Date: Thu, 20 Jan 2005 16:56:07 -0500 From: Paul Mather <paul@gromit.dlib.vt.edu> To: Mike Jakubik <mikej@rogers.com> Cc: freebsd-stable@freebsd.org Subject: Re: CFLAGS=-O2 -pipe problems in RELENG_5 ? Message-ID: <1106258167.582.10.camel@zappa.Chelsea-Ct.Org> In-Reply-To: <52406.207.219.213.162.1106257499.squirrel@207.219.213.162> References: <3aaaa3a0501181530975fecf@mail.gmail.com> <XFMail.20050120085633.jdp@polstra.com> <3aaaa3a050120105459f7d015@mail.gmail.com> <3aaaa3a050120111777ada357@mail.gmail.com> <1106256780.582.5.camel@zappa.Chelsea-Ct.Org> <52406.207.219.213.162.1106257499.squirrel@207.219.213.162>
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On Thu, 2005-01-20 at 16:44 -0500, Mike Jakubik wrote:
> Paul Mather said:
>
> > On Thu, 2005-01-20 at 19:17 +0000, Chris wrote:
> >> what does -fno-strict-alias do? I cannot find it in man gcc
> >
> > It is a truncation of "-fno-strict-aliasing". The flag does not appear
> > to be described in the gcc man page, but is documented in the gcc info
> > page (search for "-fstrict-aliasing"). To quote the info page,
> > -fstrict-aliasing "allows the compiler to assume the strictest aliasing
> > rules applicable to the language being compiled. ..."
>
> Wouldn't we want strict aliasing then?
Yes, but unfortunately some ports circumvent the strict aliasing rules,
which is why those ports break when building with -O2 (which causes
-fstrict-aliasing to be enabled).
Cheers,
Paul.
--
e-mail: paul@gromit.dlib.vt.edu
"Without music to decorate it, time is just a bunch of boring production
deadlines or dates by which bills must be paid."
--- Frank Vincent Zappa
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