Implement C++20 p1424 - 'constexpr' feature macro concerns...

2019-09-09  Edward Smith-Rowland  <3dw4rd@verizon.net>

	Implement C++20 p1424 - 'constexpr' feature macro concerns,
	Issue 3256 - Feature testing macro for constexpr algorithms,
	and Issue 3257 - Missing feature testing macro update from P0858.
	* include/std/version (__cpp_lib_constexpr_algorithms): Bump value.
	* include/bits/algorithmfwd.h: Ditto.
	* include/std/utility: Ditto.
	* testsuite/25_algorithms/constexpr_macro.cc: Ditto.
	* testsuite/25_algorithms/cpp_lib_constexpr.cc: New check for
	__cpp_lib_constexpr macro in <algorith>.
	* testsuite/20_util/exchange/constexpr.cc: Add check for
	__cpp_lib_constexpr macro in <utility>.
	* testsuite/25_algorithms/adjacent_find/constexpr.cc: Remove check for
	__cpp_lib_constexpr_algorithms.
	* testsuite/25_algorithms/all_of/constexpr.cc: Ditto.
	* testsuite/25_algorithms/any_of/constexpr.cc: Ditto.
	* testsuite/25_algorithms/binary_search/constexpr.cc: Ditto.
	* testsuite/25_algorithms/copy/constexpr.cc: Ditto.
	* testsuite/25_algorithms/copy_backward/constexpr.cc: Ditto.
	* testsuite/25_algorithms/copy_if/constexpr.cc: Ditto.
	* testsuite/25_algorithms/copy_n/constexpr.cc: Ditto.
	* testsuite/25_algorithms/count/constexpr.cc: Ditto.
	* testsuite/25_algorithms/count_if/constexpr.cc: Ditto.
	* testsuite/25_algorithms/equal/constexpr.cc: Ditto.
	* testsuite/25_algorithms/equal_range/constexpr.cc: Ditto.
	* testsuite/25_algorithms/fill/constexpr.cc: Ditto.
	* testsuite/25_algorithms/fill_n/constexpr.cc: Ditto.
	* testsuite/25_algorithms/find/constexpr.cc: Ditto.
	* testsuite/25_algorithms/find_end/constexpr.cc: Ditto.
	* testsuite/25_algorithms/find_first_of/constexpr.cc: Ditto.
	* testsuite/25_algorithms/find_if/constexpr.cc: Ditto.
	* testsuite/25_algorithms/find_if_not/constexpr.cc: Ditto.
	* testsuite/25_algorithms/for_each/constexpr.cc: Ditto.
	* testsuite/25_algorithms/generate/constexpr.cc: Ditto.
	* testsuite/25_algorithms/generate_n/constexpr.cc: Ditto.
	* testsuite/25_algorithms/is_heap/constexpr.cc: Ditto.
	* testsuite/25_algorithms/is_heap_until/constexpr.cc: Ditto.
	* testsuite/25_algorithms/is_partitioned/constexpr.cc: Ditto.
	* testsuite/25_algorithms/is_permutation/constexpr.cc: Ditto.
	* testsuite/25_algorithms/is_sorted/constexpr.cc: Ditto.
	* testsuite/25_algorithms/is_sorted_until/constexpr.cc: Ditto.
	* testsuite/25_algorithms/lexicographical_compare/constexpr.cc: Ditto.
	* testsuite/25_algorithms/lower_bound/constexpr.cc: Ditto.
	* testsuite/25_algorithms/merge/constexpr.cc: Ditto.
	* testsuite/25_algorithms/mismatch/constexpr.cc: Ditto.
	* testsuite/25_algorithms/none_of/constexpr.cc: Ditto.
	* testsuite/25_algorithms/partition_copy/constexpr.cc: Ditto.
	* testsuite/25_algorithms/partition_point/constexpr.cc: Ditto.
	* testsuite/25_algorithms/remove/constexpr.cc: Ditto.
	* testsuite/25_algorithms/remove_copy/constexpr.cc: Ditto.
	* testsuite/25_algorithms/remove_copy_if/constexpr.cc: Ditto.
	* testsuite/25_algorithms/remove_if/constexpr.cc: Ditto.
	* testsuite/25_algorithms/replace_copy/constexpr.cc: Ditto.
	* testsuite/25_algorithms/replace_copy_if/constexpr.cc: Ditto.
	* testsuite/25_algorithms/replace_if/constexpr.cc: Ditto.
	* testsuite/25_algorithms/reverse_copy/constexpr.cc: Ditto.
	* testsuite/25_algorithms/rotate_copy/constexpr.cc: Ditto.
	* testsuite/25_algorithms/search/constexpr.cc: Ditto.
	* testsuite/25_algorithms/search_n/constexpr.cc: Ditto.
	* testsuite/25_algorithms/set_difference/constexpr.cc: Ditto.
	* testsuite/25_algorithms/set_intersection/constexpr.cc: Ditto.
	* testsuite/25_algorithms/set_symmetric_difference/constexpr.cc: Ditto.
	* testsuite/25_algorithms/set_union/constexpr.cc: Ditto.
	* testsuite/25_algorithms/transform/constexpr.cc: Ditto.
	* testsuite/25_algorithms/unique/constexpr.cc: Ditto.
	* testsuite/25_algorithms/unique_copy/constexpr.cc: Ditto.
	* testsuite/25_algorithms/upper_bound/constexpr.cc: Ditto.

From-SVN: r275560

79 files changed, 111 insertions, 430 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 982d63b..7f37934 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,74 @@
 2019-09-09  Edward Smith-Rowland  <3dw4rd@verizon.net>
 
+	Implement C++20 p1424 - 'constexpr' feature macro concerns,
+	Issue 3256 - Feature testing macro for constexpr algorithms,
+	and Issue 3257 - Missing feature testing macro update from P0858.
+	* include/std/version (__cpp_lib_constexpr_algorithms): Bump value.
+	* include/bits/algorithmfwd.h: Ditto.
+	* include/std/utility: Ditto.
+	* testsuite/25_algorithms/constexpr_macro.cc: Ditto.
+	* testsuite/25_algorithms/cpp_lib_constexpr.cc: New check for
+	__cpp_lib_constexpr macro in <algorith>.
+	* testsuite/20_util/exchange/constexpr.cc: Add check for
+	__cpp_lib_constexpr macro in <utility>.
+	* testsuite/25_algorithms/adjacent_find/constexpr.cc: Remove check for
+	__cpp_lib_constexpr_algorithms.
+	* testsuite/25_algorithms/all_of/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/any_of/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/binary_search/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/copy/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/copy_backward/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/copy_if/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/copy_n/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/count/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/count_if/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/equal/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/equal_range/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/fill/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/fill_n/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/find/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/find_end/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/find_first_of/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/find_if/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/find_if_not/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/for_each/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/generate/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/generate_n/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/is_heap/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/is_heap_until/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/is_partitioned/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/is_permutation/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/is_sorted/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/is_sorted_until/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/lexicographical_compare/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/lower_bound/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/merge/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/mismatch/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/none_of/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/partition_copy/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/partition_point/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/remove/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/remove_copy/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/remove_copy_if/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/remove_if/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/replace_copy/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/replace_copy_if/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/replace_if/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/reverse_copy/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/rotate_copy/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/search/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/search_n/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/set_difference/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/set_intersection/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/set_symmetric_difference/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/set_union/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/transform/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/unique/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/unique_copy/constexpr.cc: Ditto.
+	* testsuite/25_algorithms/upper_bound/constexpr.cc: Ditto.
+
+2019-09-09  Edward Smith-Rowland  <3dw4rd@verizon.net>
+
 	Update docs for recent <span> and constexpr lib changes.
 	* doc/xml/manual/status_cxx2020.xml: Update p0202r3, p0858r0, p0879r0,
 	p1023r0, p1085r2 status.
diff --git a/libstdc++-v3/include/bits/algorithmfwd.h b/libstdc++-v3/include/bits/algorithmfwd.h
index 9c511f0..21b58eb 100644
--- a/libstdc++-v3/include/bits/algorithmfwd.h
+++ b/libstdc++-v3/include/bits/algorithmfwd.h
@@ -192,8 +192,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // adjacent_find
 
 #if __cplusplus > 201703L
-#  define __cpp_lib_constexpr_algorithms 201711L
-#  define __cpp_lib_constexpr_swap_algorithms 201806L
+#  define __cpp_lib_constexpr_algorithms 201806L
 #endif
 
 #if __cplusplus >= 201103L
diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index e29775a..420fea6 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -70,7 +70,7 @@
 #endif
 
 #if __cplusplus > 201402L
-# define __cpp_lib_array_constexpr 201603
+# define __cpp_lib_array_constexpr 201803
 #endif
 
 namespace std _GLIBCXX_VISIBILITY(default)
diff --git a/libstdc++-v3/include/std/string_view b/libstdc++-v3/include/std/string_view
index e8b6ed3..ff1c0c3 100644
--- a/libstdc++-v3/include/std/string_view
+++ b/libstdc++-v3/include/std/string_view
@@ -47,7 +47,7 @@ namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
-#define __cpp_lib_string_view 201603
+#define __cpp_lib_string_view 201803
 
   // Helper for basic_string and basic_string_view members.
   constexpr size_t
diff --git a/libstdc++-v3/include/std/utility b/libstdc++-v3/include/std/utility
index 5f496f6..246e3a3 100644
--- a/libstdc++-v3/include/std/utility
+++ b/libstdc++-v3/include/std/utility
@@ -281,7 +281,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #define __cpp_lib_exchange_function 201304
 
 #if __cplusplus > 201703L
-#  define __cpp_lib_constexpr_algorithms 201711L
+#  define __cpp_lib_constexpr_algorithms 201806L
 #endif
 
   /// Assign @p __new_val to @p __obj and return its previous value.
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index 7625d39..f758bcd 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -90,7 +90,7 @@
 #define __cpp_lib_addressof_constexpr 201603
 #define __cpp_lib_any 201606L
 #define __cpp_lib_apply 201603
-#define __cpp_lib_array_constexpr 201603
+#define __cpp_lib_array_constexpr 201803
 #define __cpp_lib_as_const 201510
 #define __cpp_lib_atomic_is_always_lock_free 201603
 #define __cpp_lib_bool_constant 201505
@@ -138,7 +138,7 @@
 # define __cpp_lib_shared_mutex 201505
 #endif
 #define __cpp_lib_shared_ptr_weak_type 201606
-#define __cpp_lib_string_view 201603
+#define __cpp_lib_string_view 201803
 // #define __cpp_lib_to_chars 201611L
 #define __cpp_lib_type_trait_variable_templates 201510L
 #define __cpp_lib_uncaught_exceptions 201411L
@@ -153,8 +153,8 @@
 #define __cpp_lib_atomic_ref 201806L
 #define __cpp_lib_bind_front 201907L
 #define __cpp_lib_bounded_array_traits 201902L
-#define __cpp_lib_constexpr_algorithms 201711L
-#define __cpp_lib_constexpr_swap_algorithms 201806L
+#define __cpp_lib_constexpr 201711L
+#define __cpp_lib_constexpr_algorithms 201806L
 #if __cpp_impl_destroying_delete
 # define __cpp_lib_destroying_delete 201806L
 #endif
diff --git a/libstdc++-v3/testsuite/20_util/exchange/constexpr.cc b/libstdc++-v3/testsuite/20_util/exchange/constexpr.cc
index 38edfaa..9c84134 100644
--- a/libstdc++-v3/testsuite/20_util/exchange/constexpr.cc
+++ b/libstdc++-v3/testsuite/20_util/exchange/constexpr.cc
@@ -20,6 +20,12 @@
 
 #include <utility>
 
+#ifndef __cpp_lib_constexpr_algorithms
+# error "Feature-test macro for constexpr algorithms missing"
+#elif __cpp_lib_constexpr_algorithms < 201806L
+# error "Feature-test macro for constexpr algorithms has wrong value"
+#endif
+
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/adjacent_find/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/adjacent_find/constexpr.cc
index e62f43c..bcfd806 100644
--- a/libstdc++-v3/testsuite/25_algorithms/adjacent_find/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/adjacent_find/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> car{{0, 1, 2, 3, 4, 5, 6, 6, 8, 9, 9, 11}};
 
 constexpr auto out0x = std::adjacent_find(car.begin(), car.end());
diff --git a/libstdc++-v3/testsuite/25_algorithms/all_of/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/all_of/constexpr.cc
index e3d187c..7f62bbb 100644
--- a/libstdc++-v3/testsuite/25_algorithms/all_of/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/all_of/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 6> cae{{0, 2, 4, 6, 8, 10}};
 
 constexpr auto out2 = std::all_of(cae.begin(), cae.end(),
diff --git a/libstdc++-v3/testsuite/25_algorithms/any_of/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/any_of/constexpr.cc
index 0ff427c..a1e64e8 100644
--- a/libstdc++-v3/testsuite/25_algorithms/any_of/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/any_of/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/binary_search/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/binary_search/constexpr.cc
index aaa4112..8406b3d 100644
--- a/libstdc++-v3/testsuite/25_algorithms/binary_search/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/binary_search/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/constexpr_macro.cc b/libstdc++-v3/testsuite/25_algorithms/constexpr_macro.cc
index 07808ee..cff2769 100644
--- a/libstdc++-v3/testsuite/25_algorithms/constexpr_macro.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/constexpr_macro.cc
@@ -22,6 +22,6 @@
 
 #ifndef __cpp_lib_constexpr_algorithms
 # error "Feature-test macro for constexpr algorithms missing in <version>"
-#elif __cpp_lib_constexpr_algorithms != 201711L
+#elif __cpp_lib_constexpr_algorithms < 201806L
 # error "Feature-test macro for constexpr algorithms has wrong value in <version>"
 #endif
diff --git a/libstdc++-v3/testsuite/25_algorithms/copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/copy/constexpr.cc
index 9a4aa25..67910b8 100644
--- a/libstdc++-v3/testsuite/25_algorithms/copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/copy_backward/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/copy_backward/constexpr.cc
index 25cf97f..ed74879 100644
--- a/libstdc++-v3/testsuite/25_algorithms/copy_backward/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/copy_backward/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/copy_if/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/copy_if/constexpr.cc
index 59deacf..ef2de8c 100644
--- a/libstdc++-v3/testsuite/25_algorithms/copy_if/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/copy_if/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 
 constexpr bool
diff --git a/libstdc++-v3/testsuite/25_algorithms/copy_n/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/copy_n/constexpr.cc
index 72bc1e6..3711281 100644
--- a/libstdc++-v3/testsuite/25_algorithms/copy_n/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/copy_n/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 
 constexpr bool
diff --git a/libstdc++-v3/testsuite/25_algorithms/count/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/count/constexpr.cc
index d7cd56d..144a83d 100644
--- a/libstdc++-v3/testsuite/25_algorithms/count/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/count/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/count_if/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/count_if/constexpr.cc
index 2a1c7d0..63f7a73 100644
--- a/libstdc++-v3/testsuite/25_algorithms/count_if/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/count_if/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 
 constexpr auto out9 = std::count_if(ca0.begin(), ca0.end(),
diff --git a/libstdc++-v3/testsuite/25_algorithms/cpp_lib_constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/cpp_lib_constexpr.cc
new file mode 100644
index 0000000..a195a45
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/cpp_lib_constexpr.cc
@@ -0,0 +1,27 @@
+// 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <algorithm>
+
+#ifndef __cpp_lib_constexpr_algorithms
+# error "Feature-test macro for constexpr algorithms missing"
+#elif __cpp_lib_constexpr_algorithms < 201806L
+# error "Feature-test macro for constexpr algorithms has wrong value"
+#endif
diff --git a/libstdc++-v3/testsuite/25_algorithms/equal/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/equal/constexpr.cc
index a95704d..c578f5e 100644
--- a/libstdc++-v3/testsuite/25_algorithms/equal/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/equal/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/equal_range/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/equal_range/constexpr.cc
index 2d57096..ace753c 100644
--- a/libstdc++-v3/testsuite/25_algorithms/equal_range/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/equal_range/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/fill/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/fill/constexpr.cc
index 31e3568..02cf6d3 100644
--- a/libstdc++-v3/testsuite/25_algorithms/fill/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/fill/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/fill_n/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/fill_n/constexpr.cc
index a201191..45c6003 100644
--- a/libstdc++-v3/testsuite/25_algorithms/fill_n/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/fill_n/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/find/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/find/constexpr.cc
index 7d59de2..b9d538c 100644
--- a/libstdc++-v3/testsuite/25_algorithms/find/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/find/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5,  6, 7, 8,  9, 10, 11}};
 
 constexpr auto oute = std::find(ca0.begin(), ca0.end(), 5);
diff --git a/libstdc++-v3/testsuite/25_algorithms/find_end/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/find_end/constexpr.cc
index 88d6cc7..8da8ad2 100644
--- a/libstdc++-v3/testsuite/25_algorithms/find_end/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/find_end/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/find_first_of/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/find_first_of/constexpr.cc
index 99cbed2..3d76aaf 100644
--- a/libstdc++-v3/testsuite/25_algorithms/find_first_of/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/find_first_of/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6,  7,  8,  9, 10, 11}};
 constexpr std::array<int, 12> cas{{3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14}};
 
diff --git a/libstdc++-v3/testsuite/25_algorithms/find_if/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/find_if/constexpr.cc
index 395a21e..4f69ed5 100644
--- a/libstdc++-v3/testsuite/25_algorithms/find_if/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/find_if/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/find_if_not/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/find_if_not/constexpr.cc
index 5b1b9c3..9d8e7c3 100644
--- a/libstdc++-v3/testsuite/25_algorithms/find_if_not/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/find_if_not/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 
 constexpr auto outk = std::find_if_not(ca0.begin(), ca0.end(),
diff --git a/libstdc++-v3/testsuite/25_algorithms/for_each/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/for_each/constexpr.cc
index d900ef4..ee3d2d5 100644
--- a/libstdc++-v3/testsuite/25_algorithms/for_each/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/for_each/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 
 constexpr bool
diff --git a/libstdc++-v3/testsuite/25_algorithms/generate/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/generate/constexpr.cc
index b0e26b69d..38fd407 100644
--- a/libstdc++-v3/testsuite/25_algorithms/generate/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/generate/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/generate_n/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/generate_n/constexpr.cc
index f2a203e..ed70be7 100644
--- a/libstdc++-v3/testsuite/25_algorithms/generate_n/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/generate_n/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/is_heap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/is_heap/constexpr.cc
index 5f25a30..aeaab67 100644
--- a/libstdc++-v3/testsuite/25_algorithms/is_heap/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/is_heap/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 // heap
 constexpr std::array<int, 23>
 ah{{22,
diff --git a/libstdc++-v3/testsuite/25_algorithms/is_heap_until/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/is_heap_until/constexpr.cc
index ddd4cdd..e4c0e9c 100644
--- a/libstdc++-v3/testsuite/25_algorithms/is_heap_until/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/is_heap_until/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 // heap
 constexpr std::array<int, 23>
 ahu{{22,
diff --git a/libstdc++-v3/testsuite/25_algorithms/is_partitioned/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/is_partitioned/constexpr.cc
index 527746f..8363c76 100644
--- a/libstdc++-v3/testsuite/25_algorithms/is_partitioned/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/is_partitioned/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/is_permutation/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/is_permutation/constexpr.cc
index 3f5df35..1cd0cb8 100644
--- a/libstdc++-v3/testsuite/25_algorithms/is_permutation/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/is_permutation/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/is_sorted/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/is_sorted/constexpr.cc
index 623d72c..0be2f5f 100644
--- a/libstdc++-v3/testsuite/25_algorithms/is_sorted/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/is_sorted/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 
 constexpr auto outv = std::is_sorted(ca0.begin(), ca0.end());
diff --git a/libstdc++-v3/testsuite/25_algorithms/is_sorted_until/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/is_sorted_until/constexpr.cc
index f109ee8..1352c8b 100644
--- a/libstdc++-v3/testsuite/25_algorithms/is_sorted_until/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/is_sorted_until/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/iter_swap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/iter_swap/constexpr.cc
index 9444bf4..385065d 100644
--- a/libstdc++-v3/testsuite/25_algorithms/iter_swap/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/iter_swap/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/constexpr.cc
index 93dee5d..aa1bb66 100644
--- a/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/lexicographical_compare/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/lower_bound/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/lower_bound/constexpr.cc
index f8c191b..45eeeba 100644
--- a/libstdc++-v3/testsuite/25_algorithms/lower_bound/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/lower_bound/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/make_heap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/make_heap/constexpr.cc
index 426310a..11ba681 100644
--- a/libstdc++-v3/testsuite/25_algorithms/make_heap/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/make_heap/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/merge/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/merge/constexpr.cc
index e240e44..cc8d375 100644
--- a/libstdc++-v3/testsuite/25_algorithms/merge/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/merge/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/mismatch/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/mismatch/constexpr.cc
index 946199b..45fa708 100644
--- a/libstdc++-v3/testsuite/25_algorithms/mismatch/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/mismatch/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/next_permutation/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/next_permutation/constexpr.cc
index 4b5c218..20a1019 100644
--- a/libstdc++-v3/testsuite/25_algorithms/next_permutation/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/next_permutation/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/none_of/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/none_of/constexpr.cc
index 2d02ada..4655194 100644
--- a/libstdc++-v3/testsuite/25_algorithms/none_of/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/none_of/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/nth_element/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/nth_element/constexpr.cc
index 1c43074..3149e66 100644
--- a/libstdc++-v3/testsuite/25_algorithms/nth_element/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/nth_element/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/partial_sort/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/partial_sort/constexpr.cc
index b31be71..64285bb 100644
--- a/libstdc++-v3/testsuite/25_algorithms/partial_sort/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/partial_sort/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/partial_sort_copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/partial_sort_copy/constexpr.cc
index b7f538f..d2adcb7 100644
--- a/libstdc++-v3/testsuite/25_algorithms/partial_sort_copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/partial_sort_copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/partition/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/partition/constexpr.cc
index bd678af..17a5a41 100644
--- a/libstdc++-v3/testsuite/25_algorithms/partition/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/partition/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/partition_copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/partition_copy/constexpr.cc
index 11c42ee..5e282b2 100644
--- a/libstdc++-v3/testsuite/25_algorithms/partition_copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/partition_copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/partition_point/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/partition_point/constexpr.cc
index 4ba8284..ccfc514 100644
--- a/libstdc++-v3/testsuite/25_algorithms/partition_point/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/partition_point/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> caeo{{0, 2, 4, 6, 8, 10, 1, 3, 5, 7, 9, 11}};
 
 constexpr bool
diff --git a/libstdc++-v3/testsuite/25_algorithms/pop_heap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/pop_heap/constexpr.cc
index ff9ca7bb..b0501c4 100644
--- a/libstdc++-v3/testsuite/25_algorithms/pop_heap/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/pop_heap/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/prev_permutation/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/prev_permutation/constexpr.cc
index a3a038c..39ef203 100644
--- a/libstdc++-v3/testsuite/25_algorithms/prev_permutation/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/prev_permutation/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/push_heap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/push_heap/constexpr.cc
index 04b5688..2bca83c 100644
--- a/libstdc++-v3/testsuite/25_algorithms/push_heap/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/push_heap/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/remove/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/remove/constexpr.cc
index 580ac10..33b804e 100644
--- a/libstdc++-v3/testsuite/25_algorithms/remove/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/remove/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/remove_copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/remove_copy/constexpr.cc
index a20e529..2c289f3 100644
--- a/libstdc++-v3/testsuite/25_algorithms/remove_copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/remove_copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/remove_copy_if/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/remove_copy_if/constexpr.cc
index 0758d10..b743b76 100644
--- a/libstdc++-v3/testsuite/25_algorithms/remove_copy_if/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/remove_copy_if/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/remove_if/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/remove_if/constexpr.cc
index e8c0048..980af4a 100644
--- a/libstdc++-v3/testsuite/25_algorithms/remove_if/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/remove_if/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/replace_copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/replace_copy/constexpr.cc
index 754b879..ddb46fa 100644
--- a/libstdc++-v3/testsuite/25_algorithms/replace_copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/replace_copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8,  9, 10, 11}};
 
 constexpr bool
diff --git a/libstdc++-v3/testsuite/25_algorithms/replace_copy_if/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/replace_copy_if/constexpr.cc
index 1fa6bb0..ff643a7 100644
--- a/libstdc++-v3/testsuite/25_algorithms/replace_copy_if/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/replace_copy_if/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 constexpr bool
 test()
diff --git a/libstdc++-v3/testsuite/25_algorithms/replace_if/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/replace_if/constexpr.cc
index 1dc28e1..00b784f 100644
--- a/libstdc++-v3/testsuite/25_algorithms/replace_if/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/replace_if/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/reverse/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/reverse/constexpr.cc
index 8e1065b..ba1f47b 100644
--- a/libstdc++-v3/testsuite/25_algorithms/reverse/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/reverse/constexpr.cc
@@ -20,12 +20,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/reverse_copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/reverse_copy/constexpr.cc
index 2240109..fc60306 100644
--- a/libstdc++-v3/testsuite/25_algorithms/reverse_copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/reverse_copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/rotate/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/rotate/constexpr.cc
index b586287..b58f7f1 100644
--- a/libstdc++-v3/testsuite/25_algorithms/rotate/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/rotate/constexpr.cc
@@ -20,12 +20,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/rotate_copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/rotate_copy/constexpr.cc
index 63bca00..1ee7c21 100644
--- a/libstdc++-v3/testsuite/25_algorithms/rotate_copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/rotate_copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/search/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/search/constexpr.cc
index a611c1c..a033576 100644
--- a/libstdc++-v3/testsuite/25_algorithms/search/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/search/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/search_n/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/search_n/constexpr.cc
index ac33920..8769797 100644
--- a/libstdc++-v3/testsuite/25_algorithms/search_n/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/search_n/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> car{{0, 1, 2, 3, 4, 5, 6, 6, 8, 9, 9, 11}};
 
 constexpr auto outuu = std::search_n(car.begin(), car.end(), 2, 6);
diff --git a/libstdc++-v3/testsuite/25_algorithms/set_difference/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/set_difference/constexpr.cc
index ff913ea..3ea252e 100644
--- a/libstdc++-v3/testsuite/25_algorithms/set_difference/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/set_difference/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/set_intersection/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/set_intersection/constexpr.cc
index f1a95a2..3f9b6bd 100644
--- a/libstdc++-v3/testsuite/25_algorithms/set_intersection/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/set_intersection/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/set_symmetric_difference/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/set_symmetric_difference/constexpr.cc
index ff913ea..3ea252e 100644
--- a/libstdc++-v3/testsuite/25_algorithms/set_symmetric_difference/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/set_symmetric_difference/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/set_union/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/set_union/constexpr.cc
index 61d3f1e..a47503b 100644
--- a/libstdc++-v3/testsuite/25_algorithms/set_union/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/set_union/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/sort/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/sort/constexpr.cc
index 7b91b75..382e114 100644
--- a/libstdc++-v3/testsuite/25_algorithms/sort/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/sort/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/sort_heap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/sort_heap/constexpr.cc
index fa6e309..ed52a1b 100644
--- a/libstdc++-v3/testsuite/25_algorithms/sort_heap/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/sort_heap/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/swap/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/swap/constexpr.cc
index 7f2d1f8..a834a9e 100644
--- a/libstdc++-v3/testsuite/25_algorithms/swap/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/swap/constexpr.cc
@@ -20,12 +20,6 @@
 
 #include <algorithm>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/swap_ranges/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/swap_ranges/constexpr.cc
index a99155b..4d19018 100644
--- a/libstdc++-v3/testsuite/25_algorithms/swap_ranges/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/swap_ranges/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_swap_algorithms
-# error "Feature-test macro for constexpr swap algorithms missing"
-#elif __cpp_lib_constexpr_swap_algorithms < 201806L
-# error "Feature-test macro for constexpr swap algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/transform/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/transform/constexpr.cc
index 03c6d71..e35e9c1 100644
--- a/libstdc++-v3/testsuite/25_algorithms/transform/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/transform/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr std::array<int, 12> ca0{{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}};
 constexpr bool
 test()
diff --git a/libstdc++-v3/testsuite/25_algorithms/unique/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/unique/constexpr.cc
index f90aaac..261dfa9 100644
--- a/libstdc++-v3/testsuite/25_algorithms/unique/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/unique/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/unique_copy/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/unique_copy/constexpr.cc
index f13f388..da7eabb 100644
--- a/libstdc++-v3/testsuite/25_algorithms/unique_copy/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/unique_copy/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {
diff --git a/libstdc++-v3/testsuite/25_algorithms/upper_bound/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/upper_bound/constexpr.cc
index a0a8e25..f6312b8 100644
--- a/libstdc++-v3/testsuite/25_algorithms/upper_bound/constexpr.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/upper_bound/constexpr.cc
@@ -21,12 +21,6 @@
 #include <algorithm>
 #include <array>
 
-#ifndef __cpp_lib_constexpr_algorithms
-# error "Feature-test macro for constexpr algorithms missing"
-#elif __cpp_lib_constexpr_algorithms < 201711L
-# error "Feature-test macro for constexpr algorithms has wrong value"
-#endif
-
 constexpr bool
 test()
 {