Directly use C++ builtin of ArrayPush for String.prototype.split.

src/string.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 626 matching lines @@
     return result;
   }
 
   if (limit === 0) return [];
 
   // Separator is a regular expression.
   return StringSplitOnRegExp(subject, separator, limit, length);
 }
 
 
+var ArrayPushBuiltin = $Array.prototype.push;
+
 function StringSplitOnRegExp(subject, separator, limit, length) {
   %_Log('regexp', 'regexp-split,%0S,%1r', [subject, separator]);
 
   if (length === 0) {
     if (DoRegExpExec(separator, subject, 0, 0) != null) {
       return [];
     }
     return [subject];
   }
 
   var currentIndex = 0;
   var startIndex = 0;
   var startMatch = 0;
-  var result = new InternalArray();
+  var result = [];
 
   outer_loop:
   while (true) {
 
     if (startIndex === length) {
-      result.push(%_SubString(subject, currentIndex, length));
+      %_CallFunction(result, %_SubString(subject, currentIndex, length),
+                     ArrayPushBuiltin);
       break;
     }
 
     var matchInfo = DoRegExpExec(separator, subject, startIndex);
     if (matchInfo == null || length === (startMatch = matchInfo[CAPTURE0])) {
-      result.push(%_SubString(subject, currentIndex, length));
+      %_CallFunction(result, %_SubString(subject, currentIndex, length),
+                     ArrayPushBuiltin);
       break;
     }
     var endIndex = matchInfo[CAPTURE1];
 
     // We ignore a zero-length match at the currentIndex.
     if (startIndex === endIndex && endIndex === currentIndex) {
       startIndex++;
       continue;
     }
 
-    result.push(%_SubString(subject, currentIndex, startMatch));
+    %_CallFunction(result, %_SubString(subject, currentIndex, startMatch),
+                   ArrayPushBuiltin);
 
     if (result.length === limit) break;
 
     var matchinfo_len = NUMBER_OF_CAPTURES(matchInfo) + REGEXP_FIRST_CAPTURE;
     for (var i = REGEXP_FIRST_CAPTURE + 2; i < matchinfo_len; ) {
       var start = matchInfo[i++];
       var end = matchInfo[i++];
       if (end != -1) {
-        result.push(%_SubString(subject, start, end));
+        %_CallFunction(result, %_SubString(subject, start, end),
+                       ArrayPushBuiltin);
       } else {
-        result.push(void 0);
+        %_CallFunction(result, void 0, ArrayPushBuiltin);
       }
       if (result.length === limit) break outer_loop;
     }
 
     startIndex = currentIndex = endIndex;
   }
-  return %MoveArrayContents(result, []);
+  return result;
 }
 
 
 // ECMA-262 section 15.5.4.15
 function StringSubstring(start, end) {
   if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) {
     throw MakeTypeError("called_on_null_or_undefined",
                         ["String.prototype.subString"]);
   }
   var s = TO_STRING_INLINE(this);
@@ skipping 288 matching lines @@
     "fixed", StringFixed,
     "italics", StringItalics,
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup
   ));
 }
 
 SetUpString();