Date: Sat, 5 Mar 2005 15:22:35 +0000 From: Kris Kennaway <kris@FreeBSD.org> To: freebsd-amd64@freebsd.org Subject: Re: Is -O2 supported for world? Message-ID: <20050305152235.GE26240@hub.freebsd.org> In-Reply-To: <20050305043006.GN83265@afflictions.org> References: <20050305043006.GN83265@afflictions.org>
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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
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