3 ms·

> It's state of the art Does the officially released version support OpenMP by now? A few weeks ago at least I still failed at installing that properly from of

> It's state of the art Does the officially released version support OpenMP by now? A few weeks ago at least I still failed at installing that properly from official sources. There seems to be an OpenMP-in-clang project going on, but it was far from obvious what had to go where. So about this “state of the art”…

TillE 11y ago
It took them forever, but yes, they support OpenMP 3.1 as of clang 3.7. MSVC still only supports OpenMP 2.0.
- bluecalm 11y ago
  Thanks for the information. I must be doing something wrong then as I've recently downloaded 3.7.0 for Windows and while it compiles with -fopenmp it doesn't work correctly (only one thread is launched). I guess some investigation is needed, any ideas why that could be? The code works correctly when compiled with GCC so that can't be an issue. I am launching OpenMP threads from a Windows thread (not the main one) so maybe that's the issue (MinGW packages had problems with it forever and it's pretty tough to find one without this bug present).
- claudius 11y ago
  This: ./clang++ --version clang version 3.8.0 (trunk 246030) Target: x86_64-unknown-linux-gnu Thread model: posix does not support OpenMP to my knowledge.
  - gopowerranger 11y ago
    You have to enable it using -fopenmp http://blog.llvm.org/2015/05/openmp-support_22.html http://blog.llvm.org/2015/05/openmp-support_22.html http://clang-omp.github.io/ http://clang-omp.github.io/
    - claudius 11y ago
      Hmm, interesting. It works in a simple test case, but fails to compile my codebase and throws an error ./inc/bla.h:163:9: error: unexpected '#pragma omp ...' in program [-Werror,-Wsource-uses-openmp] #pragma omp parallel for num_threads(Threading::num), schedule(dynamic, 1) Unfortunately I wasn’t able to build a minimally failing example so far, I will have to investigate this further. Thanks for the heads-up in any case! Edit: Turns out everything fails if -Weverything is supplied. I didn’t offer a runtime library (nor did the compiler define the _OPENMP macro even when having -fopenmp on the command line, otherwise it would have complained about a missing <omp.h>…). If -Weverything is not there, the thing compiles but only runs with one thread.

TillE 11y ago

It took them forever, but yes, they support OpenMP 3.1 as of clang 3.7. MSVC still only supports OpenMP 2.0.

bluecalm 11y ago
Thanks for the information. I must be doing something wrong then as I've recently downloaded 3.7.0 for Windows and while it compiles with -fopenmp it doesn't work correctly (only one thread is launched). I guess some investigation is needed, any ideas why that could be? The code works correctly when compiled with GCC so that can't be an issue. I am launching OpenMP threads from a Windows thread (not the main one) so maybe that's the issue (MinGW packages had problems with it forever and it's pretty tough to find one without this bug present).
claudius 11y ago
This: ./clang++ --version clang version 3.8.0 (trunk 246030) Target: x86_64-unknown-linux-gnu Thread model: posix does not support OpenMP to my knowledge.
- gopowerranger 11y ago
  You have to enable it using -fopenmp http://blog.llvm.org/2015/05/openmp-support_22.html http://blog.llvm.org/2015/05/openmp-support_22.html http://clang-omp.github.io/ http://clang-omp.github.io/
  - claudius 11y ago
    Hmm, interesting. It works in a simple test case, but fails to compile my codebase and throws an error ./inc/bla.h:163:9: error: unexpected '#pragma omp ...' in program [-Werror,-Wsource-uses-openmp] #pragma omp parallel for num_threads(Threading::num), schedule(dynamic, 1) Unfortunately I wasn’t able to build a minimally failing example so far, I will have to investigate this further. Thanks for the heads-up in any case! Edit: Turns out everything fails if -Weverything is supplied. I didn’t offer a runtime library (nor did the compiler define the _OPENMP macro even when having -fopenmp on the command line, otherwise it would have complained about a missing <omp.h>…). If -Weverything is not there, the thing compiles but only runs with one thread.