[Patch] libstdc++/35969

[Paolo Carlini <pcarlini at suse dot de>]

Hi,

I have this small patch, which changes the debug-mode list::merge 
consistently with the resolution of DR 250 (for splice). Strictly 
speaking, the standard, even after DR 300, seems to me still a bit vague 
about merge vs iterators, but the behavior requested in the PR seems to 
me the most consistent one... Tested x86_64, I mean to apply to mainline 
only.

Paolo.

//////////////////////
2008-04-21  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/35969
	* include/debug/list (merge): Use _M_transfer_iter, consistently
	with the splice members.
	* testsuite/23_containers/list/operations/35969.cc: New.

	* testsuite/23_containers/list/operators: Rename to
	testsuite/23_containers/list/operations.

Index: include/debug/list
===================================================================
--- include/debug/list	(revision 134500)
+++ include/debug/list	(working copy)
@@ -1,6 +1,6 @@
 // Debugging list implementation -*- C++ -*-
 
-// Copyright (C) 2003, 2004, 2005, 2006, 2007
+// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -527,14 +527,19 @@
       merge(list& __x)
 #endif
       {
-	__glibcxx_check_sorted(_Base::begin(), _Base::end());
-	__glibcxx_check_sorted(__x.begin().base(), __x.end().base());
-	for (iterator __tmp = __x.begin(); __tmp != __x.end(); )
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 300. list::merge() specification incomplete
+	if (this != &__x)
 	  {
-	    iterator __victim = __tmp++;
-	    __victim._M_attach(&__x);
+	    __glibcxx_check_sorted(_Base::begin(), _Base::end());
+	    __glibcxx_check_sorted(__x.begin().base(), __x.end().base());
+	    for (iterator __tmp = __x.begin(); __tmp != __x.end();)
+	      {
+		iterator __victim = __tmp++;
+		this->_M_transfer_iter(__victim);
+	      }
+	    _Base::merge(_GLIBCXX_MOVE(__x._M_base()));
 	  }
-	_Base::merge(_GLIBCXX_MOVE(__x._M_base()));
       }
 
       template<class _Compare>
@@ -545,15 +550,21 @@
         merge(list& __x, _Compare __comp)
 #endif
         {
-	  __glibcxx_check_sorted_pred(_Base::begin(), _Base::end(), __comp);
-	  __glibcxx_check_sorted_pred(__x.begin().base(), __x.end().base(),
-				      __comp);
-	  for (iterator __tmp = __x.begin(); __tmp != __x.end(); )
+	  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	  // 300. list::merge() specification incomplete
+	  if (this != &__x)
 	    {
-	      iterator __victim = __tmp++;
-	      __victim._M_attach(&__x);
+	      __glibcxx_check_sorted_pred(_Base::begin(), _Base::end(),
+					  __comp);
+	      __glibcxx_check_sorted_pred(__x.begin().base(), __x.end().base(),
+					  __comp);
+	      for (iterator __tmp = __x.begin(); __tmp != __x.end();)
+		{
+		  iterator __victim = __tmp++;
+		  this->_M_transfer_iter(__victim);
+		}
+	      _Base::merge(_GLIBCXX_MOVE(__x._M_base()), __comp);
 	    }
-	  _Base::merge(_GLIBCXX_MOVE(__x._M_base()), __comp);
 	}
 
       void
Index: testsuite/23_containers/list/operations/35969.cc
===================================================================
--- testsuite/23_containers/list/operations/35969.cc	(revision 0)
+++ testsuite/23_containers/list/operations/35969.cc	(revision 0)
@@ -0,0 +1,82 @@
+// 2008-04-21  Paolo Carlini  <pcarlini@suse.de>
+
+// Copyright (C) 2008 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING.  If not, write to the Free
+// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+// 23.2.2.4 list operations [lib.list.ops]
+
+// { dg-options "-D_GLIBCXX_DEBUG" }
+
+#include <list>
+#include <functional>
+
+// libstdc++/35969
+void test01()
+{
+  {
+    std::list<int> list1;
+    std::list<int> list2;
+
+    for(int i = 0; i < 10; ++i)
+      {
+	list1.push_back(i);
+	list2.push_back(10 - i);
+      }
+
+    list1.sort();
+    list2.sort();
+
+    std::list<int>::iterator node_of_interest = list2.begin();
+
+    list1.splice(list1.begin(), list2, node_of_interest);
+    list2.splice(list2.begin(), list1, node_of_interest);
+
+    list1.merge(list2);
+
+    list2.splice(list2.begin(), list1, node_of_interest);
+  }
+
+  {
+    std::list<int> list1;
+    std::list<int> list2;
+
+    for(int i = 0; i < 10; ++i)
+      {
+	list1.push_back(i);
+	list2.push_back(10 - i);
+      }
+
+    list1.sort();
+    list2.sort();
+
+    std::list<int>::iterator node_of_interest = list2.begin();
+
+    list1.splice(list1.begin(), list2, node_of_interest);
+    list2.splice(list2.begin(), list1, node_of_interest);
+
+    list1.merge(list2, std::less<int>());
+
+    list2.splice(list2.begin(), list1, node_of_interest);
+  }
+}
+
+int main()
+{
+  test01();
+  return 0;
+}