diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format
index 648f847ad9692f1a84131dd63cc6089bfd287685..f3d9ae152f907a23b74230d3731084ad1faa4051 100644
--- a/libstdc++-v3/include/std/format
+++ b/libstdc++-v3/include/std/format
@@ -2083,7 +2083,7 @@ namespace __format
     };
 #endif
 
-#if defined(__FLT16_DIG__)
+#ifdef __STDCPP_FLOAT16_T__
   // Reuse __formatter_fp<C>::format<float, Out> for _Float16.
   template<__format::__char _CharT>
     struct formatter<_Float16, _CharT>
@@ -2171,7 +2171,7 @@ namespace __format
     };
 #endif
 
-#if defined(__BFLT16_DIG__)
+#ifdef __STDCPP_BFLOAT16_T__
   // Reuse __formatter_fp<C>::format<float, Out> for bfloat16_t.
   template<__format::__char _CharT>
     struct formatter<__gnu_cxx::__bfloat16_t, _CharT>
diff --git a/libstdc++-v3/include/std/limits b/libstdc++-v3/include/std/limits
index 7a59e7520ebca0f90a3f0b011ecc606475b2f13f..ec0b7a1ca7bf38b7440b6e94c692cd5937f1bf23 100644
--- a/libstdc++-v3/include/std/limits
+++ b/libstdc++-v3/include/std/limits
@@ -1982,7 +1982,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	= round_to_nearest; 						\
     }; 									\
 
-#ifdef __FLT16_DIG__
+#ifdef __STDCPP_FLOAT16_T__
 __glibcxx_float_n(16)
 #endif
 #ifdef __FLT32_DIG__
@@ -2002,7 +2002,7 @@ __glibcxx_float_n(128)
 # undef __max_digits10
 #endif
 
-#ifdef __BFLT16_DIG__
+#ifdef __STDCPP_BFLOAT16_T__
   __extension__
   template<>
     struct numeric_limits<__gnu_cxx::__bfloat16_t>
@@ -2079,7 +2079,7 @@ __glibcxx_float_n(128)
       static _GLIBCXX_USE_CONSTEXPR float_round_style round_style
 	= round_to_nearest;
     };
-#endif
+#endif // __STDCPP_BFLOAT16_T__
 
 #if defined(_GLIBCXX_USE_FLOAT128)
 // We either need Q literal suffixes, or IEEE double.