[Pkg-opencl-devel] pocl

[Rebecca N. Palmer]

On 23/04/16 10:37, Giuseppe Bilotta wrote:
> * all ICDs based on LLVM have to be built using the same version of
> LLVM, or one will get random crashes and segfaults during execution;
> this means that Pocl must be built with the same LLVM as
> mesa-opencl-icd and beignet;
> * 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).

> * 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

> * 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?