From acedaeadba2d2fb36697b476bce02522c9f7c9da Mon Sep 17 00:00:00 2001
From: Marshall Clow <marshall@idio.com>
Date: Thu, 10 Oct 2024 09:20:10 -0700
Subject: [PATCH] Undo changes to '__move_range', fix test failure in 'insert'

---
 libcxx/include/vector | 57 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 45 insertions(+), 12 deletions(-)

diff --git a/libcxx/include/vector b/libcxx/include/vector
index 787ee23c355786..ca5b774074ae43 100644
--- a/libcxx/include/vector
+++ b/libcxx/include/vector
@@ -1626,18 +1626,6 @@ vector<_Tp, _Allocator>::__move_range(pointer __from_s, pointer __from_e, pointe
   pointer __old_last  = this->__end_;
   difference_type __n = __old_last - __to;
 
-#if _LIBCPP_STD_VER >= 26
-  if ! consteval {
-    if constexpr (is_trivially_relocatable_v<_Tp> || is_nothrow_move_constructible_v<_Tp>) {
-      const size_t __numSpaces = __to - __from_s;
-      _ConstructTransaction __tx(*this, __numSpaces);
-      (void) relocate(std::__to_address(__from_s), std::__to_address(__from_e), std::__to_address(__to));
-      __tx.__pos_ += __numSpaces;
-      return;
-     }
-   }
-#endif
-
   {
     pointer __i = __from_s + __n;
     _ConstructTransaction __tx(*this, __from_e - __i);
@@ -1656,6 +1644,23 @@ vector<_Tp, _Allocator>::insert(const_iterator __position, const_reference __x)
     if (__p == this->__end_) {
       __construct_one_at_end(__x);
     } else {
+#if _LIBCPP_STD_VER >= 26
+       if constexpr (is_trivially_relocatable_v<_Tp> || is_nothrow_move_constructible_v<_Tp>) {
+         // Make space by trivially relocating everything
+         _ConstructTransaction __tx(*this, 1);
+         (void) relocate(std::__to_address(__p), std::__to_address(this->__end_), std::__to_address(__p + 1));
+         // construct the new element (not assign!)
+         const_pointer __xr = pointer_traits<const_pointer>::pointer_to(__x);
+         if (std::__is_pointer_in_range(std::__to_address(__p), std::__to_address(__end_), std::addressof(__x)))
+           ++__xr;
+         __alloc_traits::construct(this->__alloc(), std::__to_address(__p), *__xr);
+         ++__tx.__pos_;
+         // Need to fix up upon an exception!
+         // update all the invariants.
+         // return an iterator to the new entry
+         return __make_iter(__p);
+         }
+ #endif
       __move_range(__p, this->__end_, __p + 1);
       const_pointer __xr = pointer_traits<const_pointer>::pointer_to(__x);
       if (std::__is_pointer_in_range(std::__to_address(__p), std::__to_address(__end_), std::addressof(__x)))
@@ -1679,6 +1684,20 @@ vector<_Tp, _Allocator>::insert(const_iterator __position, value_type&& __x) {
     if (__p == this->__end_) {
       __construct_one_at_end(std::move(__x));
     } else {
+#if _LIBCPP_STD_VER >= 26
+     if constexpr (is_trivially_relocatable_v<_Tp> || is_nothrow_move_constructible_v<_Tp>) {
+       // Make space by trivially relocating everything
+       _ConstructTransaction __tx(*this, 1);
+       (void) relocate(std::__to_address(__p), std::__to_address(this->__end_), std::__to_address(__p + 1));
+       // construct the new element (not assign!)
+       __alloc_traits::construct(this->__alloc(), std::__to_address(__p), std::forward<value_type>(__x));
+       ++__tx.__pos_;
+       // Need to fix up upon an exception!
+       // update all the invariants.
+       // return an iterator to the new entry
+       return __make_iter(__p);
+       }
+ #endif
       __move_range(__p, this->__end_, __p + 1);
       *__p = std::move(__x);
     }
@@ -1701,6 +1720,20 @@ vector<_Tp, _Allocator>::emplace(const_iterator __position, _Args&&... __args) {
       __construct_one_at_end(std::forward<_Args>(__args)...);
     } else {
       __temp_value<value_type, _Allocator> __tmp(this->__alloc(), std::forward<_Args>(__args)...);
+#if _LIBCPP_STD_VER >= 26
+     if constexpr (is_trivially_relocatable_v<_Tp> || is_nothrow_move_constructible_v<_Tp>) {
+       // Make space by trivially relocating everything
+       _ConstructTransaction __tx(*this, 1);
+       (void) relocate(std::__to_address(__p), std::__to_address(this->__end_), std::__to_address(__p + 1));
+       // construct the new element
+       __alloc_traits::construct(this->__alloc(), std::__to_address(__p), std::move(__tmp.get()));
+       ++__tx.__pos_;
+       // Need to fix up upon an exception!
+       // update all the invariants.
+       // return an iterator to the new entry
+       return __make_iter(__p);
+       }
+ #endif
       __move_range(__p, this->__end_, __p + 1);
       *__p = std::move(__tmp.get());
     }