Address ldionne's review comments

Author: winner245

libcxx/include/__algorithm/for_each.h

@@ -11,6 +11,7 @@
 #define _LIBCPP___ALGORITHM_FOR_EACH_H
 
 #include <__algorithm/for_each_segment.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__iterator/segmented_iterator.h>
 #include <__ranges/movable_box.h>
@@ -26,20 +27,20 @@ _LIBCPP_PUSH_MACROS
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _InputIterator, class _Function>
+template <class, class _InputIterator, class _Function>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Function
-for_each(_InputIterator __first, _InputIterator __last, _Function __f) {
+__for_each(_InputIterator __first, _InputIterator __last, _Function& __f) {
   for (; __first != __last; ++__first)
     __f(*__first);
-  return __f;
+  return std::move(__f);
 }
 
 // __movable_box is available in C++20, but is actually a copyable-box, so optimization is only correct in C++23
 #if _LIBCPP_STD_VER >= 23
-template <class _SegmentedIterator, class _Function>
+template <class, class _SegmentedIterator, class _Function>
   requires __is_segmented_iterator<_SegmentedIterator>::value
 _LIBCPP_HIDE_FROM_ABI constexpr _Function
-for_each(_SegmentedIterator __first, _SegmentedIterator __last, _Function __func) {
+for_each(_SegmentedIterator __first, _SegmentedIterator __last, _Function& __func) {
   ranges::__movable_box<_Function> __wrapped_func(in_place, std::move(__func));
   std::__for_each_segment(__first, __last, [&](auto __lfirst, auto __llast) {
     __wrapped_func =
@@ -49,6 +50,12 @@ for_each(_SegmentedIterator __first, _SegmentedIterator __last, _Function __func
 }
 #endif // _LIBCPP_STD_VER >= 23
 
+template <class _InputIterator, class _Function>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Function
+for_each(_InputIterator __first, _InputIterator __last, _Function __f) {
+  return __for_each<_ClassicAlgPolicy>(__first, __last, __f);
+}
+
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS

libcxx/include/__algorithm/for_each_n.h

@@ -11,6 +11,7 @@
 #define _LIBCPP___ALGORITHM_FOR_EACH_N_H
 
 #include <__algorithm/for_each.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/segmented_iterator.h>
@@ -53,7 +54,7 @@ template <class _InputIterator,
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
 for_each_n(_InputIterator __first, _Size __orig_n, _Function __f) {
   _InputIterator __last = __first + __orig_n;
-  std::for_each(__first, __last, __f);
+  std::__for_each<_ClassicAlgPolicy>(__first, __last, __f);
   return __last;
 }
 

libcxx/include/__algorithm/ranges_for_each.h

@@ -11,6 +11,7 @@
 
 #include <__algorithm/for_each.h>
 #include <__algorithm/in_fun_result.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__functional/identity.h>
 #include <__functional/invoke.h>
@@ -45,7 +46,8 @@ struct __for_each {
     if constexpr (random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>) {
       auto __n   = __last - __first;
       auto __end = __first + __n;
-      std::for_each(__first, __end, [&](auto&& __val) { std::invoke(__func, std::invoke(__proj, __val)); });
+      auto __f   = [&](auto&& __val) { std::invoke(__func, std::invoke(__proj, __val)); };
+      std::__for_each<_RangeAlgPolicy>(__first, __end, __f);
       return {std::move(__end), std::move(__func)};
     } else {
       for (; __first != __last; ++__first)

libcxx/include/__algorithm/ranges_for_each_n.h

@@ -11,6 +11,7 @@
 
 #include <__algorithm/for_each.h>
 #include <__algorithm/in_fun_result.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__functional/identity.h>
 #include <__functional/invoke.h>
@@ -43,7 +44,8 @@ struct __for_each_n {
   operator()(_Iter __first, iter_difference_t<_Iter> __count, _Func __func, _Proj __proj = {}) const {
     if constexpr (random_access_iterator<_Iter>) {
       auto __last = __first + __count;
-      std::for_each(__first, __last, [&](auto&& __val) { std::invoke(__func, std::invoke(__proj, __val)); });
+      auto __f    = [&](auto&& __val) { std::invoke(__func, std::invoke(__proj, __val)); };
+      std::__for_each<_RangeAlgPolicy>(__first, __last, __f);
       return {std::move(__last), std::move(__func)};
     } else {
       while (__count-- > 0) {

libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/for_each_n.pass.cpp

@@ -47,7 +47,7 @@ struct deque_test {
 
 /*TEST_CONSTEXPR_CXX23*/
 void test_segmented_deque_iterator() { // TODO: Mark as TEST_CONSTEXPR_CXX23 once std::deque is constexpr
-  // check that segmented iterators work properly
+  // check that segmented deque iterators work properly
   int sizes[] = {0, 1, 2, 1023, 1024, 1025, 2047, 2048, 2049};
   for (const int size : sizes) {
     std::deque<int> d(size);

libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/ranges.for_each.pass.cpp

@@ -127,7 +127,7 @@ struct deque_test {
 
 /*TEST_CONSTEXPR_CXX23*/
 void test_segmented_deque_iterator() { // TODO: Mark as TEST_CONSTEXPR_CXX23 once std::deque is constexpr
-  // check that segmented iterators work properly
+  // check that segmented deque iterators work properly
   int sizes[] = {0, 1, 2, 1023, 1024, 1025, 2047, 2048, 2049};
   for (const int size : sizes) {
     std::deque<int> d(size);

libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/ranges.for_each_n.pass.cpp

@@ -83,7 +83,7 @@ struct deque_test {
 
 /*TEST_CONSTEXPR_CXX23*/
 void test_segmented_deque_iterator() { // TODO: Mark as TEST_CONSTEXPR_CXX23 once std::deque is constexpr
-  // check that segmented iterators work properly
+  // check that segmented deque iterators work properly
   int sizes[] = {0, 1, 2, 1023, 1024, 1025, 2047, 2048, 2049};
   for (const int size : sizes) {
     std::deque<int> d(size);