re PR sanitizer/86406 ([UBSAN] -fcompare-debug failure with -fsanitize=undefined)

	PR sanitizer/86406
	* cp-gimplify.c (cp_maybe_instrument_return): Skip trailing
	DEBUG_BEGIN_STMTs.

	* g++.dg/ubsan/pr86406.C: New test.

From-SVN: r262536

gcc/cp/ChangeLog

 2018-07-10  Jakub Jelinek  <jakub@redhat.com>
 
+	PR sanitizer/86406
+	* cp-gimplify.c (cp_maybe_instrument_return): Skip trailing
+	DEBUG_BEGIN_STMTs.
+
 	PR c++/86443
 	* semantics.c (handle_omp_for_class_iterator): Remove lastp argument,
 	instead of setting *lastp turn orig_declv elt into a TREE_LIST.

gcc/cp/cp-gimplify.c

@@ -1621,6 +1621,13 @@ cp_maybe_instrument_return (tree fndecl)
 	case STATEMENT_LIST:
 	  {
 	    tree_stmt_iterator i = tsi_last (t);
+	    while (!tsi_end_p (i))
+	      {
+		tree p = tsi_stmt (i);
+		if (TREE_CODE (p) != DEBUG_BEGIN_STMT)
+		  break;
+		tsi_prev (&i);
+	      }
 	    if (!tsi_end_p (i))
 	      {
 		t = tsi_stmt (i);

gcc/testsuite/ChangeLog

 2018-07-10  Jakub Jelinek  <jakub@redhat.com>
 
+	PR sanitizer/86406
+	* g++.dg/ubsan/pr86406.C: New test.
+
 	PR fortran/86421
 	* gfortran.dg/vect/pr86421.f90: New test.
 

gcc/testsuite/g++.dg/ubsan/pr86406.C

+// PR sanitizer/86406
+// { dg-do compile }
+// { dg-options "-fcompare-debug -fsanitize=undefined -g -O1" }
+
+typedef enum { } cmd_status;
+class ECell;
+class ECell_const_ptr { };
+class ECell_ptr
+{
+  ECell *mp_element;
+  ECell *getPointer () const { return mp_element; }
+public:
+  operator  ECell_const_ptr () const { return ECell_const_ptr(); }
+};
+
+extern ECell_ptr NULL_CELL;
+class VwUI_2DCellLayerView;
+class view_cell_layoutImpl
+{
+  cmd_status handleChangeFlags (VwUI_2DCellLayerView *
+                                      p_ui_celllayerview,
+                                      ECell_const_ptr p_peekCell);
+  cmd_status openCellLayoutView ();
+};
+
+cmd_status
+view_cell_layoutImpl::openCellLayoutView ()
+{
+  ECell_const_ptr pcell = NULL_CELL;
+  VwUI_2DCellLayerView *p_user_interface;
+  return handleChangeFlags (p_user_interface, pcell);
+  ;
+}