Implement new serial algorithms from Parallelism TS (P0024R2)

These new (non-parallel) algorithms were added to C++17 along with the
parallel algorithms, but were missing from libstdc++.

	* include/bits/algorithmfwd.h: Change title of doc group.
	* include/bits/stl_algo.h (for_each_n): Add new C++17 algorithm from
	P0024R2.
	* include/bits/stl_numeric.h: Define doc group and add algos to it.
	* include/std/numeric (__is_random_access_iter): New internal trait.
	(reduce, transform_reduce, exclusive_scan, inclusive_scan)
	(transform_exclusive_scan, transform_inclusive_scan): Likewise.
	* testsuite/25_algorithms/for_each/for_each_n.cc: New test.
	* testsuite/26_numerics/exclusive_scan/1.cc: New test.
	* testsuite/26_numerics/inclusive_scan/1.cc: New test.
	* testsuite/26_numerics/reduce/1.cc: New test.
	* testsuite/26_numerics/transform_exclusive_scan/1.cc: New test.
	* testsuite/26_numerics/transform_inclusive_scan/1.cc: New test.
	* testsuite/26_numerics/transform_reduce/1.cc: New test.
	* testsuite/util/testsuite_iterators.h (test_container::size()): New
	member function.

From-SVN: r272459

13 files changed, 1159 insertions, 9 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 4570ab147d5..5702523ed1c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,22 @@
 2019-06-18  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/bits/algorithmfwd.h: Change title of doc group.
+	* include/bits/stl_algo.h (for_each_n): Add new C++17 algorithm from
+	P0024R2.
+	* include/bits/stl_numeric.h: Define doc group and add algos to it.
+	* include/std/numeric (__is_random_access_iter): New internal trait.
+	(reduce, transform_reduce, exclusive_scan, inclusive_scan)
+	(transform_exclusive_scan, transform_inclusive_scan): Likewise.
+	* testsuite/25_algorithms/for_each/for_each_n.cc: New test.
+	* testsuite/26_numerics/exclusive_scan/1.cc: New test.
+	* testsuite/26_numerics/inclusive_scan/1.cc: New test.
+	* testsuite/26_numerics/reduce/1.cc: New test.
+	* testsuite/26_numerics/transform_exclusive_scan/1.cc: New test.
+	* testsuite/26_numerics/transform_inclusive_scan/1.cc: New test.
+	* testsuite/26_numerics/transform_reduce/1.cc: New test.
+	* testsuite/util/testsuite_iterators.h (test_container::size()): New
+	member function.
+
 	* include/c_global/cstddef (std::byte): Perform arithmetic operations
 	in unsigned int to avoid promotion (LWG 2950).
 
diff --git a/libstdc++-v3/include/bits/algorithmfwd.h b/libstdc++-v3/include/bits/algorithmfwd.h
index 40e051aa9e3..5e47fffe86e 100644
--- a/libstdc++-v3/include/bits/algorithmfwd.h
+++ b/libstdc++-v3/include/bits/algorithmfwd.h
@@ -154,7 +154,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
 
   /**
-   * @defgroup set_algorithms Set Operation
+   * @defgroup set_algorithms Set Operations
    * @ingroup sorting_algorithms
    *
    * These algorithms are common set operations performed on sequences
diff --git a/libstdc++-v3/include/bits/stl_algo.h b/libstdc++-v3/include/bits/stl_algo.h
index b50c642f0e6..ca957e0b9a7 100644
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -3867,6 +3867,39 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
       return __f; // N.B. [alg.foreach] says std::move(f) but it's redundant.
     }
 
+#if __cplusplus >= 201703L
+  /**
+   *  @brief Apply a function to every element of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __n      A value convertible to an integer.
+   *  @param  __f      A unary function object.
+   *  @return   `__first+__n`
+   *
+   *  Applies the function object `__f` to each element in the range
+   *  `[first, first+n)`.  `__f` must not modify the order of the sequence.
+   *  If `__f` has a return value it is ignored.
+  */
+  template<typename _InputIterator, typename _Size, typename _Function>
+    _InputIterator
+    for_each_n(_InputIterator __first, _Size __n, _Function __f)
+    {
+      auto __n2 = std::__size_to_integer(__n);
+      using _Cat = typename iterator_traits<_InputIterator>::iterator_category;
+      if constexpr (is_base_of_v<random_access_iterator_tag, _Cat>)
+	return std::for_each(__first, __first + __n2, __f);
+      else
+	{
+	  while (__n2-->0)
+	    {
+	      __f(*__first);
+	      ++__first;
+	    }
+	  return __first;
+	}
+    }
+#endif // C++17
+
   /**
    *  @brief Find the first occurrence of a value in a sequence.
    *  @ingroup non_mutating_algorithms
diff --git a/libstdc++-v3/include/bits/stl_numeric.h b/libstdc++-v3/include/bits/stl_numeric.h
index e859c76bc44..387bed91174 100644
--- a/libstdc++-v3/include/bits/stl_numeric.h
+++ b/libstdc++-v3/include/bits/stl_numeric.h
@@ -60,12 +60,16 @@
 #include <debug/debug.h>
 #include <bits/move.h> // For _GLIBCXX_MOVE
 
-#if __cplusplus >= 201103L
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
+  /** @defgroup numeric_ops Generalized Numeric operations
+   *  @ingroup algorithms
+   */
+
+#if __cplusplus >= 201103L
   /**
    *  @brief  Create a range of sequentially increasing values.
    *
@@ -76,6 +80,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  @param  __last  End of range.
    *  @param  __value  Starting value.
    *  @return  Nothing.
+   *  @ingroup numeric_ops
    */
   template<typename _ForwardIterator, typename _Tp>
     void
@@ -94,14 +99,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  ++__value;
 	}
     }
+#endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
-} // namespace std
 
-#endif
-
-namespace std _GLIBCXX_VISIBILITY(default)
-{
 _GLIBCXX_BEGIN_NAMESPACE_ALGO
 
 #if __cplusplus > 201703L
@@ -112,6 +113,9 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
 # define _GLIBCXX_MOVE_IF_20(_E) _E
 #endif
 
+  /// @addtogroup numeric_ops
+  /// @{
+
   /**
    *  @brief  Accumulate values in a range.
    *
@@ -139,8 +143,8 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
   /**
    *  @brief  Accumulate values in a range with operation.
    *
-   *  Accumulates the values in the range [first,last) using the function
-   *  object @p __binary_op.  The initial value is @p __init.  The values are
+   *  Accumulates the values in the range `[first,last)` using the function
+   *  object `__binary_op`.  The initial value is `__init`.  The values are
    *  processed in order.
    *
    *  @param  __first  Start of range.
@@ -390,6 +394,8 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
       return ++__result;
     }
 
+  // @} group numeric_ops
+
 #undef _GLIBCXX_MOVE_IF_20
 
 _GLIBCXX_END_NAMESPACE_ALGO
diff --git a/libstdc++-v3/include/std/numeric b/libstdc++-v3/include/std/numeric
index 01e3ae8e35d..66792506d10 100644
--- a/libstdc++-v3/include/std/numeric
+++ b/libstdc++-v3/include/std/numeric
@@ -205,6 +205,472 @@ _GLIBCXX_END_NAMESPACE_VERSION
 #endif // C++14
 
 #if __cplusplus > 201402L
+#include <bits/stl_function.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// @addtogroup numeric_ops
+  /// @{
+
+  /// @cond undocumented
+  template<typename _It, typename _Traits = iterator_traits<_It>,
+	   typename _Cat = typename _Traits::iterator_category>
+    using __is_random_access_iter
+      = is_base_of<random_access_iterator_tag, _Cat>;
+  /// @endcond
+
+  /**
+   *  @brief  Calculate reduction of values in a range.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op A binary function object.
+   *  @return  The final sum.
+   *
+   *  Reduce the values in the range `[first,last)` using a binary operation.
+   *  The initial value is `init`.  The values are not necessarily processed
+   *  in order.
+   *
+   *  This algorithm is similar to `std::accumulate` but is not required to
+   *  perform the operations in order from first to last. For operations
+   *  that are commutative and associative the result will be the same as
+   *  for `std::accumulate`, but for other operations (such as floating point
+   *  arithmetic) the result can be different.
+   */
+  template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
+    _Tp
+    reduce(_InputIterator __first, _InputIterator __last, _Tp __init,
+	   _BinaryOperation __binary_op)
+    {
+      using value_type = typename iterator_traits<_InputIterator>::value_type;
+      static_assert(is_invocable_r_v<_Tp, _BinaryOperation, _Tp&, _Tp&>);
+      static_assert(is_convertible_v<value_type, _Tp>);
+      if constexpr (__is_random_access_iter<_InputIterator>::value)
+	{
+	  while ((__last - __first) >= 4)
+	    {
+	      _Tp __v1 = __binary_op(__first[0], __first[1]);
+	      _Tp __v2 = __binary_op(__first[2], __first[3]);
+	      _Tp __v3 = __binary_op(__v1, __v2);
+	      __init = __binary_op(__init, __v3);
+	      __first += 4;
+	    }
+	}
+      for (; __first != __last; ++__first)
+	__init = __binary_op(__init, *__first);
+      return __init;
+    }
+
+ /**
+   *  @brief  Calculate reduction of values in a range.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @return  The final sum.
+   *
+   *  Reduce the values in the range `[first,last)` using addition.
+   *  Equivalent to calling std::reduce(first, last, init, std::plus<>())`.
+   */
+  template<typename _InputIterator, typename _Tp>
+    inline _Tp
+    reduce(_InputIterator __first, _InputIterator __last, _Tp __init)
+    { return std::reduce(__first, __last, __init, plus<>()); }
+
+  /**
+   *  @brief  Calculate reduction of values in a range.
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @return  The final sum.
+   *
+   *  Reduce the values in the range `[first,last)` using addition, with
+   *  an initial value of `T{}`, where `T` is the iterator's value type.
+   *  Equivalent to calling std::reduce(first, last, T{}, std::plus<>())`.
+   */
+  template<typename _InputIterator>
+    inline typename iterator_traits<_InputIterator>::value_type
+    reduce(_InputIterator __first, _InputIterator __last)
+    {
+      using value_type = typename iterator_traits<_InputIterator>::value_type;
+      return std::reduce(__first, __last, value_type{}, plus<>());
+    }
+
+  /**
+   *  @brief  Combine elements from two ranges and reduce
+   *
+   *  @param  __first1  Start of first range.
+   *  @param  __last1  End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op1 The function used to perform reduction.
+   *  @param  __binary_op2 The function used to combine values from the ranges.
+   *  @return  The final sum.
+   *
+   *  Call `binary_op2(first1[n],first2[n])` for each `n` in `[0,last1-first1)`
+   *  and then use `binary_op1` to reduce the values returned by `binary_op2`
+   *  to a single value of type `T`.
+   *
+   *  The range beginning at `first2` must contain at least `last1-first1`
+   *  elements.
+   */
+  template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
+	   typename _BinaryOperation1, typename _BinaryOperation2>
+    _Tp
+    transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _Tp __init,
+		     _BinaryOperation1 __binary_op1,
+		     _BinaryOperation2 __binary_op2)
+    {
+      if constexpr (__and_v<__is_random_access_iter<_InputIterator1>,
+			    __is_random_access_iter<_InputIterator2>>)
+	{
+	  while ((__last1 - __first1) >= 4)
+	    {
+	      _Tp __v1 = __binary_op1(__binary_op2(__first1[0], __first2[0]),
+				      __binary_op2(__first1[1], __first2[1]));
+	      _Tp __v2 = __binary_op1(__binary_op2(__first1[2], __first2[2]),
+				      __binary_op2(__first1[3], __first2[3]));
+	      _Tp __v3 = __binary_op1(__v1, __v2);
+	      __init = __binary_op1(__init, __v3);
+	      __first1 += 4;
+	      __first2 += 4;
+	    }
+	}
+      for (; __first1 != __last1; ++__first1, (void) ++__first2)
+	__init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
+      return __init;
+    }
+
+  /**
+   *  @brief  Combine elements from two ranges and reduce
+   *
+   *  @param  __first1  Start of first range.
+   *  @param  __last1  End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __init  Starting value to add other values to.
+   *  @return  The final sum.
+   *
+   *  Call `first1[n]*first2[n]` for each `n` in `[0,last1-first1)` and then
+   *  use addition to sum those products to a single value of type `T`.
+   *
+   *  The range beginning at `first2` must contain at least `last1-first1`
+   *  elements.
+   */
+  template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
+    inline _Tp
+    transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _Tp __init)
+    {
+      return std::transform_reduce(__first1, __last1, __first2,
+				   std::move(__init),
+				   plus<>(), multiplies<>());
+    }
+
+  /**
+   *  @brief  Transform the elements of a range and reduce
+   *
+   *  @param  __first  Start of range.
+   *  @param  __last  End of range.
+   *  @param  __init  Starting value to add other values to.
+   *  @param  __binary_op The function used to perform reduction.
+   *  @param  __unary_op The function used to transform values from the range.
+   *  @return  The final sum.
+   *
+   *  Call `unary_op(first[n])` for each `n` in `[0,last-first)` and then
+   *  use `binary_op` to reduce the values returned by `unary_op`
+   *  to a single value of type `T`.
+   */
+  template<typename _InputIterator, typename _Tp,
+	   typename _BinaryOperation, typename _UnaryOperation>
+    _Tp
+    transform_reduce(_InputIterator __first, _InputIterator __last, _Tp __init,
+		     _BinaryOperation __binary_op, _UnaryOperation __unary_op)
+    {
+      if constexpr (__is_random_access_iter<_InputIterator>::value)
+	{
+	  while ((__last - __first) >= 4)
+	    {
+	      _Tp __v1 = __binary_op(__unary_op(__first[0]),
+				     __unary_op(__first[1]));
+	      _Tp __v2 = __binary_op(__unary_op(__first[2]),
+				     __unary_op(__first[3]));
+	      _Tp __v3 = __binary_op(__v1, __v2);
+	      __init = __binary_op(__init, __v3);
+	      __first += 4;
+	    }
+	}
+      for (; __first != __last; ++__first)
+	__init = __binary_op(__init, __unary_op(*__first));
+      return __init;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __init   Initial value.
+   *  @param __binary_op Function to perform summation.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `binary_op` for summation.
+   *
+   *  This function generates an "exclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N-1 input elements,
+   *  so the Nth input element is not included.
+   */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp,
+	   typename _BinaryOperation>
+    _OutputIterator
+    exclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _Tp __init,
+		   _BinaryOperation __binary_op)
+    {
+      while (__first != __last)
+	{
+	  auto __v = __init;
+	  __init = __binary_op(__init, *__first);
+	  ++__first;
+	  *__result++ = std::move(__v);
+	}
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __init   Initial value.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `std::plus<>` for summation.
+   *
+   *  This function generates an "exclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N-1 input elements,
+   *  so the Nth input element is not included.
+   */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
+    inline _OutputIterator
+    exclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _Tp __init)
+    {
+      return std::exclusive_scan(__first, __last, __result, std::move(__init),
+				 plus<>());
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @param __init   Initial value.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation, typename _Tp>
+    _OutputIterator
+    inclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _BinaryOperation __binary_op,
+		   _Tp __init)
+    {
+      for (; __first != __last; ++__first)
+	*__result++ = __init = __binary_op(__init, *__first);
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements, using `binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation>
+    _OutputIterator
+    inclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _BinaryOperation __binary_op)
+    {
+      if (__first != __last)
+	{
+	  auto __init = *__first;
+	  *__result++ = __init;
+	  ++__first;
+	  if (__first != __last)
+	    __result = std::inclusive_scan(__first, __last, __result,
+					   __binary_op, std::move(__init));
+	}
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements, using `std::plus<>` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator>
+    inline _OutputIterator
+    inclusive_scan(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result)
+    { return std::inclusive_scan(__first, __last, __result, plus<>()); }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __init   Initial value.
+   *  @param __binary_op Function to perform summation.
+   *  @param __unary_op Function to transform elements of the input range.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `__unary_op` to transform the input elements
+   *  and using `__binary_op` for summation.
+   *
+   *  This function generates an "exclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N-1 input elements,
+   *  so the Nth input element is not included.
+   */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp,
+	   typename _BinaryOperation, typename _UnaryOperation>
+    _OutputIterator
+    transform_exclusive_scan(_InputIterator __first, _InputIterator __last,
+			     _OutputIterator __result, _Tp __init,
+			     _BinaryOperation __binary_op,
+			     _UnaryOperation __unary_op)
+    {
+      while (__first != __last)
+	{
+	  auto __v = __init;
+	  __init = __binary_op(__init, __unary_op(*__first));
+	  ++__first;
+	  *__result++ = std::move(__v);
+	}
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @param __unary_op Function to transform elements of the input range.
+   *  @param __init   Initial value.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements (and the initial value),
+   *  using `__unary_op` to transform the input elements
+   *  and using `__binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryOperation, typename _UnaryOperation, typename _Tp>
+    _OutputIterator
+    transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
+			     _OutputIterator __result,
+			     _BinaryOperation __binary_op,
+			     _UnaryOperation __unary_op,
+			     _Tp __init)
+    {
+      for (; __first != __last; ++__first)
+	*__result++ = __init = __binary_op(__init, __unary_op(*__first));
+      return __result;
+    }
+
+  /** @brief Output the cumulative sum of one range to a second range
+   *
+   *  @param __first  Start of input range.
+   *  @param __last   End of input range.
+   *  @param __result Start of output range.
+   *  @param __binary_op Function to perform summation.
+   *  @param __unary_op Function to transform elements of the input range.
+   *  @return The end of the output range.
+   *
+   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range
+   *  to the output range. Each element of the output range contains the
+   *  running total of all earlier elements,
+   *  using `__unary_op` to transform the input elements
+   *  and using `__binary_op` for summation.
+   *
+   *  This function generates an "inclusive" scan, meaning the Nth element
+   *  of the output range is the sum of the first N input elements,
+   *  so the Nth input element is included.
+   */
+  template<typename _InputIterator, typename _OutputIterator,
+	  typename _BinaryOperation, typename _UnaryOperation>
+    _OutputIterator
+    transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
+			     _OutputIterator __result,
+			     _BinaryOperation __binary_op,
+			     _UnaryOperation __unary_op)
+    {
+      if (__first != __last)
+	{
+	  auto __init = __unary_op(*__first);
+	  *__result++ = __init;
+	  ++__first;
+	  if (__first != __last)
+	    __result = std::transform_inclusive_scan(__first, __last, __result,
+						     __binary_op, __unary_op,
+						     std::move(__init));
+	}
+      return __result;
+    }
+
+  // @} group numeric_ops
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
 // Parallel STL algorithms
 # if _PSTL_EXECUTION_POLICIES_DEFINED
 // If <execution> has already been included, pull in implementations
diff --git a/libstdc++-v3/testsuite/25_algorithms/for_each/for_each_n.cc b/libstdc++-v3/testsuite/25_algorithms/for_each/for_each_n.cc
new file mode 100644
index 00000000000..57c2bbe6d36
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/for_each/for_each_n.cc
@@ -0,0 +1,57 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+void test01()
+{
+  using __gnu_test::test_container;
+  using __gnu_test::input_iterator_wrapper;
+  int array[5] = { 1, 2, 3, 4, 5 };
+  test_container<int, input_iterator_wrapper> con(array);
+
+  int sum = 0;
+  struct Func
+  {
+    Func(int& i) : i(i) { }
+    Func(Func&&) = default;
+    Func& operator=(Func&&) = delete;
+    void operator()(int n) const { i += n; }
+    int& i;
+  };
+
+  struct Size
+  {
+    Size(short v) : val(v) { }
+    operator short() const { return val; }
+    short val;
+  };
+  auto res = std::for_each_n(con.begin(), Size(con.size()), Func(sum));
+
+  VERIFY( res.ptr == con.end().ptr );
+  VERIFY( sum == 15 );
+}
+
+int main()
+{
+  test01();
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/exclusive_scan/1.cc b/libstdc++-v3/testsuite/26_numerics/exclusive_scan/1.cc
new file mode 100644
index 00000000000..05a0135d7ab
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/exclusive_scan/1.cc
@@ -0,0 +1,94 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++17 29.8.7 [exclusive.scan]
+
+#include <numeric>
+#include <iterator>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+
+using __gnu_test::test_container;
+using __gnu_test::input_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+
+/*
+template<class InputIterator, class OutputIterator, class T>
+  OutputIterator
+  exclusive_scan(InputIterator, InputIterator, OutputIterator, T);
+*/
+void
+test01()
+{
+  int out[10];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::exclusive_scan(ca.begin(), ca.end(), co.begin(), 5);
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+10 );
+  VERIFY( out[0] == 5 );
+  VERIFY( out[1] == 6 );
+  VERIFY( out[2] == 8 );
+  VERIFY( out[3] == 11 );
+  VERIFY( out[4] == 15 );
+  VERIFY( out[5] == 20 );
+  VERIFY( out[6] == 26 );
+  VERIFY( out[7] == 33 );
+  VERIFY( out[8] == 41 );
+  VERIFY( out[9] == 50 );
+}
+
+/*
+template<class InputIterator, class OutputIterator, class T,
+	 class BinaryOperation>
+  OutputIterator
+  exclusive_scan(InputIterator, InputIterator, OutputIterator, T,
+		 BinaryOperation);
+*/
+void
+test02()
+{
+  int out[10];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::exclusive_scan(ca.begin(), ca.end(), co.begin(), 2,
+				 [](int i, int j) { return 2*i + 2*j; });
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+10 );
+  VERIFY( out[0] == 2 );
+  VERIFY( out[1] == 6 );
+  VERIFY( out[2] == 16 );
+  VERIFY( out[3] == 38 );
+  VERIFY( out[4] == 84 );
+  VERIFY( out[5] == 178 );
+  VERIFY( out[6] == 368 );
+  VERIFY( out[7] == 750 );
+  VERIFY( out[8] == 1516 );
+  VERIFY( out[9] == 3050 );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/inclusive_scan/1.cc b/libstdc++-v3/testsuite/26_numerics/inclusive_scan/1.cc
new file mode 100644
index 00000000000..68f1578928c
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/inclusive_scan/1.cc
@@ -0,0 +1,123 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++17 29.8.8 [inclusive.scan]
+
+#include <numeric>
+#include <iterator>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+
+using __gnu_test::test_container;
+using __gnu_test::input_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+
+/*
+template<class InputIterator, class OutputIterator>
+  OutputIterator
+  inclusive_scan(InputIterator, InputIterator, OutputIterator);
+*/
+void
+test01()
+{
+  int out[10];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::inclusive_scan(ca.begin(), ca.end(), co.begin());
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+10 );
+  VERIFY( out[0] == 1 );
+  VERIFY( out[1] == (1+2) );
+  VERIFY( out[2] == (1+2+3) );
+  VERIFY( out[3] == (1+2+3+4) );
+  VERIFY( out[4] == (1+2+3+4+5) );
+  VERIFY( out[5] == (1+2+3+4+5+6) );
+  VERIFY( out[6] == (1+2+3+4+5+6+7) );
+  VERIFY( out[7] == (1+2+3+4+5+6+7+8) );
+  VERIFY( out[8] == (1+2+3+4+5+6+7+8+9) );
+  VERIFY( out[9] == (1+2+3+4+5+6+7+8+9+10) );
+}
+
+/*
+template<class InputIterator, class OutputIterator, class BinaryOperation>
+  OutputIterator
+  inclusive_scan(InputIterator, InputIterator, OutputIterator,
+		 BinaryOperation);
+*/
+void
+test02()
+{
+  int out[10];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::inclusive_scan(ca.begin(), ca.end(), co.begin(),
+				 [](int i, int j) { return 2*i + 2*j; });
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+10 );
+  VERIFY( out[0] == 1 );
+  VERIFY( out[1] == (2*1+2*2) );
+  VERIFY( out[2] == (2*6+2*3) );
+  VERIFY( out[3] == (2*18+2*4) );
+  VERIFY( out[4] == (2*44+2*5) );
+  VERIFY( out[5] == (2*98+2*6));
+  VERIFY( out[6] == (2*208+2*7) );
+  VERIFY( out[7] == (2*430+2*8) );
+  VERIFY( out[8] == (2*876+2*9) );
+  VERIFY( out[9] == (2*1770+2*10) );
+}
+
+/*
+template<class InputIterator, class OutputIterator, class BinaryOperation, T>
+  OutputIterator
+  inclusive_scan(InputIterator, InputIterator, OutputIterator,
+		 BinaryOperation, T);
+*/
+void
+test03()
+{
+  int out[10];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::inclusive_scan(ca.begin(), ca.end(), co.begin(),
+				 [](int i, int j) { return 2*i + 2*j; },
+				 1);
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+10 );
+  VERIFY( out[0] == 4 );
+  VERIFY( out[1] == (2*4+2*2) );
+  VERIFY( out[2] == (2*12+2*3) );
+  VERIFY( out[3] == (2*30+2*4) );
+  VERIFY( out[4] == (2*68+2*5) );
+  VERIFY( out[5] == (2*146+2*6) );
+  VERIFY( out[6] == (2*304+2*7));
+  VERIFY( out[7] == (2*622+2*8) );
+  VERIFY( out[8] == (2*1260+2*9) );
+  VERIFY( out[9] == (2*2538+2*10) );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/reduce/1.cc b/libstdc++-v3/testsuite/26_numerics/reduce/1.cc
new file mode 100644
index 00000000000..0434d2ecf49
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/reduce/1.cc
@@ -0,0 +1,82 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++17 29.8.3 [reduce]
+
+#include <numeric>
+#include <iterator>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+/*
+template<class InputIterator>
+  iterator_traits<InputIterator>::value_type
+  reduce(InputIterator, InputIterator);
+*/
+void
+test01()
+{
+  using __gnu_test::test_container;
+  using __gnu_test::input_iterator_wrapper;
+  int array[5] = { 1, 2, 3, 4, 5 };
+  test_container<int, input_iterator_wrapper> con(array);
+  int res = std::reduce(con.begin(), con.end());
+  VERIFY( res == 15 );
+}
+
+/*
+template<class InputIterator, class T>
+  T reduce(InputIterator, InputIterator, T);
+*/
+void
+test02()
+{
+  bool b[] = {true, false, true, true, false, true, false, true, true, false};
+  int res = std::reduce(std::begin(b), std::end(b), 100);
+  VERIFY( res == 106 );
+}
+
+/*
+template<class InputIterator, class T>
+  T reduce(InputIterator, InputIterator, T);
+template<class InputIterator, class T, class BinaryOperation>
+  T reduce(InputIterator, InputIterator, T, BinaryOperation);
+*/
+void
+test03()
+{
+  int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+
+  auto res = std::reduce(std::begin(a), std::end(a), (short)11);
+  static_assert(std::is_same_v<decltype(res), short>);
+  VERIFY( res == 66 );
+
+  auto res2 = std::reduce(std::begin(a), std::end(a), -1l, std::multiplies<>());
+  static_assert(std::is_same_v<decltype(res2), long>);
+  VERIFY( res2 == -3628800 );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/transform_exclusive_scan/1.cc b/libstdc++-v3/testsuite/26_numerics/transform_exclusive_scan/1.cc
new file mode 100644
index 00000000000..61dca6af6ac
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/transform_exclusive_scan/1.cc
@@ -0,0 +1,65 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++17 29.8.9 [transform.exclusive.scan]
+
+#include <numeric>
+#include <iterator>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+int a[] = {1, 2, 3, 4, 5, 6, 7};
+
+using __gnu_test::test_container;
+using __gnu_test::input_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+
+/*
+template<class InputIterator, class OutputIterator, class T,
+	 class BinaryOperation, class UnaryOperation>
+  OutputIterator
+  transform_exclusive_scan(InputIterator, InputIterator, OutputIterator, T,
+			   BinaryOperation, UnaryOperation);
+*/
+void
+test01()
+{
+  int out[7];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::transform_exclusive_scan(ca.begin(), ca.end(), co.begin(), 5,
+					   std::multiplies<>(),
+					   std::negate<>());
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+7 );
+  VERIFY( out[0] == 5 );
+  VERIFY( out[1] == -5 );
+  VERIFY( out[2] == 10 );
+  VERIFY( out[3] == -30 );
+  VERIFY( out[4] == 120 );
+  VERIFY( out[5] == -600 );
+  VERIFY( out[6] == 3600 );
+}
+
+int
+main()
+{
+  test01();
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/transform_inclusive_scan/1.cc b/libstdc++-v3/testsuite/26_numerics/transform_inclusive_scan/1.cc
new file mode 100644
index 00000000000..16eeedb58ee
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/transform_inclusive_scan/1.cc
@@ -0,0 +1,94 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++17 29.8.10 [transform.inclusive.scan]
+
+#include <numeric>
+#include <iterator>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+int a[] = {1, 2, 3, 4, 5, 6, 7};
+
+using __gnu_test::test_container;
+using __gnu_test::input_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+
+/*
+template<class InputIterator, class OutputIterator, class BinaryOperation,
+	 class UnaryOperation>
+  OutputIterator
+  transform_inclusive_scan(InputIterator, InputIterator, OutputIterator,
+			   BinaryOperation, UnaryOperation);
+*/
+void
+test01()
+{
+  int out[7];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::transform_inclusive_scan(ca.begin(), ca.end(), co.begin(),
+					   std::multiplies<>(),
+					   [](int i) { return i+1; });
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+7 );
+  VERIFY( out[0] == 2 );
+  VERIFY( out[1] == (2*3) );
+  VERIFY( out[2] == (2*3*4) );
+  VERIFY( out[3] == (2*3*4*5) );
+  VERIFY( out[4] == (2*3*4*5*6) );
+  VERIFY( out[5] == (2*3*4*5*6*7) );
+  VERIFY( out[6] == (2*3*4*5*6*7*8) );
+}
+
+/*
+template<class InputIterator, class OutputIterator, class BinaryOperation,
+	 class UnaryOperation, class T>
+  OutputIterator
+  transform_inclusive_scan(InputIterator, InputIterator, OutputIterator,
+			   BinaryOperation, UnaryOperation, T);
+*/
+void
+test02()
+{
+  int out[7];
+  test_container<int, output_iterator_wrapper> co(out);
+  test_container<int, input_iterator_wrapper> ca(a);
+  auto end = std::transform_inclusive_scan(ca.begin(), ca.end(), co.begin(),
+					   std::multiplies<>(),
+					   [](int i) { return i+1; },
+					   3);
+  static_assert(std::is_same_v<decltype(end), decltype(co.begin())>);
+  VERIFY( end.ptr == out+7 );
+  VERIFY( out[0] == 3*2 );
+  VERIFY( out[1] == (3*2*3) );
+  VERIFY( out[2] == (3*2*3*4) );
+  VERIFY( out[3] == (3*2*3*4*5) );
+  VERIFY( out[4] == (3*2*3*4*5*6) );
+  VERIFY( out[5] == (3*2*3*4*5*6*7) );
+  VERIFY( out[6] == (3*2*3*4*5*6*7*8) );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}
diff --git a/libstdc++-v3/testsuite/26_numerics/transform_reduce/1.cc b/libstdc++-v3/testsuite/26_numerics/transform_reduce/1.cc
new file mode 100644
index 00000000000..bb9a5bbce7e
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/transform_reduce/1.cc
@@ -0,0 +1,109 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// C++17 29.8.5 [transform.reduce]
+
+#include <numeric>
+#include <iterator>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+double b[] = {0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5};
+
+using __gnu_test::test_container;
+using __gnu_test::input_iterator_wrapper;
+
+/*
+template<class InputIterator1, class InputIterator2, class T>
+  T transform_reduce(InputIterator1, InputIterator1, InputIterator2, T);
+*/
+void
+test01()
+{
+  auto res = std::transform_reduce(std::begin(a), std::end(a), std::begin(b),
+				   1.0f);
+  static_assert(std::is_same_v<decltype(res), float>);
+  VERIFY( res == (float)(1 + 0.5 + 1 + 1.5 + 2 + 2.5 + 3 + 3.5 + 4 + 4.5 + 5) );
+
+  test_container<int, input_iterator_wrapper> ca(a);
+  test_container<double, input_iterator_wrapper> cb(b);
+
+  auto res2 = std::transform_reduce(ca.begin(), ca.end(), cb.begin(),
+				   1.0f);
+  static_assert(std::is_same_v<decltype(res2), float>);
+  VERIFY( res2 == res );
+}
+
+/*
+template<class InputIterator1, class InputIterator2, class T,
+	 class BinaryOperation1, class BinaryOperation2>
+  T transform_reduce(InputIterator1, InputIterator1, InputIterator2, T,
+		     BinaryOperation1, BinaryOperation2);
+*/
+void
+test02()
+{
+  auto res = std::transform_reduce(std::begin(a), std::end(a), std::begin(b),
+				    1L, std::multiplies<>(), std::plus<int>());
+  static_assert(std::is_same_v<decltype(res), long>);
+  VERIFY( res == (1L * 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10) );
+
+  test_container<int, input_iterator_wrapper> ca(a);
+  test_container<double, input_iterator_wrapper> cb(b);
+
+  auto res2 = std::transform_reduce(ca.begin(), ca.end(), cb.begin(),
+				    1L, std::multiplies<>(), std::plus<int>());
+  static_assert(std::is_same_v<decltype(res2), long>);
+  VERIFY( res2 == res );
+}
+
+/*
+template<class InputIterator, class T, class BinaryOperation,
+	 class UnaryOperation>
+  T transform_reduce(InputIterator, InputIterator, T,
+		     BinaryOperation, UnaryOperation);
+*/
+void
+test03()
+{
+  auto res = std::transform_reduce(std::begin(a), std::end(a), 10.0,
+				   std::plus<>(),
+				   [](int i) { return i * i; });
+  static_assert(std::is_same_v<decltype(res), double>);
+  VERIFY( res == (10.0 + 1 + 4 + 9 + 16 + 25 + 36 + 49 + 64 + 81 + 100) );
+
+  test_container<int, input_iterator_wrapper> ca(a);
+  test_container<double, input_iterator_wrapper> cb(b);
+
+  auto res2 = std::transform_reduce(ca.begin(), ca.end(), 10.0,
+				   std::plus<>(),
+				   [](int i) { return i * i; });
+  static_assert(std::is_same_v<decltype(res2), double>);
+  VERIFY( res2 == (10.0 + 1 + 4 + 9 + 16 + 25 + 36 + 49 + 64 + 81 + 100) );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}
diff --git a/libstdc++-v3/testsuite/util/testsuite_iterators.h b/libstdc++-v3/testsuite/util/testsuite_iterators.h
index 4636d9995c1..ac646a59cb8 100644
--- a/libstdc++-v3/testsuite/util/testsuite_iterators.h
+++ b/libstdc++-v3/testsuite/util/testsuite_iterators.h
@@ -589,6 +589,10 @@ namespace __gnu_test
     ItType<T>
     end()
     { return it(bounds.last); }
+
+    std::size_t
+    size() const
+    { return bounds.last - bounds.first; }
   };
 }
 #endif