Bug#766630: supercollider: ftbfs on ppc64el -- error: invalid parameter combination for AltiVec intrinsic

[Felipe Sateler]

Hi Fernando,

On Fri, Oct 24, 2014 at 10:41 AM, Fernando Seiti Furusato
<ferseiti at br.ibm.com> wrote:
> Source: supercollider
> Severity: normal
> Tags: patch
> User: debian-powerpc at lists.debian.org
> Usertags: ppc64el
>
> Dear Maintainer,
>
> The package fails to build from source on ppc64el because the usage of altivec is not implemented for the architecture.
> So, the workaround was to disable it for ppc64el.

What does "usage of altivec is not implemented"? In supecollider, or
in the compiler?

In any case, perhaps the solution is to disable supernova in ppc64el
as well instead of adding custom flags.

>
> While at it, Konstantinos also went ahead and fixed it for ppc32. He tested it and it builds.

I'm very ignorant on altivec (or simd in general), but I try to
understand the patch anyway. This patch seems to consist mostly of
s/vector/__vector/. Why is that? I presume the upstream code works on
apple platforms, is that an important difference? The second part is
adding -mabi=altivec and -maltivec, which is unfortunately not
possible, because that would contaminate the rest of the binaries with
altivec code. AFAIK, debian still supports non-altivec machines.
(supernova requires altivec, but for other machines we have scsynth).

Perhaps a more correct patch would alter the logic in
external_libraries/nova-simd/CMakeLists.txt to allow passing the
required flags just to nova-simd.


-- 

Saludos,
Felipe Sateler