[libcxx-commits] [libcxx] [DRAFT] [libc++] Add __is_transparently_comparable_v optimizations for set and multiset [Issue 187105] (PR #189735)
Michael Levine via libcxx-commits
libcxx-commits at lists.llvm.org
Tue Mar 31 12:48:20 PDT 2026
https://github.com/levinem created https://github.com/llvm/llvm-project/pull/189735
This PR relates to https://github.com/llvm/llvm-project/issues/187105 and https://github.com/llvm/llvm-project/pull/188799 but only handles the `std::set` and `std::multiset` portion.
It adds `__is_transparently_comparable_v` checks to `std::set` and `std::multiset`'s `find`, `count`, `contains`, `lower_bound`, `upper_bound`, and `equal_range` functions.
Tests in https://github.com/llvm/llvm-project/pull/187345 can be expanded to cover these new optimizations.
Assisted by: Claude Code
>From 1fdca3169109098032e24a1ab3e7991ffaf896c1 Mon Sep 17 00:00:00 2001
From: mlevine55 <mlevine55 at bloomberg.net>
Date: Tue, 31 Mar 2026 14:31:47 -0400
Subject: [PATCH] set and multiset optimizations
Signed-off-by: mlevine55 <mlevine55 at bloomberg.net>
---
libcxx/include/set | 80 ++++++++++++++++++++++++++++++++++------------
1 file changed, 60 insertions(+), 20 deletions(-)
diff --git a/libcxx/include/set b/libcxx/include/set
index 695b6c87e3984..ff1de085c1d8b 100644
--- a/libcxx/include/set
+++ b/libcxx/include/set
@@ -825,11 +825,15 @@ public:
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __tree_.find(__k); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __tree_.find(__k); }
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
return __tree_.find(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
return __tree_.find(__k);
}
@@ -839,7 +843,9 @@ public:
return __tree_.__count_unique(__k);
}
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
return __tree_.__count_multi(__k);
}
@@ -847,7 +853,9 @@ public:
# if _LIBCPP_STD_VER >= 20
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
return find(__k) != end();
}
@@ -864,12 +872,16 @@ public:
// The transparent versions of the lookup functions use the _multi version, since a non-element key is allowed to
// match multiple elements.
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator lower_bound(const _K2& __k) {
return __tree_.__lower_bound_multi(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator lower_bound(const _K2& __k) const {
return __tree_.__lower_bound_multi(__k);
}
@@ -884,11 +896,15 @@ public:
}
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator upper_bound(const _K2& __k) {
return __tree_.__upper_bound_multi(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator upper_bound(const _K2& __k) const {
return __tree_.__upper_bound_multi(__k);
}
@@ -901,11 +917,15 @@ public:
return __tree_.__equal_range_unique(__k);
}
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
return __tree_.__equal_range_multi(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
return __tree_.__equal_range_multi(__k);
}
@@ -1302,11 +1322,15 @@ public:
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __tree_.find(__k); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __tree_.find(__k); }
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
return __tree_.find(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
return __tree_.find(__k);
}
@@ -1316,7 +1340,9 @@ public:
return __tree_.__count_multi(__k);
}
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
return __tree_.__count_multi(__k);
}
@@ -1324,7 +1350,9 @@ public:
# if _LIBCPP_STD_VER >= 20
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
return find(__k) != end();
}
@@ -1339,12 +1367,16 @@ public:
}
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator lower_bound(const _K2& __k) {
return __tree_.__lower_bound_multi(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator lower_bound(const _K2& __k) const {
return __tree_.__lower_bound_multi(__k);
}
@@ -1359,11 +1391,15 @@ public:
}
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator upper_bound(const _K2& __k) {
return __tree_.__upper_bound_multi(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator upper_bound(const _K2& __k) const {
return __tree_.__upper_bound_multi(__k);
}
@@ -1376,11 +1412,15 @@ public:
return __tree_.__equal_range_multi(__k);
}
# if _LIBCPP_STD_VER >= 14
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
return __tree_.__equal_range_multi(__k);
}
- template <typename _K2, class _Comp = _Compare, enable_if_t<__is_transparent_v<_Comp>, int> = 0>
+ template <typename _K2,
+ class _Comp = _Compare,
+ enable_if_t<__is_transparent_v<_Comp> || __is_transparently_comparable_v<_Comp, key_type, _K2>, int> = 0>
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
return __tree_.__equal_range_multi(__k);
}
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