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 A2DC93858D33; Thu, 16 Feb 2023 18:09:26 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A2DC93858D33
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1676570966;
	bh=M2Y0dWLE5IydGNuyZCoUqB0/KymGpaN7qiR4XbxN6iE=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=eQT4pRPfR01KBqQH+Z0PGpWQo0KaeApicJnPnvbYJ/wSQwkc2ogrcixBpO/hqPTw6
	 RgV0hBBzAtQ04Bxl+VjYPhfiSb3r+ryew8deIbfRnVVL0SnNNVGLEsKNCcfbFMUTg4
	 3cvg5PHlXK2Jvdvp/QiIQWqpTQIRukD6Gwjyis3Q=
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/108826] Inefficient address generation on
 POWER and RISC-V
Date: Thu, 16 Feb 2023 18:09:26 +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: unknown
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: enhancement
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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: keywords cf_reconfirmed_on bug_status
 everconfirmed
Message-ID: <bug-108826-4-BXc8B5Q9TN@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-108826-4@http.gcc.gnu.org/bugzilla/>
References: <bug-108826-4@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=3D108826

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
   Last reconfirmed|                            |2023-02-16
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Trying 13, 14, 15 -> 16:
   13: r84:DI=3Dr83:DI+0xc8
      REG_DEAD r83:DI
   14: r85:DI=3Dr84:DI<<0x2
      REG_DEAD r84:DI
   15: r86:DI=3Dr72:DI+r85:DI
      REG_DEAD r85:DI
   16: r76:DI=3Dsign_extend([r86:DI])
      REG_DEAD r86:DI
Failed to match this instruction:
(set (reg:DI 76 [ _5 ])
    (sign_extend:DI (mem:SI (plus:DI (plus:DI (mult:DI (reg:DI 83)
                        (const_int 4 [0x4]))
                    (reg/f:DI 72 [ _nettle_aes_decrypt_T.0_1 ]))
                (const_int 800 [0x320])) [2
_nettle_aes_decrypt_T.0_1->table[2][_4]+0 S4 A32])))
Failed to match this instruction:
(set (reg/f:DI 86)
    (plus:DI (ashift:DI (reg:DI 83)
            (const_int 2 [0x2]))
        (reg/f:DI 72 [ _nettle_aes_decrypt_T.0_1 ])))


So combine does know how to combine all 4 instructions and produce the plus=
 800
there. But then it goes and splits it up and fails. I can't remember if the=
re
is 4->3 splitting or just 4->2 .=