message: [OPENMP][CUDA]Use __syncthreads when compiled by nvcc and clang >= 9.0.
  Summary:
  The problems with __syncthreads() were fixed in clang >= 9.0 and the
  original __syncthreads() can be used instead of the ptx instruction.
  Reviewers: grokos
  Subscribers: guansong, jdoerfert, openmp-commits, kkwli0, caomhin
  Tags: #openmp
diff: #endif
  #define __SYNCTHREADS_N(n) asm volatile("bar.sync %0;" : : "r"(n) : "memory");
  +// Use original __syncthreads if compiled by nvcc or clang >= 9.0.
  +#if !defined(__clang__) || __clang_major__ >= 9
  +#define __SYNCTHREADS() __syncthreads()
  +#else
  #define __SYNCTHREADS() __SYNCTHREADS_N(0)
  +#endif
  // arguments needed for L0 parallelism only.
  class omptarget_nvptx_SharedArgs {
  