Nvfortran with OpenMP: Spurious error with duplicated use

Accelerated Computing HPC Compilers nvc, nvc++ and nvfortran
1

With the following reproducer,

module coefficient_module
  implicit none
  real, allocatable :: coeff(:)

contains
  subroutine initialize_coeff(N)
      integer, intent(in) :: N
      allocate(coeff(N))
      coeff = 2.0  
  end subroutine initialize_coeff
end module coefficient_module

program openmp_example
  use coefficient_module, only: coeff, initialize_coeff
! comment out the next line to make the error disappear
  use coefficient_module, only: coeff
  implicit none
  integer :: N, i
  real, allocatable :: input(:), result(:)

  N = 100
  allocate(input(N), result(N))

  input = 1.0
  call initialize_coeff(N)

  !$omp target teams distribute parallel do defaultmap(none) default(none) & 
  !$omp map(to: input) map(tofrom: result) & 
  !$omp shared(coeff, input, result, N)
  do i = 1, N
      result(i) = input(i) * coeff(i) 
  end do

  print *, "First 5 results: ", result(1:5)
end program openmp_example

nvfortran -gpu=cuda11.8 -mp=gpu -O2 test_omp.f90

generates the following error:

NVFORTRAN-S-0155-coeff must appear in a SHARED or PRIVATE clause (test_omp.f90: 30)

This error message is somewhere between confusing and wrong. It does not appear if coeff is instead marked as private, or if the duplicate use is removed. If the compiler doesn’t like that, it should complain about that instead.

The example works fine as-is in Cray Fortran.

I’m using nvfortran 24.7-0 64-bit target on x86-64 Linux, using the nvhpc/24.7 toolkit.

2

Hi Jonathan,

Same issue as your other post which I reported as TPR #36813.

Work around is to not use the “only: coeff” and just “use coefficient_module”.

-Mat

3

Maybe you can still add it to the TPR, because here, a duplicate use statement is necessary, it works fine with a single use.

Thanks for your help!