[libc++] Optimize ranges::for_each for iterating over __trees

[philnik777]

Benchmark                                             89eef941c4ed    b96071c259fb    Difference    % Difference
--------------------------------------------------  --------------  --------------  ------------  --------------
rng::for_each(set<int>)/32                                   34.61           26.27         -8.34         -24.10%
rng::for_each(set<int>)/50                                   63.97           39.65        -24.32         -38.02%
rng::for_each(set<int>)/8                                     4.56            6.52          1.96          42.95%
rng::for_each(set<int>)/8192                              19102.12         8406.37     -10695.75         -55.99%
rng::for_each(set<int>::iterator)/32                         34.61           27.76         -6.85         -19.80%
rng::for_each(set<int>::iterator)/50                         63.98           41.98        -22.00         -34.38%
rng::for_each(set<int>::iterator)/8                           4.47            5.81          1.34          29.95%
rng::for_each(set<int>::iterator)/8192                    19055.30         8711.55     -10343.76         -54.28%

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff origin/main HEAD --extensions ,h,cpp -- libcxx/include/__algorithm/specialized_algorithms.h libcxx/include/__algorithm/for_each.h libcxx/include/__algorithm/ranges_for_each.h libcxx/include/__tree libcxx/include/map libcxx/include/set libcxx/test/benchmarks/algorithms/nonmodifying/for_each.bench.cpp libcxx/test/std/algorithms/alg.nonmodifying/alg.foreach/for_each.pass.cpp --diff_from_common_commit

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⚠️

View the diff from clang-format here.

diff --git a/libcxx/include/__algorithm/specialized_algorithms.h b/libcxx/include/__algorithm/specialized_algorithms.h
index 45078e2df..7cb0a2115 100644
--- a/libcxx/include/__algorithm/specialized_algorithms.h
+++ b/libcxx/include/__algorithm/specialized_algorithms.h
@@ -19,7 +19,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 // FIXME: This should really be an enum
 namespace _Algorithm {
-  struct __for_each {};
+struct __for_each {};
 } // namespace _Algorithm
 
 template <class, class>
diff --git a/libcxx/include/__tree b/libcxx/include/__tree
index d8e4a6da4..026cb00e1 100644
--- a/libcxx/include/__tree
+++ b/libcxx/include/__tree
@@ -1552,9 +1552,9 @@ struct __specialized_algorithm<_Algorithm::__for_each, __tree<_Tp, _Compare, _Al
   using __node_pointer _LIBCPP_NODEBUG = typename __tree<_Tp, _Compare, _Allocator>::__node_pointer;
 
   template <class _Func, class _Proj>
-#ifndef _LIBCPP_COMPILER_GCC
+#  ifndef _LIBCPP_COMPILER_GCC
   _LIBCPP_HIDE_FROM_ABI
-#endif
+#  endif
   static void __impl(__node_pointer __root, _Func& __func, _Proj& __proj) {
     if (__root->__left_)
       __impl(static_cast<__node_pointer>(__root->__left_), __func, __proj);
diff --git a/libcxx/include/map b/libcxx/include/map
index 99bda5702..3be31945c 100644
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -1440,8 +1440,8 @@ struct __specialized_algorithm<_Algorithm::__for_each, map<_Key, _Tp, _Compare,
   // set's begin() and end() are identical with and without const qualifiaction
   template <class _Map, class _Func>
   _LIBCPP_HIDE_FROM_ABI static auto operator()(_Map&& __map, _Func __func) {
-    auto [_, __func2] = __specialized_algorithm<_Algorithm::__for_each, typename __map::__base>()(
-        __map.__tree_, std::move(__func));
+    auto [_, __func2] =
+        __specialized_algorithm<_Algorithm::__for_each, typename __map::__base>()(__map.__tree_, std::move(__func));
     return std::make_pair(__map.end(), std::move(__func2));
   }
 };
@@ -2024,8 +2024,8 @@ struct __specialized_algorithm<_Algorithm::__for_each, multimap<_Key, _Tp, _Comp
   // set's begin() and end() are identical with and without const qualifiaction
   template <class _Map, class _Func>
   _LIBCPP_HIDE_FROM_ABI static auto operator()(_Map&& __map, _Func __func) {
-    auto [_, __func2] = __specialized_algorithm<_Algorithm::__for_each, typename __map::__base>()(
-        __map.__tree_, std::move(__func));
+    auto [_, __func2] =
+        __specialized_algorithm<_Algorithm::__for_each, typename __map::__base>()(__map.__tree_, std::move(__func));
     return std::make_pair(__map.end(), std::move(__func2));
   }
 };