diff --git a/libcxx/docs/FeatureTestMacroTable.rst b/libcxx/docs/FeatureTestMacroTable.rst
index ccaa784ccb088..dcf9838edd74b 100644
--- a/libcxx/docs/FeatureTestMacroTable.rst
+++ b/libcxx/docs/FeatureTestMacroTable.rst
@@ -174,7 +174,7 @@ Status
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_atomic_flag_test``                             ``201907L``
     ---------------------------------------------------------- -----------------
-    ``__cpp_lib_atomic_float``                                 *unimplemented*
+    ``__cpp_lib_atomic_float``                                 ``201711L``
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_atomic_lock_free_type_aliases``                ``201907L``
     ---------------------------------------------------------- -----------------
diff --git a/libcxx/docs/Status/Cxx20Papers.csv b/libcxx/docs/Status/Cxx20Papers.csv
index 360b5520260ce..1c060c32b6f57 100644
--- a/libcxx/docs/Status/Cxx20Papers.csv
+++ b/libcxx/docs/Status/Cxx20Papers.csv
@@ -2,7 +2,7 @@
 "`P0463R1 <https://wg21.link/P0463R1>`__","Endian just Endian","2017-07 (Toronto)","|Complete|","7",""
 "`P0674R1 <https://wg21.link/P0674R1>`__","Extending make_shared to Support Arrays","2017-07 (Toronto)","|Complete|","15",""
 "","","","","",""
-"`P0020R6 <https://wg21.link/P0020R6>`__","Floating Point Atomic","2017-11 (Albuquerque)","|Complete|","18",""
+"`P0020R6 <https://wg21.link/P0020R6>`__","Floating Point Atomic","2017-11 (Albuquerque)","|Complete|","18","The feature-test macro was not set until LLVM 20."
 "`P0053R7 <https://wg21.link/P0053R7>`__","C++ Synchronized Buffered Ostream","2017-11 (Albuquerque)","|Complete|","18",""
 "`P0202R3 <https://wg21.link/P0202R3>`__","Add constexpr modifiers to functions in <algorithm> and <utility> Headers","2017-11 (Albuquerque)","|Complete|","12",""
 "`P0415R1 <https://wg21.link/P0415R1>`__","Constexpr for ``std::complex``\ ","2017-11 (Albuquerque)","|Complete|","16",""
diff --git a/libcxx/include/version b/libcxx/include/version
index c5966b90c061d..63ead9fd5d29d 100644
--- a/libcxx/include/version
+++ b/libcxx/include/version
@@ -378,7 +378,7 @@ __cpp_lib_void_t                                        201411L <type_traits>
 # define __cpp_lib_array_constexpr                      201811L
 # define __cpp_lib_assume_aligned                       201811L
 # define __cpp_lib_atomic_flag_test                     201907L
-// # define __cpp_lib_atomic_float                         201711L
+# define __cpp_lib_atomic_float                         201711L
 # define __cpp_lib_atomic_lock_free_type_aliases        201907L
 # define __cpp_lib_atomic_ref                           201806L
 // # define __cpp_lib_atomic_shared_ptr                    201711L
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.compile.pass.cpp
index 9ed18fbfe19ac..5a21e6320bffe 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/atomic.version.compile.pass.cpp
@@ -169,17 +169,11 @@
 #   error "__cpp_lib_atomic_flag_test should have the value 201907L in c++20"
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should be defined in c++20"
-#   endif
-#   if __cpp_lib_atomic_float != 201711L
-#     error "__cpp_lib_atomic_float should have the value 201711L in c++20"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should not be defined because it is unimplemented in libc++!"
-#   endif
+# ifndef __cpp_lib_atomic_float
+#   error "__cpp_lib_atomic_float should be defined in c++20"
+# endif
+# if __cpp_lib_atomic_float != 201711L
+#   error "__cpp_lib_atomic_float should have the value 201711L in c++20"
 # endif
 
 # ifndef __cpp_lib_atomic_is_always_lock_free
@@ -262,17 +256,11 @@
 #   error "__cpp_lib_atomic_flag_test should have the value 201907L in c++23"
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should be defined in c++23"
-#   endif
-#   if __cpp_lib_atomic_float != 201711L
-#     error "__cpp_lib_atomic_float should have the value 201711L in c++23"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should not be defined because it is unimplemented in libc++!"
-#   endif
+# ifndef __cpp_lib_atomic_float
+#   error "__cpp_lib_atomic_float should be defined in c++23"
+# endif
+# if __cpp_lib_atomic_float != 201711L
+#   error "__cpp_lib_atomic_float should have the value 201711L in c++23"
 # endif
 
 # ifndef __cpp_lib_atomic_is_always_lock_free
@@ -355,17 +343,11 @@
 #   error "__cpp_lib_atomic_flag_test should have the value 201907L in c++26"
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should be defined in c++26"
-#   endif
-#   if __cpp_lib_atomic_float != 201711L
-#     error "__cpp_lib_atomic_float should have the value 201711L in c++26"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should not be defined because it is unimplemented in libc++!"
-#   endif
+# ifndef __cpp_lib_atomic_float
+#   error "__cpp_lib_atomic_float should be defined in c++26"
+# endif
+# if __cpp_lib_atomic_float != 201711L
+#   error "__cpp_lib_atomic_float should have the value 201711L in c++26"
 # endif
 
 # ifndef __cpp_lib_atomic_is_always_lock_free
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
index 137d6cb428930..1e4465d515e6b 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
@@ -3282,17 +3282,11 @@
 #   error "__cpp_lib_atomic_flag_test should have the value 201907L in c++20"
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should be defined in c++20"
-#   endif
-#   if __cpp_lib_atomic_float != 201711L
-#     error "__cpp_lib_atomic_float should have the value 201711L in c++20"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should not be defined because it is unimplemented in libc++!"
-#   endif
+# ifndef __cpp_lib_atomic_float
+#   error "__cpp_lib_atomic_float should be defined in c++20"
+# endif
+# if __cpp_lib_atomic_float != 201711L
+#   error "__cpp_lib_atomic_float should have the value 201711L in c++20"
 # endif
 
 # ifndef __cpp_lib_atomic_is_always_lock_free
@@ -4707,17 +4701,11 @@
 #   error "__cpp_lib_atomic_flag_test should have the value 201907L in c++23"
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should be defined in c++23"
-#   endif
-#   if __cpp_lib_atomic_float != 201711L
-#     error "__cpp_lib_atomic_float should have the value 201711L in c++23"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should not be defined because it is unimplemented in libc++!"
-#   endif
+# ifndef __cpp_lib_atomic_float
+#   error "__cpp_lib_atomic_float should be defined in c++23"
+# endif
+# if __cpp_lib_atomic_float != 201711L
+#   error "__cpp_lib_atomic_float should have the value 201711L in c++23"
 # endif
 
 # ifndef __cpp_lib_atomic_is_always_lock_free
@@ -6369,17 +6357,11 @@
 #   error "__cpp_lib_atomic_flag_test should have the value 201907L in c++26"
 # endif
 
-# if !defined(_LIBCPP_VERSION)
-#   ifndef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should be defined in c++26"
-#   endif
-#   if __cpp_lib_atomic_float != 201711L
-#     error "__cpp_lib_atomic_float should have the value 201711L in c++26"
-#   endif
-# else // _LIBCPP_VERSION
-#   ifdef __cpp_lib_atomic_float
-#     error "__cpp_lib_atomic_float should not be defined because it is unimplemented in libc++!"
-#   endif
+# ifndef __cpp_lib_atomic_float
+#   error "__cpp_lib_atomic_float should be defined in c++26"
+# endif
+# if __cpp_lib_atomic_float != 201711L
+#   error "__cpp_lib_atomic_float should have the value 201711L in c++26"
 # endif
 
 # ifndef __cpp_lib_atomic_is_always_lock_free
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
index 25168b9087754..8bf7633e985d5 100755
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -169,7 +169,6 @@ def add_version_header(tc):
             "name": "__cpp_lib_atomic_float",
             "values": {"c++20": 201711},
             "headers": ["atomic"],
-            "unimplemented": True,
         },
         {
             "name": "__cpp_lib_atomic_is_always_lock_free",