From owner-freebsd-amd64@FreeBSD.ORG  Tue Mar  8 16:36:01 2005
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Date: Tue, 8 Mar 2005 16:36:01 +0000
From: Kris Kennaway <kris@FreeBSD.org>
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Subject: Re: Is -O2 supported for world?
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On Mon, Mar 07, 2005 at 10:09:10PM -0800, David O'Brien wrote:
> 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:
> 
> It is suppored w/in /usr/src.
>  
> >     /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 isn't supported in /usr/ports without -fno-strict-aliasing also.
> There are a few ports that aren't happy being compiled with any form of
> -O2 (such as the old perl).
>  

No, it's worse than that.  They cannot be compiled with ANY flags when
*world* is built with -O2.  They crash when trying to run binaries
during the build, because of something going wrong in strtol() or
similar (it's been ~4 months so my memory is fuzzy on the details but
they've been pointed out to you several times).

Kris