re PR libstdc++/46830 (s.swap(s) triggers overlapped memcpy() for versa_string)

2010-12-06  Paul Pluzhnikov  <ppluzhnikov@google.com>

	PR libstdc++/46830
	* include/ext/sso_string_base.h (__sso_string_base<>::_M_swap):
	Early return when this == &__rcs.

From-SVN: r167528

libstdc++-v3/ChangeLog

+2010-12-06  Paul Pluzhnikov  <ppluzhnikov@google.com>
+
+	PR libstdc++/46830
+	* include/ext/sso_string_base.h (__sso_string_base<>::_M_swap):
+	Early return when this == &__rcs.
+
 2010-12-06  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* include/bits/shared_ptr.h (shared_ptr<>::shared_ptr(_Tp1*, _Deleter,

libstdc++-v3/include/ext/sso_string_base.h

 // Short-string-optimized versatile string base -*- C++ -*-
 
-// Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+// Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
+// 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
@@ -232,6 +233,9 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
     __sso_string_base<_CharT, _Traits, _Alloc>::
     _M_swap(__sso_string_base& __rcs)
     {
+      if (this == &__rcs)
+	return;
+
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 431. Swapping containers with unequal allocators.
       std::__alloc_swap<_CharT_alloc_type>::_S_do_it(_M_get_allocator(),