From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:36145) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R5f9O-0006GN-6y for qemu-devel@nongnu.org; Mon, 19 Sep 2011 10:48:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R5f9J-000574-UL for qemu-devel@nongnu.org; Mon, 19 Sep 2011 10:48:50 -0400 Received: from one.firstfloor.org ([213.235.205.2]:48741) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R5f9J-00056H-J1 for qemu-devel@nongnu.org; Mon, 19 Sep 2011 10:48:45 -0400 Date: Mon, 19 Sep 2011 16:48:42 +0200 From: Andi Kleen Message-ID: <20110919144842.GH7761@one.firstfloor.org> References: <4E74FC29.1050003@mail.berlios.de> <1316289634-18786-5-git-send-email-weil@mail.berlios.de> <4E75865B.5040106@mail.berlios.de> <4E759C43.5070708@redhat.com> <4E76305B.80108@redhat.com> <51221ff5190e1823f0d6b602c4ca0f4d.squirrel@www.firstfloor.org> <4E772DE1.2090407@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E772DE1.2090407@redhat.com> Subject: Re: [Qemu-devel] [PATCH 5/8] tcg: Add interpreter for bytecode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Paolo Bonzini , Andi Kleen , QEMU Developers > You generally want CSE, yes? So you can't blame gcc for getting it > wrong sometimes. There are cases where CSE pessimizes the code, .e.g when it increases memory pressure too much or caches something that is easier recomputed. This is just another one. BTW I checked again and the problem seems to be fixed in gcc 4.6, still there in 4.5, at least in my example. -Andi