[Pkg-opencl-devel] Bug#798635: Bug#798635: beignet-opencl-icd: beignet is not installable with llvm3.5v5

[Rebecca N. Palmer]

Control: retitle -1 beignet is not installable with libllvm3.5v5

> beignet was built against llvm3.5 and (the version currently in sid)
> does not support anything newer. The upcoming upload of 1.1.0 should
> support llvm3.6. But Rebecca might correct me on this :-)

LLVM 3.5 is still the upstream default, with 3.3 to 3.6 accepted 
(http://cgit.freedesktop.org/beignet/tree/CMake/FindLLVM.cmake).  The 
documentation (for both 1.0.3 and 1.1, 
http://www.freedesktop.org/wiki/Software/Beignet/ ) says:
> The recommended LLVM/CLANG version is 3.5 and/or 3.6. Based on our test result, LLVM 3.5 has best pass rate on all the test suites. Compare to LLVM 3.5, LLVM 3.6 has slightly lower pass rate(caused by one front end bug at clang 3.6) but has better performance (3% to 5% up).
As I do not have code to trigger this bug 
(http://lists.freedesktop.org/archives/beignet/2015-April/005592.html), 
I do not know whether this is still the case.

> Forcing the installation of libllvm3.5 (and therefore the removal of
> libllvm3.5v5) makes it possible to install beignet
...but may need to remove other packages, most likely libgl1-mesa-dri 
(which you want to keep if you also use your GPU for actual graphics).

> I'm not sure if beignet could be build against libllvm3.5v5
It can, and I have already requested that this be done 
(https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=794935#17), but due 
to the large number of packages needing such rebuilds for the gcc-5 
transition (the 'v5' suffix means 'built with gcc-5', and exists because 
mixtures of v5 and non-v5 C++ code may crash), this may take some time.

If you'd rather do it yourself now, make sure you have a deb-src line in 
/etc/apt/sources.list, then run:

sudo apt-get install build-essential
sudo apt-get build-dep beignet
sudo apt-get source beignet
cd beignet-1.0.3+dfsg
dpkg-buildpackage -us -uc
sudo dpkg -i beignet-opencl-icd_1.0.3-1_amd64.deb