[libcxx-commits] [libcxx] [libc++] Merge insert/emplace(const_iterator, Args...) implementations (PR #166470)

[Nikolas Klauser via libcxx-commits]

https://github.com/philnik777 updated https://github.com/llvm/llvm-project/pull/166470

>From 870d147c1d77bf2a2533b33eae0c5154d6ec26fd Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Wed, 5 Nov 2025 00:49:35 +0100
Subject: [PATCH] [libc++] Merge insert/emplace(const_iterator, Args...)
 implementations

---
 libcxx/include/deque | 114 ++++---------------------------------------
 1 file changed, 10 insertions(+), 104 deletions(-)

diff --git a/libcxx/include/deque b/libcxx/include/deque
index ab41b9db9de26..de90fdeee011b 100644
--- a/libcxx/include/deque
+++ b/libcxx/include/deque
@@ -792,7 +792,12 @@ public:
   _LIBCPP_HIDE_FROM_ABI void emplace_back(_Args&&... __args);
 #    endif
   template <class... _Args>
-  _LIBCPP_HIDE_FROM_ABI iterator emplace(const_iterator __p, _Args&&... __args);
+  _LIBCPP_HIDE_FROM_ABI iterator __emplace(const_iterator __p, _Args&&... __args);
+
+  template <class... _Args>
+  _LIBCPP_HIDE_FROM_ABI iterator emplace(const_iterator __p, _Args&&... __args) {
+    return __emplace(__p, std::forward<_Args>(__args)...);
+  }
 
   _LIBCPP_HIDE_FROM_ABI void push_front(value_type&& __v);
   _LIBCPP_HIDE_FROM_ABI void push_back(value_type&& __v);
@@ -809,13 +814,13 @@ public:
   }
 #    endif
 
-  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __v);
+  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __v) { return __emplace(__p, std::move(__v)); }
+  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __v) { return __emplace(__p, __v); }
 
   _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, initializer_list<value_type> __il) {
     return insert(__p, __il.begin(), __il.end());
   }
 #  endif // _LIBCPP_CXX03_LANG
-  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __v);
   _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, size_type __n, const value_type& __v);
   template <class _InputIter, __enable_if_t<__has_exactly_input_iterator_category<_InputIter>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _InputIter __f, _InputIter __l);
@@ -1661,56 +1666,11 @@ deque<_Tp, _Allocator>::emplace_front(_Args&&... __args) {
   return *begin();
 #    endif
 }
-
-template <class _Tp, class _Allocator>
-typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::insert(const_iterator __p, value_type&& __v) {
-  size_type __pos     = __p - begin();
-  size_type __to_end  = size() - __pos;
-  allocator_type& __a = __alloc();
-  if (__pos < __to_end) { // insert by shifting things backward
-    if (__front_spare() == 0)
-      __add_front_capacity();
-    // __front_spare() >= 1
-    __annotate_increase_front(1);
-    if (__pos == 0) {
-      __alloc_traits::construct(__a, std::addressof(*--begin()), std::move(__v));
-      --__start_;
-      ++__size();
-    } else {
-      iterator __b   = begin();
-      iterator __bm1 = std::prev(__b);
-      __alloc_traits::construct(__a, std::addressof(*__bm1), std::move(*__b));
-      --__start_;
-      ++__size();
-      if (__pos > 1)
-        __b = std::move(std::next(__b), __b + __pos, __b);
-      *__b = std::move(__v);
-    }
-  } else { // insert by shifting things forward
-    if (__back_spare() == 0)
-      __add_back_capacity();
-    // __back_capacity >= 1
-    __annotate_increase_back(1);
-    size_type __de = size() - __pos;
-    if (__de == 0) {
-      __alloc_traits::construct(__a, std::addressof(*end()), std::move(__v));
-      ++__size();
-    } else {
-      iterator __e   = end();
-      iterator __em1 = std::prev(__e);
-      __alloc_traits::construct(__a, std::addressof(*__e), std::move(*__em1));
-      ++__size();
-      if (__de > 1)
-        __e = std::move_backward(__e - __de, __em1, __e);
-      *--__e = std::move(__v);
-    }
-  }
-  return begin() + __pos;
-}
+#  endif // _LIBCPP_CXX03_LANG
 
 template <class _Tp, class _Allocator>
 template <class... _Args>
-typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::emplace(const_iterator __p, _Args&&... __args) {
+typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::__emplace(const_iterator __p, _Args&&... __args) {
   size_type __pos     = __p - begin();
   size_type __to_end  = size() - __pos;
   allocator_type& __a = __alloc();
@@ -1757,60 +1717,6 @@ typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::emplace(const_
   return begin() + __pos;
 }
 
-#  endif // _LIBCPP_CXX03_LANG
-
-template <class _Tp, class _Allocator>
-typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::insert(const_iterator __p, const value_type& __v) {
-  size_type __pos     = __p - begin();
-  size_type __to_end  = size() - __pos;
-  allocator_type& __a = __alloc();
-  if (__pos < __to_end) { // insert by shifting things backward
-    if (__front_spare() == 0)
-      __add_front_capacity();
-    // __front_spare() >= 1
-    __annotate_increase_front(1);
-    if (__pos == 0) {
-      __alloc_traits::construct(__a, std::addressof(*--begin()), __v);
-      --__start_;
-      ++__size();
-    } else {
-      const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
-      iterator __b       = begin();
-      iterator __bm1     = std::prev(__b);
-      if (__vt == pointer_traits<const_pointer>::pointer_to(*__b))
-        __vt = pointer_traits<const_pointer>::pointer_to(*__bm1);
-      __alloc_traits::construct(__a, std::addressof(*__bm1), std::move(*__b));
-      --__start_;
-      ++__size();
-      if (__pos > 1)
-        __b = __move_and_check(std::next(__b), __b + __pos, __b, __vt);
-      *__b = *__vt;
-    }
-  } else { // insert by shifting things forward
-    if (__back_spare() == 0)
-      __add_back_capacity();
-    // __back_capacity >= 1
-    __annotate_increase_back(1);
-    size_type __de = size() - __pos;
-    if (__de == 0) {
-      __alloc_traits::construct(__a, std::addressof(*end()), __v);
-      ++__size();
-    } else {
-      const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
-      iterator __e       = end();
-      iterator __em1     = std::prev(__e);
-      if (__vt == pointer_traits<const_pointer>::pointer_to(*__em1))
-        __vt = pointer_traits<const_pointer>::pointer_to(*__e);
-      __alloc_traits::construct(__a, std::addressof(*__e), std::move(*__em1));
-      ++__size();
-      if (__de > 1)
-        __e = __move_backward_and_check(__e - __de, __em1, __e, __vt);
-      *--__e = *__vt;
-    }
-  }
-  return begin() + __pos;
-}
-
 template <class _Tp, class _Allocator>
 typename deque<_Tp, _Allocator>::iterator
 deque<_Tp, _Allocator>::insert(const_iterator __p, size_type __n, const value_type& __v) {