libstdc++: Simplify noexcept-specifiers for move constructors

This puts the logic for the noexcept-specifier in one place, and then
reuses it elsewhere. This means checking whether the move constructor
can throw doesn't need to do overload resolution and then check whether
some other constructor can throw, we just get the answer directly.

libstdc++-v3/ChangeLog:

	* include/bits/hashtable.h (_Hashtable::_S_nothrow_move()):
	New function to determine noexcept-specifier for move
	constructors.
	(_Hashtable): Use _S_nothrow_move() on move constructors.
	* testsuite/23_containers/unordered_map/cons/noexcept_move_construct.cc:
	Correct static assertion message.
	* testsuite/23_containers/unordered_multimap/cons/noexcept_move_construct.cc:
	Likewise.
	* testsuite/23_containers/unordered_multiset/cons/noexcept_move_construct.cc:
	Likewise.
	* testsuite/23_containers/unordered_set/cons/noexcept_move_construct.cc:
	Likewise.

diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index fa80675..39872ce 100644 (file)
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -472,10 +472,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        __hashtable_alloc(__node_alloc_type(__a))
       { }
 
+      template<bool _No_realloc = true>
+       static constexpr bool
+       _S_nothrow_move()
+       {
+         if _GLIBCXX17_CONSTEXPR (_No_realloc)
+           if _GLIBCXX17_CONSTEXPR (is_nothrow_copy_constructible<_Hash>())
+             return is_nothrow_copy_constructible<_Equal>();
+         return false;
+       }
+
       _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
                 true_type /* alloc always equal */)
-       noexcept(std::is_nothrow_copy_constructible<_Hash>::value &&
-                std::is_nothrow_copy_constructible<_Equal>::value);
+       noexcept(_S_nothrow_move());
 
       _Hashtable(_Hashtable&&, __node_alloc_type&&,
                 false_type /* alloc always equal */);
@@ -508,19 +517,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       // Use delegating constructors.
       _Hashtable(_Hashtable&& __ht)
-       noexcept( noexcept(
-         _Hashtable(std::declval<_Hashtable>(),
-                    std::declval<__node_alloc_type>(),
-                    true_type{})) )
+       noexcept(_S_nothrow_move())
       : _Hashtable(std::move(__ht), std::move(__ht._M_node_allocator()),
                   true_type{})
       { }
 
       _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
-       noexcept( noexcept(
-         _Hashtable(std::declval<_Hashtable>(),
-                    std::declval<__node_alloc_type>(),
-                    typename __node_alloc_traits::is_always_equal{})) )
+       noexcept(_S_nothrow_move<__node_alloc_traits::_S_always_equal()>())
       : _Hashtable(std::move(__ht), __node_alloc_type(__a),
                   typename __node_alloc_traits::is_always_equal{})
       { }
@@ -1400,8 +1403,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
               _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
     _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
               true_type /* alloc always equal */)
-    noexcept(std::is_nothrow_copy_constructible<_Hash>::value &&
-            std::is_nothrow_copy_constructible<_Equal>::value)
+    noexcept(_S_nothrow_move())
     : __hashtable_base(__ht),
       __map_base(__ht),
       __rehash_base(__ht),

diff --git a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/noexcept_move_construct.cc b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/noexcept_move_construct.cc
index 96245aa..015646a 100644 (file)
--- a/libstdc++-v3/testsuite/23_containers/unordered_map/cons/noexcept_move_construct.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_map/cons/noexcept_move_construct.cc
@@ -40,7 +40,7 @@ struct not_noexcept_copy_cons_hash
 using type2 = std::unordered_map<int, int, not_noexcept_copy_cons_hash>;
 
 static_assert( !std::is_nothrow_move_constructible<type2>::value,
-              "noexcept move constructor" );
+              "not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type2, type2&&,
               const typename type2::allocator_type&>::value,
               "not noexcept move constructor with allocator" );
@@ -59,7 +59,7 @@ using type3 = std::unordered_map<int, int, std::hash<int>,
                                  not_noexcept_copy_cons_equal_to>;
 
 static_assert( !std::is_nothrow_move_constructible<type3>::value,
-              "noexcept move constructor" );
+              "not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type3, type3&&,
               const typename type3::allocator_type&>::value,
               "not noexcept move constructor with allocator" );

diff --git a/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/noexcept_move_construct.cc b/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/noexcept_move_construct.cc
index efc8d33..1e0b105 100644 (file)
--- a/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/noexcept_move_construct.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_multimap/cons/noexcept_move_construct.cc
@@ -40,7 +40,7 @@ struct not_noexcept_copy_cons_hash
 using type2 = std::unordered_multimap<int, int, not_noexcept_copy_cons_hash>;
 
 static_assert( !std::is_nothrow_move_constructible<type2>::value,
-              "noexcept move constructor" );
+              "not not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type2, type2&&,
               const typename type2::allocator_type&>::value,
               "not noexcept move constructor with allocator" );
@@ -59,7 +59,7 @@ using type3 = std::unordered_multimap<int, int, std::hash<int>,
                                       not_noexcept_copy_cons_equal_to>;
 
 static_assert( !std::is_nothrow_move_constructible<type3>::value,
-              "noexcept move constructor" );
+              "not not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type3, type3&&,
               const typename type3::allocator_type&>::value,
               "not noexcept move constructor with allocator" );

diff --git a/libstdc++-v3/testsuite/23_containers/unordered_multiset/cons/noexcept_move_construct.cc b/libstdc++-v3/testsuite/23_containers/unordered_multiset/cons/noexcept_move_construct.cc
index cc2a8e3..3e60380 100644 (file)
--- a/libstdc++-v3/testsuite/23_containers/unordered_multiset/cons/noexcept_move_construct.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_multiset/cons/noexcept_move_construct.cc
@@ -40,7 +40,7 @@ struct not_noexcept_copy_cons_hash
 using type2 = std::unordered_multiset<int, not_noexcept_copy_cons_hash>;
 
 static_assert( !std::is_nothrow_move_constructible<type2>::value,
-              "noexcept move constructor" );
+              "not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type2, type2&&,
               const typename type2::allocator_type&>::value,
               "not noexcept move constructor with allocator" );
@@ -59,7 +59,7 @@ using type3 = std::unordered_multiset<int, std::hash<int>,
                                      not_noexcept_copy_cons_equal_to>;
 
 static_assert( !std::is_nothrow_move_constructible<type3>::value,
-              "noexcept move constructor" );
+              "not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type3, type3&&,
               const typename type3::allocator_type&>::value,
               "not noexcept move constructor with allocator" );

diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/cons/noexcept_move_construct.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/noexcept_move_construct.cc
index f680953..28cb539 100644 (file)
--- a/libstdc++-v3/testsuite/23_containers/unordered_set/cons/noexcept_move_construct.cc
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/noexcept_move_construct.cc
@@ -40,7 +40,7 @@ struct not_noexcept_copy_cons_hash
 using type2 = std::unordered_set<int, not_noexcept_copy_cons_hash>;
 
 static_assert( !std::is_nothrow_move_constructible<type2>::value,
-              "noexcept move constructor" );
+              "not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type2, type2&&,
               const typename type2::allocator_type&>::value,
               "not noexcept move constructor with allocator" );
@@ -59,7 +59,7 @@ using type3 = std::unordered_set<int, std::hash<int>,
                                  not_noexcept_copy_cons_equal_to>;
 
 static_assert( !std::is_nothrow_move_constructible<type3>::value,
-              "noexcept move constructor" );
+              "not noexcept move constructor" );
 static_assert( !std::is_nothrow_constructible<type3, type3&&,
               const typename type3::allocator_type&>::value,
               "not noexcept move constructor with allocator" );