[Bug fortran/110548] New: Segfault with optional argument and OpenMP tasks

[Bug fortran/110548] New: Segfault with optional argument and OpenMP tasks

[abensonca at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110548

            Bug ID: 110548
           Summary: Segfault with optional argument and OpenMP tasks
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: abensonca at gcc dot gnu.org
  Target Milestone: ---

The following shows a segfault at run time resulting from use of an optional
argument in a function with OpenMP tasks:

module taskerMod

   type :: helper
   end type helper

   type :: tasker
      integer :: depth=-1
    contains
      final     ::            taskerDestruct
      procedure :: compute => taskerCompute
   end type tasker

 contains

   subroutine taskerDestruct(self)
     !$ use :: OMP_Lib                                                          
     implicit none
     type(tasker), intent(inout) :: self

     write (0,*) "DESTRUCT FROM DEPTH ",self%depth !$ ," :
",omp_get_thread_num()                                                          
     return
   end subroutine taskerDestruct

   recursive subroutine taskerCompute(self,helper_)
     !$ use :: OMP_Lib                                                          
     implicit none
     class(tasker), intent(inout)           :: self
     class(helper), intent(inout), optional :: helper_

     !$omp atomic                                                               
     self%depth=self%depth+1
     write (0,*) "DEPTH ",self%depth !$ ," : ",omp_get_thread_num()             
     if (self%depth < 3) then
        !$omp task untied                                                       
        call self%compute(helper_)
        !$omp end task                                                          
     end if
     return
   end subroutine taskerCompute

 end module taskerMod

 program testTasks
   use :: taskerMod
   implicit none
   type(tasker) :: tasker_
   type(helper) :: helper_

   tasker_=tasker(0)
   !$omp parallel                                                               
   !$omp single                                                                 
   !$omp taskgroup                                                              
   !$omp task untied                                                            
   call tasker_%compute()
   !$omp end task                                                               
   !$omp end taskgroup                                                          
   !$omp end single                                                             
   !$omp end parallel                                                           
 end program testTasks

$ gfortran test1.F90  -fopenmp
$ ./a.out
 DESTRUCT FROM DEPTH           -1
 DEPTH            1

Program received signal SIGSEGV: Segmentation fault - invalid memory
reference.

Backtrace for this error:
#0  0x2ac99289a1ef in ???
#1  0x401840 in ???
#2  0x2ac9925a9606 in GOMP_task
        at ../../../gcc-git/libgomp/task.c:644
#3  0x401588 in ???
#4  0x40197b in ???
#5  0x2ac9925a77a4 in gomp_barrier_handle_tasks
        at ../../../gcc-git/libgomp/task.c:1650
#6  0x2ac9925b058f in gomp_team_barrier_wait_end
        at ../../../gcc-git/libgomp/config/linux/bar.c:116
#7  0x2ac9925aeffc in gomp_team_end
        at ../../../gcc-git/libgomp/team.c:956
#8  0x401692 in ???
#9  0x4016cd in ???
#10  0x2ac992886d0c in ???
#11  0x401128 in ???
Segmentation fault

This appears to be due to the optional argument, helper_. If it is present in
the initial call, i.e.:
   call tasker_%compute(helper_)

then this runs without a segfault.

This happens with versions 12.0.0, 13.0.1, and the current HEAD of the GCC git
repo.