Will GCC eventually support SSE2 or SSE4.1?

Jakub Jelinek jakub@redhat.com
Fri May 26 09:22:10 GMT 2023


On Fri, May 26, 2023 at 10:59:03AM +0200, Stefan Kanthak wrote:
> 3) SSE4.1 is supported since Core2, but -march=core2 fails to enable it.
>    That's bad, REALITY CHECK, please!

You're wrong.
SSE4.1 first appeared in the 45nm versions of Core2, the 65nm versions
didn't have it.
The supported CPU names don't distinguish between core2 submodels,
so if you have core2 with sse4.1, you should either be using -march=native
if compiling on such a machine, or use -march=core2 -msse4.1,
there is no -march={conroe,allendale,wolfdale,merom,penryn,...}.
> 
> 4) If the documenation is right, then the behaviour of GCC is wrong: it
>    doesn't allow to use SSE4.1 without SSE4.2!

If you aren't able to read the documentation, it is hard to argue.

	Jakub



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