From 7611eb4869db50bd35e7bdac0cadccc5533e78a2 Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2@gmail.com>
Date: Tue, 7 Jun 2022 13:16:52 -0400
Subject: [PATCH] [libc++][NFC] Simplify enable_if for std::copy optimization

Get rid of the __is_trivially_copy_assignable_unwrapped helper, which
is only used in one place, and use __iter_value_type instead of
iterator_traits<T>::value_type.

Differential Revision: https://reviews.llvm.org/D127230
---
 libcxx/include/__algorithm/copy.h | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/libcxx/include/__algorithm/copy.h b/libcxx/include/__algorithm/copy.h
index a09e03e..2a4e535 100644
--- a/libcxx/include/__algorithm/copy.h
+++ b/libcxx/include/__algorithm/copy.h
@@ -56,16 +56,11 @@ pair<_InValueT*, _OutValueT*> __copy_impl(_InValueT* __first, _InValueT* __last,
   return std::make_pair(__first + __n, __result + __n);
 }
 
-template <class _Iter>
-using __is_trivially_copy_assignable_unwrapped =
-    _And<__is_cpp17_contiguous_iterator<_Iter>, is_trivially_copy_assignable<__iter_value_type<_Iter> > >;
-
-template <class _InIter,
-          class _OutIter,
-          class = __enable_if_t<is_same<typename remove_const<typename iterator_traits<_InIter>::value_type>::type,
-                                        typename iterator_traits<_OutIter>::value_type>::value
-                             && __is_trivially_copy_assignable_unwrapped<_InIter>::value
-                             && __is_trivially_copy_assignable_unwrapped<_OutIter>::value> >
+template <class _InIter, class _OutIter,
+          __enable_if_t<is_same<typename remove_const<__iter_value_type<_InIter> >::type, __iter_value_type<_OutIter> >::value
+                      && __is_cpp17_contiguous_iterator<_InIter>::value
+                      && __is_cpp17_contiguous_iterator<_OutIter>::value
+                      && is_trivially_copy_assignable<__iter_value_type<_OutIter> >::value, int> = 0>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
 pair<reverse_iterator<_InIter>, reverse_iterator<_OutIter> >
 __copy_impl(reverse_iterator<_InIter> __first,
-- 
2.7.4