diff --git a/config/check_spidermonkey_style.py b/config/check_spidermonkey_style.py
index 615ac0404ece..8a074cc98d0f 100644
--- a/config/check_spidermonkey_style.py
+++ b/config/check_spidermonkey_style.py
@@ -66,6 +66,7 @@ included_inclnames_to_ignore = set([
     'jsautokw.h',               # generated in $OBJDIR
     'jscustomallocator.h',      # provided by embedders;  allowed to be missing
     'js-config.h',              # generated in $OBJDIR
+    'fdlibm.h',                 # fdlibm
     'pratom.h',                 # NSPR
     'prcvar.h',                 # NSPR
     'prerror.h',                # NSPR
diff --git a/js/src/jsmath.cpp b/js/src/jsmath.cpp
index 3f4ddd9b4b87..4e92ddb2b10c 100644
--- a/js/src/jsmath.cpp
+++ b/js/src/jsmath.cpp
@@ -22,6 +22,8 @@
 # include <unistd.h>
 #endif
 
+#include "fdlibm.h"
+
 #ifdef XP_WIN
 # include "jswin.h"
 #endif
@@ -139,14 +141,14 @@ double
 js::math_acos_impl(MathCache* cache, double x)
 {
     ACOS_IF_OUT_OF_RANGE(x);
-    return cache->lookup(acos, x, MathCache::Acos);
+    return cache->lookup(fdlibm::acos, x, MathCache::Acos);
 }
 
 double
 js::math_acos_uncached(double x)
 {
     ACOS_IF_OUT_OF_RANGE(x);
-    return acos(x);
+    return fdlibm::acos(x);
 }
 
 #undef ACOS_IF_OUT_OF_RANGE
@@ -184,14 +186,14 @@ double
 js::math_asin_impl(MathCache* cache, double x)
 {
     ASIN_IF_OUT_OF_RANGE(x);
-    return cache->lookup(asin, x, MathCache::Asin);
+    return cache->lookup(fdlibm::asin, x, MathCache::Asin);
 }
 
 double
 js::math_asin_uncached(double x)
 {
     ASIN_IF_OUT_OF_RANGE(x);
-    return asin(x);
+    return fdlibm::asin(x);
 }
 
 #undef ASIN_IF_OUT_OF_RANGE
@@ -222,13 +224,13 @@ js::math_asin(JSContext* cx, unsigned argc, Value* vp)
 double
 js::math_atan_impl(MathCache* cache, double x)
 {
-    return cache->lookup(atan, x, MathCache::Atan);
+    return cache->lookup(fdlibm::atan, x, MathCache::Atan);
 }
 
 double
 js::math_atan_uncached(double x)
 {
-    return atan(x);
+    return fdlibm::atan(x);
 }
 
 bool
@@ -281,7 +283,7 @@ js::ecmaAtan2(double y, double x)
             return y;
     }
 #endif
-    return atan2(y, x);
+    return fdlibm::atan2(y, x);
 }
 
 bool
@@ -315,7 +317,7 @@ js::math_ceil_impl(double x)
     if (x < 0 && x > -1.0)
         return js_copysign(0, -1);
 #endif
-    return ceil(x);
+    return fdlibm::ceil(x);
 }
 
 bool
@@ -417,14 +419,14 @@ double
 js::math_exp_impl(MathCache* cache, double x)
 {
     EXP_IF_OUT_OF_RANGE(x);
-    return cache->lookup(exp, x, MathCache::Exp);
+    return cache->lookup(fdlibm::exp, x, MathCache::Exp);
 }
 
 double
 js::math_exp_uncached(double x)
 {
     EXP_IF_OUT_OF_RANGE(x);
-    return exp(x);
+    return fdlibm::exp(x);
 }
 
 #undef EXP_IF_OUT_OF_RANGE
@@ -455,7 +457,7 @@ js::math_exp(JSContext* cx, unsigned argc, Value* vp)
 double
 js::math_floor_impl(double x)
 {
-    return floor(x);
+    return fdlibm::floor(x);
 }
 
 bool
@@ -559,7 +561,7 @@ double
 js::math_log_uncached(double x)
 {
     LOG_IF_OUT_OF_RANGE(x);
-    return log(x);
+    return fdlibm::log(x);
 }
 
 #undef LOG_IF_OUT_OF_RANGE
@@ -843,7 +845,7 @@ js::math_round_impl(double x)
         return x;
 
     double add = (x >= 0) ? GetBiggestNumberLessThan(0.5) : 0.5;
-    return js_copysign(floor(x + add), x);
+    return js_copysign(fdlibm::floor(x + add), x);
 }
 
 float
@@ -858,7 +860,7 @@ js::math_roundf_impl(float x)
         return x;
 
     float add = (x >= 0) ? GetBiggestNumberLessThan(0.5f) : 0.5f;
-    return js_copysign(floorf(x + add), x);
+    return js_copysign(fdlibm::floorf(x + add), x);
 }
 
 bool /* ES5 15.8.2.15. */
@@ -876,12 +878,6 @@ js::math_round(JSContext* cx, unsigned argc, Value* vp)
 
 double
 js::math_sin_impl(MathCache* cache, double x)
-{
-    return cache->lookup(math_sin_uncached, x, MathCache::Sin);
-}
-
-double
-js::math_sin_uncached(double x)
 {
 #ifdef _WIN64
     // Workaround MSVC bug where sin(-0) is +0 instead of -0 on x64 on
@@ -889,6 +885,12 @@ js::math_sin_uncached(double x)
     if (IsNegativeZero(x))
         return -0.0;
 #endif
+    return cache->lookup(math_sin_uncached, x, MathCache::Sin);
+}
+
+double
+js::math_sin_uncached(double x)
+{
     return sin(x);
 }
 
@@ -1046,13 +1048,13 @@ static bool math_function(JSContext* cx, unsigned argc, Value* vp)
 double
 js::math_log10_impl(MathCache* cache, double x)
 {
-    return cache->lookup(log10, x, MathCache::Log10);
+    return cache->lookup(fdlibm::log10, x, MathCache::Log10);
 }
 
 double
 js::math_log10_uncached(double x)
 {
-    return log10(x);
+    return fdlibm::log10(x);
 }
 
 bool
@@ -1071,13 +1073,13 @@ double log2(double x)
 double
 js::math_log2_impl(MathCache* cache, double x)
 {
-    return cache->lookup(log2, x, MathCache::Log2);
+    return cache->lookup(fdlibm::log2, x, MathCache::Log2);
 }
 
 double
 js::math_log2_uncached(double x)
 {
-    return log2(x);
+    return fdlibm::log2(x);
 }
 
 bool
@@ -1114,14 +1116,14 @@ double
 js::math_log1p_impl(MathCache* cache, double x)
 {
     LOG1P_IF_OUT_OF_RANGE(x);
-    return cache->lookup(log1p, x, MathCache::Log1p);
+    return cache->lookup(fdlibm::log1p, x, MathCache::Log1p);
 }
 
 double
 js::math_log1p_uncached(double x)
 {
     LOG1P_IF_OUT_OF_RANGE(x);
-    return log1p(x);
+    return fdlibm::log1p(x);
 }
 
 #undef LOG1P_IF_OUT_OF_RANGE
@@ -1156,13 +1158,13 @@ double expm1(double x)
 double
 js::math_expm1_impl(MathCache* cache, double x)
 {
-    return cache->lookup(expm1, x, MathCache::Expm1);
+    return cache->lookup(fdlibm::expm1, x, MathCache::Expm1);
 }
 
 double
 js::math_expm1_uncached(double x)
 {
-    return expm1(x);
+    return fdlibm::expm1(x);
 }
 
 bool
@@ -1185,13 +1187,13 @@ double sqrt1pm1(double x)
 double
 js::math_cosh_impl(MathCache* cache, double x)
 {
-    return cache->lookup(cosh, x, MathCache::Cosh);
+    return cache->lookup(fdlibm::cosh, x, MathCache::Cosh);
 }
 
 double
 js::math_cosh_uncached(double x)
 {
-    return cosh(x);
+    return fdlibm::cosh(x);
 }
 
 bool
@@ -1203,13 +1205,13 @@ js::math_cosh(JSContext* cx, unsigned argc, Value* vp)
 double
 js::math_sinh_impl(MathCache* cache, double x)
 {
-    return cache->lookup(sinh, x, MathCache::Sinh);
+    return cache->lookup(fdlibm::sinh, x, MathCache::Sinh);
 }
 
 double
 js::math_sinh_uncached(double x)
 {
-    return sinh(x);
+    return fdlibm::sinh(x);
 }
 
 bool
@@ -1221,13 +1223,13 @@ js::math_sinh(JSContext* cx, unsigned argc, Value* vp)
 double
 js::math_tanh_impl(MathCache* cache, double x)
 {
-    return cache->lookup(tanh, x, MathCache::Tanh);
+    return cache->lookup(fdlibm::tanh, x, MathCache::Tanh);
 }
 
 double
 js::math_tanh_uncached(double x)
 {
-    return tanh(x);
+    return fdlibm::tanh(x);
 }
 
 bool
@@ -1270,13 +1272,13 @@ double acosh(double x)
 double
 js::math_acosh_impl(MathCache* cache, double x)
 {
-    return cache->lookup(acosh, x, MathCache::Acosh);
+    return cache->lookup(fdlibm::acosh, x, MathCache::Acosh);
 }
 
 double
 js::math_acosh_uncached(double x)
 {
-    return acosh(x);
+    return fdlibm::acosh(x);
 }
 
 bool
@@ -1324,7 +1326,7 @@ double
 js::math_asinh_impl(MathCache* cache, double x)
 {
 #ifdef HAVE_ASINH
-    return cache->lookup(asinh, x, MathCache::Asinh);
+    return cache->lookup(fdlibm::asinh, x, MathCache::Asinh);
 #else
     return cache->lookup(my_asinh, x, MathCache::Asinh);
 #endif
@@ -1334,7 +1336,7 @@ double
 js::math_asinh_uncached(double x)
 {
 #ifdef HAVE_ASINH
-    return asinh(x);
+    return fdlibm::asinh(x);
 #else
     return my_asinh(x);
 #endif
@@ -1377,13 +1379,13 @@ double atanh(double x)
 double
 js::math_atanh_impl(MathCache* cache, double x)
 {
-    return cache->lookup(atanh, x, MathCache::Atanh);
+    return cache->lookup(fdlibm::atanh, x, MathCache::Atanh);
 }
 
 double
 js::math_atanh_uncached(double x)
 {
-    return atanh(x);
+    return fdlibm::atanh(x);
 }
 
 bool
@@ -1405,7 +1407,7 @@ js::ecmaHypot(double x, double y)
         return mozilla::PositiveInfinity<double>();
     }
 #endif
-    return hypot(x, y);
+    return fdlibm::hypot(x, y);
 }
 
 static inline
@@ -1505,13 +1507,13 @@ js::math_hypot_handle(JSContext* cx, HandleValueArray args, MutableHandleValue r
 double
 js::math_trunc_impl(MathCache* cache, double x)
 {
-    return cache->lookup(trunc, x, MathCache::Trunc);
+    return cache->lookup(fdlibm::trunc, x, MathCache::Trunc);
 }
 
 double
 js::math_trunc_uncached(double x)
 {
-    return trunc(x);
+    return fdlibm::trunc(x);
 }
 
 bool
@@ -1562,13 +1564,13 @@ double cbrt(double x)
 double
 js::math_cbrt_impl(MathCache* cache, double x)
 {
-    return cache->lookup(cbrt, x, MathCache::Cbrt);
+    return cache->lookup(fdlibm::cbrt, x, MathCache::Cbrt);
 }
 
 double
 js::math_cbrt_uncached(double x)
 {
-    return cbrt(x);
+    return fdlibm::cbrt(x);
 }
 
 bool