From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 470C03851888; Wed, 23 Nov 2022 18:06:39 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 470C03851888
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1669226799;
	bh=tt06lSrQaLUsPrL/Gk/xWS2a7mDaOThZHVCDxtowesM=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=HivZk2s4pMkE2/raN6PDbepSO/6UFEuAGmnyI8cSdoXPjsO0yhTWx+QjogRnTL5Po
	 GQY7o6iyY5Xk5pz1/XDbX//QmmDA1w0l5H6Fx6YIv5yITXclTOSJZe7yc98mtjA8tw
	 acP8dOPsvnhK7rMIT7lvig/j1BY5/1G/KSlBK9+M=
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/107837] [10/11/12/13 Regression] Missed
 optimization: Using memcpy to load a struct unnecessary uses stack space
Date: Wed, 23 Nov 2022 18:06:36 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: missed-optimization, needs-bisection
X-Bugzilla-Severity: normal
X-Bugzilla-Who: pinskia at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 10.5
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_status cf_reconfirmed_on short_desc keywords
 cf_known_to_work target_milestone cf_known_to_fail everconfirmed
Message-ID: <bug-107837-4-4sesUGm71g@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-107837-4@http.gcc.gnu.org/bugzilla/>
References: <bug-107837-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107837

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2022-11-23
            Summary|Missed optimization: Using  |[10/11/12/13 Regression]
                   |memcpy to load a struct     |Missed optimization: Using
                   |unnecessary uses stack      |memcpy to load a struct
                   |space                       |unnecessary uses stack
                   |                            |space
           Keywords|                            |needs-bisection
      Known to work|                            |4.5.3, 4.7.3, 5.1.0, 7.5.0
   Target Milestone|---                         |10.5
      Known to fail|                            |8.1.0
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, GCC 7 did the right thing ...
Even on the gimple level:

  x$v$0_8 =3D MEM[(char * {ref-all})src_6(D)];
  x$v$1_9 =3D MEM[(char * {ref-all})src_6(D) + 8B];
  x$v$2_10 =3D MEM[(char * {ref-all})src_6(D) + 16B];
  x$v$3_11 =3D MEM[(char * {ref-all})src_6(D) + 24B];
  _1 =3D __builtin_bswap64 (x$v$3_11);
  _2 =3D __builtin_bswap64 (x$v$2_10);
  _3 =3D __builtin_bswap64 (x$v$1_9);
  _4 =3D __builtin_bswap64 (x$v$0_8);
  MEM[(struct uint256 *)o_7(D)] =3D _1;
  MEM[(struct uint256 *)o_7(D) + 8B] =3D _2;
  MEM[(struct uint256 *)o_7(D) + 16B] =3D _3;
  MEM[(struct uint256 *)o_7(D) + 24B] =3D _4;=