From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-337698-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 16389 invoked by alias); 19 Nov 2010 08:58:25 -0000
Received: (qmail 16379 invoked by uid 22791); 19 Nov 2010 08:58:24 -0000
X-SWARE-Spam-Status: No, hits=-2.7 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00,TW_LW,TW_SL,TW_WZ
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO gcc.gnu.org) (127.0.0.1)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 19 Nov 2010 08:58:19 +0000
From: "amodra at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/46556] New: Code size regression in struct access
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: amodra at gmail dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-46556-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Date: Fri, 19 Nov 2010 09:04:00 -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
X-SW-Source: 2010-11/txt/msg02431.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46556

           Summary: Code size regression in struct access
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: amodra@gmail.com


/* -Os -mcpu=405 -msoft-float */
struct x
{
  unsigned int a[16];
  unsigned int b[16];
  unsigned int c[16];
};

void
f (struct x *p, unsigned int n)
{
  extern void foo (int, int, int);
  int a = p->a[n];
  int c = p->c[n];
  int b = p->b[n];

  foo (a, c, b);
}

results in

f:
        stwu 1,-16(1)
        mflr 0
        addi 11,4,32
        stw 0,20(1)
        addi 0,4,16
        mr 9,3
        slwi 10,4,2
        slwi 0,0,2
        slwi 11,11,2
        lwzx 5,9,0
        lwzx 3,3,10
        lwzx 4,9,11
        bl foo
        lwz 0,20(1)
        addi 1,1,16
        mtlr 0
        blr

a four instruction code size regression against gcc-4.2, which produces

f:
        stwu 1,-16(1)
        mflr 0
        slwi 4,4,2
        stw 0,20(1)
        add 9,4,3
        lwz 5,64(9)
        lwzx 3,4,3
        lwz 4,128(9)
        bl foo
        lwz 0,20(1)
        addi 1,1,16
        mtlr 0
        blr

gcc regressed on this testcase at 4.3.0