[PATCH] Define std::allocator::is_always_equal

[Jonathan Wakely]

I somehow only added the is_always_equal nested typedef to the
allocator<void> specialization, not the primary template. All the
containers still do the right thing, because they use
allocator_traits<allocator<T>>::is_always_equal which gives the right
answer, but we still need to provide allocator<T>::is_always_equal to
be conforming.

        * include/bits/allocator.h (allocator<T>::is_always_equal): Define.
        * testsuite/20_util/allocator/requirements/typedefs.cc: Test for
        is_always_equal.
        * testsuite/util/testsuite_allocator.h
        (uneq_allocator::is_always_equal): Define as false_type.

Tested powerpc64le-linux, committed to trunk/



commit f5020f0fa1dc815eda37d8b1040e7c16f1554114
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Mon Oct 10 12:04:24 2016 +0100

    Define std::allocator<T>::is_always_equal
    
        * include/bits/allocator.h (allocator<T>::is_always_equal): Define.
        * testsuite/20_util/allocator/requirements/typedefs.cc: Test for
        is_always_equal.
        * testsuite/util/testsuite_allocator.h
        (uneq_allocator::is_always_equal): Define as false_type.

diff --git a/libstdc++-v3/include/bits/allocator.h 
b/libstdc++-v3/include/bits/allocator.h
index 984d800..8e78165 100644
--- a/libstdc++-v3/include/bits/allocator.h
+++ b/libstdc++-v3/include/bits/allocator.h
@@ -50,6 +50,9 @@
 #endif
 
 #define __cpp_lib_incomplete_container_elements 201505
+#if __cplusplus >= 201103L
+# define __cpp_lib_allocator_is_always_equal 201411
+#endif
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
@@ -80,7 +83,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       // 2103. std::allocator propagate_on_container_move_assignment
       typedef true_type propagate_on_container_move_assignment;
 
-#define __cpp_lib_allocator_is_always_equal 201411
       typedef true_type is_always_equal;
 #endif
     };
@@ -113,6 +115,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 2103. std::allocator propagate_on_container_move_assignment
       typedef true_type propagate_on_container_move_assignment;
+
+      typedef true_type is_always_equal;
 #endif
 
       allocator() throw() { }
diff --git a/libstdc++-v3/testsuite/20_util/allocator/requirements/typedefs.cc 
b/libstdc++-v3/testsuite/20_util/allocator/requirements/typedefs.cc
index 028daa9..1b3f14f 100644
--- a/libstdc++-v3/testsuite/20_util/allocator/requirements/typedefs.cc
+++ b/libstdc++-v3/testsuite/20_util/allocator/requirements/typedefs.cc
@@ -48,3 +48,6 @@ static_assert( is_same<allocator<int>::rebind<char>::other,
 static_assert( is_same<allocator<int>::propagate_on_container_move_assignment,
                        std::true_type>::value,
                "propagate_on_container_move_assignment" );
+
+static_assert( is_same<allocator<int>::is_always_equal, std::true_type>::value,
+               "is_always_equal" );
diff --git a/libstdc++-v3/testsuite/util/testsuite_allocator.h 
b/libstdc++-v3/testsuite/util/testsuite_allocator.h
index 8537a83..dd7e22d 100644
--- a/libstdc++-v3/testsuite/util/testsuite_allocator.h
+++ b/libstdc++-v3/testsuite/util/testsuite_allocator.h
@@ -297,6 +297,7 @@ namespace __gnu_test
 
 #if __cplusplus >= 201103L
       typedef std::true_type                   propagate_on_container_swap;
+      typedef std::false_type                  is_always_equal;
 #endif
 
       template<typename Tp1>