title: Compiling C code with openmp using clang-cl
body: <p>I am trying to compile C code in Visual Studio using Clang-Cl (via llvm-vs2014 in the platform toolset) with openmp code. When I enable openmp with /openmp I get a warning in clang-cl.exe that it was not used during compilation and my test code confirms that openmp is not working.</p>
  
  <p>In addition I've tried Clang 3.7 with Microsoft CodeGen but it doesn't appear to support openmp yet (as verified by code).</p>
  
  <p>Switching to Visual Studio 2015 allows the code to work but my default code (without any openmp) runs 50% slower.</p>
  
  <p>Is there some way of getting openmp to work with the llvm-vs2014 platform toolset? Should I be using something outside of visual studio to get this to work?</p>