LI81228: INTERNAL COMPILER ERROR USING OPENMP DATA MAP FUNCTION POINTERS GPU

APAR status

• Closed as program error.

Error description

• An Internal Compiler Error (ICE) is encountered when attempting
  to compile a possibly invalid implementation of an attempt to
  map over a function pointer to the GPU using a map operation.
  It is desirable to replace the ICE with a meaningful message to
  help the user identify the coding violation.
  
  
  ===== COMPILE COMMAND:
  $ xlf2003 -O0 -g -qoffload -qsmp=omp -c -qdebug=except ice.f90
  
  
  ===== TESTCASE:
  $ cat ice.f90
          program Main
  
          implicit none
          abstract interface
  
                  function func (z)
                          !$OMP declare target
                          integer :: func
                          integer, intent (in) :: z
                  end function func
  
          end interface
          integer,parameter::scaler=2
  
          !$OMP declare target(scaler)
  
          call Driver
  
          contains
  
  !###############################################################
  ########
          subroutine Driver
  
                  implicit none
                  procedure(func),pointer:: fun_pointer
                  integer::counter
                  integer::vector(100)
                  integer:: var1
                  !$OMP declare target(fun_pointer)
  
                  var1=1
  
                  !$OMP target enter data map(to: fun_pointer)
                  !$OMP target
                          fun_pointer=>Fun_of_x
                  !$OMP end target
  
                  write(*,*)'After pointer assignment'
                  !$OMP target teams distribute parallel do
                  do counter=1,100
  
  
  vector(counter)=Eval_Fun(fun_pointer,counter,var1)
  !                       vector(counter)=Eval_Fun(counter,var1)
                  enddo
                  !$OMP end target teams distribute parallel do
  
                  do counter=1,100
  
  write(*,*)'vector(counter)=',vector(counter)
                  enddo
                  !$OMP target exit data map(delete:fun_pointer)
  
          end subroutine Driver
  
  !###############################################################
  ########
  !       subroutine Set_Pointer(fun_pointer)
  !
  !               implicit none
  !               !$OMP declare target
  !               procedure(func),pointer,intent(inout)::
  fun_pointer
  !
  !               fun_pointer=>Fun_of_x
  !
  !       end subroutine Set_Pointer
  
  !###############################################################
  ########
          function Fun_of_x(x)
  
                  implicit none
                  !$OMP declare target
                  integer, intent(in)::x
                  integer::Fun_of_x
  
                  Fun_of_x=scaler*x
  
          end function Fun_of_x
  
  !###############################################################
  ########
  
          function Eval_Fun(fun_pointer,x,var1)
  
                  implicit none
                  procedure(func),pointer,intent(in)::fun_pointer
                  integer,intent(in)::x,var1
                  integer::Eval_Fun
  
                  !$OMP target data map(tofrom: x,var1)
  
                  Eval_Fun=fun_pointer(x)-var1
  
                  !$OMP end target data
  
          end function Eval_Fun
  !###############################################################
  #########
  ! !     function Eval_Fun(x,var1)
  ! !
  ! !             implicit none
  ! !             !$OMP declare target
  ! !             integer,intent(in)::x,var1
  ! !             integer::Eval_Fun
  ! !
  ! !             !$OMP target data map(tofrom: x,var1,Eval_Fun)
  ! !
  ! !             Eval_Fun=Fun_of_x(x)-var1
  ! !
  ! !             !$OMP end target data
  ! !
  ! !     end function Eval_Fun
  
  !###############################################################
  ########
  
  
  $
  
  
  ===== ACTUAL OUTPUT:
  Compiler produces an internal compiler error
  
  
  ===== EXPECTED OUTPUT:
  Should compile cleanly
  

Local fix

• N/A
  

Problem summary

• USERS AFFECTED:
  Users using OpenMP data map GPU function pointers might be
  affected by this issue.
  
  PROBLEM DESCRIPTION:
  The semantics of mapping function pointer is not defined in the
  OpenMP Spec. However, this APAR is fix the internal compiler
  error.
  

Problem conclusion

• The internal compiler error has been resolved.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  IJ24693

Fix information

• Fixed component name

  XL FORTRAN LINU

• Fixed component ID

  5725C7510

Applicable component levels