--- a/libcxx/include/bitset	Mon May 25 11:55:54 2020 +0900
+++ b/libcxx/include/bitset	Tue Jun 08 06:07:14 2021 +0900
@@ -114,12 +114,12 @@
 
 #include <__config>
 #include <__bit_reference>
+#include <__functional_base>
+#include <climits>
 #include <cstddef>
-#include <climits>
+#include <iosfwd>
+#include <stdexcept>
 #include <string>
-#include <stdexcept>
-#include <iosfwd>
-#include <__functional_base>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
@@ -202,7 +202,7 @@
     void __init(unsigned long long __v, false_type) _NOEXCEPT;
     _LIBCPP_INLINE_VISIBILITY
     void __init(unsigned long long __v, true_type) _NOEXCEPT;
-#endif  // _LIBCPP_CXX03_LANG
+#endif // _LIBCPP_CXX03_LANG
     unsigned long to_ulong(false_type) const;
     _LIBCPP_INLINE_VISIBILITY
     unsigned long to_ulong(true_type) const;
@@ -258,7 +258,7 @@
     _VSTD::fill(__first_ + 1, __first_ + sizeof(__first_)/sizeof(__first_[0]), __storage_type(0));
 }
 
-#endif  // _LIBCPP_CXX03_LANG
+#endif // _LIBCPP_CXX03_LANG
 
 template <size_t _N_words, size_t _Size>
 inline
@@ -380,7 +380,7 @@
 __bitset<_N_words, _Size>::to_ullong(true_type, true_type) const
 {
     unsigned long long __r = __first_[0];
-    for (std::size_t __i = 1; __i < sizeof(unsigned long long) / sizeof(__storage_type); ++__i)
+    for (size_t __i = 1; __i < sizeof(unsigned long long) / sizeof(__storage_type); ++__i)
         __r |= static_cast<unsigned long long>(__first_[__i]) << (sizeof(__storage_type) * CHAR_BIT);
     return __r;
 }
@@ -625,13 +625,13 @@
     explicit _LIBCPP_CONSTEXPR __bitset(unsigned long long) _NOEXCEPT;
 
     _LIBCPP_INLINE_VISIBILITY reference __make_ref(size_t) _NOEXCEPT
-        {return reference(0, 1);}
+        {return reference(nullptr, 1);}
     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __make_ref(size_t) const _NOEXCEPT
-        {return const_reference(0, 1);}
+        {return const_reference(nullptr, 1);}
     _LIBCPP_INLINE_VISIBILITY iterator __make_iter(size_t) _NOEXCEPT
-        {return iterator(0, 0);}
+        {return iterator(nullptr, 0);}
     _LIBCPP_INLINE_VISIBILITY const_iterator __make_iter(size_t) const _NOEXCEPT
-        {return const_iterator(0, 0);}
+        {return const_iterator(nullptr, 0);}
 
     _LIBCPP_INLINE_VISIBILITY void operator&=(const __bitset&) _NOEXCEPT {}
     _LIBCPP_INLINE_VISIBILITY void operator|=(const __bitset&) _NOEXCEPT {}
@@ -775,10 +775,7 @@
     for (; __i < _Mp; ++__i)
     {
         _CharT __c = __str[_Mp - 1 - __i];
-        if (__c == __zero)
-            (*this)[__i] = false;
-        else
-            (*this)[__i] = true;
+        (*this)[__i] = (__c == __one);
     }
     _VSTD::fill(base::__make_iter(__i), base::__make_iter(_Size), false);
 }
@@ -803,10 +800,7 @@
     for (; __i < _Mp; ++__i)
     {
         _CharT __c = __str[__pos + _Mp - 1 - __i];
-        if (_Traits::eq(__c, __zero))
-            (*this)[__i] = false;
-        else
-            (*this)[__i] = true;
+        (*this)[__i] = _Traits::eq(__c, __one);
     }
     _VSTD::fill(base::__make_iter(__i), base::__make_iter(_Size), false);
 }
@@ -990,7 +984,7 @@
 size_t
 bitset<_Size>::count() const _NOEXCEPT
 {
-    return static_cast<size_t>(__count_bool_true(base::__make_iter(0), _Size));
+    return static_cast<size_t>(_VSTD::__count_bool_true(base::__make_iter(0), _Size));
 }
 
 template <size_t _Size>
@@ -1106,4 +1100,4 @@
 
 _LIBCPP_POP_MACROS
 
-#endif  // _LIBCPP_BITSET
+#endif // _LIBCPP_BITSET