diff --git a/src/runtime.js b/src/runtime.js
index 8e3883f..3e4d473 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -559,20 +559,15 @@
 // ES5, section 9.12
 function SameValue(x, y) {
   if (typeof x != typeof y) return false;
-  if (IS_NULL_OR_UNDEFINED(x)) return true;
   if (IS_NUMBER(x)) {
     if (NUMBER_IS_NAN(x) && NUMBER_IS_NAN(y)) return true;
-    // x is +0 and y is -0 or vice versa
-    if (x === 0 && y === 0 && !%_IsSmi(x) && !%_IsSmi(y) &&
-        ((1 / x < 0 && 1 / y > 0) || (1 / x > 0 && 1 / y < 0))) {
+    // x is +0 and y is -0 or vice versa.
+    if (x === 0 && y === 0 && (1 / x) != (1 / y)) {
       return false;
     }
-    return x == y;
+    return x === y;
   }
-  if (IS_STRING(x)) return %StringEquals(x, y);
-  if (IS_BOOLEAN(x))return %NumberEquals(%ToNumber(x),%ToNumber(y));
-
-  return %_ObjectEquals(x, y);
+  return x === y
 }