https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80878
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #38 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Please see PR104688 . We got a response from Intel, where they guaranteed
atomicity of certain 16-byte load instructions for Intel CPUs with AVX support.
AFAIK we didn't get similar guarantee from AMD.
The current state is that on the libatomic side when ifuncs are possible we use
those atomic loads etc. on Intel with AVX, and do what we used to do before for
other CPUs.
We haven't changed what the compiler emits, I think we'd need to introduce some
new option for it (guarantee code will run only on Intel CPUs) and imply that
from -march= listing Intel CPUs (with AVX). If AMD would give a similar
guarantee, it would be much easier, we could just emit that whenever -mavx.
