Bug 16599 part 2: Make std::pair's constructors and comparison operators (and make_pair) constexpr.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@186430 91177308-0d34-0410-b5e6-96231b3b80d8

include/utility

@@ -66,10 +66,10 @@ struct pair
     pair(const pair&) = default;
     pair(pair&&) = default;
     constexpr pair();
-    pair(const T1& x, const T2& y);
+    pair(const T1& x, const T2& y);                          // constexpr in C++14
-    template <class U, class V> pair(U&& x, V&& y);
+    template <class U, class V> pair(U&& x, V&& y);          // constexpr in C++14
-    template <class U, class V> pair(const pair<U, V>& p);
+    template <class U, class V> pair(const pair<U, V>& p);   // constexpr in C++14
-    template <class U, class V> pair(pair<U, V>&& p);
+    template <class U, class V> pair(pair<U, V>&& p);        // constexpr in C++14
     template <class... Args1, class... Args2>
         pair(piecewise_construct_t, tuple<Args1...> first_args,
              tuple<Args2...> second_args);
@@ -83,14 +83,14 @@ struct pair
                                 noexcept(swap(second, p.second)));
 };
 
-template <class T1, class T2> bool operator==(const pair<T1,T2>&, const pair<T1,T2>&);
+template <class T1, class T2> bool operator==(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
-template <class T1, class T2> bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&);
+template <class T1, class T2> bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
-template <class T1, class T2> bool operator< (const pair<T1,T2>&, const pair<T1,T2>&);
+template <class T1, class T2> bool operator< (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
-template <class T1, class T2> bool operator> (const pair<T1,T2>&, const pair<T1,T2>&);
+template <class T1, class T2> bool operator> (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
-template <class T1, class T2> bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&);
+template <class T1, class T2> bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
-template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&);
+template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
 
-template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);
+template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);   // constexpr in C++14
 template <class T1, class T2>
 void
 swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
@@ -258,11 +258,12 @@ struct _LIBCPP_TYPE_VIS pair
 
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR pair() : first(), second() {}
 
-    _LIBCPP_INLINE_VISIBILITY pair(const _T1& __x, const _T2& __y)
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(const _T1& __x, const _T2& __y)
         : first(__x), second(__y) {}
 
     template<class _U1, class _U2>
-        _LIBCPP_INLINE_VISIBILITY
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
         pair(const pair<_U1, _U2>& __p
 #ifndef _LIBCPP_HAS_NO_ADVANCED_SFINAE
                  ,typename enable_if<is_convertible<const _U1&, _T1>::value &&
@@ -271,6 +272,10 @@ struct _LIBCPP_TYPE_VIS pair
                                       )
             : first(__p.first), second(__p.second) {}
 
+#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+    _LIBCPP_INLINE_VISIBILITY
+    pair(const pair& __p) = default;
+#else
     _LIBCPP_INLINE_VISIBILITY
     pair(const pair& __p)
         _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
@@ -279,6 +284,7 @@ struct _LIBCPP_TYPE_VIS pair
           second(__p.second)
     {
     }
+#endif
 
     _LIBCPP_INLINE_VISIBILITY
     pair& operator=(const pair& __p)
@@ -295,20 +301,24 @@ struct _LIBCPP_TYPE_VIS pair
     template <class _U1, class _U2,
               class = typename enable_if<is_convertible<_U1, first_type>::value &&
                                          is_convertible<_U2, second_type>::value>::type>
-        _LIBCPP_INLINE_VISIBILITY
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
         pair(_U1&& __u1, _U2&& __u2)
             : first(_VSTD::forward<_U1>(__u1)),
               second(_VSTD::forward<_U2>(__u2))
             {}
 
     template<class _U1, class _U2>
-        _LIBCPP_INLINE_VISIBILITY
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
         pair(pair<_U1, _U2>&& __p,
                  typename enable_if<is_convertible<_U1, _T1>::value &&
                                     is_convertible<_U2, _T2>::value>::type* = 0)
             : first(_VSTD::forward<_U1>(__p.first)),
               second(_VSTD::forward<_U2>(__p.second)) {}
 
+#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+    _LIBCPP_INLINE_VISIBILITY
+    pair(pair&& __p) = default;
+#else
     _LIBCPP_INLINE_VISIBILITY
     pair(pair&& __p) _NOEXCEPT_(is_nothrow_move_constructible<first_type>::value &&
                                 is_nothrow_move_constructible<second_type>::value)
@@ -316,6 +326,7 @@ struct _LIBCPP_TYPE_VIS pair
           second(_VSTD::forward<second_type>(__p.second))
     {
     }
+#endif
 
     _LIBCPP_INLINE_VISIBILITY
     pair&
@@ -331,7 +342,7 @@ struct _LIBCPP_TYPE_VIS pair
 
     template<class _Tuple,
              class = typename enable_if<__tuple_convertible<_Tuple, pair>::value>::type>
-        _LIBCPP_INLINE_VISIBILITY
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
         pair(_Tuple&& __p)
             : first(_VSTD::forward<typename tuple_element<0,
                                   typename __make_tuple_types<_Tuple>::type>::type>(get<0>(__p))),
@@ -387,7 +398,7 @@ private:
 };
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 bool
 operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 {
@@ -395,7 +406,7 @@ operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 }
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 bool
 operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 {
@@ -403,7 +414,7 @@ operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 }
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 bool
 operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 {
@@ -411,7 +422,7 @@ operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 }
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 bool
 operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 {
@@ -419,7 +430,7 @@ operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 }
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 bool
 operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 {
@@ -427,7 +438,7 @@ operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 }
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 bool
 operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
 {
@@ -472,7 +483,7 @@ struct __make_pair_return
 };
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
 make_pair(_T1&& __t1, _T2&& __t2)
 {
@@ -615,42 +626,42 @@ template <class _T1, class _T2>
 _LIBCPP_INLINE_VISIBILITY inline
 constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
 {
-	return __get_pair<0>::get(__p);
+    return __get_pair<0>::get(__p);
 }
 
 template <class _T1, class _T2>
 _LIBCPP_INLINE_VISIBILITY inline
 constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
 {
-	return __get_pair<0>::get(__p);
+    return __get_pair<0>::get(__p);
 }
 
 template <class _T1, class _T2>
 _LIBCPP_INLINE_VISIBILITY inline
 constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
 {
-	return __get_pair<0>::get(_VSTD::move(__p));
+    return __get_pair<0>::get(_VSTD::move(__p));
 }
 
 template <class _T1, class _T2>
 _LIBCPP_INLINE_VISIBILITY inline
 constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
 {
-	return __get_pair<1>::get(__p);
+    return __get_pair<1>::get(__p);
 }
 
 template <class _T1, class _T2>
 _LIBCPP_INLINE_VISIBILITY inline
 constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
 {
-	return __get_pair<1>::get(__p);
+    return __get_pair<1>::get(__p);
 }
 
 template <class _T1, class _T2>
 _LIBCPP_INLINE_VISIBILITY inline
 constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
 {
-	return __get_pair<1>::get(_VSTD::move(__p));
+    return __get_pair<1>::get(_VSTD::move(__p));
 }
 
 #endif

test/utilities/utility/pairs/pair.astuple/get_const.pass.cpp

@@ -26,4 +26,15 @@ int main()
         assert(std::get<0>(p) == 3);
         assert(std::get<1>(p) == 4);
     }
+
+#if __cplusplus > 201103L
+    {
+        typedef std::pair<int, short> P;
+        constexpr P p1(3, 4);
+        static_assert(p1.first == 3, "" ); // for now!
+        static_assert(p1.second == 4, "" ); // for now!
+//         static_assert(std::get<0>(p1) == 3, "");
+//         static_assert(std::get<1>(p1) == 4, "");
+    }
+#endif
 }

test/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp

@@ -22,9 +22,20 @@ class A
 public:
     A(int data) : data_(data) {}
 
-    bool operator==(const A& a) {return data_ == a.data_;}
+    bool operator==(const A& a) const {return data_ == a.data_;}
 };
 
+#if _LIBCPP_STD_VER > 11
+class AC
+{
+    int data_;
+public:
+    constexpr AC(int data) : data_(data) {}
+
+    constexpr bool operator==(const AC& a) const {return data_ == a.data_;}
+};
+#endif
+
 int main()
 {
     {
@@ -39,4 +50,19 @@ int main()
         assert(p.first == A(1));
         assert(p.second == 2);
     }
+
+#if _LIBCPP_STD_VER > 11
+    {
+        typedef std::pair<float, short*> P;
+        constexpr P p(3.5f, 0);
+        static_assert(p.first == 3.5f, "");
+        static_assert(p.second == nullptr, "");
+    }
+    {
+        typedef std::pair<AC, int> P;
+        constexpr P p(1, 2);
+        static_assert(p.first == AC(1), "");
+        static_assert(p.second == 2, "");
+    }
+#endif
 }

test/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp

@@ -26,4 +26,15 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+#if _LIBCPP_STD_VER > 11
+    {
+        typedef std::pair<int, short> P1;
+        typedef std::pair<double, long> P2;
+        constexpr P1 p1(3, 4);
+        constexpr P2 p2 = p1;
+        static_assert(p2.first == 3, "");
+        static_assert(p2.second == 4, "");
+    }
+#endif
 }

test/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp

@@ -25,4 +25,14 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+#if _LIBCPP_STD_VER > 11
+    {
+        typedef std::pair<int, short> P1;
+        constexpr P1 p1(3, 4);
+        constexpr P1 p2 = p1;
+        static_assert(p2.first == 3, "");
+        static_assert(p2.second == 4, "");
+    }
+#endif
 }

test/utilities/utility/pairs/pairs.pair/default.pass.cpp

@@ -18,8 +18,19 @@
 
 int main()
 {
+    {
     typedef std::pair<float, short*> P;
     P p;
     assert(p.first == 0.0f);
     assert(p.second == nullptr);
+	}
+	
+#if _LIBCPP_STD_VER > 11
+    {
+    typedef std::pair<float, short*> P;
+    constexpr P p;
+    static_assert(p.first == 0.0f, "");
+    static_assert(p.second == nullptr, "");
+    }
+#endif
 }

test/utilities/utility/pairs/pairs.spec/comparison.pass.cpp

@@ -78,4 +78,18 @@ int main()
         assert( (p1 >  p2));
         assert( (p1 >= p2));
     }
+
+#if _LIBCPP_STD_VER > 11
+    {
+        typedef std::pair<int, short> P;
+        constexpr P p1(3, 4);
+        constexpr P p2(3, 2);
+        static_assert(!(p1 == p2), "");
+        static_assert( (p1 != p2), "");
+        static_assert(!(p1 <  p2), "");
+        static_assert(!(p1 <= p2), "");
+        static_assert( (p1 >  p2), "");
+        static_assert( (p1 >= p2), "");
+    }
+#endif
 }

test/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp

@@ -23,6 +23,7 @@ int main()
         assert(p1.first == 3);
         assert(p1.second == 4);
     }
+    
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     {
         typedef std::pair<std::unique_ptr<int>, short> P1;
@@ -37,4 +38,14 @@ int main()
         assert(p1.second == 4);
     }
 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+#if _LIBCPP_STD_VER > 11
+    {
+        typedef std::pair<int, short> P1;
+        constexpr P1 p1 = std::make_pair(3, 4);
+        static_assert(p1.first == 3, "");
+        static_assert(p1.second == 4, "");
+    }
+#endif
+
 }