From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39697) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZRMa7-0003P3-Sl for qemu-devel@nongnu.org; Mon, 17 Aug 2015 11:44:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZRMa4-0005PK-HX for qemu-devel@nongnu.org; Mon, 17 Aug 2015 11:44:15 -0400 Received: from mail-qk0-x230.google.com ([2607:f8b0:400d:c09::230]:35939) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZRMa4-0005PG-Dj for qemu-devel@nongnu.org; Mon, 17 Aug 2015 11:44:12 -0400 Received: by qkdv3 with SMTP id v3so47708205qkd.3 for ; Mon, 17 Aug 2015 08:44:12 -0700 (PDT) Sender: Richard Henderson References: <1423806229-17766-1-git-send-email-rth@twiddle.net> <1423806229-17766-6-git-send-email-rth@twiddle.net> From: Richard Henderson Message-ID: <55D20148.9060303@twiddle.net> Date: Mon, 17 Aug 2015 08:44:08 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PULL 5/8] tcg: Put opcodes in a linked list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Artyom Tarasenko Cc: qemu-devel On 08/17/2015 04:35 AM, Artyom Tarasenko wrote: > Hi Richard, > > this patch seems to break a build when USE_LIVENESS_ANALYSIS is undefined. I suppose that's possible. If so, it must be a trivial error somewhere. Why in the world would you want !USE_LIVENESS_ANALYSIS? Are you simply trying to see what sort of performance impact it has? I can tell you it's fairly important for generating x86 code. The two operand nature of the ISA means that if we don't know that the source operand is dead, we often have to introduce an extra move to preserve it. r~