Will GCC eventually support SSE2 or SSE4.1?

Jonathan Wakely jwakely.gcc@gmail.com
Fri May 26 09:51:53 GMT 2023

On Fri, 26 May 2023 at 10:31, Hagen Paul Pfeifer wrote:
> * Jonathan Wakely via Gcc | 2023-05-26 08:30:06 [+0100]:
> >On Fri, 26 May 2023, 08:01 Andrew Pinski via Gcc, <gcc@gcc.gnu.org> wrote:
> >
> >> > GCC 13.3: gcc -m32 -O3 demo.c
> >> >
> >> > NOTE: -mtune=native is the default!
> >>
> >> You need to use -march=native and not -mtune=native .... to turn on
> >> the architecture features.
> >
> >Yes this is just user error. You didn't use the right options to say you
> >want SSE2. GCC supports it fine already.
> >
> >This is also the wrong mailing list for this kind of question, please use
> >gcc-help@gcc.gnu.org for this kind of thing, thanks.
> Correct, that was also my first thought - but: this mistake has been repeated
> again and again for decades. Here specifically Stefan Kanthak realized that
> something is wrong - in many cases simply mtune=native is used and the error
> is not realized.

I suppose we could give a warning if -mtune is used without an
explicit -march but it would probably annoy a lot of people.

It's not *always* wrong to use -mtune without -march. It's fine if you
know what the compiler's default -march is and you're happy with that

> Maybe we should think about how you can support the users better? Maybe by an
> explicit hint in the documentation or by a info message at execution time. And
> for such discussions this is the right mailing list! ;-)

Yes :-)

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