Wed, 02 Apr 2014 04:35:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 4.8.3
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: anton at samba dot org
X-Bugzilla-Status: UNCONFIRMED
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_id short_desc product version bug_status bug_severity priority component assigned_to reporter
Message-ID: <bug-60737-4@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: 2014-04/txt/msg00108.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60737

            Bug ID: 60737
           Summary: rs6000 expand_block_clear uses word stores on double
                    word pointer
           Product: gcc
           Version: 4.8.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: anton at samba dot org

The following code:

#include <string.h>

void foo(long *p)
{   
    memset(p, 0, 16);
}

When built with a 64bit target:

gcc -mcpu=power8 -O2 -S foo.c

Ends up using 32 byte stores:

foo:
    li 9,0
    stw 9,0(3)
    stw 9,4(3)
    stw 9,8(3)
    stw 9,12(3)
    blr

expand_block_move has a similar issue