diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 49acfc9bbc3..f40d6a99f3e 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -127,19 +127,19 @@ JS_Now()
 JS_PUBLIC_API(jsval)
 JS_GetNaNValue(JSContext *cx)
 {
-    return DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+    return cx->runtime->NaNValue;
 }
 
 JS_PUBLIC_API(jsval)
 JS_GetNegativeInfinityValue(JSContext *cx)
 {
-    return DOUBLE_TO_JSVAL(cx->runtime->jsNegativeInfinity);
+    return cx->runtime->negativeInfinityValue;
 }
 
 JS_PUBLIC_API(jsval)
 JS_GetPositiveInfinityValue(JSContext *cx)
 {
-    return DOUBLE_TO_JSVAL(cx->runtime->jsPositiveInfinity);
+    return cx->runtime->positiveInfinityValue;
 }
 
 JS_PUBLIC_API(jsval)
diff --git a/js/src/jsarray.cpp b/js/src/jsarray.cpp
index 272f42e15cf..80075bd056c 100644
--- a/js/src/jsarray.cpp
+++ b/js/src/jsarray.cpp
@@ -1708,11 +1708,11 @@ InitArrayElements(JSContext *cx, JSObject *obj, jsuint start, jsuint count, jsva
 
     JS_ASSERT(start == MAXINDEX);
     jsval tmp[2] = {JSVAL_NULL, JSVAL_NULL};
-    jsdouble* dp = js_NewWeaklyRootedDouble(cx, MAXINDEX);
-    if (!dp)
-        return JS_FALSE;
-    tmp[0] = DOUBLE_TO_JSVAL(dp);
     JSAutoTempValueRooter tvr(cx, JS_ARRAY_LENGTH(tmp), tmp);
+    if (!js_NewDoubleInRootedValue(cx, MAXINDEX, &tmp[0]))
+        return JS_FALSE;
+    jsdouble *dp = JSVAL_TO_DOUBLE(tmp[0]);
+    JS_ASSERT(*dp == MAXINDEX);
     JSAutoTempIdRooter idr(cx);
     do {
         tmp[1] = *vector++;
diff --git a/js/src/jsbuiltins.cpp b/js/src/jsbuiltins.cpp
index f491f3efdc2..6a56e5ba035 100644
--- a/js/src/jsbuiltins.cpp
+++ b/js/src/jsbuiltins.cpp
@@ -66,8 +66,6 @@
 using namespace avmplus;
 using namespace nanojit;
 
-extern jsdouble js_NaN;
-
 JS_FRIEND_API(void)
 js_SetTraceableNativeFailed(JSContext *cx)
 {
diff --git a/js/src/jscntxt.h b/js/src/jscntxt.h
index faeb4d1f1c1..042b8e8a142 100644
--- a/js/src/jscntxt.h
+++ b/js/src/jscntxt.h
@@ -533,9 +533,9 @@ struct JSRuntime {
     JSSetSlotRequest    *setSlotRequests;
 
     /* Well-known numbers held for use by this runtime's contexts. */
-    jsdouble            *jsNaN;
-    jsdouble            *jsNegativeInfinity;
-    jsdouble            *jsPositiveInfinity;
+    jsval               NaNValue;
+    jsval               negativeInfinityValue;
+    jsval               positiveInfinityValue;
 
 #ifdef JS_THREADSAFE
     JSLock              *deflatedStringCacheLock;
diff --git a/js/src/jsdate.cpp b/js/src/jsdate.cpp
index 5b0157fcab3..749d33679b2 100644
--- a/js/src/jsdate.cpp
+++ b/js/src/jsdate.cpp
@@ -478,7 +478,7 @@ msFromTime(jsdouble t)
 
 #define TIMECLIP(d) ((JSDOUBLE_IS_FINITE(d) \
                       && !((d < 0 ? -d : d) > HalfTimeDomain)) \
-                     ? js_DoubleToInteger(d + (+0.)) : *cx->runtime->jsNaN)
+                     ? js_DoubleToInteger(d + (+0.)) : js_NaN)
 
 /**
  * end of ECMA 'support' functions
@@ -595,7 +595,7 @@ date_msecFromArgs(JSContext *cx, uintN argc, jsval *argv, jsdouble *rval)
                 return JS_FALSE;
             /* return NaN if any arg is not finite */
             if (!JSDOUBLE_IS_FINITE(d)) {
-                *rval = *cx->runtime->jsNaN;
+                *rval = js_NaN;
                 return JS_TRUE;
             }
             array[loop] = js_DoubleToInteger(d);
@@ -1164,16 +1164,16 @@ date_parse(JSContext *cx, uintN argc, jsval *vp)
     jsdouble result;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
-        return JS_TRUE;
+        *vp = cx->runtime->NaNValue;
+        return true;
     }
     str = js_ValueToString(cx, vp[2]);
     if (!str)
         return JS_FALSE;
     vp[2] = STRING_TO_JSVAL(str);
     if (!date_parseString(str, &result)) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
-        return JS_TRUE;
+        *vp = cx->runtime->NaNValue;
+        return true;
     }
 
     result = TIMECLIP(result);
@@ -1218,11 +1218,10 @@ SetDateToNaN(JSContext *cx, JSObject *obj, jsval *vp = NULL)
 {
     JS_ASSERT(OBJ_GET_CLASS(cx, obj) == &js_DateClass);
 
-    jsval nan = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
-    obj->fslots[JSSLOT_LOCAL_TIME] = nan;
-    obj->fslots[JSSLOT_UTC_TIME] = nan;
+    obj->fslots[JSSLOT_LOCAL_TIME] = cx->runtime->NaNValue;
+    obj->fslots[JSSLOT_UTC_TIME] = cx->runtime->NaNValue;
     if (vp)
-        *vp = nan;
+        *vp = cx->runtime->NaNValue;
 }
 
 /*
@@ -1233,7 +1232,7 @@ SetUTCTime(JSContext *cx, JSObject *obj, jsdouble t, jsval *vp = NULL)
 {
     JS_ASSERT(OBJ_GET_CLASS(cx, obj) == &js_DateClass);
 
-    obj->fslots[JSSLOT_LOCAL_TIME] = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+    obj->fslots[JSSLOT_LOCAL_TIME] = cx->runtime->NaNValue;
     if (!js_NewDoubleInRootedValue(cx, t, &obj->fslots[JSSLOT_UTC_TIME]))
         return false;
     if (vp)
@@ -1248,33 +1247,24 @@ SetUTCTime(JSContext *cx, JSObject *obj, jsdouble t, jsval *vp = NULL)
 static JSBool
 GetAndCacheLocalTime(JSContext *cx, JSObject *obj, jsval *vp, jsdouble *dp)
 {
-    jsval v;
-    jsdouble result;
-    jsdouble *cached;
-
     if (!obj || !JS_InstanceOf(cx, obj, &js_DateClass, vp ? vp + 2 : NULL))
-        return JS_FALSE;
-    v = obj->fslots[JSSLOT_LOCAL_TIME];
-
-    result = *JSVAL_TO_DOUBLE(v);
+        return false;
 
+    jsval *slotp = &obj->fslots[JSSLOT_LOCAL_TIME];
+    jsdouble result = *JSVAL_TO_DOUBLE(*vp);
     if (JSDOUBLE_IS_NaN(result)) {
-        if (!GetUTCTime(cx, obj, vp, &result))
-            return JS_FALSE;
+        result = *JSVAL_TO_DOUBLE(obj->fslots[JSSLOT_UTC_TIME]);
 
         /* if result is NaN, it couldn't be finite. */
         if (JSDOUBLE_IS_FINITE(result))
             result = LocalTime(result);
 
-        cached = js_NewWeaklyRootedDouble(cx, result);
-        if (!cached)
-            return JS_FALSE;
-
-        obj->fslots[JSSLOT_LOCAL_TIME] = DOUBLE_TO_JSVAL(cached);
+        if (!js_NewDoubleInRootedValue(cx, result, slotp))
+            return false;
     }
 
     *dp = result;
-    return JS_TRUE;
+    return true;
 }
 
 /*
diff --git a/js/src/jsmath.cpp b/js/src/jsmath.cpp
index 53e4c69eade..b26a0ae678f 100644
--- a/js/src/jsmath.cpp
+++ b/js/src/jsmath.cpp
@@ -56,8 +56,6 @@
 #include "jslibmath.h"
 #include "jsobj.h"
 
-extern jsdouble js_NaN;
-
 #ifndef M_E
 #define M_E             2.7182818284590452354
 #endif
@@ -109,7 +107,7 @@ math_abs(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -125,7 +123,7 @@ math_acos(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -133,7 +131,7 @@ math_acos(JSContext *cx, uintN argc, jsval *vp)
         return JS_FALSE;
 #if defined(SOLARIS) && defined(__GNUC__)
     if (x < -1 || 1 < x) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
 #endif
@@ -147,7 +145,7 @@ math_asin(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -155,7 +153,7 @@ math_asin(JSContext *cx, uintN argc, jsval *vp)
         return JS_FALSE;
 #if defined(SOLARIS) && defined(__GNUC__)
     if (x < -1 || 1 < x) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
 #endif
@@ -169,7 +167,7 @@ math_atan(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -215,7 +213,7 @@ math_atan2(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, y;
 
     if (argc <= 1) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -243,7 +241,7 @@ js_math_ceil(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -259,7 +257,7 @@ math_cos(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -275,7 +273,7 @@ math_exp(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -283,11 +281,11 @@ math_exp(JSContext *cx, uintN argc, jsval *vp)
         return JS_FALSE;
 #ifdef _WIN32
     if (!JSDOUBLE_IS_NaN(x)) {
-        if (x == *cx->runtime->jsPositiveInfinity) {
-            *vp = DOUBLE_TO_JSVAL(cx->runtime->jsPositiveInfinity);
+        if (x == js_PositiveInfinity) {
+            *vp = cx->runtime->positiveInfinityValue;
             return JS_TRUE;
         }
-        if (x == *cx->runtime->jsNegativeInfinity) {
+        if (x == js_NegativeInfinity) {
             *vp = JSVAL_ZERO;
             return JS_TRUE;
         }
@@ -303,7 +301,7 @@ js_math_floor(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -319,7 +317,7 @@ math_log(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -327,7 +325,7 @@ math_log(JSContext *cx, uintN argc, jsval *vp)
         return JS_FALSE;
 #if defined(SOLARIS) && defined(__GNUC__)
     if (x < 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
 #endif
@@ -338,12 +336,12 @@ math_log(JSContext *cx, uintN argc, jsval *vp)
 JSBool
 js_math_max(JSContext *cx, uintN argc, jsval *vp)
 {
-    jsdouble x, z = *cx->runtime->jsNegativeInfinity;
+    jsdouble x, z = js_NegativeInfinity;
     jsval *argv;
     uintN i;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNegativeInfinity);
+        *vp = cx->runtime->negativeInfinityValue;
         return JS_TRUE;
     }
     argv = vp + 2;
@@ -352,7 +350,7 @@ js_math_max(JSContext *cx, uintN argc, jsval *vp)
         if (JSVAL_IS_NULL(argv[i]))
             return JS_FALSE;
         if (JSDOUBLE_IS_NaN(x)) {
-            *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+            *vp = cx->runtime->NaNValue;
             return JS_TRUE;
         }
         if (x == 0 && x == z) {
@@ -368,12 +366,12 @@ js_math_max(JSContext *cx, uintN argc, jsval *vp)
 JSBool
 js_math_min(JSContext *cx, uintN argc, jsval *vp)
 {
-    jsdouble x, z = *cx->runtime->jsPositiveInfinity;
+    jsdouble x, z = js_PositiveInfinity;
     jsval *argv;
     uintN i;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsPositiveInfinity);
+        *vp = cx->runtime->positiveInfinityValue;
         return JS_TRUE;
     }
     argv = vp + 2;
@@ -382,7 +380,7 @@ js_math_min(JSContext *cx, uintN argc, jsval *vp)
         if (JSVAL_IS_NULL(argv[i]))
             return JS_FALSE;
         if (JSDOUBLE_IS_NaN(x)) {
-            *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+            *vp = cx->runtime->NaNValue;
             return JS_TRUE;
         }
         if (x == 0 && x == z) {
@@ -401,7 +399,7 @@ math_pow(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, y, z;
 
     if (argc <= 1) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -415,7 +413,7 @@ math_pow(JSContext *cx, uintN argc, jsval *vp)
      * we need to wrap the libm call to make it ECMA compliant.
      */
     if (!JSDOUBLE_IS_FINITE(y) && (x == 1.0 || x == -1.0)) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     /* pow(x, +-0) is always 1, even for x = NaN. */
@@ -492,7 +490,7 @@ js_math_round(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -508,7 +506,7 @@ math_sin(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -524,7 +522,7 @@ math_sqrt(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -540,7 +538,7 @@ math_tan(JSContext *cx, uintN argc, jsval *vp)
     jsdouble x, z;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     x = js_ValueToNumber(cx, &vp[2]);
@@ -602,12 +600,10 @@ static jsdouble FASTCALL
 math_exp_tn(JSContext *cx, jsdouble d)
 {
     if (!JSDOUBLE_IS_NaN(d)) {
-        if (d == *cx->runtime->jsPositiveInfinity) {
-            return *cx->runtime->jsPositiveInfinity;
-        }
-        if (d == *cx->runtime->jsNegativeInfinity) {
+        if (d == js_PositiveInfinity)
+            return js_PositiveInfinity;
+        if (d == js_NegativeInfinity)
             return 0.0;
-        }
     }
     return exp(d);
 }
diff --git a/js/src/jsnum.cpp b/js/src/jsnum.cpp
index 9cb21293752..43dc6874b2f 100644
--- a/js/src/jsnum.cpp
+++ b/js/src/jsnum.cpp
@@ -141,7 +141,7 @@ num_parseFloat(JSContext *cx, uintN argc, jsval *vp)
     const jschar *bp, *end, *ep;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     str = js_ValueToString(cx, vp[2]);
@@ -151,7 +151,7 @@ num_parseFloat(JSContext *cx, uintN argc, jsval *vp)
     if (!js_strtod(cx, bp, end, &ep, &d))
         return JS_FALSE;
     if (ep == bp) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     return js_NewNumberInRootedValue(cx, d, vp);
@@ -183,7 +183,7 @@ num_parseInt(JSContext *cx, uintN argc, jsval *vp)
     const jschar *bp, *end, *ep;
 
     if (argc == 0) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     if (argc > 1) {
@@ -194,7 +194,7 @@ num_parseInt(JSContext *cx, uintN argc, jsval *vp)
         radix = 0;
     }
     if (radix != 0 && (radix < 2 || radix > 36)) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
 
@@ -210,7 +210,7 @@ num_parseInt(JSContext *cx, uintN argc, jsval *vp)
     if (!js_strtointeger(cx, bp, end, &ep, radix, &d))
         return JS_FALSE;
     if (ep == bp) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     return js_NewNumberInRootedValue(cx, d, vp);
@@ -669,7 +669,8 @@ static JSConstDoubleSpec number_constants[] = {
 };
 
 jsdouble js_NaN;
-
+jsdouble js_PositiveInfinity;
+jsdouble js_NegativeInfinity;
 
 #if (defined __GNUC__ && defined __i386__)
 
@@ -694,41 +695,37 @@ inline void FIX_FPU() {
 JSBool
 js_InitRuntimeNumberState(JSContext *cx)
 {
-    JSRuntime *rt;
-    jsdpun u;
-    struct lconv *locale;
+    JS_STATIC_ASSERT(JSVAL_NULL == jsval(0));
 
-    rt = cx->runtime;
-    JS_ASSERT(!rt->jsNaN);
+    JSRuntime *rt = cx->runtime;
+    JS_ASSERT(JSVAL_IS_NULL(rt->NaNValue));
 
     FIX_FPU();
 
+    jsdpun u;
     u.s.hi = JSDOUBLE_HI32_EXPMASK | JSDOUBLE_HI32_MANTMASK;
     u.s.lo = 0xffffffff;
     number_constants[NC_NaN].dval = js_NaN = u.d;
-    rt->jsNaN = js_NewWeaklyRootedDouble(cx, js_NaN);
-    if (!rt->jsNaN)
-        return JS_FALSE;
+    if (!js_NewDoubleInRootedValue(cx, u.d, &rt->NaNValue))
+        return false;
 
     u.s.hi = JSDOUBLE_HI32_EXPMASK;
     u.s.lo = 0x00000000;
-    number_constants[NC_POSITIVE_INFINITY].dval = u.d;
-    rt->jsPositiveInfinity = js_NewWeaklyRootedDouble(cx, u.d);
-    if (!rt->jsPositiveInfinity)
-        return JS_FALSE;
+    number_constants[NC_POSITIVE_INFINITY].dval = js_PositiveInfinity = u.d;
+    if (!js_NewDoubleInRootedValue(cx, u.d, &rt->positiveInfinityValue))
+        return false;
 
     u.s.hi = JSDOUBLE_HI32_SIGNBIT | JSDOUBLE_HI32_EXPMASK;
     u.s.lo = 0x00000000;
-    number_constants[NC_NEGATIVE_INFINITY].dval = u.d;
-    rt->jsNegativeInfinity = js_NewWeaklyRootedDouble(cx, u.d);
-    if (!rt->jsNegativeInfinity)
-        return JS_FALSE;
+    number_constants[NC_NEGATIVE_INFINITY].dval = js_NegativeInfinity = u.d;
+    if (!js_NewDoubleInRootedValue(cx, u.d, &rt->negativeInfinityValue))
+        return false;
 
     u.s.hi = 0;
     u.s.lo = 1;
     number_constants[NC_MIN_VALUE].dval = u.d;
 
-    locale = localeconv();
+    struct lconv *locale = localeconv();
     rt->thousandsSeparator =
         JS_strdup(cx, locale->thousands_sep ? locale->thousands_sep : "'");
     rt->decimalSeparator =
@@ -742,15 +739,18 @@ js_InitRuntimeNumberState(JSContext *cx)
 void
 js_TraceRuntimeNumberState(JSTracer *trc)
 {
-    JSRuntime *rt;
+    JSRuntime *rt = trc->context->runtime;
 
-    rt = trc->context->runtime;
-    if (rt->jsNaN)
-        JS_CALL_DOUBLE_TRACER(trc, rt->jsNaN, "NaN");
-    if (rt->jsPositiveInfinity)
-        JS_CALL_DOUBLE_TRACER(trc, rt->jsPositiveInfinity, "+Infinity");
-    if (rt->jsNegativeInfinity)
-        JS_CALL_DOUBLE_TRACER(trc, rt->jsNegativeInfinity, "-Infinity");
+    if (!JSVAL_IS_NULL(rt->NaNValue))
+        JS_CALL_DOUBLE_TRACER(trc, JSVAL_TO_DOUBLE(rt->NaNValue), "NaN");
+    if (!JSVAL_IS_NULL(rt->positiveInfinityValue)) {
+        JS_CALL_DOUBLE_TRACER(trc, JSVAL_TO_DOUBLE(rt->positiveInfinityValue),
+                              "+Infinity");
+    }
+    if (!JSVAL_IS_NULL(rt->negativeInfinityValue)) {
+        JS_CALL_DOUBLE_TRACER(trc, JSVAL_TO_DOUBLE(rt->negativeInfinityValue),
+                              "-Infinity");
+    }
 }
 
 void
@@ -758,13 +758,13 @@ js_FinishRuntimeNumberState(JSContext *cx)
 {
     JSRuntime *rt = cx->runtime;
 
-    rt->jsNaN = NULL;
-    rt->jsNegativeInfinity = NULL;
-    rt->jsPositiveInfinity = NULL;
+    rt->NaNValue = JSVAL_NULL;
+    rt->negativeInfinityValue = JSVAL_NULL;
+    rt->positiveInfinityValue = JSVAL_NULL;
 
-    cx->free((void *)rt->thousandsSeparator);
-    cx->free((void *)rt->decimalSeparator);
-    cx->free((void *)rt->numGrouping);
+    cx->free((void *) rt->thousandsSeparator);
+    cx->free((void *) rt->decimalSeparator);
+    cx->free((void *) rt->numGrouping);
     rt->thousandsSeparator = rt->decimalSeparator = rt->numGrouping = NULL;
 }
 
@@ -790,14 +790,13 @@ js_InitNumberClass(JSContext *cx, JSObject *obj)
 
     /* ECMA 15.1.1.1 */
     rt = cx->runtime;
-    if (!JS_DefineProperty(cx, obj, js_NaN_str, DOUBLE_TO_JSVAL(rt->jsNaN),
+    if (!JS_DefineProperty(cx, obj, js_NaN_str, rt->NaNValue,
                            NULL, NULL, JSPROP_PERMANENT)) {
         return NULL;
     }
 
     /* ECMA 15.1.1.2 */
-    if (!JS_DefineProperty(cx, obj, js_Infinity_str,
-                           DOUBLE_TO_JSVAL(rt->jsPositiveInfinity),
+    if (!JS_DefineProperty(cx, obj, js_Infinity_str, rt->positiveInfinityValue,
                            NULL, NULL, JSPROP_PERMANENT)) {
         return NULL;
     }
@@ -942,7 +941,7 @@ js_ValueToNumber(JSContext *cx, jsval *vp)
     jsval v;
     JSString *str;
     const jschar *bp, *end, *ep;
-    jsdouble d, *dp;
+    jsdouble d;
     JSObject *obj;
 
     v = *vp;
@@ -1020,9 +1019,8 @@ js_ValueToNumber(JSContext *cx, jsval *vp)
             break;
     }
 
-    dp = cx->runtime->jsNaN;
-    *vp = DOUBLE_TO_JSVAL(dp);
-    return *dp;
+    *vp = cx->runtime->NaNValue;
+    return js_NaN;
 }
 
 int32
@@ -1193,15 +1191,15 @@ js_strtod(JSContext *cx, const jschar *s, const jschar *send,
     if ((negative = (*istr == '-')) != 0 || *istr == '+')
         istr++;
     if (*istr == 'I' && !strncmp(istr, js_Infinity_str, sizeof js_Infinity_str - 1)) {
-        d = *(negative ? cx->runtime->jsNegativeInfinity : cx->runtime->jsPositiveInfinity);
+        d = negative ? js_NegativeInfinity : js_PositiveInfinity;
         estr = istr + 8;
     } else {
         int err;
         d = JS_strtod(cstr, &estr, &err);
         if (d == HUGE_VAL)
-            d = *cx->runtime->jsPositiveInfinity;
+            d = js_PositiveInfinity;
         else if (d == -HUGE_VAL)
-            d = *cx->runtime->jsNegativeInfinity;
+            d = js_NegativeInfinity;
     }
 
     i = estr - cstr;
@@ -1336,7 +1334,7 @@ js_strtointeger(JSContext *cx, const jschar *s, const jschar *send,
                 return JS_FALSE;
             }
             if (err == JS_DTOA_ERANGE && value == HUGE_VAL)
-                value = *cx->runtime->jsPositiveInfinity;
+                value = js_PositiveInfinity;
             cx->free(cstr);
         } else if ((base & (base - 1)) == 0) {
             /*
diff --git a/js/src/jsnum.h b/js/src/jsnum.h
index dea4737df00..f3e7a253dfe 100644
--- a/js/src/jsnum.h
+++ b/js/src/jsnum.h
@@ -169,6 +169,8 @@ JS_HASH_DOUBLE(jsdouble d)
 #endif
 
 extern jsdouble js_NaN;
+extern jsdouble js_PositiveInfinity;
+extern jsdouble js_NegativeInfinity;
 
 /* Initialize number constants and runtime state for the first context. */
 extern JSBool
diff --git a/js/src/jsops.cpp b/js/src/jsops.cpp
index 5d0dab85116..1448943c5fb 100644
--- a/js/src/jsops.cpp
+++ b/js/src/jsops.cpp
@@ -1095,15 +1095,15 @@ BEGIN_CASE(JSOP_DIV)
 #ifdef XP_WIN
         /* XXX MSVC miscompiles such that (NaN == 0) */
         if (JSDOUBLE_IS_NaN(d2))
-            rval = DOUBLE_TO_JSVAL(rt->jsNaN);
+            rval = rt->NaNValue;
         else
 #endif
         if (d == 0 || JSDOUBLE_IS_NaN(d))
-            rval = DOUBLE_TO_JSVAL(rt->jsNaN);
+            rval = rt->NaNValue;
         else if (JSDOUBLE_IS_NEG(d) != JSDOUBLE_IS_NEG(d2))
-            rval = DOUBLE_TO_JSVAL(rt->jsNegativeInfinity);
+            rval = rt->negativeInfinityValue;
         else
-            rval = DOUBLE_TO_JSVAL(rt->jsPositiveInfinity);
+            rval = rt->positiveInfinityValue;
         STORE_OPND(-1, rval);
     } else {
         d /= d2;
@@ -1116,7 +1116,7 @@ BEGIN_CASE(JSOP_MOD)
     FETCH_NUMBER(cx, -2, d);
     regs.sp--;
     if (d2 == 0) {
-        STORE_OPND(-1, DOUBLE_TO_JSVAL(rt->jsNaN));
+        STORE_OPND(-1, rt->NaNValue);
     } else {
         d = js_fmod(d, d2);
         STORE_NUMBER(cx, -1, d);
diff --git a/js/src/jsparse.cpp b/js/src/jsparse.cpp
index cfba4a438ec..0880b060278 100644
--- a/js/src/jsparse.cpp
+++ b/js/src/jsparse.cpp
@@ -8449,15 +8449,15 @@ FoldBinaryNumeric(JSContext *cx, JSOp op, JSParseNode *pn1, JSParseNode *pn2,
 #if defined(XP_WIN)
             /* XXX MSVC miscompiles such that (NaN == 0) */
             if (JSDOUBLE_IS_NaN(d2))
-                d = *cx->runtime->jsNaN;
+                d = js_NaN;
             else
 #endif
             if (d == 0 || JSDOUBLE_IS_NaN(d))
-                d = *cx->runtime->jsNaN;
+                d = js_NaN;
             else if (JSDOUBLE_IS_NEG(d) != JSDOUBLE_IS_NEG(d2))
-                d = *cx->runtime->jsNegativeInfinity;
+                d = js_NegativeInfinity;
             else
-                d = *cx->runtime->jsPositiveInfinity;
+                d = js_PositiveInfinity;
         } else {
             d /= d2;
         }
@@ -8465,7 +8465,7 @@ FoldBinaryNumeric(JSContext *cx, JSOp op, JSParseNode *pn1, JSParseNode *pn2,
 
       case JSOP_MOD:
         if (d2 == 0) {
-            d = *cx->runtime->jsNaN;
+            d = js_NaN;
         } else {
             d = js_fmod(d, d2);
         }
diff --git a/js/src/jsstr.cpp b/js/src/jsstr.cpp
index 5a54d566b29..cf8405850bb 100644
--- a/js/src/jsstr.cpp
+++ b/js/src/jsstr.cpp
@@ -1004,7 +1004,6 @@ out_of_range:
 }
 
 #ifdef JS_TRACER
-extern jsdouble js_NaN;
 
 jsdouble FASTCALL
 js_String_p_charCodeAt(JSString* str, jsdouble d)
diff --git a/js/src/jstracer.cpp b/js/src/jstracer.cpp
index 548be2d9da8..acca03c7365 100644
--- a/js/src/jstracer.cpp
+++ b/js/src/jstracer.cpp
@@ -8659,7 +8659,7 @@ TraceRecorder::equalityHelper(jsval l, jsval r, LIns* l_ins, LIns* r_ins,
                 args[0] = l_ins, args[1] = cx_ins;
                 l_ins = lir->insCall(&js_BooleanOrUndefinedToNumber_ci, args);
                 l = (l == JSVAL_VOID)
-                    ? DOUBLE_TO_JSVAL(cx->runtime->jsNaN)
+                    ? cx->runtime->NaNValue
                     : INT_TO_JSVAL(l == JSVAL_TRUE);
                 return equalityHelper(l, r, l_ins, r_ins, negate,
                                       tryBranchAfterCond, rval);
@@ -8673,7 +8673,7 @@ TraceRecorder::equalityHelper(jsval l, jsval r, LIns* l_ins, LIns* r_ins,
                 args[0] = r_ins, args[1] = cx_ins;
                 r_ins = lir->insCall(&js_BooleanOrUndefinedToNumber_ci, args);
                 r = (r == JSVAL_VOID)
-                    ? DOUBLE_TO_JSVAL(cx->runtime->jsNaN)
+                    ? cx->runtime->NaNValue
                     : INT_TO_JSVAL(r == JSVAL_TRUE);
                 return equalityHelper(l, r, l_ins, r_ins, negate,
                                       tryBranchAfterCond, rval);
diff --git a/js/src/jsxml.cpp b/js/src/jsxml.cpp
index 53df64fa418..de62a2bbfa5 100644
--- a/js/src/jsxml.cpp
+++ b/js/src/jsxml.cpp
@@ -5578,7 +5578,7 @@ xml_childIndex(JSContext *cx, uintN argc, jsval *vp)
     NON_LIST_XML_METHOD_PROLOG;
     parent = xml->parent;
     if (!parent || xml->xml_class == JSXML_CLASS_ATTRIBUTE) {
-        *vp = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);
+        *vp = cx->runtime->NaNValue;
         return JS_TRUE;
     }
     for (i = 0, n = JSXML_LENGTH(parent); i < n; i++) {