[libc++] Optimize copy construction and assignment of __tree #151304

philnik777 · 2025-07-30T10:26:31Z

----------------------------------------------------------------------------------------------------------
Benchmark                                                                              old             new
----------------------------------------------------------------------------------------------------------
std::map<int, int>::ctor(const&)/0                                                 15.5 ns         14.9 ns
std::map<int, int>::ctor(const&)/32                                                 474 ns          321 ns
std::map<int, int>::ctor(const&)/1024                                             24591 ns        11101 ns
std::map<int, int>::ctor(const&)/8192                                            236153 ns        98868 ns
std::map<std::string, int>::ctor(const&)/0                                         15.2 ns         14.9 ns
std::map<std::string, int>::ctor(const&)/32                                        2673 ns         2340 ns
std::map<std::string, int>::ctor(const&)/1024                                    115354 ns        86088 ns
std::map<std::string, int>::ctor(const&)/8192                                   1298510 ns       626876 ns
std::map<int, int>::operator=(const&) (into cleared Container)/0                   16.5 ns         16.1 ns
std::map<int, int>::operator=(const&) (into cleared Container)/32                   548 ns          323 ns
std::map<int, int>::operator=(const&) (into cleared Container)/1024               28418 ns        11026 ns
std::map<int, int>::operator=(const&) (into cleared Container)/8192              281827 ns        97113 ns
std::map<int, int>::operator=(const&) (into populated Container)/0                 2.42 ns         1.85 ns
std::map<int, int>::operator=(const&) (into populated Container)/32                 369 ns         73.0 ns
std::map<int, int>::operator=(const&) (into populated Container)/1024             24078 ns         2322 ns
std::map<int, int>::operator=(const&) (into populated Container)/8192            266537 ns        22963 ns
std::map<std::string, int>::operator=(const&) (into cleared Container)/0           16.6 ns         16.2 ns
std::map<std::string, int>::operator=(const&) (into cleared Container)/32          2614 ns         1622 ns
std::map<std::string, int>::operator=(const&) (into cleared Container)/1024      116826 ns        63281 ns
std::map<std::string, int>::operator=(const&) (into cleared Container)/8192     1316655 ns       649177 ns
std::map<std::string, int>::operator=(const&) (into populated Container)/0         2.42 ns         1.89 ns
std::map<std::string, int>::operator=(const&) (into populated Container)/32        1264 ns          581 ns
std::map<std::string, int>::operator=(const&) (into populated Container)/1024    238826 ns        39943 ns
std::map<std::string, int>::operator=(const&) (into populated Container)/8192   2412327 ns       379456 ns

Fixes #77658
Fixes #62571

llvmbot · 2025-07-30T12:34:27Z

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

----------------------------------------------------------------------------------------------------------
Benchmark                                                                              old             new
----------------------------------------------------------------------------------------------------------
std::map&lt;int, int&gt;::ctor(const&amp;)/0                                                 15.5 ns         14.9 ns
std::map&lt;int, int&gt;::ctor(const&amp;)/32                                                 474 ns          321 ns
std::map&lt;int, int&gt;::ctor(const&amp;)/1024                                             24591 ns        11101 ns
std::map&lt;int, int&gt;::ctor(const&amp;)/8192                                            236153 ns        98868 ns
std::map&lt;std::string, int&gt;::ctor(const&amp;)/0                                         15.2 ns         14.9 ns
std::map&lt;std::string, int&gt;::ctor(const&amp;)/32                                        2673 ns         2340 ns
std::map&lt;std::string, int&gt;::ctor(const&amp;)/1024                                    115354 ns        86088 ns
std::map&lt;std::string, int&gt;::ctor(const&amp;)/8192                                   1298510 ns       626876 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into cleared Container)/0                   16.5 ns         16.1 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into cleared Container)/32                   548 ns          323 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into cleared Container)/1024               28418 ns        11026 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into cleared Container)/8192              281827 ns        97113 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into populated Container)/0                 2.42 ns         1.85 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into populated Container)/32                 369 ns         73.0 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into populated Container)/1024             24078 ns         2322 ns
std::map&lt;int, int&gt;::operator=(const&amp;) (into populated Container)/8192            266537 ns        22963 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into cleared Container)/0           16.6 ns         16.2 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into cleared Container)/32          2614 ns         1622 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into cleared Container)/1024      116826 ns        63281 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into cleared Container)/8192     1316655 ns       649177 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into populated Container)/0         2.42 ns         1.89 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into populated Container)/32        1264 ns          581 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into populated Container)/1024    238826 ns        39943 ns
std::map&lt;std::string, int&gt;::operator=(const&amp;) (into populated Container)/8192   2412327 ns       379456 ns

Full diff: https://github.com/llvm/llvm-project/pull/151304.diff

6 Files Affected:

(modified) libcxx/docs/ReleaseNotes/22.rst (+3)
(modified) libcxx/include/__tree (+105-13)
(modified) libcxx/include/map (+2-6)
(modified) libcxx/include/set (+2-6)
(modified) libcxx/test/benchmarks/containers/associative/associative_container_benchmarks.h (+16-1)
(modified) libcxx/test/benchmarks/containers/associative/map.bench.cpp (+1)

diff --git a/libcxx/docs/ReleaseNotes/22.rst b/libcxx/docs/ReleaseNotes/22.rst
index 15bf46d44b07f..8b8dce5083149 100644
--- a/libcxx/docs/ReleaseNotes/22.rst
+++ b/libcxx/docs/ReleaseNotes/22.rst
@@ -43,6 +43,9 @@ Implemented Papers
 Improvements and New Features
 -----------------------------
 
+- The performance of ``map::map(const map&)`` has been improved up to 2.3x
+- The performance of ``map::operator=(const map&)`` has been improved by up to 11x
+
 Deprecations and Removals
 -------------------------
 
diff --git a/libcxx/include/__tree b/libcxx/include/__tree
index f8bb4f01b1e29..c1f667b7ec74f 100644
--- a/libcxx/include/__tree
+++ b/libcxx/include/__tree
@@ -1213,6 +1213,80 @@ private:
     __node_pointer __cache_root_;
     __node_pointer __cache_elem_;
   };
+
+  class __tree_deleter {
+    __node_allocator& __alloc_;
+
+  public:
+    using pointer = __node_pointer;
+
+    _LIBCPP_HIDE_FROM_ABI __tree_deleter(__node_allocator& __alloc) : __alloc_(__alloc) {}
+
+    void operator()(__node_pointer __ptr) {
+      if (!__ptr)
+        return;
+
+      (*this)(static_cast<__node_pointer>(__ptr->__left_));
+
+      auto __right = __ptr->__right_;
+
+      __node_traits::destroy(__alloc_, std::addressof(__ptr->__value_));
+      __node_traits::deallocate(__alloc_, __ptr, 1);
+
+      (*this)(static_cast<__node_pointer>(__right));
+    }
+  };
+
+  _LIBCPP_HIDE_FROM_ABI __node_pointer __copy_construct_tree(__node_pointer __src) {
+    if (!__src)
+      return nullptr;
+
+    __node_holder __new_node = __construct_node(__src->__value_);
+
+    unique_ptr<__node, __tree_deleter> __left(
+        __copy_construct_tree(static_cast<__node_pointer>(__src->__left_)), __node_alloc_);
+    __node_pointer __right = __copy_construct_tree(static_cast<__node_pointer>(__src->__right_));
+
+    __node_pointer __new_node_ptr = __new_node.release();
+
+    __new_node_ptr->__is_black_ = __src->__is_black_;
+    __new_node_ptr->__left_     = static_cast<__node_base_pointer>(__left.release());
+    __new_node_ptr->__right_    = static_cast<__node_base_pointer>(__right);
+    if (__new_node_ptr->__left_)
+      __new_node_ptr->__left_->__parent_ = static_cast<__end_node_pointer>(__new_node_ptr);
+    if (__new_node_ptr->__right_)
+      __new_node_ptr->__right_->__parent_ = static_cast<__end_node_pointer>(__new_node_ptr);
+    return __new_node_ptr;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI __node_pointer __copy_assign_tree(__node_pointer __assign_to, __node_pointer __src) {
+    if (!__src) {
+      destroy(__assign_to);
+      return nullptr;
+    }
+
+    __assign_value(__assign_to->__value_, __src->__value_);
+
+    if (__assign_to->__left_) {
+      __assign_to->__left_ = static_cast<__node_base_pointer>(__copy_assign_tree(
+          static_cast<__node_pointer>(__assign_to->__left_), static_cast<__node_pointer>(__src->__left_)));
+    } else if (__src->__left_) {
+      auto __new_left       = __copy_construct_tree(static_cast<__node_pointer>(__src->__left_));
+      __assign_to->__left_  = static_cast<__node_base_pointer>(__new_left);
+      __new_left->__parent_ = static_cast<__end_node_pointer>(__assign_to);
+    }
+
+    if (__assign_to->__right_) {
+      __assign_to->__right_ = static_cast<__node_base_pointer>(__copy_assign_tree(
+          static_cast<__node_pointer>(__assign_to->__right_), static_cast<__node_pointer>(__src->__right_)));
+    } else if (__src->__right_) {
+      auto __new_right       = __copy_construct_tree(static_cast<__node_pointer>(__src->__right_));
+      __assign_to->__right_  = static_cast<__node_base_pointer>(__new_right);
+      __new_right->__parent_ = static_cast<__end_node_pointer>(__assign_to);
+    }
+
+    return __assign_to;
+  }
 };
 
 template <class _Tp, class _Compare, class _Allocator>
@@ -1277,11 +1351,28 @@ __tree<_Tp, _Compare, _Allocator>::_DetachedTreeCache::__detach_next(__node_poin
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>& __tree<_Tp, _Compare, _Allocator>::operator=(const __tree& __t) {
-  if (this != std::addressof(__t)) {
-    value_comp() = __t.value_comp();
-    __copy_assign_alloc(__t);
-    __assign_multi(__t.begin(), __t.end());
+  if (this == std::addressof(__t))
+    return *this;
+
+  value_comp() = __t.value_comp();
+  __copy_assign_alloc(__t);
+
+  if (__t.size() == 0) {
+    clear();
+    return *this;
+  }
+
+  if (__size_ != 0) {
+    __end_node_.__left_ = static_cast<__node_base_pointer>(__copy_assign_tree(
+        static_cast<__node_pointer>(__end_node_.__left_), static_cast<__node_pointer>(__t.__end_node_.__left_)));
+  } else {
+    __end_node_.__left_ =
+        static_cast<__node_base_pointer>(__copy_construct_tree(static_cast<__node_pointer>(__t.__end_node_.__left_)));
+    __end_node_.__left_->__parent_ = __end_node();
   }
+  __begin_node_ = static_cast<__end_node_pointer>(std::__tree_min(static_cast<__node_base_pointer>(__end_node())));
+  __size_       = __t.__size_;
+
   return *this;
 }
 
@@ -1327,11 +1418,18 @@ void __tree<_Tp, _Compare, _Allocator>::__assign_multi(_InputIterator __first, _
 
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(const __tree& __t)
-    : __begin_node_(),
+    : __begin_node_(__end_node()),
       __node_alloc_(__node_traits::select_on_container_copy_construction(__t.__node_alloc())),
       __size_(0),
       __value_comp_(__t.value_comp()) {
-  __begin_node_ = __end_node();
+  if (__t.__size_ == 0)
+    return;
+
+  __end_node_.__left_ =
+      static_cast<__node_base_pointer>(__copy_construct_tree(static_cast<__node_pointer>(__t.__end_node_.__left_)));
+  __end_node_.__left_->__parent_ = __end_node();
+  __begin_node_ = static_cast<__end_node_pointer>(std::__tree_min(static_cast<__node_base_pointer>(__end_node())));
+  __size_       = __t.__size_;
 }
 
 template <class _Tp, class _Compare, class _Allocator>
@@ -1430,13 +1528,7 @@ __tree<_Tp, _Compare, _Allocator>::~__tree() {
 
 template <class _Tp, class _Compare, class _Allocator>
 void __tree<_Tp, _Compare, _Allocator>::destroy(__node_pointer __nd) _NOEXCEPT {
-  if (__nd != nullptr) {
-    destroy(static_cast<__node_pointer>(__nd->__left_));
-    destroy(static_cast<__node_pointer>(__nd->__right_));
-    __node_allocator& __na = __node_alloc();
-    __node_traits::destroy(__na, std::addressof(__nd->__value_));
-    __node_traits::deallocate(__na, __nd, 1);
-  }
+  (__tree_deleter(__node_alloc_))(__nd);
 }
 
 template <class _Tp, class _Compare, class _Allocator>
diff --git a/libcxx/include/map b/libcxx/include/map
index 2251565801470..0a43bd09a0b16 100644
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -970,7 +970,7 @@ public:
       : map(from_range, std::forward<_Range>(__range), key_compare(), __a) {}
 #  endif
 
-  _LIBCPP_HIDE_FROM_ABI map(const map& __m) : __tree_(__m.__tree_) { insert(__m.begin(), __m.end()); }
+  _LIBCPP_HIDE_FROM_ABI map(const map& __m) = default;
 
   _LIBCPP_HIDE_FROM_ABI map& operator=(const map& __m) = default;
 
@@ -1637,11 +1637,7 @@ public:
       : multimap(from_range, std::forward<_Range>(__range), key_compare(), __a) {}
 #  endif
 
-  _LIBCPP_HIDE_FROM_ABI multimap(const multimap& __m)
-      : __tree_(__m.__tree_.value_comp(),
-                __alloc_traits::select_on_container_copy_construction(__m.__tree_.__alloc())) {
-    insert(__m.begin(), __m.end());
-  }
+  _LIBCPP_HIDE_FROM_ABI multimap(const multimap& __m) = default;
 
   _LIBCPP_HIDE_FROM_ABI multimap& operator=(const multimap& __m) = default;
 
diff --git a/libcxx/include/set b/libcxx/include/set
index 1f2fd7fc91bbb..342a5294c814f 100644
--- a/libcxx/include/set
+++ b/libcxx/include/set
@@ -660,7 +660,7 @@ public:
       : set(from_range, std::forward<_Range>(__range), key_compare(), __a) {}
 #  endif
 
-  _LIBCPP_HIDE_FROM_ABI set(const set& __s) : __tree_(__s.__tree_) { insert(__s.begin(), __s.end()); }
+  _LIBCPP_HIDE_FROM_ABI set(const set& __s) = default;
 
   _LIBCPP_HIDE_FROM_ABI set& operator=(const set& __s) = default;
 
@@ -1119,11 +1119,7 @@ public:
       : multiset(from_range, std::forward<_Range>(__range), key_compare(), __a) {}
 #  endif
 
-  _LIBCPP_HIDE_FROM_ABI multiset(const multiset& __s)
-      : __tree_(__s.__tree_.value_comp(),
-                __alloc_traits::select_on_container_copy_construction(__s.__tree_.__alloc())) {
-    insert(__s.begin(), __s.end());
-  }
+  _LIBCPP_HIDE_FROM_ABI multiset(const multiset& __s) = default;
 
   _LIBCPP_HIDE_FROM_ABI multiset& operator=(const multiset& __s) = default;
 
diff --git a/libcxx/test/benchmarks/containers/associative/associative_container_benchmarks.h b/libcxx/test/benchmarks/containers/associative/associative_container_benchmarks.h
index 0ff7f15164d8a..6cf2dcfc59e13 100644
--- a/libcxx/test/benchmarks/containers/associative/associative_container_benchmarks.h
+++ b/libcxx/test/benchmarks/containers/associative/associative_container_benchmarks.h
@@ -151,7 +151,7 @@ void associative_container_benchmarks(std::string container) {
   /////////////////////////
   // Assignment
   /////////////////////////
-  bench("operator=(const&)", [=](auto& st) {
+  bench("operator=(const&) (into cleared Container)", [=](auto& st) {
     const std::size_t size = st.range(0);
     std::vector<Value> in  = make_value_types(generate_unique_keys(size));
     Container src(in.begin(), in.end());
@@ -172,6 +172,21 @@ void associative_container_benchmarks(std::string container) {
     }
   });
 
+  bench("operator=(const&) (into populated Container)", [=](auto& st) {
+    const std::size_t size = st.range(0);
+    std::vector<Value> in  = make_value_types(generate_unique_keys(size));
+    Container src(in.begin(), in.end());
+    Container c[BatchSize];
+
+    while (st.KeepRunningBatch(BatchSize)) {
+      for (std::size_t i = 0; i != BatchSize; ++i) {
+        c[i] = src;
+        benchmark::DoNotOptimize(c[i]);
+        benchmark::ClobberMemory();
+      }
+    }
+  });
+
   /////////////////////////
   // Insertion
   /////////////////////////
diff --git a/libcxx/test/benchmarks/containers/associative/map.bench.cpp b/libcxx/test/benchmarks/containers/associative/map.bench.cpp
index cee669ae0a667..bd664dbb56ee7 100644
--- a/libcxx/test/benchmarks/containers/associative/map.bench.cpp
+++ b/libcxx/test/benchmarks/containers/associative/map.bench.cpp
@@ -29,6 +29,7 @@ struct support::adapt_operations<std::map<K, V>> {
 
 int main(int argc, char** argv) {
   support::associative_container_benchmarks<std::map<int, int>>("std::map<int, int>");
+  support::associative_container_benchmarks<std::map<std::string, int>>("std::map<std::string, int>");
 
   benchmark::Initialize(&argc, argv);
   benchmark::RunSpecifiedBenchmarks();

ldionne

I think this is amazing!

ldionne · 2025-07-30T13:37:47Z

libcxx/include/__tree

@@ -1213,6 +1213,80 @@ private:
    __node_pointer __cache_root_;
    __node_pointer __cache_elem_;


Can you please add a comment explaining what you learned about our __tree implementation? This can be a followup NFC patch, but I think it would be useful because none of it is documented at the moment.

libcxx/include/__tree

ldionne · 2025-07-30T14:04:26Z

libcxx/include/__tree

@@ -1277,11 +1351,28 @@ __tree<_Tp, _Compare, _Allocator>::_DetachedTreeCache::__detach_next(__node_poin



As a follow-up, I might clean up these __assign_multi and __assign_unique methods which seem a bit like dead weight now.

libcxx/include/__tree

libcxx/include/map

libcxx/test/benchmarks/containers/associative/associative_container_benchmarks.h

libcxx/test/benchmarks/containers/associative/map.bench.cpp

github-actions · 2025-07-31T13:04:37Z

✅ With the latest revision this PR passed the C/C++ code formatter.

libcxx/test/std/containers/associative/map/map.cons/copy.pass.cpp

libcxx/test/std/containers/associative/map/map.cons/copy_alloc.pass.cpp

libcxx/test/std/containers/associative/map/map.cons/copy_assign.pass.cpp

ldionne

This looks great, thanks! LGTM with a few last minor comments.

libcxx/include/__tree

libcxx/test/benchmarks/containers/associative/associative_container_benchmarks.h

libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp

alazarev · 2025-08-05T17:04:21Z

Looks like this PR broke ubsan:
https://lab.llvm.org/buildbot/#/builders/25/builds/10410/steps/2/logs/stdio

…lvm#151304)" This reverts commit 1cac2be.

This has been introduced by #151304. This problem is diagnosed by UBSan with optimizations enabled. Since we run UBSan only with optimizations disabled currently, this isn't caught in our CI. We should look into enabling UBSan with optimizations enabled to catch these sorts of issues before landing a patch.

This has been introduced by llvm#151304. This problem is diagnosed by UBSan with optimizations enabled. Since we run UBSan only with optimizations disabled currently, this isn't caught in our CI. We should look into enabling UBSan with optimizations enabled to catch these sorts of issues before landing a patch.

This has been introduced by #151304. This problem is diagnosed by UBSan with optimizations enabled. Since we run UBSan only with optimizations disabled currently, this isn't caught in our CI. We should look into enabling UBSan with optimizations enabled to catch these sorts of issues before landing a patch.

…1304) ``` ---------------------------------------------------------------------------------------------------------- Benchmark old new ---------------------------------------------------------------------------------------------------------- std::map<int, int>::ctor(const&)/0 15.5 ns 14.9 ns std::map<int, int>::ctor(const&)/32 474 ns 321 ns std::map<int, int>::ctor(const&)/1024 24591 ns 11101 ns std::map<int, int>::ctor(const&)/8192 236153 ns 98868 ns std::map<std::string, int>::ctor(const&)/0 15.2 ns 14.9 ns std::map<std::string, int>::ctor(const&)/32 2673 ns 2340 ns std::map<std::string, int>::ctor(const&)/1024 115354 ns 86088 ns std::map<std::string, int>::ctor(const&)/8192 1298510 ns 626876 ns std::map<int, int>::operator=(const&) (into cleared Container)/0 16.5 ns 16.1 ns std::map<int, int>::operator=(const&) (into cleared Container)/32 548 ns 323 ns std::map<int, int>::operator=(const&) (into cleared Container)/1024 28418 ns 11026 ns std::map<int, int>::operator=(const&) (into cleared Container)/8192 281827 ns 97113 ns std::map<int, int>::operator=(const&) (into populated Container)/0 2.42 ns 1.85 ns std::map<int, int>::operator=(const&) (into populated Container)/32 369 ns 73.0 ns std::map<int, int>::operator=(const&) (into populated Container)/1024 24078 ns 2322 ns std::map<int, int>::operator=(const&) (into populated Container)/8192 266537 ns 22963 ns std::map<std::string, int>::operator=(const&) (into cleared Container)/0 16.6 ns 16.2 ns std::map<std::string, int>::operator=(const&) (into cleared Container)/32 2614 ns 1622 ns std::map<std::string, int>::operator=(const&) (into cleared Container)/1024 116826 ns 63281 ns std::map<std::string, int>::operator=(const&) (into cleared Container)/8192 1316655 ns 649177 ns std::map<std::string, int>::operator=(const&) (into populated Container)/0 2.42 ns 1.89 ns std::map<std::string, int>::operator=(const&) (into populated Container)/32 1264 ns 581 ns std::map<std::string, int>::operator=(const&) (into populated Container)/1024 238826 ns 39943 ns std::map<std::string, int>::operator=(const&) (into populated Container)/8192 2412327 ns 379456 ns ``` Fixes llvm#77658 Fixes llvm#62571

This has been introduced by llvm#151304. This problem is diagnosed by UBSan with optimizations enabled. Since we run UBSan only with optimizations disabled currently, this isn't caught in our CI. We should look into enabling UBSan with optimizations enabled to catch these sorts of issues before landing a patch.

philnik777 force-pushed the optimize_tree_copy branch from 01b932d to 651b570 Compare July 30, 2025 11:36

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philnik777 requested a review from a team as a code owner July 30, 2025 12:33

llvmbot added the libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi. label Jul 30, 2025

ldionne reviewed Jul 30, 2025

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ldionne added the performance label Jul 30, 2025

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philnik777 force-pushed the optimize_tree_copy branch from 651b570 to 97e4cc5 Compare July 31, 2025 13:02

ldionne reviewed Jul 31, 2025

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philnik777 force-pushed the optimize_tree_copy branch from 88d4197 to cc5178c Compare August 4, 2025 12:10

[libc++] Optimize copy construction and assignment of __tree

da4f174

philnik777 force-pushed the optimize_tree_copy branch from cc5178c to da4f174 Compare August 4, 2025 12:45

philnik777 merged commit 1cac2be into llvm:main Aug 5, 2025
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philnik777 deleted the optimize_tree_copy branch August 5, 2025 07:49

alazarev added a commit to alazarev/llvm-project that referenced this pull request Aug 5, 2025

Revert "[libc++] Optimize copy construction and assignment of __tree (l…

36c8b1e

…lvm#151304)" This reverts commit 1cac2be.

alazarev mentioned this pull request Aug 5, 2025

Revert "[libc++] Optimize copy construction and assignment of __tree" #152180

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vitalybuka mentioned this pull request Aug 5, 2025

Investigate why CI or check-cxx with ubsan does not detect the issue #152184

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philnik777 mentioned this pull request Aug 6, 2025

[libc++] Fix incorrect down cast in __tree::operator= #152285

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		@@ -1213,6 +1213,80 @@ private:
		__node_pointer __cache_root_;
		__node_pointer __cache_elem_;

		@@ -1277,11 +1351,28 @@ __tree<_Tp, _Compare, _Allocator>::_DetachedTreeCache::__detach_next(__node_poin

[libc++] Optimize copy construction and assignment of __tree #151304

[libc++] Optimize copy construction and assignment of __tree #151304

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llvmbot commented Jul 30, 2025

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github-actions bot commented Jul 31, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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alazarev commented Aug 5, 2025

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philnik777 commented Jul 30, 2025 •

edited by ldionne

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github-actions bot commented Jul 31, 2025 •

edited

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