[libcxx-commits] [PATCH] D147741: [libc++, std::vector] call the optimized version of __uninitialized_allocator_copy for trivial types

[Aditya Kumar via Phabricator via libcxx-commits]

hiraditya updated this revision to Diff 517757.
hiraditya added a comment.

Using @philnik's suggestion again as it works once a non-const version of the `__uninitialized_allocator_copy` is added.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D147741/new/

https://reviews.llvm.org/D147741

Files:
  libcxx/include/__memory/uninitialized_algorithms.h


Index: libcxx/include/__memory/uninitialized_algorithms.h
===================================================================
--- libcxx/include/__memory/uninitialized_algorithms.h
+++ libcxx/include/__memory/uninitialized_algorithms.h
@@ -12,6 +12,7 @@
 
 #include <__algorithm/copy.h>
 #include <__algorithm/move.h>
+#include <__algorithm/unwrap_iter.h>
 #include <__config>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/reverse_iterator.h>
@@ -545,7 +546,7 @@
 // already copied elements are destroyed in reverse order of their construction.
 template <class _Alloc, class _Iter1, class _Sent1, class _Iter2>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter2
-__uninitialized_allocator_copy(_Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
+__uninitialized_allocator_copy_impl(_Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
   auto __destruct_first = __first2;
   auto __guard =
       std::__make_exception_guard(_AllocatorDestroyRangeReverse<_Alloc, _Iter2>(__alloc, __destruct_first, __first2));
@@ -567,12 +568,14 @@
 template <class _Alloc,
           class _Type,
           class _RawType = __remove_const_t<_Type>,
+          class _Up,
           __enable_if_t<
               // using _RawType because of the allocator<T const> extension
               is_trivially_copy_constructible<_RawType>::value && is_trivially_copy_assignable<_RawType>::value &&
+              is_same<__remove_cv_t<_Type>, __remove_cv_t<_Up> >::value &&
               __allocator_has_trivial_copy_construct<_Alloc, _RawType>::value>* = nullptr>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Type*
-__uninitialized_allocator_copy(_Alloc&, const _Type* __first1, const _Type* __last1, _Type* __first2) {
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Up*
+__uninitialized_allocator_copy_impl(_Alloc&, _Type* __first1, _Type* __last1, _Up* __first2) {
   // TODO: Remove the const_cast once we drop support for std::allocator<T const>
   if (__libcpp_is_constant_evaluated()) {
     while (__first1 != __last1) {
@@ -586,6 +589,35 @@
   }
 }
 
+template <class _Alloc,
+          class _Type,
+          class _RawType = __remove_const_t<_Type>,
+          class _Up,
+          __enable_if_t<
+              // using _RawType because of the allocator<T const> extension
+              is_trivially_copy_constructible<_RawType>::value && is_trivially_copy_assignable<_RawType>::value &&
+              is_same<__remove_cv_t<_Type>, __remove_cv_t<_Up> >::value &&
+              __allocator_has_trivial_copy_construct<_Alloc, _RawType>::value>* = nullptr>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Up*
+__uninitialized_allocator_copy_impl(_Alloc&, const _Type* __first1, const _Type* __last1, _Up* __first2) {
+  // TODO: Remove the const_cast once we drop support for std::allocator<T const>
+  if (__libcpp_is_constant_evaluated()) {
+    while (__first1 != __last1) {
+      std::__construct_at(std::__to_address(__first2), *__first1);
+      ++__first1;
+      ++__first2;
+    }
+    return __first2;
+  } else {
+    return std::copy(__first1, __last1, const_cast<_RawType*>(__first2));
+  }
+}
+
+template <class _Alloc, class _Iter1, class _Sent1, class _Iter2>
+constexpr _Iter2 __uninitialized_allocator_copy(_Alloc& __alloc, _Iter1 __first1, _Sent1 __last1, _Iter2 __first2) {
+    return std::__rewrap_iter(__first2, std::__uninitialized_allocator_copy_impl(__alloc, std::__unwrap_iter(__first1), std::__unwrap_iter(__last1), std::__unwrap_iter(__first2)));
+}
+
 // Move-construct the elements [__first1, __last1) into [__first2, __first2 + N)
 // if the move constructor is noexcept, where N is distance(__first1, __last1).
 //


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