From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-477430-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 20235 invoked by alias); 16 Feb 2015 14:38:55 -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 20219 invoked by uid 48); 16 Feb 2015 14:38:52 -0000
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/65078] [5.0 Regression] 4.9 and 5.0 generate more spill-fill in comparison with 4.8.2
Date: Mon, 16 Feb 2015 14:38:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Version: 5.0
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rguenth at gcc dot gnu.org
X-Bugzilla-Status: NEW
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 cf_reconfirmed_on everconfirmed
Message-ID: <bug-65078-4-jo02tyD5L6@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-65078-4@http.gcc.gnu.org/bugzilla/>
References: <bug-65078-4@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: 2015-02/txt/msg01763.txt.bz2

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65078

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-02-16
     Ever confirmed|0                           |1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

4.8 has

  _62 = MEM[(__m64 * {ref-all})dest_284];
  _63 = VIEW_CONVERT_EXPR<long long int>(_62);
  _64 = {_63, 0};
  _65 = VIEW_CONVERT_EXPR<vector(16) char>(_64);
  _66 = __builtin_ia32_punpcklbw128 (_65, { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0 });
  _67 = VIEW_CONVERT_EXPR<__m128i>(_66);
  _68 = VIEW_CONVERT_EXPR<vector(8) short int>(_67);
  _70 = __builtin_ia32_paddw128 (pretmp_327, _68);
  _71 = __builtin_ia32_packuswb128 (_70, _70);
  _72 = VIEW_CONVERT_EXPR<__m128i>(_71);
  _73 = __builtin_ia32_vec_ext_v2di (_72, 0);
  MEM[(long long int *)dest_284] = _73;

while 5

  _79 = MEM[(__m64 * {ref-all})dest_268];
  _78 = VIEW_CONVERT_EXPR<long long int>(_79);
  _77 = {_78, 0};
  _74 = VIEW_CONVERT_EXPR<vector(16) char>(_77);
  _73 = __builtin_ia32_punpcklbw128 (_74, { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0 });
  _69 = VIEW_CONVERT_EXPR<vector(8) short unsigned int>(_73);
  _68 = _69 + pretmp_312;
  _67 = VIEW_CONVERT_EXPR<vector(8) short int>(_68);
  _64 = __builtin_ia32_packuswb128 (_67, _67);
  _63 = VIEW_CONVERT_EXPR<__m128i>(_64);
  _62 = BIT_FIELD_REF <_63, 64, 0>;
  MEM[(long long int *)dest_268] = _62;

so some intrinsics are no longer builtins.  But the real difference is
the following weird store sequence

        packuswb        %xmm1, %xmm2
        movaps  %xmm2, (%esp)
        movl    (%esp), %esi
        movl    4(%esp), %edi
        movl    %esi, (%eax)
        movl    %edi, 4(%eax)

compared to just

        packuswb        %xmm1, %xmm1
        movq    %xmm1, (%edx)