Index: libcxx/CMakeLists.txt
===================================================================
--- libcxx/CMakeLists.txt
+++ libcxx/CMakeLists.txt
@@ -94,6 +94,11 @@
    support the C functionality for wide characters. When wide characters are
    not supported, several parts of the library will be disabled, notably the
    wide character specializations of std::basic_string." ON)
+option(LIBCXX_ENABLE_LONG_DOUBLE_MATH
+  "Whether to include support for long double math functions in the library.
+   Disabling long double support can be useful when porting to platforms that
+   don't support the C long double math functions. When long doubles are not
+   supported, several cmath and math.h the library will be disabled." ON)
 option(LIBCXX_ENABLE_VENDOR_AVAILABILITY_ANNOTATIONS
   "Whether to turn on vendor availability annotations on declarations that depend
    on definitions in a shared library. By default, we assume that we're not building
@@ -857,6 +862,7 @@
 config_define_if_not(LIBCXX_ENABLE_LOCALIZATION _LIBCPP_HAS_NO_LOCALIZATION)
 config_define_if_not(LIBCXX_ENABLE_UNICODE _LIBCPP_HAS_NO_UNICODE)
 config_define_if_not(LIBCXX_ENABLE_WIDE_CHARACTERS _LIBCPP_HAS_NO_WIDE_CHARACTERS)
+config_define_if_not(LIBCXX_ENABLE_LONG_DOUBLE_MATH _LIBCPP_HAS_NO_LONG_DOUBLE_MATH)
 config_define_if_not(LIBCXX_ENABLE_VENDOR_AVAILABILITY_ANNOTATIONS _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
 config_define_if(LIBCXX_ENABLE_DEBUG_MODE _LIBCPP_ENABLE_DEBUG_MODE)
 if (LIBCXX_ENABLE_ASSERTIONS)
Index: libcxx/docs/BuildingLibcxx.rst
===================================================================
--- libcxx/docs/BuildingLibcxx.rst
+++ libcxx/docs/BuildingLibcxx.rst
@@ -265,6 +265,16 @@
    support for ``wchar_t``. This is especially useful in embedded settings where
    C Standard Libraries don't always provide all the usual bells and whistles.
 
+.. option:: LIBCXX_ENABLE_LONG_DOUBLE_MATH:BOOL
+
+   **Default**: ``ON``
+
+   This option can be used to disable support for ``long double`` in the math
+   library. It also allows the math library to work on top of a C Standard
+   Library that does not provide support for ``long double`` math functions.
+   This is especially useful in embedded settings where C Standard Libraries
+   don't always provide all the usual bells and whistles.
+
 .. option:: LIBCXX_INSTALL_LIBRARY_DIR:PATH
 
   **Default**: ``lib${LIBCXX_LIBDIR_SUFFIX}``
Index: libcxx/include/__config_site.in
===================================================================
--- libcxx/include/__config_site.in
+++ libcxx/include/__config_site.in
@@ -29,6 +29,7 @@
 #cmakedefine _LIBCPP_HAS_NO_RANDOM_DEVICE
 #cmakedefine _LIBCPP_HAS_NO_LOCALIZATION
 #cmakedefine _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#cmakedefine _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 #cmakedefine01 _LIBCPP_ENABLE_ASSERTIONS_DEFAULT
 #cmakedefine _LIBCPP_ENABLE_DEBUG_MODE
 
Index: libcxx/include/cmath
===================================================================
--- libcxx/include/cmath
+++ libcxx/include/cmath
@@ -541,7 +541,9 @@
 #if _LIBCPP_STD_VER > 14
 inline _LIBCPP_INLINE_VISIBILITY float       hypot(       float __x,       float __y,       float __z ) { return sqrt(__x*__x + __y*__y + __z*__z); }
 inline _LIBCPP_INLINE_VISIBILITY double      hypot(      double __x,      double __y,      double __z ) { return sqrt(__x*__x + __y*__y + __z*__z); }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double hypot( long double __x, long double __y, long double __z ) { return sqrt(__x*__x + __y*__y + __z*__z); }
+#endif
 
 template <class _A1, class _A2, class _A3>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -643,8 +645,10 @@
 _LIBCPP_HIDE_FROM_ABI constexpr double
 lerp(double __a, double __b, double __t)                _NOEXCEPT { return __lerp(__a, __b, __t); }
 
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 _LIBCPP_HIDE_FROM_ABI constexpr long double
 lerp(long double __a, long double __b, long double __t) _NOEXCEPT { return __lerp(__a, __b, __t); }
+#endif
 
 template <class _A1, class _A2, class _A3>
 inline _LIBCPP_HIDE_FROM_ABI
Index: libcxx/include/math.h
===================================================================
--- libcxx/include/math.h
+++ libcxx/include/math.h
@@ -510,9 +510,11 @@
 bool
 isinf(double __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
 
+#  ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY
 bool
 isinf(long double __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
+#  endif
 #endif
 
 #endif // isinf
@@ -558,9 +560,11 @@
 bool
 isnan(double __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
 
+#  ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY
 bool
 isnan(long double __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
+#  endif
 #endif
 
 #endif // isnan
@@ -791,8 +795,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       acos(float __lcpp_x) _NOEXCEPT       {return ::acosf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double acos(long double __lcpp_x) _NOEXCEPT {return ::acosl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -803,8 +809,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       asin(float __lcpp_x) _NOEXCEPT       {return ::asinf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double asin(long double __lcpp_x) _NOEXCEPT {return ::asinl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -815,8 +823,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       atan(float __lcpp_x) _NOEXCEPT       {return ::atanf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double atan(long double __lcpp_x) _NOEXCEPT {return ::atanl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -827,8 +837,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       atan2(float __lcpp_y, float __lcpp_x) _NOEXCEPT             {return ::atan2f(__lcpp_y, __lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double atan2(long double __lcpp_y, long double __lcpp_x) _NOEXCEPT {return ::atan2l(__lcpp_y, __lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -850,8 +862,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       ceil(float __lcpp_x) _NOEXCEPT       {return ::ceilf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double ceil(long double __lcpp_x) _NOEXCEPT {return ::ceill(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -862,8 +876,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       cos(float __lcpp_x) _NOEXCEPT       {return ::cosf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double cos(long double __lcpp_x) _NOEXCEPT {return ::cosl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -874,8 +890,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       cosh(float __lcpp_x) _NOEXCEPT       {return ::coshf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double cosh(long double __lcpp_x) _NOEXCEPT {return ::coshl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -886,8 +904,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       exp(float __lcpp_x) _NOEXCEPT       {return ::expf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double exp(long double __lcpp_x) _NOEXCEPT {return ::expl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -898,8 +918,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       fabs(float __lcpp_x) _NOEXCEPT       {return ::fabsf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double fabs(long double __lcpp_x) _NOEXCEPT {return ::fabsl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -910,8 +932,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       floor(float __lcpp_x) _NOEXCEPT       {return ::floorf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double floor(long double __lcpp_x) _NOEXCEPT {return ::floorl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -922,8 +946,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       fmod(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fmodf(__lcpp_x, __lcpp_y);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double fmod(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fmodl(__lcpp_x, __lcpp_y);}
 #    endif
+#    endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -945,8 +971,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       frexp(float __lcpp_x, int* __lcpp_e) _NOEXCEPT       {return ::frexpf(__lcpp_x, __lcpp_e);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double frexp(long double __lcpp_x, int* __lcpp_e) _NOEXCEPT {return ::frexpl(__lcpp_x, __lcpp_e);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -957,8 +985,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       ldexp(float __lcpp_x, int __lcpp_e) _NOEXCEPT       {return ::ldexpf(__lcpp_x, __lcpp_e);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double ldexp(long double __lcpp_x, int __lcpp_e) _NOEXCEPT {return ::ldexpl(__lcpp_x, __lcpp_e);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -969,8 +999,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       log(float __lcpp_x) _NOEXCEPT       {return ::logf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double log(long double __lcpp_x) _NOEXCEPT {return ::logl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -981,8 +1013,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       log10(float __lcpp_x) _NOEXCEPT       {return ::log10f(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double log10(long double __lcpp_x) _NOEXCEPT {return ::log10l(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -993,15 +1027,19 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       modf(float __lcpp_x, float* __lcpp_y) _NOEXCEPT             {return ::modff(__lcpp_x, __lcpp_y);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double modf(long double __lcpp_x, long double* __lcpp_y) _NOEXCEPT {return ::modfl(__lcpp_x, __lcpp_y);}
 #    endif
+#    endif
 
 // pow
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       pow(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::powf(__lcpp_x, __lcpp_y);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double pow(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::powl(__lcpp_x, __lcpp_y);}
 #    endif
+#    endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1023,7 +1061,9 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       sin(float __lcpp_x) _NOEXCEPT       {return ::sinf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double sin(long double __lcpp_x) _NOEXCEPT {return ::sinl(__lcpp_x);}
+#    endif
 #endif
 
 template <class _A1>
@@ -1035,8 +1075,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       sinh(float __lcpp_x) _NOEXCEPT       {return ::sinhf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double sinh(long double __lcpp_x) _NOEXCEPT {return ::sinhl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1047,8 +1089,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       sqrt(float __lcpp_x) _NOEXCEPT       {return ::sqrtf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double sqrt(long double __lcpp_x) _NOEXCEPT {return ::sqrtl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1059,8 +1103,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       tan(float __lcpp_x) _NOEXCEPT       {return ::tanf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double tan(long double __lcpp_x) _NOEXCEPT {return ::tanl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1071,8 +1117,10 @@
 
 #    if !defined(__sun__)
 inline _LIBCPP_INLINE_VISIBILITY float       tanh(float __lcpp_x) _NOEXCEPT       {return ::tanhf(__lcpp_x);}
+#    ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double tanh(long double __lcpp_x) _NOEXCEPT {return ::tanhl(__lcpp_x);}
 #    endif
+#    endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1082,7 +1130,9 @@
 // acosh
 
 inline _LIBCPP_INLINE_VISIBILITY float       acosh(float __lcpp_x) _NOEXCEPT       {return ::acoshf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double acosh(long double __lcpp_x) _NOEXCEPT {return ::acoshl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1092,7 +1142,9 @@
 // asinh
 
 inline _LIBCPP_INLINE_VISIBILITY float       asinh(float __lcpp_x) _NOEXCEPT       {return ::asinhf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double asinh(long double __lcpp_x) _NOEXCEPT {return ::asinhl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1102,7 +1154,10 @@
 // atanh
 
 inline _LIBCPP_INLINE_VISIBILITY float       atanh(float __lcpp_x) _NOEXCEPT       {return ::atanhf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double atanh(long double __lcpp_x) _NOEXCEPT {return ::atanhl(__lcpp_x);}
+#endif
+
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1112,7 +1167,9 @@
 // cbrt
 
 inline _LIBCPP_INLINE_VISIBILITY float       cbrt(float __lcpp_x) _NOEXCEPT       {return ::cbrtf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double cbrt(long double __lcpp_x) _NOEXCEPT {return ::cbrtl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1143,6 +1200,7 @@
 #endif
 }
 
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 #if __has_builtin(__builtin_copysignl)
 _LIBCPP_CONSTEXPR
 #endif
@@ -1153,6 +1211,7 @@
   return ::copysignl(__lcpp_x, __lcpp_y);
 #endif
 }
+#endif
 
 template <class _A1, class _A2>
 #if __has_builtin(__builtin_copysign)
@@ -1180,9 +1239,11 @@
   return ::__libcpp_copysign(__lcpp_x, __lcpp_y);
 }
 
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double copysign(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {
   return ::__libcpp_copysign(__lcpp_x, __lcpp_y);
 }
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1199,7 +1260,9 @@
 // erf
 
 inline _LIBCPP_INLINE_VISIBILITY float       erf(float __lcpp_x) _NOEXCEPT       {return ::erff(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double erf(long double __lcpp_x) _NOEXCEPT {return ::erfl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1209,7 +1272,9 @@
 // erfc
 
 inline _LIBCPP_INLINE_VISIBILITY float       erfc(float __lcpp_x) _NOEXCEPT       {return ::erfcf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double erfc(long double __lcpp_x) _NOEXCEPT {return ::erfcl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1219,7 +1284,9 @@
 // exp2
 
 inline _LIBCPP_INLINE_VISIBILITY float       exp2(float __lcpp_x) _NOEXCEPT       {return ::exp2f(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double exp2(long double __lcpp_x) _NOEXCEPT {return ::exp2l(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1229,7 +1296,9 @@
 // expm1
 
 inline _LIBCPP_INLINE_VISIBILITY float       expm1(float __lcpp_x) _NOEXCEPT       {return ::expm1f(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double expm1(long double __lcpp_x) _NOEXCEPT {return ::expm1l(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1239,7 +1308,9 @@
 // fdim
 
 inline _LIBCPP_INLINE_VISIBILITY float       fdim(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fdimf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double fdim(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fdiml(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1267,6 +1338,7 @@
     return ::fmaf(__lcpp_x, __lcpp_y, __lcpp_z);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double fma(long double __lcpp_x, long double __lcpp_y, long double __lcpp_z) _NOEXCEPT
 {
 #if __has_builtin(__builtin_fmal)
@@ -1275,6 +1347,7 @@
     return ::fmal(__lcpp_x, __lcpp_y, __lcpp_z);
 #endif
 }
+#endif
 
 template <class _A1, class _A2, class _A3>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1301,7 +1374,9 @@
 // fmax
 
 inline _LIBCPP_INLINE_VISIBILITY float       fmax(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fmaxf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double fmax(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fmaxl(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1322,7 +1397,9 @@
 // fmin
 
 inline _LIBCPP_INLINE_VISIBILITY float       fmin(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fminf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double fmin(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fminl(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1343,7 +1420,9 @@
 // hypot
 
 inline _LIBCPP_INLINE_VISIBILITY float       hypot(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::hypotf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double hypot(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::hypotl(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1364,7 +1443,9 @@
 // ilogb
 
 inline _LIBCPP_INLINE_VISIBILITY int ilogb(float __lcpp_x) _NOEXCEPT       {return ::ilogbf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY int ilogb(long double __lcpp_x) _NOEXCEPT {return ::ilogbl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1374,7 +1455,9 @@
 // lgamma
 
 inline _LIBCPP_INLINE_VISIBILITY float       lgamma(float __lcpp_x) _NOEXCEPT       {return ::lgammaf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double lgamma(long double __lcpp_x) _NOEXCEPT {return ::lgammal(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1391,6 +1474,7 @@
     return ::llrintf(__lcpp_x);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long long llrint(long double __lcpp_x) _NOEXCEPT
 {
 #if __has_builtin(__builtin_llrintl)
@@ -1399,6 +1483,7 @@
     return ::llrintl(__lcpp_x);
 #endif
 }
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1422,6 +1507,7 @@
     return ::llroundf(__lcpp_x);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long long llround(long double __lcpp_x) _NOEXCEPT
 {
 #if __has_builtin(__builtin_llroundl)
@@ -1430,6 +1516,7 @@
     return ::llroundl(__lcpp_x);
 #endif
 }
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1446,7 +1533,9 @@
 // log1p
 
 inline _LIBCPP_INLINE_VISIBILITY float       log1p(float __lcpp_x) _NOEXCEPT       {return ::log1pf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double log1p(long double __lcpp_x) _NOEXCEPT {return ::log1pl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1456,7 +1545,9 @@
 // log2
 
 inline _LIBCPP_INLINE_VISIBILITY float       log2(float __lcpp_x) _NOEXCEPT       {return ::log2f(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double log2(long double __lcpp_x) _NOEXCEPT {return ::log2l(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1466,7 +1557,9 @@
 // logb
 
 inline _LIBCPP_INLINE_VISIBILITY float       logb(float __lcpp_x) _NOEXCEPT       {return ::logbf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double logb(long double __lcpp_x) _NOEXCEPT {return ::logbl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1483,6 +1576,7 @@
     return ::lrintf(__lcpp_x);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long lrint(long double __lcpp_x) _NOEXCEPT
 {
 #if __has_builtin(__builtin_lrintl)
@@ -1491,6 +1585,7 @@
     return ::lrintl(__lcpp_x);
 #endif
 }
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1514,6 +1609,7 @@
     return ::lroundf(__lcpp_x);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long lround(long double __lcpp_x) _NOEXCEPT
 {
 #if __has_builtin(__builtin_lroundl)
@@ -1522,6 +1618,7 @@
     return ::lroundl(__lcpp_x);
 #endif
 }
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1540,7 +1637,9 @@
 // nearbyint
 
 inline _LIBCPP_INLINE_VISIBILITY float       nearbyint(float __lcpp_x) _NOEXCEPT       {return ::nearbyintf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double nearbyint(long double __lcpp_x) _NOEXCEPT {return ::nearbyintl(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1550,7 +1649,9 @@
 // nextafter
 
 inline _LIBCPP_INLINE_VISIBILITY float       nextafter(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::nextafterf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double nextafter(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::nextafterl(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1570,6 +1671,7 @@
 
 // nexttoward
 
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY float       nexttoward(float __lcpp_x, long double __lcpp_y) _NOEXCEPT       {return ::nexttowardf(__lcpp_x, __lcpp_y);}
 inline _LIBCPP_INLINE_VISIBILITY long double nexttoward(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::nexttowardl(__lcpp_x, __lcpp_y);}
 
@@ -1577,11 +1679,14 @@
 inline _LIBCPP_INLINE_VISIBILITY
 typename std::enable_if<std::is_integral<_A1>::value, double>::type
 nexttoward(_A1 __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::nexttoward((double)__lcpp_x, __lcpp_y);}
+#endif
 
 // remainder
 
 inline _LIBCPP_INLINE_VISIBILITY float       remainder(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::remainderf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double remainder(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::remainderl(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1602,7 +1707,9 @@
 // remquo
 
 inline _LIBCPP_INLINE_VISIBILITY float       remquo(float __lcpp_x, float __lcpp_y, int* __lcpp_z) _NOEXCEPT             {return ::remquof(__lcpp_x, __lcpp_y, __lcpp_z);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double remquo(long double __lcpp_x, long double __lcpp_y, int* __lcpp_z) _NOEXCEPT {return ::remquol(__lcpp_x, __lcpp_y, __lcpp_z);}
+#endif
 
 template <class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1630,6 +1737,7 @@
     return ::rintf(__lcpp_x);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double rint(long double __lcpp_x) _NOEXCEPT
 {
 #if __has_builtin(__builtin_rintl)
@@ -1638,6 +1746,7 @@
     return ::rintl(__lcpp_x);
 #endif
 }
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1661,6 +1770,7 @@
     return ::round(__lcpp_x);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double round(long double __lcpp_x) _NOEXCEPT
 {
 #if __has_builtin(__builtin_roundl)
@@ -1669,6 +1779,7 @@
     return ::roundl(__lcpp_x);
 #endif
 }
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1685,7 +1796,9 @@
 // scalbln
 
 inline _LIBCPP_INLINE_VISIBILITY float       scalbln(float __lcpp_x, long __lcpp_y) _NOEXCEPT       {return ::scalblnf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double scalbln(long double __lcpp_x, long __lcpp_y) _NOEXCEPT {return ::scalblnl(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1695,7 +1808,9 @@
 // scalbn
 
 inline _LIBCPP_INLINE_VISIBILITY float       scalbn(float __lcpp_x, int __lcpp_y) _NOEXCEPT       {return ::scalbnf(__lcpp_x, __lcpp_y);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double scalbn(long double __lcpp_x, int __lcpp_y) _NOEXCEPT {return ::scalbnl(__lcpp_x, __lcpp_y);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1705,7 +1820,9 @@
 // tgamma
 
 inline _LIBCPP_INLINE_VISIBILITY float       tgamma(float __lcpp_x) _NOEXCEPT       {return ::tgammaf(__lcpp_x);}
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double tgamma(long double __lcpp_x) _NOEXCEPT {return ::tgammal(__lcpp_x);}
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1722,6 +1839,7 @@
     return ::trunc(__lcpp_x);
 #endif
 }
+#ifndef _LIBCPP_HAS_NO_LONG_DOUBLE_MATH
 inline _LIBCPP_INLINE_VISIBILITY long double trunc(long double __lcpp_x) _NOEXCEPT
 {
 #if __has_builtin(__builtin_truncl)
@@ -1730,6 +1848,7 @@
     return ::truncl(__lcpp_x);
 #endif
 }
+#endif
 
 template <class _A1>
 inline _LIBCPP_INLINE_VISIBILITY