Ensure newly allocated empty Arrays are transitioned to FAST_ELEMENT

test/mjsunit/elements-kind.js

Index: test/mjsunit/elements-kind.js
diff --git a/test/mjsunit/elements-kind.js b/test/mjsunit/elements-kind.js
index e5b5a66c44eba60951c683717d71577b796717e3..40a8d69f77258aff397d13692127b6a115da8bed 100644
--- a/test/mjsunit/elements-kind.js
+++ b/test/mjsunit/elements-kind.js
@@ -39,9 +39,19 @@ support_smi_only_arrays = %HasFastSmiOnlyElements([1,2,3,4,5,6,7,8,9,10]);
 if (support_smi_only_arrays) {
   print("Tests include smi-only arrays.");
 } else {
-  print("Tests do NOT include smi-only arrays.");

[Jakob Kummerow, 2012/01/04 20:55:17]

intentional removal?

+  print("Tests do NOT include smi-only.");
 }
 
+// Ensure that there is a global bais for not aggressively transitioning Arrays

[Jakob Kummerow, 2012/01/04 20:55:17]

suggestion: "Ensure that Arrays default to SMI_ONLY elements."

+// to FAST_ELEMENTs.
+// TODO(danno): Remove this code when bias for early ElementsKind transition is
+// tracked per allocation site and not globally.
+[1,2,3][0] = 1.5;
+[1,2,3][0] = 1.5;
+[1,2,3][0] = 1.5;
+[1,2,3][0] = 1.5;
+[1,2,3][0] = 1.5;
+
 var elements_kind = {
   fast_smi_only            :  'fast smi only elements',
   fast                     :  'fast elements',
@@ -115,7 +125,7 @@ too.drink = 0xC0C0A;
 assertKind(elements_kind.fast_smi_only, too);
 
 // Make sure the element kind transitions from smionly when a non-smi is stored.
-var you = new Array();
+var you = new Array(1);
 assertKind(elements_kind.fast_smi_only, you);
 for (var i = 0; i < 1337; i++) {
   var val = i;