clang 13.0.0 without openMP support warning

[denisbertini]

Trying to compile picongpu on our new centos7 singularity container i got the following warning from the find_package in PMacc:

  CMake Warning at /lustre/rz/dbertini/gpu/picongpu/include/pmacc/PMaccConfig.cmake:363 (message):
  OpenMP host side acceleration is disabled: CUDA/HIP compilation with clang
  is not supporting OpenMP.
Call Stack (most recent call first):
  CMakeLists.txt:150 (find_package)

How to add the openMP support in clang ?

[sbastrakov]

@psychocoderHPC do you have an idea?

[PrometheusPi]

Ping @psychocoderHPC

[denisbertini]

this issue is related to llvm and kinda tricky. According to rocm/aomp:

AOMP is a scripted build of LLVM and supporting software. [...]
Some sources to support OpenMP target offload on AMD GPUs have not yet been merged into the upstream LLVM trunk. [...]