Generic-mode kernel is executed with a customized state machine that requires a fallback. [OMP132]

This analysis remark indicates that a state machine rewrite occurred, but could not be done fully because of unknown calls to functions that may contain parallel regions. The state machine handles scheduling work between parallel worker threads on the device when operating in generic-mode. If there are unknown parallel regions it prevents the optimization from fully rewriting the state machine.

Examples

This will occur for any generic-mode kernel that may contain unknown parallel regions. This is typically coupled with the OMP133 remark.

extern void setup();

void foo() {
#pragma omp target
{
  setup();
  #pragma omp parallel
  {
    work();
  }
}
}

$ clang++ -fopenmp -fopenmp-targets=nvptx64 -O2 -Rpass-analysis=openmp-opt omp132.cpp
omp133.cpp:4:1: remark: Generic-mode kernel is executed with a customized state machine
that requires a fallback. [OMP132]
#pragma omp target
^

Diagnostic Scope

OpenMP target offloading analysis remark.