diff --git a/include/algorithm b/include/algorithm
index f357177..ee06250 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -39,43 +39,43 @@
     InputIterator for_each_n(InputIterator first, Size n, Function f); // C++17
 
 template <class InputIterator, class T>
-    constexpr InputIterator   // constexpr in C++20
+    constexpr InputIterator     // constexpr in C++20
     find(InputIterator first, InputIterator last, const T& value);
 
 template <class InputIterator, class Predicate>
-    constexpr InputIterator // constexpr in C++20
+    constexpr InputIterator     // constexpr in C++20
     find_if(InputIterator first, InputIterator last, Predicate pred);
 
 template<class InputIterator, class Predicate>
-    InputIterator
+    InputIterator               // constexpr in C++20
     find_if_not(InputIterator first, InputIterator last, Predicate pred);
 
 template <class ForwardIterator1, class ForwardIterator2>
-    ForwardIterator1
+    ForwardIterator1            // constexpr in C++20
     find_end(ForwardIterator1 first1, ForwardIterator1 last1,
              ForwardIterator2 first2, ForwardIterator2 last2);
 
 template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
-    ForwardIterator1
+    ForwardIterator1            // constexpr in C++20
     find_end(ForwardIterator1 first1, ForwardIterator1 last1,
              ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
 
 template <class ForwardIterator1, class ForwardIterator2>
-    ForwardIterator1
+    constexpr ForwardIterator1  // constexpr in C++20
     find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
                   ForwardIterator2 first2, ForwardIterator2 last2);
 
 template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
-    ForwardIterator1
+    constexpr ForwardIterator1  // constexpr in C++20
     find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
                   ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
 
 template <class ForwardIterator>
-    ForwardIterator
+    constexpr ForwardIterator   // constexpr in C++20
     adjacent_find(ForwardIterator first, ForwardIterator last);
 
 template <class ForwardIterator, class BinaryPredicate>
-    ForwardIterator
+    constexpr ForwardIterator   // constexpr in C++20
     adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
 
 template <class InputIterator, class T>
@@ -1016,7 +1016,7 @@
 // find_if_not
 
 template<class _InputIterator, class _Predicate>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
 _InputIterator
 find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred)
 {
@@ -1029,7 +1029,7 @@
 // find_end
 
 template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
-_ForwardIterator1
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
 __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
            _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
            forward_iterator_tag, forward_iterator_tag)
@@ -1071,7 +1071,7 @@
 }
 
 template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
-_BidirectionalIterator1
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator1
 __find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1,
            _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BinaryPredicate __pred,
            bidirectional_iterator_tag, bidirectional_iterator_tag)
@@ -1151,7 +1151,7 @@
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
 _ForwardIterator1
 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
          _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
@@ -1163,7 +1163,7 @@
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
 _ForwardIterator1
 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
          _ForwardIterator2 __first2, _ForwardIterator2 __last2)
@@ -1189,7 +1189,7 @@
 
 
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY  _LIBCPP_CONSTEXPR_AFTER_CXX17
 _ForwardIterator1
 find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
               _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
@@ -1198,7 +1198,7 @@
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY  _LIBCPP_CONSTEXPR_AFTER_CXX17
 _ForwardIterator1
 find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
               _ForwardIterator2 __first2, _ForwardIterator2 __last2)
@@ -1211,7 +1211,7 @@
 // adjacent_find
 
 template <class _ForwardIterator, class _BinaryPredicate>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
 _ForwardIterator
 adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
 {
@@ -1229,7 +1229,7 @@
 }
 
 template <class _ForwardIterator>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
 _ForwardIterator
 adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
 {