diff --git a/libcxx/include/__algorithm/inplace_merge.h b/libcxx/include/__algorithm/inplace_merge.h
--- a/libcxx/include/__algorithm/inplace_merge.h
+++ b/libcxx/include/__algorithm/inplace_merge.h
@@ -225,7 +225,7 @@
     difference_type __len1 = _IterOps<_AlgPolicy>::distance(__first, __middle);
     difference_type __len2 = _IterOps<_AlgPolicy>::distance(__middle, __last);
     difference_type __buf_size = _VSTD::min(__len1, __len2);
-    auto __buf = std::__make_uninitialized_buffer<value_type[]>(nothrow, __buf_size);
+    auto __buf = std::__make_uninitialized_buffer<value_type>(__buf_size);
     return std::__inplace_merge<_AlgPolicy>(
         std::move(__first),
         std::move(__middle),
diff --git a/libcxx/include/__algorithm/stable_partition.h b/libcxx/include/__algorithm/stable_partition.h
--- a/libcxx/include/__algorithm/stable_partition.h
+++ b/libcxx/include/__algorithm/stable_partition.h
@@ -139,9 +139,9 @@
     // *__first is known to be false
     difference_type __len = _IterOps<_AlgPolicy>::distance(__first, __last);
 
-    __uninitialized_buffer_t<value_type[]> __buf;
+    __uninitialized_buffer_t<value_type> __buf;
     if (__len >= __alloc_limit)
-        __buf = std::__make_uninitialized_buffer<value_type[]>(nothrow, __len);
+        __buf = std::__make_uninitialized_buffer<value_type>(__len);
 
     return std::__stable_partition_impl<_AlgPolicy, _Predicate&>(
         std::move(__first),
@@ -292,9 +292,9 @@
     // *__last is known to be true
     // __len >= 2
     difference_type __len = _IterOps<_AlgPolicy>::distance(__first, __last) + 1;
-    __uninitialized_buffer_t<value_type[]> __buf;
+    __uninitialized_buffer_t<value_type> __buf;
     if (__len >= __alloc_limit)
-        __buf = std::__make_uninitialized_buffer<value_type[]>(nothrow, __len);
+        __buf = std::__make_uninitialized_buffer<value_type>( __len);
 
     return std::__stable_partition_impl<_AlgPolicy, _Predicate&>(
         std::move(__first),
diff --git a/libcxx/include/__algorithm/stable_sort.h b/libcxx/include/__algorithm/stable_sort.h
--- a/libcxx/include/__algorithm/stable_sort.h
+++ b/libcxx/include/__algorithm/stable_sort.h
@@ -249,9 +249,10 @@
   using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
 
   difference_type __len = __last - __first;
-  __uninitialized_buffer_t<value_type[]> __buf;
+
+  __uninitialized_buffer_t<value_type> __buf;
   if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
-        __buf = std::__make_uninitialized_buffer<value_type[]>(nothrow, __len);
+        __buf = std::__make_uninitialized_buffer<value_type>(__len);
 
   std::__stable_sort<_AlgPolicy, __comp_ref_type<_Compare> >(
       __first, __last, __comp, __len, __buf.get(), __buf ? __len : 0);
diff --git a/libcxx/include/__memory/uninitialized_buffer.h b/libcxx/include/__memory/uninitialized_buffer.h
--- a/libcxx/include/__memory/uninitialized_buffer.h
+++ b/libcxx/include/__memory/uninitialized_buffer.h
@@ -10,11 +10,7 @@
 #define _LIBCPP___MEMORY_UNINITIALIZED_BUFFER_H
 
 #include <__config>
-#include <__memory/construct_at.h>
 #include <__memory/unique_ptr.h>
-#include <__type_traits/is_array.h>
-#include <__type_traits/is_default_constructible.h>
-#include <__type_traits/remove_extent.h>
 #include <__utility/move.h>
 #include <cstddef>
 #include <new>
@@ -29,51 +25,30 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Destructor>
 class __uninitialized_buffer_deleter {
   size_t __count_;
-  _Destructor __destructor_;
 
 public:
-  template <class _Dummy = int, __enable_if_t<is_default_constructible<_Destructor>::value, _Dummy> = 0>
-  _LIBCPP_HIDE_FROM_ABI __uninitialized_buffer_deleter() : __count_(0) {}
-
-  _LIBCPP_HIDE_FROM_ABI __uninitialized_buffer_deleter(size_t __count, _Destructor __destructor)
-      : __count_(__count), __destructor_(std::move(__destructor)) {}
+  _LIBCPP_HIDE_FROM_ABI
+  explicit constexpr __uninitialized_buffer_deleter(size_t __count = 0) noexcept
+      : __count_(__count) {}
 
   template <class _Tp>
-  _LIBCPP_HIDE_FROM_ABI void operator()(_Tp* __ptr) {
-    __destructor_(__ptr, __count_);
-#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
-    ::operator delete(__ptr);
-#else
-    ::operator delete(__ptr, __count_ * sizeof(_Tp), align_val_t(_LIBCPP_ALIGNOF(_Tp)));
-#endif
+  _LIBCPP_HIDE_FROM_ABI void operator()(_Tp* __ptr) const noexcept {
+    std::__libcpp_deallocate(__ptr, __count_ * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
   }
 };
 
-struct __noop {
-  template <class... _Args>
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void operator()(_Args&&...) const {}
-};
-
-template <class _Array, class _Destructor = __noop>
-using __uninitialized_buffer_t = unique_ptr<_Array, __uninitialized_buffer_deleter<_Destructor> >;
-
-template <class _Array, class _Destructor = __noop>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI __uninitialized_buffer_t<_Array, _Destructor>
-__make_uninitialized_buffer(nothrow_t, size_t __count, _Destructor __destructor = __noop()) {
-  static_assert(is_array<_Array>::value, "");
-  using _Tp = __remove_extent_t<_Array>;
+template <class _Tp>
+using __uninitialized_buffer_t = unique_ptr<_Tp, __uninitialized_buffer_deleter>;
 
-#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
-  _Tp* __ptr = static_cast<_Tp*>(::operator new(sizeof(_Tp) * __count, nothrow));
-#else
-  _Tp* __ptr = static_cast<_Tp*>(::operator new(sizeof(_Tp) * __count, align_val_t(_LIBCPP_ALIGNOF(_Tp)), nothrow));
-#endif
+template <class _Tp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI __uninitialized_buffer_t<_Tp>
+__make_uninitialized_buffer(size_t __count) {
+  _Tp* __ptr = static_cast<_Tp*>(std::__libcpp_allocate(sizeof(_Tp) * __count, _LIBCPP_ALIGNOF(_Tp), nothrow));
 
-  using _Deleter = __uninitialized_buffer_deleter<_Destructor>;
-  return unique_ptr<_Array, _Deleter>(__ptr, _Deleter(__count, std::move(__destructor)));
+  using _Deleter = __uninitialized_buffer_deleter;
+  return __uninitialized_buffer_t<_Tp>(__ptr, _Deleter(__ptr ? __count : 0));
 }
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/new b/libcxx/include/new
--- a/libcxx/include/new
+++ b/libcxx/include/new
@@ -294,6 +294,19 @@
   return __libcpp_operator_new(__size);
 }
 
+inline _LIBCPP_INLINE_VISIBILITY
+void *__libcpp_allocate(size_t __size, size_t __align, nothrow_t) {
+#ifndef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+  if (__is_overaligned_for_new(__align)) {
+    const align_val_t __align_val = static_cast<align_val_t>(__align);
+    return __libcpp_operator_new(__size, __align_val, nothrow);
+  }
+#endif
+
+  (void)__align;
+  return __libcpp_operator_new(__size, nothrow);
+}
+
 template <class ..._Args>
 _LIBCPP_INLINE_VISIBILITY
 void __do_deallocate_handle_size(void *__ptr, size_t __size, _Args ...__args) {