[libcxx-commits] [libcxx] [libc++] Refactor ranges::{min, max, min_element, max_element} to use std::__min_element (PR #132418)
Peng Liu via libcxx-commits
libcxx-commits at lists.llvm.org
Fri Mar 21 09:43:21 PDT 2025
https://github.com/winner245 created https://github.com/llvm/llvm-project/pull/132418
Previously, `ranges::min_element` delegated to `ranges::__min_element_impl`, which duplicated the definition of `std::__min_element`. This patch updates `ranges::min_element` to directly call `std::__min_element`, which allows us to remove the redundant code in `ranges::__min_element_impl`.
Upon removal of `ranges::__min_element_impl`, the other ranges algorithms `ranges::{min, max, max_element}`, which previously delegated to `ranges::__min_element_impl`, have been updated to call `std::__min_element` instead.
This refactoring unifies the implementation across these algorithms, ensuring that future optimizations or maintenance work only need to be applied in one place.
>From 0183279513ad412fd363263b75df077449932fc8 Mon Sep 17 00:00:00 2001
From: Peng Liu <winner245 at hotmail.com>
Date: Fri, 21 Mar 2025 12:36:52 -0400
Subject: [PATCH] Refactor ranges::{min, max, min_element, max_element} to use
std::__min_element
---
libcxx/include/__algorithm/ranges_max.h | 6 +++---
.../include/__algorithm/ranges_max_element.h | 6 +++---
libcxx/include/__algorithm/ranges_min.h | 6 +++---
.../include/__algorithm/ranges_min_element.h | 19 +++----------------
4 files changed, 12 insertions(+), 25 deletions(-)
diff --git a/libcxx/include/__algorithm/ranges_max.h b/libcxx/include/__algorithm/ranges_max.h
index f631344422ed5..a8fe13a734f5b 100644
--- a/libcxx/include/__algorithm/ranges_max.h
+++ b/libcxx/include/__algorithm/ranges_max.h
@@ -9,7 +9,7 @@
#ifndef _LIBCPP___ALGORITHM_RANGES_MAX_H
#define _LIBCPP___ALGORITHM_RANGES_MAX_H
-#include <__algorithm/ranges_min_element.h>
+#include <__algorithm/min_element.h>
#include <__assert>
#include <__concepts/copyable.h>
#include <__config>
@@ -57,7 +57,7 @@ struct __max {
__il.begin() != __il.end(), "initializer_list must contain at least one element");
auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool { return std::invoke(__comp, __rhs, __lhs); };
- return *ranges::__min_element_impl(__il.begin(), __il.end(), __comp_lhs_rhs_swapped, __proj);
+ return *std::__min_element(__il.begin(), __il.end(), __comp_lhs_rhs_swapped, __proj);
}
template <input_range _Rp,
@@ -75,7 +75,7 @@ struct __max {
auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool {
return std::invoke(__comp, __rhs, __lhs);
};
- return *ranges::__min_element_impl(std::move(__first), std::move(__last), __comp_lhs_rhs_swapped, __proj);
+ return *std::__min_element(std::move(__first), std::move(__last), __comp_lhs_rhs_swapped, __proj);
} else {
range_value_t<_Rp> __result = *__first;
while (++__first != __last) {
diff --git a/libcxx/include/__algorithm/ranges_max_element.h b/libcxx/include/__algorithm/ranges_max_element.h
index 869f71ecc8d20..db6d5f6b9c276 100644
--- a/libcxx/include/__algorithm/ranges_max_element.h
+++ b/libcxx/include/__algorithm/ranges_max_element.h
@@ -9,7 +9,7 @@
#ifndef _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H
#define _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H
-#include <__algorithm/ranges_min_element.h>
+#include <__algorithm/min_element.h>
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
@@ -40,7 +40,7 @@ struct __max_element {
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip
operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const {
auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool { return std::invoke(__comp, __rhs, __lhs); };
- return ranges::__min_element_impl(__first, __last, __comp_lhs_rhs_swapped, __proj);
+ return std::__min_element(__first, __last, __comp_lhs_rhs_swapped, __proj);
}
template <forward_range _Rp,
@@ -49,7 +49,7 @@ struct __max_element {
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Rp>
operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool { return std::invoke(__comp, __rhs, __lhs); };
- return ranges::__min_element_impl(ranges::begin(__r), ranges::end(__r), __comp_lhs_rhs_swapped, __proj);
+ return std::__min_element(ranges::begin(__r), ranges::end(__r), __comp_lhs_rhs_swapped, __proj);
}
};
diff --git a/libcxx/include/__algorithm/ranges_min.h b/libcxx/include/__algorithm/ranges_min.h
index 302b5d7975b00..9f1c78eaa9e25 100644
--- a/libcxx/include/__algorithm/ranges_min.h
+++ b/libcxx/include/__algorithm/ranges_min.h
@@ -9,7 +9,7 @@
#ifndef _LIBCPP___ALGORITHM_RANGES_MIN_H
#define _LIBCPP___ALGORITHM_RANGES_MIN_H
-#include <__algorithm/ranges_min_element.h>
+#include <__algorithm/min_element.h>
#include <__assert>
#include <__concepts/copyable.h>
#include <__config>
@@ -54,7 +54,7 @@ struct __min {
operator()(initializer_list<_Tp> __il, _Comp __comp = {}, _Proj __proj = {}) const {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
__il.begin() != __il.end(), "initializer_list must contain at least one element");
- return *ranges::__min_element_impl(__il.begin(), __il.end(), __comp, __proj);
+ return *std::__min_element(__il.begin(), __il.end(), __comp, __proj);
}
template <input_range _Rp,
@@ -67,7 +67,7 @@ struct __min {
auto __last = ranges::end(__r);
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__first != __last, "range must contain at least one element");
if constexpr (forward_range<_Rp> && !__is_cheap_to_copy<range_value_t<_Rp>>) {
- return *ranges::__min_element_impl(__first, __last, __comp, __proj);
+ return *std::__min_element(__first, __last, __comp, __proj);
} else {
range_value_t<_Rp> __result = *__first;
while (++__first != __last) {
diff --git a/libcxx/include/__algorithm/ranges_min_element.h b/libcxx/include/__algorithm/ranges_min_element.h
index fb92ae56bcd62..5deb409ccd85e 100644
--- a/libcxx/include/__algorithm/ranges_min_element.h
+++ b/libcxx/include/__algorithm/ranges_min_element.h
@@ -9,6 +9,7 @@
#ifndef _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_H
#define _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_H
+#include <__algorithm/min_element.h>
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
@@ -32,20 +33,6 @@ _LIBCPP_PUSH_MACROS
_LIBCPP_BEGIN_NAMESPACE_STD
namespace ranges {
-
-// TODO(ranges): `ranges::min_element` can now simply delegate to `std::__min_element`.
-template <class _Ip, class _Sp, class _Proj, class _Comp>
-_LIBCPP_HIDE_FROM_ABI constexpr _Ip __min_element_impl(_Ip __first, _Sp __last, _Comp& __comp, _Proj& __proj) {
- if (__first == __last)
- return __first;
-
- _Ip __i = __first;
- while (++__i != __last)
- if (std::invoke(__comp, std::invoke(__proj, *__i), std::invoke(__proj, *__first)))
- __first = __i;
- return __first;
-}
-
struct __min_element {
template <forward_iterator _Ip,
sentinel_for<_Ip> _Sp,
@@ -53,7 +40,7 @@ struct __min_element {
indirect_strict_weak_order<projected<_Ip, _Proj>> _Comp = ranges::less>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip
operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const {
- return ranges::__min_element_impl(__first, __last, __comp, __proj);
+ return std::__min_element(__first, __last, __comp, __proj);
}
template <forward_range _Rp,
@@ -61,7 +48,7 @@ struct __min_element {
indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Rp>
operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
- return ranges::__min_element_impl(ranges::begin(__r), ranges::end(__r), __comp, __proj);
+ return std::__min_element(ranges::begin(__r), ranges::end(__r), __comp, __proj);
}
};
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