diff --git a/libcxx/docs/FeatureTestMacroTable.rst b/libcxx/docs/FeatureTestMacroTable.rst
--- a/libcxx/docs/FeatureTestMacroTable.rst
+++ b/libcxx/docs/FeatureTestMacroTable.rst
@@ -198,6 +198,8 @@
     ------------------------------------------------- -----------------
     ``__cpp_lib_ranges``                              *unimplemented*  
     ------------------------------------------------- -----------------
+    ``__cpp_lib_span``                                ``202002L``      
+    ------------------------------------------------- -----------------
     ``__cpp_lib_three_way_comparison``                *unimplemented*  
     ------------------------------------------------- -----------------
     ``__cpp_lib_to_array``                            ``201907L``      
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/execution.version.pass.cpp
@@ -1,4 +1,3 @@
-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
@@ -7,29 +6,62 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// <execution> feature macros
+// WARNING: This test was generated by generate_feature_test_macro_components.py
+// and should not be edited manually.
+
+// <execution>
 
-/*  Constant                                    Value
-    __cpp_lib_execution                         201603L
+// Test the feature test macros defined by <execution>
 
+/*  Constant               Value
+    __cpp_lib_execution    201603L [C++17]
 */
 
-// XFAIL
-// #include <execution>
-#include <cassert>
+#include <execution>
 #include "test_macros.h"
 
-int main(int, char**)
-{
-//  ensure that the macros that are supposed to be defined in <execution> are defined.
+#if TEST_STD_VER < 14
 
-/*
-#if !defined(__cpp_lib_fooby)
-# error "__cpp_lib_fooby is not defined"
-#elif __cpp_lib_fooby < 201606L
-# error "__cpp_lib_fooby has an invalid value"
-#endif
-*/
+# ifdef __cpp_lib_execution
+#   error "__cpp_lib_execution should not be defined before c++17"
+# endif
+
+#elif TEST_STD_VER == 14
+
+# ifdef __cpp_lib_execution
+#   error "__cpp_lib_execution should not be defined before c++17"
+# endif
+
+#elif TEST_STD_VER == 17
+
+# if !defined(_LIBCPP_VERSION)
+#   ifndef __cpp_lib_execution
+#     error "__cpp_lib_execution should be defined in c++17"
+#   endif
+#   if __cpp_lib_execution != 201603L
+#     error "__cpp_lib_execution should have the value 201603L in c++17"
+#   endif
+# else // _LIBCPP_VERSION
+#   ifdef __cpp_lib_execution
+#     error "__cpp_lib_execution should not be defined because it is unimplemented in libc++!"
+#   endif
+# endif
+
+#elif TEST_STD_VER > 17
+
+# if !defined(_LIBCPP_VERSION)
+#   ifndef __cpp_lib_execution
+#     error "__cpp_lib_execution should be defined in c++2a"
+#   endif
+#   if __cpp_lib_execution != 201603L
+#     error "__cpp_lib_execution should have the value 201603L in c++2a"
+#   endif
+# else // _LIBCPP_VERSION
+#   ifdef __cpp_lib_execution
+#     error "__cpp_lib_execution should not be defined because it is unimplemented in libc++!"
+#   endif
+# endif
+
+#endif // TEST_STD_VER > 17
 
-  return 0;
-}
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/span.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/span.version.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/span.version.pass.cpp
@@ -0,0 +1,52 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// WARNING: This test was generated by generate_feature_test_macro_components.py
+// and should not be edited manually.
+
+// <span>
+
+// Test the feature test macros defined by <span>
+
+/*  Constant          Value
+    __cpp_lib_span    202002L [C++2a]
+*/
+
+#include <span>
+#include "test_macros.h"
+
+#if TEST_STD_VER < 14
+
+# ifdef __cpp_lib_span
+#   error "__cpp_lib_span should not be defined before c++2a"
+# endif
+
+#elif TEST_STD_VER == 14
+
+# ifdef __cpp_lib_span
+#   error "__cpp_lib_span should not be defined before c++2a"
+# endif
+
+#elif TEST_STD_VER == 17
+
+# ifdef __cpp_lib_span
+#   error "__cpp_lib_span should not be defined before c++2a"
+# endif
+
+#elif TEST_STD_VER > 17
+
+# ifndef __cpp_lib_span
+#   error "__cpp_lib_span should be defined in c++2a"
+# endif
+# if __cpp_lib_span != 202002L
+#   error "__cpp_lib_span should have the value 202002L in c++2a"
+# endif
+
+#endif // TEST_STD_VER > 17
+
+int main(int, char**) { return 0; }
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp
@@ -85,6 +85,7 @@
     __cpp_lib_shared_ptr_arrays                    201611L [C++17]
     __cpp_lib_shared_ptr_weak_type                 201606L [C++17]
     __cpp_lib_shared_timed_mutex                   201402L [C++14]
+    __cpp_lib_span                                 202002L [C++2a]
     __cpp_lib_string_udls                          201304L [C++14]
     __cpp_lib_string_view                          201606L [C++17]
     __cpp_lib_three_way_comparison                 201711L [C++2a]
@@ -391,6 +392,10 @@
 #   error "__cpp_lib_shared_timed_mutex should not be defined before c++14"
 # endif
 
+# ifdef __cpp_lib_span
+#   error "__cpp_lib_span should not be defined before c++2a"
+# endif
+
 # ifdef __cpp_lib_string_udls
 #   error "__cpp_lib_string_udls should not be defined before c++14"
 # endif
@@ -784,6 +789,10 @@
 #   endif
 # endif
 
+# ifdef __cpp_lib_span
+#   error "__cpp_lib_span should not be defined before c++2a"
+# endif
+
 # ifndef __cpp_lib_string_udls
 #   error "__cpp_lib_string_udls should be defined in c++14"
 # endif
@@ -1381,6 +1390,10 @@
 #   endif
 # endif
 
+# ifdef __cpp_lib_span
+#   error "__cpp_lib_span should not be defined before c++2a"
+# endif
+
 # ifndef __cpp_lib_string_udls
 #   error "__cpp_lib_string_udls should be defined in c++17"
 # endif
@@ -2116,6 +2129,13 @@
 #   endif
 # endif
 
+# ifndef __cpp_lib_span
+#   error "__cpp_lib_span should be defined in c++2a"
+# endif
+# if __cpp_lib_span != 202002L
+#   error "__cpp_lib_span should have the value 202002L in c++2a"
+# endif
+
 # ifndef __cpp_lib_string_udls
 #   error "__cpp_lib_string_udls should be defined in c++2a"
 # endif
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -591,6 +591,12 @@
    },
    "headers": ["array"],
    },
+  {"name": "__cpp_lib_span",
+   "values": {
+     "c++2a": int(202002),
+   },
+   "headers": ["span"],
+   },
 ]], key=lambda tc: tc["name"])
 
 def get_std_dialects():