From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2069 invoked by alias); 16 Apr 2003 17:46:03 -0000 Mailing-List: contact gcc-prs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-prs-owner@gcc.gnu.org Received: (qmail 2007 invoked by uid 71); 16 Apr 2003 17:46:01 -0000 Date: Wed, 16 Apr 2003 17:46:00 -0000 Message-ID: <20030416174601.2006.qmail@sources.redhat.com> To: ebotcazou@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, From: Vladimir Makarov Subject: Re: optimization/10160: [3.3/3.4 regression][SPARC] compile time regression; inordinate time spent in "scheduling" Reply-To: Vladimir Makarov X-SW-Source: 2003-04/txt/msg00763.txt.bz2 List-Id: The following reply was made to PR optimization/10160; it has been noted by GNATS. From: Vladimir Makarov To: ebotcazou@gcc.gnu.org, china@thewrittenword.com, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, vmakarov@gcc.gnu.org, gcc-gnats@gcc.gnu.org Cc: Subject: Re: optimization/10160: [3.3/3.4 regression][SPARC] compile time regression; inordinate time spent in "scheduling" Date: Wed, 16 Apr 2003 13:39:59 -0400 ebotcazou@gcc.gnu.org wrote: > > Synopsis: [3.3/3.4 regression][SPARC] compile time regression; inordinate time spent in "scheduling" > > Responsible-Changed-From-To: vmakarov->ebotcazou > Responsible-Changed-By: ebotcazou > Responsible-Changed-When: Wed Apr 16 13:14:39 2003 > Responsible-Changed-Why: > Hum... I don't think that the scheduler is to be blamed here, > rather the tree inliner: cutting the inlining limit by 10 > (-finline-limit=60) brings the compile time on par with that > of the 3.2.x branch. > > The new logic of the tree inliner is not exactly adapted to this testcase. > > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10160 You are absolutely right. I was afraid that it is because of the first cycle multipass insn scheduling. So I switched it off and got the same result. So this is not because of the recent insn scheduling changes. Simply insn scheduling (even simplest heuristic list one) is O(n*2) algorithm. So it may behave very nasty when the input is big. There are some heuristics constraining number of dependencies but they do not help in this case. Even without insn scheduling compilation of this file takes 12 minutes on my sparc computer. Vlad