From owner-freebsd-current Wed Apr 7 11:35:47 1999 Delivered-To: freebsd-current@freebsd.org Received: from mgate2.telekabel.at (mgate2.telekabel.at [195.34.133.21]) by hub.freebsd.org (Postfix) with ESMTP id 04D7214C89 for ; Wed, 7 Apr 1999 11:35:19 -0700 (PDT) (envelope-from hfwirth@teleweb.at) Received: from teleweb.at ([212.17.91.153]) by mgate2.telekabel.at (Post.Office MTA v3.1.2 release (PO203-101c) ID# 0-57067U15000L15000S0V35) with ESMTP id AAA14029; Wed, 7 Apr 1999 20:33:08 +0200 Message-ID: <370BA4C7.831215CE@teleweb.at> Date: Wed, 07 Apr 1999 20:32:39 +0200 From: Helmut Wirth Reply-To: hfwirth@teleweb.at X-Mailer: Mozilla 4.07 [en] (X11; U; FreeBSD 3.0-RELEASE i386) MIME-Version: 1.0 To: Alex Zepeda , current@freebsd.org Subject: Re: EGCS optimizations References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Alex Zepeda wrote: > > On Mon, 5 Apr 1999, Matthew Dillon wrote: > > > There is nothing beyond -O2. Well, there's -O3, which tries to > > inline static functions, but that typically isn't beneficial because > > it really bloats up the code and subroutine calls on intel cpus are > > very fast. > > Really? > > The pgcc web page (goof.com/pcg) lead me to believe that there were a few > more optimizations turned on by -O5 && -O6.. > > - alex > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message As far as I know, pgcc is different from egcs. I had pgcc, it did *significantly* better code than gcc at the time (about 1 to 2 years before), especially in floating point code, but it was buggy. I have egcs-1.2 (on a current-3.0) and I am rather disappointed with the code performance. With standard code without floating point calculations it does a bit worse than old gcc-2.7.x. In floating point (as in Mesa, ..) it is awful. It generates much slower code, than gcc-2.7.x. I am using an old Linpack benchmark (Calculate n linear equations) and I can get best perfomance usually with gcc-2.7.x using -O (*not* -O2!!). The same seems to be true with egcs, but more so. Egcs with x86-prozessors work best with -O, don't use more (-marchxxx does nothing significant). I understand there are reasons to switch to egcs (exceptions, C++ enhancements,..) but I hope they will do something for egcs' code performance. (Does code size really matter that much. Sure, it accumulates, but...). -- Helmut F. Wirth Email: hfwirth@teleweb.at To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message