@@ -6714,14 +6714,14 @@
 \indexlibraryglobal{stable_sort}%
 \begin{itemdecl}
 template<class RandomAccessIterator>
-  void stable_sort(RandomAccessIterator first, RandomAccessIterator last);
+  constexpr void stable_sort(RandomAccessIterator first, RandomAccessIterator last);
 template<class ExecutionPolicy, class RandomAccessIterator>
   void stable_sort(ExecutionPolicy&& exec,
                    RandomAccessIterator first, RandomAccessIterator last);
 
 template<class RandomAccessIterator, class Compare>
-  void stable_sort(RandomAccessIterator first, RandomAccessIterator last,
-                   Compare comp);
+  constexpr void stable_sort(RandomAccessIterator first, RandomAccessIterator last,
+                             Compare comp);
 template<class ExecutionPolicy, class RandomAccessIterator, class Compare>
   void stable_sort(ExecutionPolicy&& exec,
                    RandomAccessIterator first, RandomAccessIterator last,
@@ -6730,10 +6730,10 @@
 template<@\libconcept{random_access_iterator}@ I, @\libconcept{sentinel_for}@<I> S, class Comp = ranges::less,
          class Proj = identity>
   requires @\libconcept{sortable}@<I, Comp, Proj>
-  I ranges::stable_sort(I first, S last, Comp comp = {}, Proj proj = {});
+  constexpr I ranges::stable_sort(I first, S last, Comp comp = {}, Proj proj = {});
 template<@\libconcept{random_access_range}@ R, class Comp = ranges::less, class Proj = identity>
   requires @\libconcept{sortable}@<iterator_t<R>, Comp, Proj>
-  borrowed_iterator_t<R>
+  constexpr borrowed_iterator_t<R>
     ranges::stable_sort(R&& r, Comp comp = {}, Proj proj = {});
 \end{itemdecl}
 
@@ -7512,7 +7512,8 @@
 \begin{itemdecl}
 template<class BidirectionalIterator, class Predicate>
   BidirectionalIterator
-    stable_partition(BidirectionalIterator first, BidirectionalIterator last, Predicate pred);
+    constexpr stable_partition(BidirectionalIterator first, BidirectionalIterator last,
+                               Predicate pred);
 template<class ExecutionPolicy, class BidirectionalIterator, class Predicate>
   BidirectionalIterator
     stable_partition(ExecutionPolicy&& exec,
@@ -7521,11 +7522,11 @@
 template<@\libconcept{bidirectional_iterator}@ I, @\libconcept{sentinel_for}@<I> S, class Proj = identity,
          @\libconcept{indirect_unary_predicate}@<projected<I, Proj>> Pred>
   requires @\libconcept{permutable}@<I>
-  subrange<I> ranges::stable_partition(I first, S last, Pred pred, Proj proj = {});
+  constexpr subrange<I> ranges::stable_partition(I first, S last, Pred pred, Proj proj = {});
 template<@\libconcept{bidirectional_range}@ R, class Proj = identity,
          @\libconcept{indirect_unary_predicate}@<projected<iterator_t<R>, Proj>> Pred>
   requires @\libconcept{permutable}@<iterator_t<R>>
-  borrowed_subrange_t<R> ranges::stable_partition(R&& r, Pred pred, Proj proj = {});
+  constexpr borrowed_subrange_t<R> ranges::stable_partition(R&& r, Pred pred, Proj proj = {});
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -7792,19 +7793,19 @@
 \indexlibraryglobal{inplace_merge}%
 \begin{itemdecl}
 template<class BidirectionalIterator>
-  void inplace_merge(BidirectionalIterator first,
-                     BidirectionalIterator middle,
-                     BidirectionalIterator last);
+  constexpr void inplace_merge(BidirectionalIterator first,
+                               BidirectionalIterator middle,
+                               BidirectionalIterator last);
 template<class ExecutionPolicy, class BidirectionalIterator>
   void inplace_merge(ExecutionPolicy&& exec,
                      BidirectionalIterator first,
                      BidirectionalIterator middle,
                      BidirectionalIterator last);
 
 template<class BidirectionalIterator, class Compare>
-  void inplace_merge(BidirectionalIterator first,
-                     BidirectionalIterator middle,
-                     BidirectionalIterator last, Compare comp);
+  constexpr void inplace_merge(BidirectionalIterator first,
+                               BidirectionalIterator middle,
+                               BidirectionalIterator last, Compare comp);
 template<class ExecutionPolicy, class BidirectionalIterator, class Compare>
   void inplace_merge(ExecutionPolicy&& exec,
                      BidirectionalIterator first,
@@ -7814,7 +7815,7 @@
 template<@\libconcept{bidirectional_iterator}@ I, @\libconcept{sentinel_for}@<I> S, class Comp = ranges::less,
          class Proj = identity>
   requires @\libconcept{sortable}@<I, Comp, Proj>
-  I ranges::inplace_merge(I first, I middle, S last, Comp comp = {}, Proj proj = {});
+  constexpr I ranges::inplace_merge(I first, I middle, S last, Comp comp = {}, Proj proj = {});
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -7865,7 +7866,7 @@
 \begin{itemdecl}
 template<@\libconcept{bidirectional_range}@ R, class Comp = ranges::less, class Proj = identity>
   requires @\libconcept{sortable}@<iterator_t<R>, Comp, Proj>
-  borrowed_iterator_t<R>
+  constexpr borrowed_iterator_t<R>
     ranges::inplace_merge(R&& r, iterator_t<R> middle, Comp comp = {}, Proj proj = {});
 \end{itemdecl}