diff --git a/libstdc++-v3/include/bits/stl_numeric.h b/libstdc++-v3/include/bits/stl_numeric.h
index dd4683fe92e..f95c86a0d48 100644
--- a/libstdc++-v3/include/bits/stl_numeric.h
+++ b/libstdc++-v3/include/bits/stl_numeric.h
@@ -83,6 +83,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  @ingroup numeric_ops
    */
   template<typename _ForwardIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     void
     iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value)
     {
@@ -128,6 +129,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    *  @return  The final sum.
    */
   template<typename _InputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     inline _Tp
     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
     {
@@ -154,6 +156,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    *  @return  The final sum.
    */
   template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
     inline _Tp
     accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
 	       _BinaryOperation __binary_op)
@@ -182,6 +185,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    *  @return  The final inner product.
    */
   template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     inline _Tp
     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 		  _InputIterator2 __first2, _Tp __init)
@@ -214,6 +218,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    */
   template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
 	   typename _BinaryOperation1, typename _BinaryOperation2>
+    _GLIBCXX20_CONSTEXPR
     inline _Tp
     inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
 		  _InputIterator2 __first2, _Tp __init,
@@ -246,6 +251,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    *  @return  Iterator pointing just beyond the values written to __result.
    */
   template<typename _InputIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     partial_sum(_InputIterator __first, _InputIterator __last,
 		_OutputIterator __result)
@@ -287,6 +293,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    */
   template<typename _InputIterator, typename _OutputIterator,
 	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     partial_sum(_InputIterator __first, _InputIterator __last,
 		_OutputIterator __result, _BinaryOperation __binary_op)
@@ -326,6 +333,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    *  DR 539. partial_sum and adjacent_difference should mention requirements
    */
   template<typename _InputIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     adjacent_difference(_InputIterator __first,
 			_InputIterator __last, _OutputIterator __result)
@@ -369,6 +377,7 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
    */
   template<typename _InputIterator, typename _OutputIterator,
 	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     adjacent_difference(_InputIterator __first, _InputIterator __last,
 			_OutputIterator __result, _BinaryOperation __binary_op)
diff --git a/libstdc++-v3/include/std/numeric b/libstdc++-v3/include/std/numeric
index cf35191cb47..8a7830ffd85 100644
--- a/libstdc++-v3/include/std/numeric
+++ b/libstdc++-v3/include/std/numeric
@@ -249,6 +249,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  arithmetic) the result can be different.
    */
   template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _Tp
     reduce(_InputIterator __first, _InputIterator __last, _Tp __init,
 	   _BinaryOperation __binary_op)
@@ -284,6 +285,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  Equivalent to calling `std::reduce(first, last, init, std::plus<>())`.
    */
   template<typename _InputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     inline _Tp
     reduce(_InputIterator __first, _InputIterator __last, _Tp __init)
     { return std::reduce(__first, __last, std::move(__init), plus<>()); }
@@ -300,6 +302,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  Equivalent to calling `std::reduce(first, last, T{}, std::plus<>())`.
    */
   template<typename _InputIterator>
+    _GLIBCXX20_CONSTEXPR
     inline typename iterator_traits<_InputIterator>::value_type
     reduce(_InputIterator __first, _InputIterator __last)
     {
@@ -327,6 +330,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
 	   typename _BinaryOperation1, typename _BinaryOperation2>
+    _GLIBCXX20_CONSTEXPR
     _Tp
     transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
 		     _InputIterator2 __first2, _Tp __init,
@@ -369,6 +373,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  elements.
    */
   template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     inline _Tp
     transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
 		     _InputIterator2 __first2, _Tp __init)
@@ -394,6 +399,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator, typename _Tp,
 	   typename _BinaryOperation, typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _Tp
     transform_reduce(_InputIterator __first, _InputIterator __last, _Tp __init,
 		     _BinaryOperation __binary_op, _UnaryOperation __unary_op)
@@ -436,6 +442,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator, typename _OutputIterator, typename _Tp,
 	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     exclusive_scan(_InputIterator __first, _InputIterator __last,
 		   _OutputIterator __result, _Tp __init,
@@ -469,6 +476,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  so the Nth input element is not included.
    */
   template<typename _InputIterator, typename _OutputIterator, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     inline _OutputIterator
     exclusive_scan(_InputIterator __first, _InputIterator __last,
 		   _OutputIterator __result, _Tp __init)
@@ -497,6 +505,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator, typename _OutputIterator,
 	   typename _BinaryOperation, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     inclusive_scan(_InputIterator __first, _InputIterator __last,
 		   _OutputIterator __result, _BinaryOperation __binary_op,
@@ -525,6 +534,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator, typename _OutputIterator,
 	   typename _BinaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     inclusive_scan(_InputIterator __first, _InputIterator __last,
 		   _OutputIterator __result, _BinaryOperation __binary_op)
@@ -557,6 +567,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  so the Nth input element is included.
    */
   template<typename _InputIterator, typename _OutputIterator>
+    _GLIBCXX20_CONSTEXPR
     inline _OutputIterator
     inclusive_scan(_InputIterator __first, _InputIterator __last,
 		   _OutputIterator __result)
@@ -584,6 +595,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator, typename _OutputIterator, typename _Tp,
 	   typename _BinaryOperation, typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     transform_exclusive_scan(_InputIterator __first, _InputIterator __last,
 			     _OutputIterator __result, _Tp __init,
@@ -622,6 +634,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator, typename _OutputIterator,
 	   typename _BinaryOperation, typename _UnaryOperation, typename _Tp>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
 			     _OutputIterator __result,
@@ -655,6 +668,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   template<typename _InputIterator, typename _OutputIterator,
 	  typename _BinaryOperation, typename _UnaryOperation>
+    _GLIBCXX20_CONSTEXPR
     _OutputIterator
     transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
 			     _OutputIterator __result,
@@ -676,6 +690,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   // @} group numeric_ops
 
+#if __cplusplus > 201703L
+#define __cpp_lib_constexpr_numeric 201911L
+#endif
+
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
diff --git a/libstdc++-v3/testsuite/26_numerics/accumulate/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/accumulate/constexpr.cc
new file mode 100644
index 00000000000..6fefd5a3f98
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/accumulate/constexpr.cc
@@ -0,0 +1,42 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[5] = {1,2,3,4,5};
+  auto sum = std::accumulate(x, x+5, 0);
+  return sum == 15;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[5] = {1,2,3,4,5};
+  auto prod = std::accumulate(x, x+5, 1, std::multiplies{});
+  return prod == 120;
+}
+
+static_assert(test02());
diff --git a/libstdc++-v3/testsuite/26_numerics/adjacent_difference/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/adjacent_difference/constexpr.cc
new file mode 100644
index 00000000000..5f79284e268
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/adjacent_difference/constexpr.cc
@@ -0,0 +1,44 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[5] = {1,2,3,4,5};
+  int y[5];
+  std::adjacent_difference(x, x+5, y);
+  return y[0] == 1 && y[1] == 1 && y[2] == 1 && y[3] == 1 && y[4] == 1;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[5] = {1,2,3,4,5};
+  int y[5];
+  std::adjacent_difference(x, x+5, y, std::multiplies{});
+  return y[0] == 1 && y[1] == 2 && y[2] == 6 && y[3] == 12 && y[4] == 20;
+}
+
+static_assert(test02());
diff --git a/libstdc++-v3/testsuite/26_numerics/exclusive_scan/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/exclusive_scan/constexpr.cc
new file mode 100644
index 00000000000..c885ba5dbd1
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/exclusive_scan/constexpr.cc
@@ -0,0 +1,44 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::exclusive_scan(x, x+3, y, 0);
+  return y[0] == 0 && y[1] == 1 && y[2] == 3;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::exclusive_scan(x, x+3, y, 1, std::multiplies{});
+  return y[0] == 1 && y[1] == 1 && y[2] == 2;
+}
+
+static_assert(test02());
diff --git a/libstdc++-v3/testsuite/26_numerics/inclusive_scan/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/inclusive_scan/constexpr.cc
new file mode 100644
index 00000000000..a50a70e9fc2
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/inclusive_scan/constexpr.cc
@@ -0,0 +1,55 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::inclusive_scan(x, x+3, y);
+  return y[0] == 1 && y[1] == 3 && y[2] == 6;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::inclusive_scan(x, x+3, y, std::multiplies{});
+  return y[0] == 1 && y[1] == 2 && y[2] == 6;
+}
+
+static_assert(test02());
+
+constexpr bool
+test03()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::inclusive_scan(x, x+3, y, std::multiplies{}, 2);
+  return y[0] == 2 && y[1] == 4 && y[2] == 12;
+}
+
+static_assert(test03());
diff --git a/libstdc++-v3/testsuite/26_numerics/inner_product/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/inner_product/constexpr.cc
new file mode 100644
index 00000000000..a6aaf351560
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/inner_product/constexpr.cc
@@ -0,0 +1,45 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[5] = {1,2,3,4,5};
+  int y[5] = {2,4,6,8,10};
+  auto ret = std::inner_product(x, x+5, y, 0);
+  return ret == 110;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[5] = {1,2,3,4,5};
+  int y[5] = {2,4,6,8,10};
+  auto ret = std::inner_product(x, x+5, y, 1,
+				std::multiplies{}, std::plus{});
+  return ret == 3*6*9*12*15;
+}
+
+static_assert(test02());
diff --git a/libstdc++-v3/testsuite/26_numerics/iota/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/iota/constexpr.cc
new file mode 100644
index 00000000000..50eecf8b605
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/iota/constexpr.cc
@@ -0,0 +1,31 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[3] = {0};
+  std::iota(x, x+3, 0);
+  return x[0] == 0 && x[1] == 1 && x[2] == 2;
+}
+
+static_assert(test01());
diff --git a/libstdc++-v3/testsuite/26_numerics/partial_sum/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/partial_sum/constexpr.cc
new file mode 100644
index 00000000000..c2e758492e4
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/partial_sum/constexpr.cc
@@ -0,0 +1,44 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::partial_sum(x, x+3, y);
+  return y[0] == 1 && y[1] == 3 && y[2] == 6;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::partial_sum(x, x+3, y, std::multiplies{});
+  return y[0] == 1 && y[1] == 2 && y[2] == 6;
+}
+
+static_assert(test02());
diff --git a/libstdc++-v3/testsuite/26_numerics/reduce/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/reduce/constexpr.cc
new file mode 100644
index 00000000000..5ed48892df2
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/reduce/constexpr.cc
@@ -0,0 +1,52 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[5] = {1,2,3,4,5};
+  auto sum = std::reduce(x, x+5);
+  return sum == 15;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[5] = {1,2,3,4,5};
+  auto sum = std::reduce(x, x+5, 0);
+  return sum == 15;
+}
+
+static_assert(test02());
+
+constexpr bool
+test03()
+{
+  int x[5] = {1,2,3,4,5};
+  auto prod = std::reduce(x, x+5, 1, std::multiplies{});
+  return prod == 120;
+}
+
+static_assert(test03());
diff --git a/libstdc++-v3/testsuite/26_numerics/transform_exclusive_scan/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/transform_exclusive_scan/constexpr.cc
new file mode 100644
index 00000000000..f01fd241a8a
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/transform_exclusive_scan/constexpr.cc
@@ -0,0 +1,33 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::transform_exclusive_scan(x, x+3, y, 0, std::plus{}, std::negate{});
+  return y[0] == 0 && y[1] == -1 && y[2] == -3;
+}
+
+static_assert(test01());
diff --git a/libstdc++-v3/testsuite/26_numerics/transform_inclusive_scan/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/transform_inclusive_scan/constexpr.cc
new file mode 100644
index 00000000000..6f072b74569
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/transform_inclusive_scan/constexpr.cc
@@ -0,0 +1,44 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::transform_inclusive_scan(x, x+3, y, std::plus{}, std::negate{}, 0);
+  return y[0] == -1 && y[1] == -3 && y[2] == -6;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[3] = {1,2,3};
+  int y[3];
+  std::transform_inclusive_scan(x, x+3, y, std::plus{}, std::negate{});
+  return y[0] == -1 && y[1] == -3 && y[2] == -6;
+}
+
+static_assert(test02());
diff --git a/libstdc++-v3/testsuite/26_numerics/transform_reduce/constexpr.cc b/libstdc++-v3/testsuite/26_numerics/transform_reduce/constexpr.cc
new file mode 100644
index 00000000000..eb054c1f8af
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/transform_reduce/constexpr.cc
@@ -0,0 +1,55 @@
+// Copyright (C) 2020 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <functional>
+#include <numeric>
+
+constexpr bool
+test01()
+{
+  int x[5] = {1,2,3,4,5};
+  int y[5] = {2,4,6,8,10};
+  auto ret = std::transform_reduce(x, x+5, y, 0);
+  return ret == 110;
+}
+
+static_assert(test01());
+
+constexpr bool
+test02()
+{
+  int x[5] = {1,2,3,4,5};
+  int y[5] = {2,4,6,8,10};
+  auto ret = std::transform_reduce(x, x+5, y, 1,
+				   std::multiplies{}, std::plus{});
+  return ret == 3*6*9*12*15;
+}
+
+static_assert(test02());
+
+constexpr bool
+test03()
+{
+  int x[5] = {1,2,3,4,5};
+  auto ret = std::transform_reduce(x, x+5, 0, std::plus{}, std::negate{});
+  return ret == -15;
+}
+
+static_assert(test03());
