Date: Thu, 10 Mar 2011 00:43:46 +0100 From: Dimitry Andric <dim@FreeBSD.org> To: Martin Matuska <mm@freebsd.org>, current@freebsd.org, gerald@freebsd.org Subject: Re: [TESTING] ssse3 backport from gcc 4.3 Message-ID: <4D7810B2.4090207@FreeBSD.org> In-Reply-To: <20110309211820.GA46520@zim.MIT.EDU> References: <4D7799FD.9040008@FreeBSD.org> <20110309211820.GA46520@zim.MIT.EDU>
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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.
Clang has a similar mechanism, -mno-sse disables all 'higher' SSE
variants too.
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