functional_hash.h (hash<string>, [...]): Move, per DR 1182 to...

2010-02-22  Paolo Carlini  <paolo.carlini@oracle.com>

	* include/bits/functional_hash.h (hash<string>, hash<wstring>,
	hash<u16string>, hash<u32string>, hash<error_code>): Move, per
	DR 1182 to...
	* include/bits/basic_string.h: ... here.
	* include/std/system_error: ... and here, respectively.
	* src/hash-aux.cc (hash<long double>::operator()(long double)):
	Move definition...
	* src/hash_c++0x.cc: ... here, new file.
	* src/hash_tr1.cc: ... and here, tweak includes.
	* src/compatibility-c++0x.cc (hash, _Fnv_hash): Remove.
	* src/Makefile.am: Adjust.
	* src/Makefile.in: Regenerate.
	* include/std/functional: Include <bits/functexcept.h>.
	* include/std/unordered_set: Remove redundant include.
	* include/std/unordered_map: Likewise.
	* include/tr1/functional_hash.h: Remove spurious trailing semicolon.
	* testsuite/20_util/weak_ptr/comparison/cmp_neg.cc: Remove
	dg-excess.

From-SVN: r156971

libstdc++-v3/ChangeLog

+2010-02-22  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* include/bits/functional_hash.h (hash<string>, hash<wstring>,
+	hash<u16string>, hash<u32string>, hash<error_code>): Move, per
+	DR 1182 to...
+	* include/bits/basic_string.h: ... here.
+	* include/std/system_error: ... and here, respectively.
+	* src/hash-aux.cc (hash<long double>::operator()(long double)):
+	Move definition...
+	* src/hash_c++0x.cc: ... here, new file.
+	* src/hash_tr1.cc: ... and here, tweak includes.
+	* src/compatibility-c++0x.cc (hash, _Fnv_hash): Remove.
+	* src/Makefile.am: Adjust.
+	* src/Makefile.in: Regenerate.
+	* include/std/functional: Include <bits/functexcept.h>.
+	* include/std/unordered_set: Remove redundant include.
+	* include/std/unordered_map: Likewise.
+	* include/tr1/functional_hash.h: Remove spurious trailing semicolon.
+	* testsuite/20_util/weak_ptr/comparison/cmp_neg.cc: Remove
+	dg-excess.
+
 2010-02-21  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* include/std/complex (proj): Change return type per DR 1137.

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

@@ -2869,6 +2869,73 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
 
 _GLIBCXX_END_NAMESPACE
 
+#endif /* __GXX_EXPERIMENTAL_CXX0X__ && _GLIBCXX_USE_C99 ... */
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+
+#include <bits/functional_hash.h>
+
+_GLIBCXX_BEGIN_NAMESPACE(std)
+
+  // DR 1182.
+
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
+  /// std::hash specialization for string.
+  template<>
+    struct hash<string>
+    : public std::unary_function<string, size_t>
+    {
+      size_t
+      operator()(const string& __s) const
+      { return _Fnv_hash<>::hash(__s.data(), __s.length()); }
+    };
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  /// std::hash specialization for wstring.
+  template<>
+    struct hash<wstring>
+    : public std::unary_function<wstring, size_t>
+    {
+      size_t
+      operator()(const wstring& __s) const
+      {
+	const char* __p = reinterpret_cast<const char*>(__s.data());
+	return _Fnv_hash<>::hash(__p, __s.length() * sizeof(wchar_t));
+      }
+    };
 #endif
+#endif /* _GLIBCXX_COMPATIBILITY_CXX0X */
+
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+  /// std::hash specialization for u16string.
+  template<>
+    struct hash<u16string>
+    : public std::unary_function<u16string, size_t>
+    {
+      size_t
+      operator()(const u16string& __s) const
+      {
+	const char* __p = reinterpret_cast<const char*>(__s.data());
+	return _Fnv_hash<>::hash(__p, __s.length() * sizeof(char16_t));
+      }
+    };
+
+  /// std::hash specialization for u32string.
+  template<>
+    struct hash<u32string>
+    : public std::unary_function<u32string, size_t>
+    {
+      size_t
+      operator()(const u32string& __s) const
+      {
+	const char* __p = reinterpret_cast<const char*>(__s.data());
+	return _Fnv_hash<>::hash(__p, __s.length() * sizeof(char32_t));
+      }
+    };
+#endif
+
+_GLIBCXX_END_NAMESPACE
+
+#endif /* __GXX_EXPERIMENTAL_CXX0X__ */
 
 #endif /* _BASIC_STRING_H */

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

@@ -32,8 +32,8 @@
 
 #pragma GCC system_header
 
-#include <string>
-#include <system_error>
+#include <cstddef>
+#include <bits/stl_function.h>
 
 namespace std
 {
@@ -44,10 +44,14 @@ namespace std
    *
    *  @{
    */
- 
+
   /// Primary class template hash.
   template<typename _Tp>
-    struct hash;
+    struct hash : public std::unary_function<_Tp, size_t>
+    {
+      size_t
+      operator()(_Tp __val) const;
+    };
 
   /// Partial specializations for pointer types.
   template<typename _Tp>
@@ -59,14 +63,11 @@ namespace std
     };
 
   // Explicit specializations for integer types.
-#define _Cxx_hashtable_define_trivial_hash(_Tp) 	       \
-  template<>						       \
-    struct hash<_Tp> : public std::unary_function<_Tp, size_t> \
-    {                                                          \
-      size_t                                                   \
-      operator()(_Tp __val) const		               \
-      { return static_cast<size_t>(__val); }		       \
-    };
+#define _Cxx_hashtable_define_trivial_hash(_Tp) 	\
+  template<>						\
+    inline size_t					\
+    hash<_Tp>::operator()(_Tp __val) const		\
+    { return static_cast<size_t>(__val); }
 
   /// Explicit specialization for bool.
   _Cxx_hashtable_define_trivial_hash(bool);
@@ -83,13 +84,11 @@ namespace std
   /// Explicit specialization for wchar_t.
   _Cxx_hashtable_define_trivial_hash(wchar_t);
 
-#ifdef _GLIBCXX_USE_C99_STDINT_TR1
   /// Explicit specialization for char16_t.
   _Cxx_hashtable_define_trivial_hash(char16_t);
 
   /// Explicit specialization for char32_t.
   _Cxx_hashtable_define_trivial_hash(char32_t);
-#endif
 
   /// Explicit specialization for short.
   _Cxx_hashtable_define_trivial_hash(short);
@@ -118,10 +117,13 @@ namespace std
 #undef _Cxx_hashtable_define_trivial_hash
 
   // Fowler / Noll / Vo (FNV) Hash (type FNV-1a)
-  // (Used by the next specializations of std::tr1::hash.)
+  // (Used by the next specializations of std::hash.)
 
-  // Dummy generic implementation (for sizeof(size_t) != 4, 8).
   template<size_t = sizeof(size_t)>
+    struct _Fnv_hash;
+
+  // Dummy generic implementation (for sizeof(size_t) != 4, 8).
+  template<size_t>
     struct _Fnv_hash
     {
       static size_t
@@ -167,139 +169,39 @@ namespace std
       }
     };
 
-  /// Explicit specializations for float.
+  /// Specialization for float.
   template<>
-    struct hash<float>
-    : public std::unary_function<float, size_t>
+    inline size_t
+    hash<float>::operator()(float __val) const
     {
-      size_t
-      operator()(float __val) const
-      {
-	size_t __result = 0;
+      size_t __result = 0;
       
-	// 0 and -0 both hash to zero.
-	if (__val != 0.0f)
-	  __result = _Fnv_hash<>::hash(reinterpret_cast<const char*>(&__val),
-				       sizeof(__val));
-	return __result;
-      }
-    };
-
-  /// Explicit specializations for double.
-  template<>
-    struct hash<double>
-    : public std::unary_function<double, size_t>
-    {
-      size_t
-      operator()(double __val) const
-      {
-	size_t __result = 0;
-
-	// 0 and -0 both hash to zero.
-	if (__val != 0.0)
-	  __result = _Fnv_hash<>::hash(reinterpret_cast<const char*>(&__val),
-				       sizeof(__val));
-	return __result;
-      }
-    };
-
-  /// Explicit specializations for long double.
-  template<>
-    struct hash<long double>
-    : public std::unary_function<long double, size_t>
-    {
-      size_t
-      operator()(long double __val) const
-      {
-	size_t __result = 0;
-
-	int __exponent;
-	__val = __builtin_frexpl(__val, &__exponent);
-	__val = __val < 0.0l ? -(__val + 0.5l) : __val;
-
-	const long double __mult =
-	  __gnu_cxx::__numeric_traits<size_t>::__max + 1.0l;
-	__val *= __mult;
-
-	// Try to use all the bits of the mantissa (really necessary only
-	// on 32-bit targets, at least for 80-bit floating point formats).
-	const size_t __hibits = (size_t)__val;
-	__val = (__val - (long double)__hibits) * __mult;
-
-	const size_t __coeff =
-	  __gnu_cxx::__numeric_traits<size_t>::__max / __LDBL_MAX_EXP__;
-
-	__result = __hibits + (size_t)__val + __coeff * __exponent;
-
-	return __result;
-      }
-    };
-
-  /// Explicit specializations for string.
+      // 0 and -0 both hash to zero.
+      if (__val != 0.0f)
+	__result = _Fnv_hash<>::hash(reinterpret_cast<const char*>(&__val),
+				     sizeof(__val));
+      return __result;
+    }
+
+  /// Specialization for double.
   template<>
-    struct hash<string>
-    : public std::unary_function<string, size_t>
+    inline size_t
+    hash<double>::operator()(double __val) const
     {
-      size_t
-      operator()(const string& __s) const
-      { return _Fnv_hash<>::hash(__s.data(), __s.length()); }
-    };
+      size_t __result = 0;
 
-#ifdef _GLIBCXX_USE_WCHAR_T
-  /// Explicit specializations for wstring.
-  template<>
-    struct hash<wstring>
-    : public std::unary_function<wstring, size_t>
-    {
-      size_t
-      operator()(const wstring& __s) const
-      {
-	const char* __p = reinterpret_cast<const char*>(__s.data());
-	return _Fnv_hash<>::hash(__p, __s.length() * sizeof(wchar_t));
-      }
-    };
-#endif
+      // 0 and -0 both hash to zero.
+      if (__val != 0.0)
+	__result = _Fnv_hash<>::hash(reinterpret_cast<const char*>(&__val),
+				     sizeof(__val));
+      return __result;
+    }
 
-#ifdef _GLIBCXX_USE_C99_STDINT_TR1
-  /// Explicit specializations for u16string.
+  /// Specialization for long double.
   template<>
-    struct hash<u16string>
-    : public std::unary_function<u16string, size_t>
-    {
-      size_t
-      operator()(const u16string& __s) const
-      {
-	const char* __p = reinterpret_cast<const char*>(__s.data());
-	return _Fnv_hash<>::hash(__p, __s.length() * sizeof(char16_t));
-      }
-    };
-
-  /// Explicit specializations for u32string.
-  template<>
-    struct hash<u32string>
-    : public std::unary_function<u32string, size_t>
-    {
-      size_t
-      operator()(const u32string& __s) const
-      {
-	const char* __p = reinterpret_cast<const char*>(__s.data());
-	return _Fnv_hash<>::hash(__p, __s.length() * sizeof(char32_t));
-      }
-    };
-#endif
+    size_t
+    hash<long double>::operator()(long double __val) const;
 
-  /// Explicit specializations for error_code.
-  template<>
-    struct hash<error_code>
-    : public std::unary_function<error_code, size_t>
-    {
-      size_t
-      operator()(const error_code& __e) const
-      {
-	const char* __p = reinterpret_cast<const char*>(&__e);
-	return _Fnv_hash<>::hash(__p, sizeof(__e));
-      }
-    };
   // @} group hashes
 }
 

libstdc++-v3/include/std/functional

@@ -55,6 +55,7 @@
 #include <new>
 #include <tuple>
 #include <type_traits>
+#include <bits/functexcept.h>
 #include <bits/functional_hash.h>
 
 namespace std

libstdc++-v3/include/std/system_error

@@ -335,6 +335,30 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
 
 _GLIBCXX_END_NAMESPACE
 
+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
+
+#include <bits/functional_hash.h>
+
+_GLIBCXX_BEGIN_NAMESPACE(std)
+
+  // DR 1182.
+  /// std::hash specialization for error_code.
+  template<>
+    struct hash<error_code>
+    : public std::unary_function<error_code, size_t>
+    {
+      size_t
+      operator()(const error_code& __e) const
+      {
+	const char* __p = reinterpret_cast<const char*>(&__e);
+	return _Fnv_hash<>::hash(__p, sizeof(__e));
+      }
+    };
+
+_GLIBCXX_END_NAMESPACE
+
+#endif // _GLIBCXX_COMPATIBILITY_CXX0X
+
 #endif // __GXX_EXPERIMENTAL_CXX0X__
 
 #endif // _GLIBCXX_SYSTEM_ERROR

libstdc++-v3/include/std/unordered_map

@@ -41,7 +41,6 @@
 #include <bits/stl_algobase.h>
 #include <bits/allocator.h>
 #include <bits/stl_function.h> // equal_to, _Identity, _Select1st
-#include <bits/stringfwd.h>
 #include <bits/functional_hash.h>
 #include <bits/hashtable.h>
 #include <bits/unordered_map.h>

libstdc++-v3/include/std/unordered_set

@@ -41,7 +41,6 @@
 #include <bits/stl_algobase.h>
 #include <bits/allocator.h>
 #include <bits/stl_function.h> // equal_to, _Identity, _Select1st
-#include <bits/stringfwd.h>
 #include <bits/functional_hash.h>
 #include <bits/hashtable.h>
 #include <bits/unordered_set.h>

libstdc++-v3/include/tr1/functional_hash.h

@@ -140,7 +140,7 @@ namespace tr1
 	__result = _Fnv_hash<>::hash(reinterpret_cast<const char*>(&__val),
 				     sizeof(__val));
       return __result;
-    };
+    }
 
   /// Explicit specializations for double.
   template<>
@@ -154,7 +154,7 @@ namespace tr1
 	  __result = _Fnv_hash<>::hash(reinterpret_cast<const char*>(&__val),
 				       sizeof(__val));
 	return __result;
-    };
+    }
 
   /// Explicit specializations for long double.
   template<>

libstdc++-v3/src/Makefile.am

@@ -148,10 +148,11 @@ sources = \
 	ctype.cc \
 	debug.cc \
 	functexcept.cc \
-	hash_tr1.cc \
 	globals_io.cc \
-	hashtable_tr1.cc \
+	hash_c++0x.cc \
+	hash_tr1.cc \
 	hashtable_c++0x.cc \
+	hashtable_tr1.cc \
 	ios.cc \
 	ios_failure.cc \
 	ios_init.cc \
@@ -272,6 +273,11 @@ compatibility-c++0x.lo: compatibility-c++0x.cc
 compatibility-c++0x.o: compatibility-c++0x.cc
 	$(CXXCOMPILE) -std=gnu++0x -c $<
 
+hash_c++0x.lo: hash_c++0x.cc
+	$(LTCXXCOMPILE) -std=gnu++0x -c $<
+hash_c++0x.o: hash_c++0x.cc
+	$(CXXCOMPILE) -std=gnu++0x -c $<
+
 hashtable_c++0x.lo: hashtable_c++0x.cc
 	$(LTCXXCOMPILE) -std=gnu++0x -c $<
 hashtable_c++0x.o: hashtable_c++0x.cc

libstdc++-v3/src/Makefile.in

@@ -89,10 +89,10 @@ am__libstdc___la_SOURCES_DIST = atomic.cc bitmap_allocator.cc \
 	pool_allocator.cc mt_allocator.cc codecvt.cc compatibility.cc \
 	compatibility-c++0x.cc compatibility-debug_list.cc \
 	compatibility-list.cc complex_io.cc ctype.cc debug.cc \
-	functexcept.cc hash_tr1.cc globals_io.cc hashtable_tr1.cc \
-	hashtable_c++0x.cc ios.cc ios_failure.cc ios_init.cc \
-	ios_locale.cc limits.cc list.cc debug_list.cc locale.cc \
-	locale_init.cc locale_facets.cc localename.cc \
+	functexcept.cc globals_io.cc hash_c++0x.cc hash_tr1.cc \
+	hashtable_c++0x.cc hashtable_tr1.cc ios.cc ios_failure.cc \
+	ios_init.cc ios_locale.cc limits.cc list.cc debug_list.cc \
+	locale.cc locale_init.cc locale_facets.cc localename.cc \
 	math_stubs_float.cc math_stubs_long_double.cc stdexcept.cc \
 	strstream.cc system_error.cc tree.cc allocator-inst.cc \
 	concept-inst.cc fstream-inst.cc ext-inst.cc ios-inst.cc \
@@ -119,10 +119,10 @@ am__objects_5 = atomic.lo bitmap_allocator.lo pool_allocator.lo \
 	mt_allocator.lo codecvt.lo compatibility.lo \
 	compatibility-c++0x.lo compatibility-debug_list.lo \
 	compatibility-list.lo complex_io.lo ctype.lo debug.lo \
-	functexcept.lo hash_tr1.lo globals_io.lo hashtable_tr1.lo \
-	hashtable_c++0x.lo ios.lo ios_failure.lo ios_init.lo \
-	ios_locale.lo limits.lo list.lo debug_list.lo locale.lo \
-	locale_init.lo locale_facets.lo localename.lo \
+	functexcept.lo globals_io.lo hash_c++0x.lo hash_tr1.lo \
+	hashtable_c++0x.lo hashtable_tr1.lo ios.lo ios_failure.lo \
+	ios_init.lo ios_locale.lo limits.lo list.lo debug_list.lo \
+	locale.lo locale_init.lo locale_facets.lo localename.lo \
 	math_stubs_float.lo math_stubs_long_double.lo stdexcept.lo \
 	strstream.lo system_error.lo tree.lo allocator-inst.lo \
 	concept-inst.lo fstream-inst.lo ext-inst.lo ios-inst.lo \
@@ -394,10 +394,11 @@ sources = \
 	ctype.cc \
 	debug.cc \
 	functexcept.cc \
-	hash_tr1.cc \
 	globals_io.cc \
-	hashtable_tr1.cc \
+	hash_c++0x.cc \
+	hash_tr1.cc \
 	hashtable_c++0x.cc \
+	hashtable_tr1.cc \
 	ios.cc \
 	ios_failure.cc \
 	ios_init.cc \
@@ -907,6 +908,11 @@ compatibility-c++0x.lo: compatibility-c++0x.cc
 compatibility-c++0x.o: compatibility-c++0x.cc
 	$(CXXCOMPILE) -std=gnu++0x -c $<
 
+hash_c++0x.lo: hash_c++0x.cc
+	$(LTCXXCOMPILE) -std=gnu++0x -c $<
+hash_c++0x.o: hash_c++0x.cc
+	$(CXXCOMPILE) -std=gnu++0x -c $<
+
 hashtable_c++0x.lo: hashtable_c++0x.cc
 	$(LTCXXCOMPILE) -std=gnu++0x -c $<
 hashtable_c++0x.o: hashtable_c++0x.cc

libstdc++-v3/src/compatibility-c++0x.cc

@@ -22,9 +22,8 @@
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.
 
-#include <cstddef>
+#define _GLIBCXX_COMPATIBILITY_CXX0X
 #include <string>
-#include <cmath>
 #include <system_error>
 
 #ifndef __GXX_EXPERIMENTAL_CXX0X__
@@ -50,59 +49,6 @@ namespace std
 
   // We need these due to the symbols exported since GLIBCXX_3.4.10.
   // See libstdc++/41662 for details.
-  template<typename _Tp>
-    struct hash : public std::unary_function<_Tp, size_t>
-    {
-      size_t
-      operator()(_Tp __val) const;
-    };
-
-  /// Dummy generic implementation (for sizeof(size_t) != 4, 8).
-  template<size_t = sizeof(size_t)>
-    struct _Fnv_hash
-    {
-      static size_t
-      hash(const char* __first, size_t __length)
-      {
-	size_t __result = 0;
-	for (; __length > 0; --__length)
-	  __result = (__result * 131) + *__first++;
-	return __result;
-      }
-    };
-
-  template<>
-    struct _Fnv_hash<4>
-    {
-      static size_t
-      hash(const char* __first, size_t __length)
-      {
-	size_t __result = static_cast<size_t>(2166136261UL);
-	for (; __length > 0; --__length)
-	  {
-	    __result ^= static_cast<size_t>(*__first++);
-	    __result *= static_cast<size_t>(16777619UL);
-	  }
-	return __result;
-      }
-    };
-  
-  template<>
-    struct _Fnv_hash<8>
-    {
-      static size_t
-      hash(const char* __first, size_t __length)
-      {
-	size_t __result =
-	  static_cast<size_t>(14695981039346656037ULL);
-	for (; __length > 0; --__length)
-	  {
-	    __result ^= static_cast<size_t>(*__first++);
-	    __result *= static_cast<size_t>(1099511628211ULL);
-	  }
-	return __result;
-      }
-    };
 
 #include "hash-aux.cc"
 

libstdc++-v3/src/hash-aux.cc

 //  std::hash and std::tr1::hash definitions -*- C++ -*-
 
-// Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+// Copyright (C) 2007, 2008, 2009, 2010 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
@@ -22,35 +22,6 @@
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.
 
-  // For long double, careful with random padding bits (e.g., on x86,
-  // 10 bytes -> 12 bytes) and resort to frexp.
-  template<>
-    size_t
-    hash<long double>::operator()(long double __val) const
-    {
-      size_t __result = 0;
-
-      int __exponent;
-      __val = std::frexp(__val, &__exponent);
-      __val = __val < 0.0l ? -(__val + 0.5l) : __val;
-
-      const long double __mult =
-      __gnu_cxx::__numeric_traits<size_t>::__max + 1.0l;
-      __val *= __mult;
-
-      // Try to use all the bits of the mantissa (really necessary only
-      // on 32-bit targets, at least for 80-bit floating point formats).
-      const size_t __hibits = (size_t)__val;
-      __val = (__val - (long double)__hibits) * __mult;
-
-      const size_t __coeff =
-	__gnu_cxx::__numeric_traits<size_t>::__max / __LDBL_MAX_EXP__;
-
-      __result = __hibits + (size_t)__val + __coeff * __exponent;
-
-      return __result;
-    };
-
 #ifndef _GLIBCXX_LONG_DOUBLE_COMPAT_IMPL
   template<>
     size_t
@@ -79,4 +50,5 @@
       return _Fnv_hash<>::hash(__p, __s.length() * sizeof(wchar_t));
     }
 #endif
+
 #endif

libstdc++-v3/src/hash_c++0x.cc

+// std::hash definitions -*- C++ -*-
+
+// Copyright (C) 2010 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef __GXX_EXPERIMENTAL_CXX0X__
+# error "hash_c++0x.cc must be compiled with -std=gnu++0x"
+#endif
+
+#include <bits/functional_hash.h>
+
+namespace std
+{
+  /// std::hash specialization for long double.
+  template<>
+    size_t
+    hash<long double>::operator()(long double __val) const
+    {
+      size_t __result = 0;
+
+      int __exponent;
+      __val = __builtin_frexpl(__val, &__exponent);
+      __val = __val < 0.0l ? -(__val + 0.5l) : __val;
+
+      const long double __mult = __SIZE_MAX__ + 1.0l;
+      __val *= __mult;
+
+      // Try to use all the bits of the mantissa (really necessary only
+      // on 32-bit targets, at least for 80-bit floating point formats).
+      const size_t __hibits = (size_t)__val;
+      __val = (__val - (long double)__hibits) * __mult;
+
+      const size_t __coeff = __SIZE_MAX__ / __LDBL_MAX_EXP__;
+
+      __result = __hibits + (size_t)__val + __coeff * __exponent;
+	
+      return __result;
+    }  
+}

libstdc++-v3/src/hash_tr1.cc

-// std::hash definitions -*- C++ -*-
+// std::tr1::hash definitions -*- C++ -*-
 
 // Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
 //
@@ -22,9 +22,7 @@
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.
 
-#include <cstddef>
 #include <string>
-#include <cmath>
 #include <tr1/functional>
 
 namespace std
@@ -32,5 +30,32 @@ namespace std
   namespace tr1 
   {
 #include "hash-aux.cc"
+
+    // For long double, careful with random padding bits (e.g., on x86,
+    // 10 bytes -> 12 bytes) and resort to frexp.
+    template<>
+      size_t
+      hash<long double>::operator()(long double __val) const
+      {
+	size_t __result = 0;
+
+	int __exponent;
+	__val = __builtin_frexpl(__val, &__exponent);
+	__val = __val < 0.0l ? -(__val + 0.5l) : __val;
+
+	const long double __mult = __SIZE_MAX__ + 1.0l;
+	__val *= __mult;
+
+	// Try to use all the bits of the mantissa (really necessary only
+	// on 32-bit targets, at least for 80-bit floating point formats).
+	const size_t __hibits = (size_t)__val;
+	__val = (__val - (long double)__hibits) * __mult;
+
+	const size_t __coeff = __SIZE_MAX__ / __LDBL_MAX_EXP__;
+
+	__result = __hibits + (size_t)__val + __coeff * __exponent;
+
+	return __result;
+      }
   }
 }

libstdc++-v3/testsuite/20_util/weak_ptr/comparison/cmp_neg.cc

@@ -30,7 +30,6 @@ int
 test01()
 {
   std::weak_ptr<A> p1;
-  // { dg-excess-errors "candidates are" }
   p1 < p1;  // { dg-error "no match" }
   return 0;
 }