Created attachment 57466 [details]
OpenACC run-time testcase

The problem with acc_attach is that it does not like any temporary variable.

For
   call acc_attach(var%v)

We need at the end:
   acc_attach(&var.v.data)

But we will easily get:
   parm.v.data = var.v.data;
   ...
   acc_attach(&parm.v.data)
which won't work


=> This requires a builtin in the GCC front end to handle this as no Fortran semantic will handle this. Note that:

    subroutine acc_attach (ptr_addr) bind(C)
      type(*), dimension(*), target, optional :: ptr_addr
    end subroutine

comes close but gets 'acc_attach (var.v.data)' and not '&var.v.data' as argument.