diff --git a/gcc/fortran/trans-openmp.c b/gcc/fortran/trans-openmp.c
index 67e370f8b57..349df1cc346 100644
--- a/gcc/fortran/trans-openmp.c
+++ b/gcc/fortran/trans-openmp.c
@@ -64,7 +64,9 @@ gfc_omp_is_allocatable_or_ptr (const_tree decl)
 /* True if the argument is an optional argument; except that false is also
    returned for arguments with the value attribute (nonpointers) and for
    assumed-shape variables (decl is a local variable containing arg->data).
-   Note that pvoid_type_node is for 'type(c_ptr), value.  */
+   Note that for 'procedure(), optional' the value false is used as that's
+   always a pointer and no additional indirection is used.
+   Note that pvoid_type_node is for 'type(c_ptr), value' (and c_funloc).  */
 
 static bool
 gfc_omp_is_optional_argument (const_tree decl)
@@ -73,6 +75,7 @@ gfc_omp_is_optional_argument (const_tree decl)
 	  && DECL_LANG_SPECIFIC (decl)
 	  && TREE_CODE (TREE_TYPE (decl)) == POINTER_TYPE
 	  && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl)))
+	  && TREE_CODE (TREE_TYPE (TREE_TYPE (decl))) != FUNCTION_TYPE
 	  && GFC_DECL_OPTIONAL_ARGUMENT (decl));
 }
 
diff --git a/libgomp/testsuite/libgomp.fortran/dummy-procs-1.f90 b/libgomp/testsuite/libgomp.fortran/dummy-procs-1.f90
new file mode 100644
index 00000000000..fcb17ce69a9
--- /dev/null
+++ b/libgomp/testsuite/libgomp.fortran/dummy-procs-1.f90
@@ -0,0 +1,393 @@
+! { dg-do run }
+!
+! PR fortran/99171
+!
+! Check dummy procedure arguments, especially optional ones
+!
+module m
+  use iso_c_binding
+  implicit none (type, external)
+  integer :: cnt
+  integer :: cnt2
+contains
+  subroutine proc()
+    cnt = cnt + 1
+  end subroutine
+
+  subroutine proc2()
+    cnt2 = cnt2 + 1
+  end subroutine
+
+  subroutine check(my_proc)
+    procedure(proc) :: my_proc
+    cnt = 42
+    call my_proc()
+    if (cnt /= 43) stop 1
+
+    !$omp parallel
+      call my_proc()
+    !$omp end parallel
+    if (cnt <= 43) stop 2 
+  end
+
+  subroutine check_opt(my_proc)
+    procedure(proc), optional :: my_proc
+    logical :: is_present
+    is_present = present(my_proc)
+    cnt = 55
+    if (present (my_proc)) then
+      call my_proc()
+      if (cnt /= 56) stop 3
+    endif
+
+    !$omp parallel
+      if (is_present .neqv. present (my_proc)) stop 4
+      if (present (my_proc)) then
+        call my_proc()
+        if (cnt <= 56) stop 5
+      end if
+    !$omp end parallel
+    if (is_present) then
+      if (cnt <= 56) stop 6
+    else if (cnt /= 55) then
+      stop 7
+    end if
+  end
+
+  subroutine check_ptr(my_proc)
+    procedure(proc), pointer :: my_proc
+    logical :: is_assoc
+    integer :: mycnt
+    is_assoc = associated (my_proc)
+
+    cnt = 10
+    cnt2 = 20
+    if (associated (my_proc)) then
+      call my_proc()
+      if (cnt /= 11 .or. cnt2 /= 20) stop 8
+    endif
+
+    !$omp parallel
+      if (is_assoc .neqv. associated (my_proc)) stop 9
+      if (associated (my_proc)) then
+        if (.not. associated (my_proc, proc)) stop 10
+        call my_proc()
+        if (cnt <= 11 .or. cnt2 /= 20) stop 11
+      else if (cnt /= 10 .or. cnt2 /= 20) then
+        stop 12
+      end if
+    !$omp end parallel
+    if (is_assoc .neqv. associated (my_proc)) stop 13
+    if (associated (my_proc)) then
+      if (cnt <= 11 .or. cnt2 /= 20) stop 14
+    else if (is_assoc .and. (cnt /= 11 .or. cnt2 /= 20)) then
+      stop 15
+    end if
+
+    cnt = 30
+    cnt2 = 40
+    mycnt = 0
+    !$omp parallel shared(mycnt)
+      !$omp critical
+         my_proc => proc2
+         if (.not.associated (my_proc, proc2)) stop 17
+         mycnt = mycnt + 1
+         call my_proc()
+         if (cnt2 /= 40 + mycnt .or. cnt /= 30) stop 18
+      !$omp end critical
+    !$omp end parallel
+    if (.not.associated (my_proc, proc2)) stop 19
+    if (cnt2 /= 40 + mycnt .or. cnt /= 30) stop 20
+  end
+
+  subroutine check_ptr_opt(my_proc)
+    procedure(proc), pointer, optional :: my_proc
+    logical :: is_assoc, is_present
+    integer :: mycnt
+    is_assoc = .false.
+    is_present = present(my_proc)
+
+    cnt = 10
+    cnt2 = 20
+    if (present (my_proc)) then
+      is_assoc = associated (my_proc)
+      if (associated (my_proc)) then
+        call my_proc()
+        if (cnt /= 11 .or. cnt2 /= 20) stop 21
+      endif
+   end if
+
+    !$omp parallel
+      if (is_present .neqv. present (my_proc)) stop 22
+      if (present (my_proc)) then
+        if (is_assoc .neqv. associated (my_proc)) stop 23
+        if (associated (my_proc)) then
+          if (.not. associated (my_proc, proc)) stop 24
+          call my_proc()
+          if (cnt <= 11 .or. cnt2 /= 20) stop 25
+        else if (cnt /= 10 .or. cnt2 /= 20) then
+          stop 26
+        end if
+      end if
+    !$omp end parallel
+    if (present (my_proc)) then
+      if (is_assoc .neqv. associated (my_proc)) stop 27
+      if (associated (my_proc)) then
+        if (cnt <= 11 .or. cnt2 /= 20) stop 28
+      else if (is_assoc .and. (cnt /= 11 .or. cnt2 /= 20)) then
+        stop 29
+      end if
+    end if
+
+    cnt = 30
+    cnt2 = 40
+    mycnt = 0
+    !$omp parallel shared(mycnt)
+      if (is_present .neqv. present (my_proc)) stop 30
+      !$omp critical
+         if (present (my_proc)) then
+           my_proc => proc2
+           if (.not.associated (my_proc, proc2)) stop 31
+           mycnt = mycnt + 1
+           call my_proc()
+           if (cnt2 /= 40 + mycnt .or. cnt /= 30) stop 32
+         end if
+      !$omp end critical
+    !$omp end parallel
+    if (present (my_proc)) then
+      if (.not.associated (my_proc, proc2)) stop 33
+      if (cnt2 /= 40 + mycnt .or. cnt /= 30) stop 34
+    end if
+  end
+
+  ! ----------------------
+
+  subroutine cfun_check(my_cfun)
+    type(c_funptr) :: my_cfun
+    procedure(proc), pointer :: pptr
+    logical :: has_cfun
+
+    has_cfun = c_associated (my_cfun)
+    pptr => null()
+    cnt = 42
+    call c_f_procpointer (my_cfun, pptr)
+    if (has_cfun) then
+      call pptr()
+      if (cnt /= 43) stop 35
+    end if
+
+    pptr => null()
+    !$omp parallel
+      if (has_cfun .neqv. c_associated (my_cfun)) stop 36
+      !$omp critical
+        call c_f_procpointer (my_cfun, pptr)
+      !$omp end critical
+      if (has_cfun) then
+        call pptr()
+        if (cnt <= 43) stop 37
+      else
+        if (associated (pptr)) stop 38
+      end if
+    !$omp end parallel
+  end
+
+  subroutine cfun_check_opt(my_cfun)
+    type(c_funptr), optional :: my_cfun
+    procedure(proc), pointer :: pptr
+    logical :: has_cfun, is_present
+
+    has_cfun = .false.
+    is_present = present (my_cfun)
+    if (is_present) has_cfun = c_associated (my_cfun)
+
+    cnt = 1
+    pptr => null()
+    !$omp parallel
+      if (is_present .neqv. present (my_cfun)) stop 39
+      if (is_present) then
+        if (has_cfun .neqv. c_associated (my_cfun, c_funloc(proc))) stop 40
+        !$omp critical
+          call c_f_procpointer (my_cfun, pptr)
+        !$omp end critical
+        if (has_cfun) then
+          call pptr()
+          if (cnt <= 1) stop 41
+        else
+          if (associated (pptr)) stop 42
+        end if
+      end if
+    !$omp end parallel
+  end
+
+  subroutine cfun_check_ptr(my_cfun)
+    type(c_funptr), pointer :: my_cfun
+    procedure(proc), pointer :: pptr
+    logical :: has_cfun, is_assoc
+
+    has_cfun = .false.
+    is_assoc = associated (my_cfun)
+    if (is_assoc) has_cfun = c_associated (my_cfun)
+
+    cnt = 1
+    pptr => null()
+    !$omp parallel
+      if (is_assoc .neqv. associated (my_cfun)) stop 43
+      if (is_assoc) then
+        if (has_cfun .neqv. c_associated (my_cfun, c_funloc(proc))) stop 44
+        !$omp critical
+          call c_f_procpointer (my_cfun, pptr)
+        !$omp end critical
+        if (has_cfun) then
+          call pptr()
+          if (cnt <= 1) stop 45
+        else
+          if (associated (pptr)) stop 46
+        end if
+      end if
+    !$omp end parallel
+
+    cnt = 42
+    cnt2 = 1
+    pptr => null()
+    !$omp parallel
+      if (is_assoc .neqv. associated (my_cfun)) stop 47
+      if (is_assoc) then
+        !$omp critical
+          my_cfun = c_funloc (proc2)
+          call c_f_procpointer (my_cfun, pptr)
+        !$omp end critical
+        if (.not. associated (pptr, proc2)) stop 48
+        if (.not. c_associated (my_cfun, c_funloc(proc2))) stop 49
+        call pptr()
+        if (cnt /= 42 .or. cnt2 <= 1) stop 50
+      end if
+    !$omp end parallel
+    if (is_assoc) then
+      if (.not. associated (pptr, proc2)) stop 51
+      if (.not. c_associated (my_cfun, c_funloc(proc2))) stop 52
+    else
+      if (associated (pptr)) stop 53
+    end if
+  end
+
+  subroutine cfun_check_ptr_opt (my_cfun)
+    type(c_funptr), pointer, optional :: my_cfun
+    procedure(proc), pointer :: pptr
+    logical :: is_present, has_cfun, is_assoc
+
+    has_cfun = .false.
+    is_assoc = .false.
+    is_present = present (my_cfun)
+    if (is_present) then
+      is_assoc = associated (my_cfun)
+      if (is_assoc) has_cfun = c_associated (my_cfun)
+    end if
+
+    cnt = 1
+    pptr => null()
+    !$omp parallel
+      if (is_present .neqv. present (my_cfun)) stop 54
+      if (is_present) then
+        if (is_assoc .neqv. associated (my_cfun)) stop 55
+        if (is_assoc) then
+          if (has_cfun .neqv. c_associated (my_cfun, c_funloc(proc))) stop 56
+          !$omp critical
+            call c_f_procpointer (my_cfun, pptr)
+          !$omp end critical
+          if (has_cfun) then
+            call pptr()
+            if (cnt <= 1) stop 57
+          else
+            if (associated (pptr)) stop 58
+          end if
+        end if
+      end if
+    !$omp end parallel
+
+    cnt = 42
+    cnt2 = 1
+    pptr => null()
+    !$omp parallel
+      if (is_present .neqv. present (my_cfun)) stop 59
+      if (is_present) then
+        if (is_assoc .neqv. associated (my_cfun)) stop 60
+        if (is_assoc) then
+          !$omp critical
+            my_cfun = c_funloc (proc2)
+            call c_f_procpointer (my_cfun, pptr)
+          !$omp end critical
+          if (.not. associated (pptr, proc2)) stop 61
+          if (.not. c_associated (my_cfun, c_funloc(proc2))) stop 62
+          call pptr()
+          if (cnt /= 42 .or. cnt2 <= 1) stop 63
+        end if
+      end if
+    !$omp end parallel
+    if (is_present .and. is_assoc) then
+      if (.not. associated (pptr, proc2)) stop 64
+      if (.not. c_associated (my_cfun, c_funloc(proc2))) stop 65
+    else
+      if (associated (pptr)) stop 66
+    end if
+  end
+end module m
+
+
+
+program main
+  use m
+  implicit none (type, external)
+  procedure(proc), pointer :: pptr
+  type(c_funptr), target :: cfun
+  type(c_funptr), pointer :: cfun_ptr
+
+  call check(proc)
+  call check_opt()
+  call check_opt(proc)
+
+  pptr => null()
+  call check_ptr(pptr)
+  pptr => proc
+  call check_ptr(pptr)
+
+  call check_ptr_opt()
+  pptr => null()
+  call check_ptr_opt(pptr)
+  pptr => proc
+  call check_ptr_opt(pptr)
+
+  ! -------------------
+  pptr => null()
+
+  cfun = c_funloc (pptr)
+  call cfun_check(cfun)
+
+  cfun = c_funloc (proc)
+  call cfun_check(cfun)
+
+  call cfun_check_opt()
+
+  cfun = c_funloc (pptr)
+  call cfun_check_opt(cfun)
+
+  cfun = c_funloc (proc)
+  call cfun_check_opt(cfun)
+
+  ! - - - -
+  cfun_ptr => null()
+  call cfun_check_ptr (cfun_ptr)
+
+  cfun = c_funloc (proc)
+  cfun_ptr => cfun
+  call cfun_check_ptr (cfun_ptr)
+
+  ! - - - -
+  call cfun_check_ptr_opt ()
+
+  cfun_ptr => null()
+  call cfun_check_ptr_opt (cfun_ptr)
+
+  cfun = c_funloc (proc)
+  cfun_ptr => cfun
+  call cfun_check_ptr_opt (cfun_ptr)
+end program