On Sun, Aug 28, 2016 at 2:01 PM, K. Macy <kmacy at freebsd.org>
wrote:>>>
>>
>> With 11, one can even simply install devel/openmp which will only
install the libopenmp bits from llvm, and after that, base cc can do openmp.
>
> This isn't really useful unless the clang in base knows where to find
> libomp. Considering that even the devel/llvm ports aren't configured
> properly for that I don't see -fopenmp working. Without patching
> makefiles or configure. So although this is better than having to
> installing a complete copy of the compiler for the sake of a single
> library it's still forcing FreeBSD users to jump through extra hoops
> that they don't have to with gcc or on other platforms.
I just tried this on Ubuntu and it looks like even there clang doesn't
invoke ld correctly to make -fopenmp work. Both icc and gcc do this
automatically. Thus I wonder if anyone is actually using openmp in
earnest with clang.
mmacy at pandemonium:~$ clang++ -fopenmp omp.cpp
/usr/bin/ld: cannot find -liomp5
clang-3.5: error: linker command failed with exit code 1 (use -v to
see invocation)
mmacy at pandemonium:~$ clang++-3.8 -fopenmp omp.cpp
/usr/bin/ld: cannot find -lomp
clang: error: linker command failed with exit code 1 (use -v to see invocation)
mmacy at pandemonium:~$ g++ -fopenmp omp.cpp
mmacy at pandemonium:~$ g++-4.9 -fopenmp omp.cpp
mmacy at pandemonium:~$
-M