GNU FORTRAN OpenACC Accessing an allocatable member of a derived type on device

Question

I need to access an allocatable member of a derived type on device. I found a good solution here. However, it uses a PGI compiler. I could not figure out how to install that compiler with all the licensing hurdles. So I am looking for a solution with GNU Fortran (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0.

The sample program below runs fine without the -fopenacc flag. However, once the flag is enabled, I get the below error:

libgomp: cuStreamSynchronize error: an illegal memory access was encountered

Here is how I run the code (saved in a file named: stackOverflow.f95) without OpenACC:

$ gfortran -c stackOverflow.f95 
$ gfortran stackOverflow.o -o stackOverflow
$ ./stackOverflow 

Here is how I run the code with OpenACC:

$ gfortran -fopenacc -c stackOverflow.f95 
$ gfortran -fopenacc stackOverflow.o -o stackOverflow
$ ./stackOverflow 

Please see if there is a solution? Here is the sample code:

module modTest2

use openacc
implicit none
 
type :: Container
  sequence
  integer :: n
  integer, allocatable :: arr(:)
end type Container

interface Container
  procedure :: new_Container
end interface Container
   
contains

  type(Container) function new_Container(n)
    integer, intent(in) :: n
    
    allocate(new_Container%arr(n))
  end function new_Container
end module modTest2




program test2

  use modTest2
  implicit none
  

  integer :: n, i
  type(Container) :: c


  print *, "Enter array size: "
  read *, n  
  print *, "Allocating..."
  c = Container(n)
  print *, "Allocation complete!"

  
  print *, "Initializing..."
  !$acc data copyin(c)
  !$acc parallel loop present(c)
  do i = 1, n
    c%arr(i) = i*20
  end do
  !$acc end data
  print *, "Initialization complete..."

  do i = 1, n
    print *, i, c%arr(i)
  end do

end program test2

Answer 1

Instead of Syntax error in OpenMP variable list, current GCC diagnoses mixed component and non-component accesses for !$acc data copyin(c) copyout(c%arr) as well as !$acc enter data copyin(c) create(c%arr) and !$acc exit data copyout(c%arr) delete(c). It's not clear if that is meant to be supported by OpenACC -- I'm aware there are unresolved issues with respect to clause processing ordering etc., that the OpenACC Technical Committee needs to look into. (I'm a member of that committee, too.) So what PGI/NVHPC are implementing may not actually be standard OpenACC.

That said, I'm able to make the program work with GCC/OpenACC as follows: Split the !$acc data copyin(c) copyout(c%arr) into two nested data regions:

!$acc data copyin(c) 
!$acc data copyout(c%arr)
[...]
!$acc end data
!$acc end data

Or alternatively, instead of !$acc enter data copyin(c) create(c%arr) and !$acc exit data copyout(c%arr) delete(c) split these up into:

!$acc enter data copyin(c)
!$acc enter data create(c%arr)
[...]
!$acc exit data copyout(c%arr)
!$acc exit data delete(c)

With both these variants, I'm then getting the same results as what Mat posted above.