From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26898 invoked by alias); 19 Aug 2009 14:44:32 -0000 Received: (qmail 26889 invoked by uid 22791); 19 Aug 2009 14:44:31 -0000 X-SWARE-Spam-Status: No, hits=-1.6 required=5.0 tests=AWL,BAYES_00,SARE_MSGID_LONG40,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mail-yw0-f178.google.com (HELO mail-yw0-f178.google.com) (209.85.211.178) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 19 Aug 2009 14:44:25 +0000 Received: by ywh8 with SMTP id 8so5602881ywh.8 for ; Wed, 19 Aug 2009 07:44:23 -0700 (PDT) MIME-Version: 1.0 Received: by 10.101.10.13 with SMTP id n13mr7168399ani.88.1250693062854; Wed, 19 Aug 2009 07:44:22 -0700 (PDT) Date: Wed, 19 Aug 2009 22:51:00 -0000 Message-ID: Subject: Question about the difference between two instruction scheduling passes From: "Amker.Cheng" To: gcc@gcc.gnu.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org X-SW-Source: 2009-08/txt/msg00344.txt.bz2 Hi all: I'm currently studying implementation of instruction sched in gcc. it is possible to schedule insns directly from queue in case there is nothing better to do and there are still vacant dispatch slots in the current cycle. Gcc only does this work in the second pass, but what's the point? Is it wrong or just not necessary in the first sched pass? Thanks. -- Best Regards.