1 files changed, 21 insertions, 1 deletions
diff --git a/libcxx/include/__algorithm/make_projected.h b/libcxx/include/__algorithm/make_projected.h
index 8141c4ed176f..6d8ebfd3d90e 100644
--- a/libcxx/include/__algorithm/make_projected.h
+++ b/libcxx/include/__algorithm/make_projected.h
@@ -13,6 +13,8 @@
 #include <__config>
 #include <__functional/identity.h>
 #include <__functional/invoke.h>
+#include <__type_traits/decay.h>
+#include <__type_traits/is_member_pointer.h>
 #include <__utility/forward.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -28,7 +30,7 @@ namespace ranges {
 template <class _Comp, class _Proj>
 _LIBCPP_HIDE_FROM_ABI constexpr static
 decltype(auto) __make_projected_comp(_Comp& __comp, _Proj& __proj) {
-  if constexpr (same_as<_Proj, identity>) {
+  if constexpr (same_as<decay_t<_Proj>, identity> && !is_member_pointer_v<decay_t<_Comp>>) {
     // Avoid creating the lambda and just use the pristine comparator -- for certain algorithms, this would enable
     // optimizations that rely on the type of the comparator.
     return __comp;
@@ -42,6 +44,24 @@ decltype(auto) __make_projected_comp(_Comp& __comp, _Proj& __proj) {
   }
 }
 
+template <class _Comp, class _Proj1, class _Proj2>
+_LIBCPP_HIDE_FROM_ABI constexpr static
+decltype(auto) __make_projected_comp(_Comp& __comp, _Proj1& __proj1, _Proj2& __proj2) {
+  if constexpr (same_as<decay_t<_Proj1>, identity> && same_as<decay_t<_Proj2>, identity> &&
+                !is_member_pointer_v<decay_t<_Comp>>) {
+    // Avoid creating the lambda and just use the pristine comparator -- for certain algorithms, this would enable
+    // optimizations that rely on the type of the comparator.
+    return __comp;
+
+  } else {
+    return [&](auto&& __lhs, auto&& __rhs) {
+      return std::invoke(__comp,
+                        std::invoke(__proj1, std::forward<decltype(__lhs)>(__lhs)),
+                        std::invoke(__proj2, std::forward<decltype(__rhs)>(__rhs)));
+    };
+  }
+}
+
 } // namespace ranges
 
 _LIBCPP_END_NAMESPACE_STD