Re: Ryzen PPA znver1 optimizations

[Richard Biener <richard.guenther@gmail.com>]

On Fri, Mar 8, 2019 at 8:56 AM Vanida Plamondon
<vanida.plamondon@gmail.com> wrote:
>
> I have been working on some PPA's that will provide standard Ubuntu
> and Linux Mint packages that are compiled with the znver1 cpu
> optimisations (Ryzen CPU). It has been quite tedious (though not
> particularly hard) to modify existing packages to be compiled with
> "-march=znver1" cflags and cxxflags, and since I started creating a
> toolchain to make the builds in the PPAs compile more reliably while
> producing broken less packages, I decided to modify GCC to always spit
> out ryzen optimised code automatically regardless of what code is
> thrown at it.
>
> I changed each instance of =generic in gcc/config.gcc to =znver1, and
> each instance of cpu=<something> to cpu=znver1, and each instance of
> arch=<something> that wasn't i386, i486, i586, i686, i786, x86-64, or
> x86_64 to arch=znver1.

You can configure with --with-arch=znver1 --with-tune=znver1 to
achieve the same effect.

> So what I think will happen is that I will set a PPA with a dependency
> on the PPA with the modified GCC, and any package I upload/copy to the
> aforementioned PPA that is compiling to x86 code will compile as
> though I set the "-march=znver1" option. Does anyone know whether or
> not this is going to work the way I think it will, or know how I can
> test to see if such is the case with the resulting binary packages?
>
> Also, is there a better way to do what I am trying to do?