[arch-dev-public] Create guidelines regarding SIMD instructions/x86 extensions

[Lukas Jirkovsky]

On Sat, 25 May 2019 at 04:27, Filipe Laíns via arch-dev-public
<arch-dev-public at archlinux.org> wrote:
> Setting `-mtune` to generic won't add any additional instruction sets
> by itself, but it does not prevent instruction sets from being added.
> Looks like GCC enables MMX, SSE and SSE2 by default, it isn't related
> at all to `-march` like I stated in the email but it still presents the
> same issue.

As far as I know, MMX, SSE and SSE2 are mandatory part of the AMD64
instruction set, so they are not enabled randomly just because someone
felt like it, but because they are be present on every x86_64 cpu.