Re: [gentoo-user] -march=native is *EXTREMELY* conservative

[Paul Hartman]

On Sat, Dec 17, 2011 at 3:07 PM, Walter Dnes <waltdnes@××××××××.org> wrote:
> -march=                               core2
> -mmmx                                 [disabled]
> -msse                                 [disabled]
> -msse2                                [disabled]
> -msse3                                [disabled]
> -mssse3                               [disabled]
>
>  It properly identified the cpu as "core2".  But mmx, sse, sse2, sse3
> (aka pni), and ssse3 are disabled!!!

I think you may be misinterpreting that output. It's not telling you
that MMX etc. are disabled, it's telling you that the /commandline
options/ are disabled. Why?

From the GCC docs:
"core2: Intel Core2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3
and SSSE3 instruction set support."

That means those features are implied by -march=core2, adding those
commandline switches would be redundant.