diff --git a/libcxx/include/limits b/libcxx/include/limits
index f15b5b1ab1d52..f022048cc2655 100644
--- a/libcxx/include/limits
+++ b/libcxx/include/limits
@@ -137,9 +137,9 @@ protected:
   typedef _Tp type;
 
   static _LIBCPP_CONSTEXPR const bool is_specialized = false;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return type(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return type(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return type(); }
 
   static _LIBCPP_CONSTEXPR const int digits       = 0;
   static _LIBCPP_CONSTEXPR const int digits10     = 0;
@@ -148,8 +148,8 @@ protected:
   static _LIBCPP_CONSTEXPR const bool is_integer  = false;
   static _LIBCPP_CONSTEXPR const bool is_exact    = false;
   static _LIBCPP_CONSTEXPR const int radix        = 0;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return type(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return type(); }
 
   static _LIBCPP_CONSTEXPR const int min_exponent   = 0;
   static _LIBCPP_CONSTEXPR const int min_exponent10 = 0;
@@ -161,10 +161,10 @@ protected:
   static _LIBCPP_CONSTEXPR const bool has_signaling_NaN                                    = false;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_absent;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const bool has_denorm_loss          = false;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return type(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return type(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return type(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return type(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return type(); }
 
   static _LIBCPP_CONSTEXPR const bool is_iec559  = false;
   static _LIBCPP_CONSTEXPR const bool is_bounded = false;
@@ -198,15 +198,15 @@ protected:
   static _LIBCPP_CONSTEXPR const int max_digits10 = 0;
   static _LIBCPP_CONSTEXPR const type __min       = __libcpp_compute_min<type, digits, is_signed>::value;
   static _LIBCPP_CONSTEXPR const type __max       = is_signed ? type(type(~0) ^ __min) : type(~0);
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __min; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __max; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return min(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __min; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __max; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return min(); }
 
   static _LIBCPP_CONSTEXPR const bool is_integer = true;
   static _LIBCPP_CONSTEXPR const bool is_exact   = true;
   static _LIBCPP_CONSTEXPR const int radix       = 2;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return type(0); }
 
   static _LIBCPP_CONSTEXPR const int min_exponent   = 0;
   static _LIBCPP_CONSTEXPR const int min_exponent10 = 0;
@@ -218,10 +218,10 @@ protected:
   static _LIBCPP_CONSTEXPR const bool has_signaling_NaN                                    = false;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_absent;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const bool has_denorm_loss          = false;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return type(0); }
 
   static _LIBCPP_CONSTEXPR const bool is_iec559  = false;
   static _LIBCPP_CONSTEXPR const bool is_bounded = true;
@@ -249,15 +249,15 @@ protected:
   static _LIBCPP_CONSTEXPR const int max_digits10 = 0;
   static _LIBCPP_CONSTEXPR const type __min       = false;
   static _LIBCPP_CONSTEXPR const type __max       = true;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __min; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __max; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return min(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __min; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __max; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return min(); }
 
   static _LIBCPP_CONSTEXPR const bool is_integer = true;
   static _LIBCPP_CONSTEXPR const bool is_exact   = true;
   static _LIBCPP_CONSTEXPR const int radix       = 2;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return type(0); }
 
   static _LIBCPP_CONSTEXPR const int min_exponent   = 0;
   static _LIBCPP_CONSTEXPR const int min_exponent10 = 0;
@@ -269,10 +269,10 @@ protected:
   static _LIBCPP_CONSTEXPR const bool has_signaling_NaN                                    = false;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_absent;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const bool has_denorm_loss          = false;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return type(0); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return type(0); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return type(0); }
 
   static _LIBCPP_CONSTEXPR const bool is_iec559  = false;
   static _LIBCPP_CONSTEXPR const bool is_bounded = true;
@@ -294,15 +294,15 @@ protected:
   static _LIBCPP_CONSTEXPR const int digits       = __FLT_MANT_DIG__;
   static _LIBCPP_CONSTEXPR const int digits10     = __FLT_DIG__;
   static _LIBCPP_CONSTEXPR const int max_digits10 = 2 + (digits * 30103l) / 100000l;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __FLT_MIN__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __FLT_MAX__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return -max(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __FLT_MIN__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __FLT_MAX__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return -max(); }
 
   static _LIBCPP_CONSTEXPR const bool is_integer = false;
   static _LIBCPP_CONSTEXPR const bool is_exact   = false;
   static _LIBCPP_CONSTEXPR const int radix       = __FLT_RADIX__;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __FLT_EPSILON__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return 0.5F; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __FLT_EPSILON__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return 0.5F; }
 
   static _LIBCPP_CONSTEXPR const int min_exponent   = __FLT_MIN_EXP__;
   static _LIBCPP_CONSTEXPR const int min_exponent10 = __FLT_MIN_10_EXP__;
@@ -314,10 +314,10 @@ protected:
   static _LIBCPP_CONSTEXPR const bool has_signaling_NaN                                    = true;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_present;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const bool has_denorm_loss          = false;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __builtin_huge_valf(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __builtin_nanf(""); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __builtin_nansf(""); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __FLT_DENORM_MIN__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __builtin_huge_valf(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __builtin_nanf(""); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __builtin_nansf(""); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __FLT_DENORM_MIN__; }
 
   static _LIBCPP_CONSTEXPR const bool is_iec559  = true;
   static _LIBCPP_CONSTEXPR const bool is_bounded = true;
@@ -343,15 +343,15 @@ protected:
   static _LIBCPP_CONSTEXPR const int digits       = __DBL_MANT_DIG__;
   static _LIBCPP_CONSTEXPR const int digits10     = __DBL_DIG__;
   static _LIBCPP_CONSTEXPR const int max_digits10 = 2 + (digits * 30103l) / 100000l;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __DBL_MIN__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __DBL_MAX__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return -max(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __DBL_MIN__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __DBL_MAX__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return -max(); }
 
   static _LIBCPP_CONSTEXPR const bool is_integer = false;
   static _LIBCPP_CONSTEXPR const bool is_exact   = false;
   static _LIBCPP_CONSTEXPR const int radix       = __FLT_RADIX__;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __DBL_EPSILON__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return 0.5; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __DBL_EPSILON__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return 0.5; }
 
   static _LIBCPP_CONSTEXPR const int min_exponent   = __DBL_MIN_EXP__;
   static _LIBCPP_CONSTEXPR const int min_exponent10 = __DBL_MIN_10_EXP__;
@@ -363,10 +363,10 @@ protected:
   static _LIBCPP_CONSTEXPR const bool has_signaling_NaN                                    = true;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_present;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const bool has_denorm_loss          = false;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __builtin_huge_val(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __builtin_nan(""); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __builtin_nans(""); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __DBL_DENORM_MIN__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __builtin_huge_val(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __builtin_nan(""); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __builtin_nans(""); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __DBL_DENORM_MIN__; }
 
   static _LIBCPP_CONSTEXPR const bool is_iec559  = true;
   static _LIBCPP_CONSTEXPR const bool is_bounded = true;
@@ -392,15 +392,15 @@ protected:
   static _LIBCPP_CONSTEXPR const int digits       = __LDBL_MANT_DIG__;
   static _LIBCPP_CONSTEXPR const int digits10     = __LDBL_DIG__;
   static _LIBCPP_CONSTEXPR const int max_digits10 = 2 + (digits * 30103l) / 100000l;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __LDBL_MIN__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __LDBL_MAX__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return -max(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __LDBL_MIN__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __LDBL_MAX__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return -max(); }
 
   static _LIBCPP_CONSTEXPR const bool is_integer = false;
   static _LIBCPP_CONSTEXPR const bool is_exact   = false;
   static _LIBCPP_CONSTEXPR const int radix       = __FLT_RADIX__;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __LDBL_EPSILON__; }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return 0.5L; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __LDBL_EPSILON__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return 0.5L; }
 
   static _LIBCPP_CONSTEXPR const int min_exponent   = __LDBL_MIN_EXP__;
   static _LIBCPP_CONSTEXPR const int min_exponent10 = __LDBL_MIN_10_EXP__;
@@ -412,10 +412,10 @@ protected:
   static _LIBCPP_CONSTEXPR const bool has_signaling_NaN                                    = true;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_present;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const bool has_denorm_loss          = false;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __builtin_huge_vall(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __builtin_nanl(""); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __builtin_nansl(""); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __LDBL_DENORM_MIN__; }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __builtin_huge_vall(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __builtin_nanl(""); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __builtin_nansl(""); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __LDBL_DENORM_MIN__; }
 
 #if defined(__powerpc__) && defined(__LONG_DOUBLE_IBM128__)
   static _LIBCPP_CONSTEXPR const bool is_iec559 = false;
@@ -441,9 +441,9 @@ class _LIBCPP_TEMPLATE_VIS numeric_limits : private __libcpp_numeric_limits<_Tp>
 
 public:
   static _LIBCPP_CONSTEXPR const bool is_specialized = __base::is_specialized;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __base::min(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __base::max(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return __base::lowest(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type min() _NOEXCEPT { return __base::min(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type max() _NOEXCEPT { return __base::max(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT { return __base::lowest(); }
 
   static _LIBCPP_CONSTEXPR const int digits       = __base::digits;
   static _LIBCPP_CONSTEXPR const int digits10     = __base::digits10;
@@ -452,8 +452,8 @@ public:
   static _LIBCPP_CONSTEXPR const bool is_integer  = __base::is_integer;
   static _LIBCPP_CONSTEXPR const bool is_exact    = __base::is_exact;
   static _LIBCPP_CONSTEXPR const int radix        = __base::radix;
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __base::epsilon(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return __base::round_error(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT { return __base::epsilon(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT { return __base::round_error(); }
 
   static _LIBCPP_CONSTEXPR const int min_exponent   = __base::min_exponent;
   static _LIBCPP_CONSTEXPR const int min_exponent10 = __base::min_exponent10;
@@ -467,10 +467,10 @@ public:
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = __base::has_denorm;
   static _LIBCPP_DEPRECATED_IN_CXX23 _LIBCPP_CONSTEXPR const bool has_denorm_loss          = __base::has_denorm_loss;
   _LIBCPP_SUPPRESS_DEPRECATED_POP
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __base::infinity(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __base::quiet_NaN(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __base::signaling_NaN(); }
-  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __base::denorm_min(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT { return __base::infinity(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT { return __base::quiet_NaN(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT { return __base::signaling_NaN(); }
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT { return __base::denorm_min(); }
 
   static _LIBCPP_CONSTEXPR const bool is_iec559  = __base::is_iec559;
   static _LIBCPP_CONSTEXPR const bool is_bounded = __base::is_bounded;
diff --git a/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.compile.pass.cpp b/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.compile.pass.cpp
new file mode 100644
index 0000000000000..a93f55b888b95
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.compile.pass.cpp
@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_NODISCARD_EXT
+
+// Check that <limits> functions aren't marked [[nodiscard]] when
+// _LIBCPP_DISABLE_NODISCARD_EXT is defined
+
+#include <limits>
+
+#include "test_macros.h"
+
+void func() {
+  // arithmetic
+  std::numeric_limits<int>::min();
+  std::numeric_limits<int>::max();
+  std::numeric_limits<int>::lowest();
+  std::numeric_limits<int>::epsilon();
+  std::numeric_limits<int>::round_error();
+  std::numeric_limits<int>::infinity();
+  std::numeric_limits<int>::quiet_NaN();
+  std::numeric_limits<int>::signaling_NaN();
+  std::numeric_limits<int>::denorm_min();
+  // bool
+  std::numeric_limits<bool>::min();
+  std::numeric_limits<bool>::max();
+  std::numeric_limits<bool>::lowest();
+  std::numeric_limits<bool>::epsilon();
+  std::numeric_limits<bool>::round_error();
+  std::numeric_limits<bool>::infinity();
+  std::numeric_limits<bool>::quiet_NaN();
+  std::numeric_limits<bool>::signaling_NaN();
+  std::numeric_limits<bool>::denorm_min();
+  // float
+  std::numeric_limits<float>::min();
+  std::numeric_limits<float>::max();
+  std::numeric_limits<float>::lowest();
+  std::numeric_limits<float>::epsilon();
+  std::numeric_limits<float>::round_error();
+  std::numeric_limits<float>::infinity();
+  std::numeric_limits<float>::quiet_NaN();
+  std::numeric_limits<float>::signaling_NaN();
+  std::numeric_limits<float>::denorm_min();
+  // double
+  std::numeric_limits<double>::min();
+  std::numeric_limits<double>::max();
+  std::numeric_limits<double>::lowest();
+  std::numeric_limits<double>::epsilon();
+  std::numeric_limits<double>::round_error();
+  std::numeric_limits<double>::infinity();
+  std::numeric_limits<double>::quiet_NaN();
+  std::numeric_limits<double>::signaling_NaN();
+  std::numeric_limits<double>::denorm_min();
+  // long double
+  std::numeric_limits<long double>::min();
+  std::numeric_limits<long double>::max();
+  std::numeric_limits<long double>::lowest();
+  std::numeric_limits<long double>::epsilon();
+  std::numeric_limits<long double>::round_error();
+  std::numeric_limits<long double>::infinity();
+  std::numeric_limits<long double>::quiet_NaN();
+  std::numeric_limits<long double>::signaling_NaN();
+  std::numeric_limits<long double>::denorm_min();
+}
diff --git a/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.verify.cpp b/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.verify.cpp
new file mode 100644
index 0000000000000..7a81b84378c52
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.verify.cpp
@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <limits> functions are marked [[nodiscard]]
+
+#include <limits>
+
+#include "test_macros.h"
+
+void func() {
+  // clang-format off
+  // arithmetic
+  std::numeric_limits<int>::min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::max(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::lowest(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::epsilon(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::round_error(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::infinity(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::quiet_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::signaling_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<int>::denorm_min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  // bool
+  std::numeric_limits<bool>::min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::max(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::lowest(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::epsilon(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::round_error(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::infinity(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::quiet_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::signaling_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<bool>::denorm_min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  // float
+  std::numeric_limits<float>::min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::max(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::lowest(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::epsilon(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::round_error(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::infinity(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::quiet_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::signaling_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<float>::denorm_min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  // double
+  std::numeric_limits<double>::min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::max(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::lowest(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::epsilon(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::round_error(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::infinity(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::quiet_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::signaling_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<double>::denorm_min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  // long double
+  std::numeric_limits<long double>::min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::max(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::lowest(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::epsilon(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::round_error(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::infinity(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::quiet_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::signaling_NaN(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::numeric_limits<long double>::denorm_min(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  // clang-format on
+}