[llvm-dev] New x86-64 micro-architecture levels

[Florian Weimer via llvm-dev]

* Dongsheng Song:

> I fully agree these names (100/101, A/B/C/D) are not very intuitive, I
> recommend using isa tags by year (e.g. x64_2010, x64_2014) like the
> python's platform tags (e.g. manylinux2010, manylinux2014).

I started out with a year number, but that was before the was Level A.
Too many new CPUs only fall under level A unfortunately because they do
not even have AVX.  This even applies to some new server CPU designs
released this year.

I'm concerned that putting a year into the level name suggests that
everything main-stream released after that year supports that level, and
that's not true.  I think for manylinux, it's different, and it actually
works out there.  No one is building a new GNU/Linux distribution that
is based on glibc 2.12 today, for example.  But not so much for x86
CPUs.

If you think my worry is unfounded, then a year-based approach sounds
compelling.

Thanks,
Florian