From 67202da49d8f86671aca7fe4deaac3af996928e5 Mon Sep 17 00:00:00 2001
From: Paolo Carlini <pcarlini@suse.de>
Date: Thu, 18 Oct 2007 19:31:22 +0000
Subject: [PATCH] allocator.h (struct __alloc_neq): Add.

2007-10-18  Paolo Carlini  <pcarlini@suse.de>

	* include/bits/allocator.h (struct __alloc_neq): Add.
	* include/bits/stl_list.h (list<>::_M_check_equal_allocators): Use it.

From-SVN: r129457
---
 libstdc++-v3/ChangeLog                |  5 +++++
 libstdc++-v3/include/bits/allocator.h | 17 +++++++++++++++++
 libstdc++-v3/include/bits/stl_list.h  |  3 ++-
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 7014fbcdd42a..be967f9c65f2 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2007-10-18  Paolo Carlini  <pcarlini@suse.de>
+
+	* include/bits/allocator.h (struct __alloc_neq): Add.
+	* include/bits/stl_list.h (list<>::_M_check_equal_allocators): Use it.
+
 2007-10-18  Benjamin Kosnik  <bkoz@redhat.com>
 
 	* include/ext/hash_map: To...
diff --git a/libstdc++-v3/include/bits/allocator.h b/libstdc++-v3/include/bits/allocator.h
index 8699fc83a028..8a0d0eec887d 100644
--- a/libstdc++-v3/include/bits/allocator.h
+++ b/libstdc++-v3/include/bits/allocator.h
@@ -156,6 +156,23 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
       }
     };
 
+  // Optimize for stateless allocators.
+  template<typename _Alloc, bool = __is_empty(_Alloc)>
+    struct __alloc_neq
+    {
+      static bool
+      _S_do_it(const _Alloc&, const _Alloc&)
+      { return false; }
+    };
+
+  template<typename _Alloc>
+    struct __alloc_neq<_Alloc, false>
+    {
+      static bool
+      _S_do_it(const _Alloc& __one, const _Alloc& __two)
+      { return __one != __two; }
+    };
+
 _GLIBCXX_END_NAMESPACE
 
 #endif
diff --git a/libstdc++-v3/include/bits/stl_list.h b/libstdc++-v3/include/bits/stl_list.h
index bb8f930e7101..4de31d814b21 100644
--- a/libstdc++-v3/include/bits/stl_list.h
+++ b/libstdc++-v3/include/bits/stl_list.h
@@ -1272,7 +1272,8 @@ _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
       void
       _M_check_equal_allocators(list& __x)
       {
-	if (_M_get_Node_allocator() != __x._M_get_Node_allocator())
+	if (std::__alloc_neq<typename _Base::_Node_alloc_type>::
+	    _S_do_it(_M_get_Node_allocator(), __x._M_get_Node_allocator()))
 	  __throw_runtime_error(__N("list::_M_check_equal_allocators"));
       }
     };