[gcc(refs/users/ppalka/heads/libstdcxx-constrained-algos)] Unwrap normal_iterators in ranges::equal

[Patrick Palka]

https://gcc.gnu.org/g:eea2d481dbe7670ce8fba27cf45386cc5cdbf9ed

commit eea2d481dbe7670ce8fba27cf45386cc5cdbf9ed
Author: Patrick Palka <ppalka@gcc.gnu.org>
Date:   Sun Jan 19 20:16:16 2020 -0500

    Unwrap normal_iterators in ranges::equal

Diff:
---
 libstdc++-v3/include/bits/ranges_algo.h            | 25 ++++++++++++++++++----
 .../testsuite/25_algorithms/equal/constrained.cc   | 13 ++++++++++-
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
index fd8fd3b..ea76cac2 100644
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -704,8 +704,8 @@ namespace ranges
 	     typename _Proj1 = identity, typename _Proj2 = identity>
       requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
       constexpr bool
-      equal(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
-	    _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {})
+      __equal(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+	      _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {})
       {
 	// TODO: implement more specializations to at least have parity with
 	// std::equal.
@@ -721,7 +721,7 @@ namespace ranges
 
 	    using _ValueType1 = iterator_traits<_Iter1>::value_type;
 	    using _ValueType2 = iterator_traits<_Iter2>::value_type;
-	    constexpr bool __simple
+	    constexpr bool __use_memcmp
 	      = ((is_integral_v<_ValueType1> || is_pointer_v<_ValueType1>)
 		 && is_same_v<_ValueType1, _ValueType2>
 		 && is_pointer_v<_Iter1>
@@ -729,7 +729,7 @@ namespace ranges
 		 && is_same_v<_Pred, ranges::equal_to>
 		 && is_same_v<_Proj1, identity>
 		 && is_same_v<_Proj2, identity>);
-	    if constexpr (__simple)
+	    if constexpr (__use_memcmp)
 	      {
 		if (const size_t __len = (__last1 - __first1))
 		  return !std::__memcmp(__first1, __first2, __len);
@@ -757,6 +757,23 @@ namespace ranges
 	  }
       }
 
+    template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
+	     input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
+	     typename _Pred = ranges::equal_to,
+	     typename _Proj1 = identity, typename _Proj2 = identity>
+      requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
+      constexpr bool
+      equal(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+	    _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {})
+      {
+	return ranges::__equal(std::__niter_base(__first1),
+			       std::__niter_base(__last1),
+			       std::__niter_base(__first2),
+			       std::__niter_base(__last2),
+			       std::move(__pred),
+			       std::move(__proj1), std::move(__proj2));
+      }
+
     template<input_range _Range1, input_range _Range2,
 	     typename _Pred = ranges::equal_to,
 	     typename _Proj1 = identity, typename _Proj2 = identity>
diff --git a/libstdc++-v3/testsuite/25_algorithms/equal/constrained.cc b/libstdc++-v3/testsuite/25_algorithms/equal/constrained.cc
index cb8f34d..b1f9977 100644
--- a/libstdc++-v3/testsuite/25_algorithms/equal/constrained.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/equal/constrained.cc
@@ -41,7 +41,7 @@ test01()
   int w[] = { {1}, {1}, {1}, {1}, {1} };
 
   VERIFY( ranges::equal(w, w+4, w+1, w+5) );
-  VERIFY( ranges::equal(w, w+5, w, w+5, std::greater<int>(),
+  VERIFY( ranges::equal(w, w+5, w, w+5, ranges::greater{},
 			[] (int a) { return a+1; }) );
 
   test_container<int, forward_iterator_wrapper> cx(x), cy(y);
@@ -71,9 +71,20 @@ test02()
   static_assert(!ranges::equal(x, y, {}, &X::i, &X::i));
 }
 
+void
+test03()
+{
+  std::vector<int> x = { {2}, {2}, {6}, {8}, {10}, {11} };
+  std::vector<int> y = { {2}, {2}, {6}, {8}, {10}, {11} };
+  std::vector<int> z = { {2}, {2}, {6}, {8}, {10}, {12} };
+  VERIFY( ranges::equal(x, y) );
+  VERIFY( !ranges::equal(x, z) );
+}
+
 int
 main()
 {
   test01();
   test02();
+  test03();
 }