From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id B28F4385770F; Wed, 17 May 2023 23:46:07 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B28F4385770F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1684367167; bh=ph8pfAPJ4c5UjEsF3dIHzW654DW1w15l/dyh2Ap+yoY=; h=From:To:Subject:Date:In-Reply-To:References:From; b=eefDjqRm5Vw30u5H2Gt9g+YBqojwU0scptDI+u3aXyb3zhrTe1+7roj0F4EGvNAUG wGR08qek2yo0qW5RKW/19m0J+dvuvr929BLVmJoY07zAHLpB45dt0+fQcEDVmQtxiR Kix+PbPoM3qJSAZE8rZbRPTX+wudJ8IDyJWGNFC4= From: "pinskia at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/109896] Missed optimisation: overflow detection in multiplication instructions for operator new Date: Wed, 17 May 2023 23:46:07 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 13.1.1 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: pinskia at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED 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: Message-ID: In-Reply-To: References: 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: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109896 --- Comment #4 from Andrew Pinski --- (In reply to Thiago Macieira from comment #3) > 5 instructions, 4 cycles (not including front-end decode), so roughly the > same as the imulq example above (4 cycles), but with far more ports to > dispatch to. If you are that picky for cycles, these cycles are not going to be a problem compared to the dynamic allocation that is just about to happen ......=