From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 25 Mar 2014 20:40:17 +0000 (+0000)
Subject: re PR libstdc++/60658 (std::atomic<T*> is unexpectedly not lock-free)
X-Git-Tag: releases/gcc-4.7.4~176
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7c073614de5d92ef4e3456924eee5a6f56d1a65e;p=thirdparty%2Fgcc.git

re PR libstdc++/60658 (std::atomic<T*> is unexpectedly not lock-free)

	PR libstdc++/60658
	* include/bits/atomic_base.h (__atomic_base<_PTp*>::is_lock_free()):
	Use sizeof pointer type not the element type.
	* testsuite/29_atomics/atomic/60658.cc: New.

From-SVN: r208821
---

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ecb98513702d..4378c9b1928e 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2014-03-25  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/60658
+	* include/bits/atomic_base.h (__atomic_base<_PTp*>::is_lock_free()):
+	Use sizeof pointer type not the element type.
+	* testsuite/29_atomics/atomic/60658.cc: New.
+
 2013-11-05 Jonathan Wakely  <jwakely.gcc@gmail.com>
 
 	* doc/xml/manual/status_cxx2011.xml: Document aligned_union as
diff --git a/libstdc++-v3/include/bits/atomic_base.h b/libstdc++-v3/include/bits/atomic_base.h
index 191db7b5f01c..8995b1b40216 100644
--- a/libstdc++-v3/include/bits/atomic_base.h
+++ b/libstdc++-v3/include/bits/atomic_base.h
@@ -722,11 +722,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       bool
       is_lock_free() const noexcept
-      { return __atomic_is_lock_free(_M_type_size(1), &_M_p); }
+      { return __atomic_is_lock_free(sizeof(__pointer_type), &_M_p); }
 
       bool
       is_lock_free() const volatile noexcept
-      { return __atomic_is_lock_free(_M_type_size(1), &_M_p); }
+      { return __atomic_is_lock_free(sizeof(__pointer_type), &_M_p); }
 
       void
       store(__pointer_type __p,
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/60658.cc b/libstdc++-v3/testsuite/29_atomics/atomic/60658.cc
new file mode 100644
index 000000000000..5634085ad4bf
--- /dev/null
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/60658.cc
@@ -0,0 +1,43 @@
+// { dg-require-atomic-builtins "" }
+// { dg-options "-std=gnu++11" }
+
+// 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/>.
+
+#include <atomic>
+#include <testsuite_hooks.h>
+
+// libstdc++/60658
+
+struct Foo {
+  char buf[1];
+};
+
+struct Bar {
+  char buf[100];
+};
+
+int
+main ()
+{
+  bool test __attribute__((unused)) = true;
+
+  std::atomic<Foo*> a;
+  std::atomic<Bar*> b;
+
+  VERIFY (a.is_lock_free() == b.is_lock_free());
+}