From owner-freebsd-amd64@FreeBSD.ORG Sat Mar 5 15:22:35 2005 Return-Path: Delivered-To: freebsd-amd64@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 758) id D33EB16A4CF; Sat, 5 Mar 2005 15:22:35 +0000 (GMT) Date: Sat, 5 Mar 2005 15:22:35 +0000 From: Kris Kennaway To: freebsd-amd64@freebsd.org Message-ID: <20050305152235.GE26240@hub.freebsd.org> References: <20050305043006.GN83265@afflictions.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050305043006.GN83265@afflictions.org> User-Agent: Mutt/1.4.2.1i Subject: Re: Is -O2 supported for world? X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 05 Mar 2005 15:22:35 -0000 On Fri, Mar 04, 2005 at 11:30:07PM -0500, Damian Gerow wrote: > I'm a little fuzzy on whether -O2 is supported for world or not: I seem to > remember on x86 it is, but the only references I've seen to amd64 were > speaking about ports. > > Is -O2 optimization supported in amd64? It most definitely doesn't work: > > /usr/src/lib/libc/i386/sys/_amd64_get_fsbase.c: In function `_amd64_get_fsbase': > /usr/src/lib/libc/i386/sys/_amd64_get_fsbase.c:40: warning: dereferencing type-punned pointer will break strict-aliasing rules > > without -fno-strict-aliasing. Not that I have any serious desire to run > with -O2, just curious. -O2 produces broken code on amd64 anyway, and a number of ports will fail to build or run when world is compiled with -O2, with or without -fno-strict-aliasing. Kris