[gcc r14-6066] Fortran: copy-out for possibly missing OPTIONAL CLASS arguments [PR112772]

[Harald Anlauf]

https://gcc.gnu.org/g:7317275497e10c4a0fb3fbaa6ca87f3463ac124d

commit r14-6066-g7317275497e10c4a0fb3fbaa6ca87f3463ac124d
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Thu Nov 30 21:53:21 2023 +0100

    Fortran: copy-out for possibly missing OPTIONAL CLASS arguments [PR112772]
    
    gcc/fortran/ChangeLog:
    
            PR fortran/112772
            * trans-expr.cc (gfc_conv_class_to_class): Make copy-out conditional
            on the presence of an OPTIONAL CLASS argument passed to an OPTIONAL
            CLASS dummy.
    
    gcc/testsuite/ChangeLog:
    
            PR fortran/112772
            * gfortran.dg/missing_optional_dummy_7.f90: New test.

Diff:
---
 gcc/fortran/trans-expr.cc                          |  9 +++
 .../gfortran.dg/missing_optional_dummy_7.f90       | 64 ++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index bfe9996ced6..6a47af39c57 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -1365,6 +1365,15 @@ gfc_conv_class_to_class (gfc_se *parmse, gfc_expr *e, gfc_typespec class_ts,
       tmp = build3_loc (input_location, COND_EXPR, void_type_node,
 			cond, tmp, tmp2);
       gfc_add_expr_to_block (&parmse->pre, tmp);
+
+      if (!elemental && full_array && copyback)
+	{
+	  tmp2 = build_empty_stmt (input_location);
+	  tmp = gfc_finish_block (&parmse->post);
+	  tmp = build3_loc (input_location, COND_EXPR, void_type_node,
+			    cond, tmp, tmp2);
+	  gfc_add_expr_to_block (&parmse->post, tmp);
+	}
     }
   else
     gfc_add_block_to_block (&parmse->pre, &block);
diff --git a/gcc/testsuite/gfortran.dg/missing_optional_dummy_7.f90 b/gcc/testsuite/gfortran.dg/missing_optional_dummy_7.f90
new file mode 100644
index 00000000000..ad9ecd8f2b6
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/missing_optional_dummy_7.f90
@@ -0,0 +1,64 @@
+! { dg-do run }
+! PR fortran/112772 - test absent OPTIONAL, ALLOCATABLE/POINTER class dummies
+
+program main
+  implicit none
+  type t
+  end type t
+  call test_c_a ()
+  call test_u_a ()
+  call test_c_p ()
+  call test_u_p ()
+contains
+  ! class, allocatable
+  subroutine test_c_a (msg1)
+    class(t), optional, allocatable :: msg1(:)
+    if (present (msg1)) stop 1
+    call assert_c_a ()
+    call assert_c_a (msg1)
+  end
+
+  subroutine assert_c_a (msg2)
+    class(t), optional, allocatable :: msg2(:)
+    if (present (msg2)) stop 2
+  end
+
+  ! unlimited polymorphic, allocatable
+  subroutine test_u_a (msg1)
+    class(*), optional, allocatable :: msg1(:)
+    if (present (msg1)) stop 3
+    call assert_u_a ()
+    call assert_u_a (msg1)
+  end
+
+  subroutine assert_u_a (msg2)
+    class(*), optional, allocatable :: msg2(:)
+    if (present (msg2)) stop 4
+  end
+
+  ! class, pointer
+  subroutine test_c_p (msg1)
+    class(t), optional, pointer :: msg1(:)
+    if (present (msg1)) stop 5
+    call assert_c_p ()
+    call assert_c_p (msg1)
+  end
+
+  subroutine assert_c_p (msg2)
+    class(t), optional, pointer :: msg2(:)
+    if (present (msg2)) stop 6
+  end
+
+  ! unlimited polymorphic, pointer
+  subroutine test_u_p (msg1)
+    class(*), optional, pointer :: msg1(:)
+    if (present (msg1)) stop 7
+    call assert_u_p ()
+    call assert_u_p (msg1)
+  end
+
+  subroutine assert_u_p (msg2)
+    class(*), optional, pointer :: msg2(:)
+    if (present (msg2)) stop 8
+  end
+end