[libc++] Make __compressed_pair fully constexpr

[philnik]

Summary

Make __compressed_pair fully constexpr

[philnik]

Added spaces

[• Quuxplusone]

libcxx/include/__memory/compressed_pair.h

61–63

Consider linebreaking before the return type, now that these lines are so long. Ditto below.

168–170

Here and below I'd prefer to leave the whitespace alone. But no big deal either way.

_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
void swap(__compressed_pair& __x)
  _NOEXCEPT_(__is_nothrow_swappable<_T1>::value &&
             __is_nothrow_swappable<_T2>::value)

libcxx/include/__memory/compressed_pair.h

 #ifndef _LIBCPP_CXX03_LANG
   template <class... _Args, size_t... _Indexes>
   _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
   __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
                          __tuple_indices<_Indexes...>)
       : __value_(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(__args))...) {}
 #endif
 
-
-  _LIBCPP_INLINE_VISIBILITY reference __get() _NOEXCEPT { return __value_; }
-  _LIBCPP_INLINE_VISIBILITY
-  const_reference __get() const _NOEXCEPT { return __value_; }
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 reference __get() _NOEXCEPT { return __value_; }
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __get() const _NOEXCEPT { return __value_; }
 
 private:
   _Tp __value_;
 };
 
 template <class _Tp, int _Idx>
 struct __compressed_pair_elem<_Tp, _Idx, true> : private _Tp {
   typedef _Tp _ParamT;
   typedef _Tp& reference;

 #ifndef _LIBCPP_CXX03_LANG
   template <class... _Args, size_t... _Indexes>
   _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
   __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
                          __tuple_indices<_Indexes...>)
       : __value_type(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(__args))...) {}
 #endif
 
-  _LIBCPP_INLINE_VISIBILITY reference __get() _NOEXCEPT { return *this; }
-  _LIBCPP_INLINE_VISIBILITY
-  const_reference __get() const _NOEXCEPT { return *this; }
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 reference __get() _NOEXCEPT { return *this; }
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __get() const _NOEXCEPT { return *this; }
 };
 
 template <class _T1, class _T2>
 class __compressed_pair : private __compressed_pair_elem<_T1, 0>,
                           private __compressed_pair_elem<_T2, 1> {
 public:
   // NOTE: This static assert should never fire because __compressed_pair
   // is *almost never* used in a scenario where it's possible for T1 == T2.
#ifndef _LIBCPP_CXX03_LANG
   __compressed_pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args,
                     tuple<_Args2...> __second_args)
       : _Base1(__pc, _VSTD::move(__first_args),
                typename __make_tuple_indices<sizeof...(_Args1)>::type()),
         _Base2(__pc, _VSTD::move(__second_args),
                typename __make_tuple_indices<sizeof...(_Args2)>::type()) {}
 #endif
 
-  _LIBCPP_INLINE_VISIBILITY
-  typename _Base1::reference first() _NOEXCEPT {
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 typename _Base1::reference first() _NOEXCEPT {
     return static_cast<_Base1&>(*this).__get();
   }
 
-  _LIBCPP_INLINE_VISIBILITY
-  typename _Base1::const_reference first() const _NOEXCEPT {
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename _Base1::const_reference first() const _NOEXCEPT {
     return static_cast<_Base1 const&>(*this).__get();
   }
 
-  _LIBCPP_INLINE_VISIBILITY
-  typename _Base2::reference second() _NOEXCEPT {
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 typename _Base2::reference second() _NOEXCEPT {
     return static_cast<_Base2&>(*this).__get();
   }
 
-  _LIBCPP_INLINE_VISIBILITY
-  typename _Base2::const_reference second() const _NOEXCEPT {
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename _Base2::const_reference second() const _NOEXCEPT {
     return static_cast<_Base2 const&>(*this).__get();
   }
 
   _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
   static _Base1* __get_first_base(__compressed_pair* __pair) _NOEXCEPT {
     return static_cast<_Base1*>(__pair);
   }
   _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
   static _Base2* __get_second_base(__compressed_pair* __pair) _NOEXCEPT {
     return static_cast<_Base2*>(__pair);
   }
 
-  _LIBCPP_INLINE_VISIBILITY
-  void swap(__compressed_pair& __x)
-    _NOEXCEPT_(__is_nothrow_swappable<_T1>::value &&
-               __is_nothrow_swappable<_T2>::value)
-  {
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 void swap(__compressed_pair& __x)
+      _NOEXCEPT_(__is_nothrow_swappable<_T1>::value && __is_nothrow_swappable<_T2>::value) {
     using _VSTD::swap;
     swap(first(), __x.first());
     swap(second(), __x.second());
   }
 };
 
 template <class _T1, class _T2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 void swap(__compressed_pair<_T1, _T2>& __x, __compressed_pair<_T1, _T2>& __y)
-    _NOEXCEPT_(__is_nothrow_swappable<_T1>::value &&
-               __is_nothrow_swappable<_T2>::value) {
+    _NOEXCEPT_(__is_nothrow_swappable<_T1>::value && __is_nothrow_swappable<_T2>::value) {
   __x.swap(__y);
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___MEMORY_COMPRESSED_PAIR_H