[Bug libstdc++/63456] unordered_map incorrectly frees _M_single_bucket. Patch Included

[FranÃois Dumont <frs dot dumont at gmail dot com>]

Hi

    I just committed this trivial bug fix.

    Shall I go ahead and apply it to 4.9 branch too ?

2014-10-05  FranÃois Dumont  <fdumont@gcc.gnu.org>

    PR libstdc++/63456
    * include/bits/hashtable.h (_M_uses_single_bucket(__bucket_type*)): 
Test
    the parameter.
    * testsuite/23_containers/unordered_set/63456.cc: New.

FranÃois

Index: include/bits/hashtable.h
===================================================================
--- include/bits/hashtable.h	(revision 215902)
+++ include/bits/hashtable.h	(working copy)
@@ -326,7 +326,7 @@
 
       bool
       _M_uses_single_bucket(__bucket_type* __bkts) const
-      { return __builtin_expect(_M_buckets == &_M_single_bucket, false); }
+      { return __builtin_expect(__bkts == &_M_single_bucket, false); }
 
       bool
       _M_uses_single_bucket() const
Index: testsuite/23_containers/unordered_set/63456.cc
===================================================================
--- testsuite/23_containers/unordered_set/63456.cc	(revision 0)
+++ testsuite/23_containers/unordered_set/63456.cc	(working copy)
@@ -0,0 +1,36 @@
+// Copyright (C) 2014 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 <unordered_set>
+
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  std::unordered_set<int> s1, s2;
+  s2.insert(2);
+
+  s1 = s2;
+}
+
+int main()
+{
+  test01();
+  return 0;
+}