re PR libstdc++/65085 (Move-assigned empty string corrupt with -D_GLIBCXX_USE_CXX11_ABI=1)

	PR libstdc++/65085
	* include/bits/basic_string.h (basic_string(basic_string&&)): Ensure
	empty string gets null-terminated.
	* testsuite/21_strings/basic_string/cons/char/65085.cc: New.

From-SVN: r220758

libstdc++-v3/ChangeLog

+2015-02-17  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/65085
+	* include/bits/basic_string.h (basic_string(basic_string&&)): Ensure
+	empty string gets null-terminated.
+	* testsuite/21_strings/basic_string/cons/char/65085.cc: New.
+
 2015-02-13  Matthew Wahab  <matthew.wahab@arm.com>
 
 	* testsuite/28_regex/traits/char/isctype.cc (test01): Fix

libstdc++-v3/include/bits/basic_string.h

@@ -476,9 +476,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       {
 	if (__str._M_is_local())
 	  {
-	    if (__str.length())
-	      traits_type::copy(_M_local_buf, __str._M_local_buf,
-				_S_local_capacity + 1);
+	    traits_type::copy(_M_local_buf, __str._M_local_buf,
+			      _S_local_capacity + 1);
 	  }
 	else
 	  {

libstdc++-v3/testsuite/21_strings/basic_string/cons/char/65085.cc

+// Copyright (C) 2015 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 3, 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 COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++11" }
+
+#include <string>
+#include <new>
+#include <cstring>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  std::string s;
+  char buf[sizeof(std::string)];
+  std::memset(buf, 0xff, sizeof(buf));
+  std::string* p = ::new(buf) std::string(std::move(s));
+  VERIFY((*p)[0] == '\0');
+  p->~basic_string();
+}
+
+int
+main()
+{
+  test01();
+}