Backout b85379036da2 because of test failures

js/src/jit-test/tests/basic/mathRoundBig.js

@@ -1,7 +0,0 @@
-/*
- * Any copyright is dedicated to the Public Domain.
- * http://creativecommons.org/licenses/publicdomain/
- */
-
-assertEq(Math.round(9007199254740991), 9007199254740991);
-assertEq(Math.round(-19007199254740990), -19007199254740990);

js/src/jsmath.cpp

@@ -577,30 +577,26 @@ js_copysign(double x, double y)
 }
 #endif
 
+jsdouble
+js_math_round_impl(jsdouble x)
+{
+    return js_copysign(floor(x + 0.5), x);
+}
+
 JSBool
 js_math_round(JSContext *cx, uintN argc, Value *vp)
 {
-    CallArgs args = CallArgsFromVp(argc, vp);
+    jsdouble x, z;
 
-    if (args.length() == 0) {
-        args.rval().setDouble(js_NaN);
-        return true;
+    if (argc == 0) {
+        vp->setDouble(js_NaN);
+        return JS_TRUE;
     }
-
-    double x;
-    if (!ToNumber(cx, args[0], &x))
-        return false;
-
-    jsdpun u;
-    u.d = x;
-    /* Some numbers are so big that adding 0.5 would give the wrong number */
-    if ((u.s.hi & JSDOUBLE_HI32_EXPMASK) > 52) {
-        args.rval().setNumber(x);
-        return true;
-    }
-
-    args.rval().setNumber(js_copysign(floor(x + 0.5), x));
-    return true;
+    if (!ToNumber(cx, vp[2], &x))
+        return JS_FALSE;
+    z = js_copysign(floor(x + 0.5), x);
+    vp->setNumber(z);
+    return JS_TRUE;
 }
 
 static JSBool

js/src/jsmath.h

@@ -121,4 +121,7 @@ js_math_ceil_impl(jsdouble x);
 extern jsdouble
 js_math_floor_impl(jsdouble x);
 
+extern jsdouble
+js_math_round_impl(jsdouble x);
+
 #endif /* jsmath_h___ */