libgomp/testsuite/libgomp.fortran/examples-4/task_dep-4.f90

! { dg-do run }

program example
   integer :: x
   x = 1
   !$omp parallel
   !$omp single
      !$omp task shared(x) depend(out: x)
         x = 2
      !$omp end task
      !$omp task shared(x) depend(in: x)
         if (x .ne. 2) stop 1
      !$omp end task
      !$omp task shared(x) depend(in: x)
         if (x .ne. 2) stop 2
      !$omp end task
   !$omp end single
   !$omp end parallel
end program