diff --git a/openmp/docs/SupportAndFAQ.rst b/openmp/docs/SupportAndFAQ.rst index 6b8f0d2f72b0d..37c5bcecfcccd 100644 --- a/openmp/docs/SupportAndFAQ.rst +++ b/openmp/docs/SupportAndFAQ.rst @@ -52,22 +52,11 @@ All patches go through the regular `LLVM review process Q: How to build an OpenMP offload capable compiler? ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -To build an *effective* OpenMP offload capable compiler we recommend a two -stage build. The first stage Clang does not require to be offload capable but -all backends that are targeted by OpenMP need to be enabled. By default, Clang -will be build with all backends enabled. This initial (stage 1) Clang is used -to create a second Clang compiler that is offload capable as well as the -:ref:`device runtime libraries ` that will be linked into the -offloaded code to provide OpenMP runtime support on the device. - -Generic information about building LLVM is available `here -`__. The CMake options for the -second stage Clang should include: - -- `LIBOMPTARGET_NVPTX_CUDA_COMPILER=$STAGE1/bin/clang` to use the stage one - compiler for the device runtime compilation. -- `LIBOMPTARGET_NVPTX_ENABLE_BCLIB=ON` to enable efficient device runtimes in - bitcode format. +To build an *effective* OpenMP offload capable compiler, only one extra CMake +option, `LLVM_ENABLE_RUNTIMES="OPENMP"`, is needed when building LLVM (Generic +information about building LLVM is available `here `__.). +Make sure all backends that are targeted by OpenMP to be enabled. By default, +Clang will be build with all backends enabled. If your build machine is not the target machine or automatic detection of the available GPUs failed, you should also set: