[Pkg-opencl-devel] pocl

[Giuseppe Bilotta]

Hello,

On Sun, Apr 24, 2016 at 2:25 PM, Rebecca N. Palmer
<rebecca_palmer at zoho.com> wrote:
> On 23/04/16 10:37, Giuseppe Bilotta wrote:
>> * Pocl needs at least LLVM 3.7, but Debian defaults to LLVM 3.6, so
>> the LLVM version must be specified manually (by the way, why is 3.6
>> still the default in Debian?)
>
> While the Debian default (i.e. what you get if you ask for plain 'clang') is
> 3.6, mesa (both -opencl-icd and graphics) already uses 3.7; beignet is
> currently on 3.6 but probably could switch (I'll try that today).

BTW this causes issues when both the mesa and beignet ICDs are
installed. (I build my own beignet because of this.)

>> * automatic build dependencies are affected by
>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=792842

> If you dynamically link libllvm (which Debian packages are supposed to do
> anyway) you don't need llvm-config --system-libs at all:
> https://anonscm.debian.org/cgit/pkg-opencl/beignet.git/tree/debian/patches/shared-llvm.patch

It's possible the pocl developers have been overzealous and include
the llvm --system-libs even in the dynamic linking case. It might be
worth suggesting them not to include them then.

>> * there is a known issue with LLVM 3.7 (at least the version that
>> ships in Debian unstable) producing the wrong shift/rotation
>> instructions for short/ushort vector types on Haswell CPUs, which
>> causes some tests to fail.
>
> https://github.com/pocl/pocl/issues/238
> Is this the same test failure Andreas is seeing?

This is definitely the test failure I am seeing on my Haswell laptop,
I wouldn't be surprised if it's also what Andreas is seeing

-- 
Giuseppe "Oblomov" Bilotta