Add binary-op stub variant to handle oddball objects more efficiently.

src/ic.cc

Index: src/ic.cc
===================================================================
--- src/ic.cc	(revision 7395)
+++ src/ic.cc	(working copy)
@@ -2131,6 +2131,7 @@
     case SMI: return "SMI";
     case INT32: return "Int32s";
     case HEAP_NUMBER: return "HeapNumbers";
+    case ODDBALL: return "Oddball";
     case STRING: return "Strings";
     case GENERIC: return "Generic";
     default: return "Invalid";
@@ -2145,6 +2146,7 @@
     case SMI:
     case INT32:
     case HEAP_NUMBER:
+    case ODDBALL:
     case STRING:
       return MONOMORPHIC;
     case GENERIC:
@@ -2192,6 +2194,10 @@
     return STRING;
   }
 
+  // Check for oddball objects.
+  if (left->IsUndefined() && right->IsNumber()) return ODDBALL;
+  if (left->IsNumber() && right->IsUndefined()) return ODDBALL;
+
   return GENERIC;
 }