Date: Thu, 10 Mar 2011 23:28:39 +0000 From: Alexander Best <arundel@freebsd.org> To: Dimitry Andric <dim@FreeBSD.org> Cc: gerald@freebsd.org, Martin Matuska <mm@freebsd.org>, current@freebsd.org Subject: Re: [TESTING] ssse3 backport from gcc 4.3 Message-ID: <20110310232839.GA5378@freebsd.org> In-Reply-To: <20110310082740.GA74075@freebsd.org> References: <4D7799FD.9040008@FreeBSD.org> <20110309211820.GA46520@zim.MIT.EDU> <4D7810B2.4090207@FreeBSD.org> <20110310082740.GA74075@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu Mar 10 11, Alexander Best wrote:
> On Thu Mar 10 11, Dimitry Andric wrote:
> > On 2011-03-09 22:18, David Schultz wrote:
> > >The proliferation of -mno-sse -mno-sse2 -mno-sse3 options in the
> > >makefiles is probably not needed: I'm pretty sure -mno-sse implies
> > >the other two, unless -msse3 is specified explicitly.
> >
> > Indeed, contrib/gcc/config/i386/i386.c has:
> >
> > static bool
> > ix86_handle_option (size_t code, const char *arg ATTRIBUTE_UNUSED, int
> > value)
> > {
> > ...
> > case OPT_msse:
> > if (!value)
> > {
> > target_flags &= ~(MASK_SSE2 | MASK_SSE3);
> > target_flags_explicit |= MASK_SSE2 | MASK_SSE3;
> > }
> > return true;
> >
> > E.g -mno-sse disables SSE2 and SSE3, unless you explicitly add -msse2 or
> > -msse3 options. In Martin's patch, this fragment uses MASK_SSSE3 too.
>
> +1 for removing -mno-sse2, -mno-sse3 and -mno-ssse3 throughout the source
> tree.
>
> ...also -mfpmath=387 is still present for amd64 and i don't think it's
> necessary. with -mno-sse i don't think -mfpmath=sse remains the default for
> amd64.
i've compiled two kernels. one with the standard -mno-sse* options in kernel.mk
and one without -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387.
CPUYTE ?= core2.
diffing showed no major differences for gcc and clang as compiler
cheers.
alex
>
> >
> > Clang has a similar mechanism, -mno-sse disables all 'higher' SSE
> > variants too.
>
> --
> a13x
--
a13x
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20110310232839.GA5378>