Merge remote-tracking branch 'gnu/gcc-4_7-branch' into rework

[pf3gnuchains/gcc-fork.git] / libstdc++-v3 / include / tr1 / shared_ptr.h

diff --git a/libstdc++-v3/include/tr1/shared_ptr.h b/libstdc++-v3/include/tr1/shared_ptr.h
index c42084c..5a1eb03 100644 (file)
--- a/libstdc++-v3/include/tr1/shared_ptr.h
+++ b/libstdc++-v3/include/tr1/shared_ptr.h
@@ -1,6 +1,7 @@
 // <tr1/shared_ptr.h> -*- C++ -*-
 
-// Copyright (C) 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+// Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012
+// 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
@@ -236,19 +237,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     _M_add_ref_lock()
     {
       // Perform lock-free add-if-not-zero operation.
-      _Atomic_word __count;
+      _Atomic_word __count = _M_use_count;
       do
        {
-         __count = _M_use_count;
          if (__count == 0)
            __throw_bad_weak_ptr();
-         
          // Replace the current counter value with the old value + 1, as
          // long as it's not changed meanwhile. 
        }
-      while (!__sync_bool_compare_and_swap(&_M_use_count, __count,
-                                          __count + 1));
-    }
+      while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
+                                         true, __ATOMIC_ACQ_REL, 
+                                         __ATOMIC_RELAXED));
+     }
 
   template<typename _Ptr, typename _Deleter, _Lock_policy _Lp>
     class _Sp_counted_base_impl