When clearing filled call target caches we should go back to the

src/objects.cc

Index: src/objects.cc
===================================================================
--- src/objects.cc	(revision 19457)
+++ src/objects.cc	(working copy)
@@ -10637,12 +10637,16 @@
   if (raw_info->IsTypeFeedbackInfo()) {
     FixedArray* feedback_vector =
         TypeFeedbackInfo::cast(raw_info)->feedback_vector();
+    Object* premonomorphic_sentinel =
+        TypeFeedbackInfo::RawPremonomorphicSentinel(heap);
     for (int i = 0; i < feedback_vector->length(); i++) {
       Object* obj = feedback_vector->get(i);
-      if (!obj->IsAllocationSite()) {
-        // TODO(mvstanton): Can't I avoid a write barrier for this sentinel?
-        feedback_vector->set(i,
-                             TypeFeedbackInfo::RawUninitializedSentinel(heap));
+      // If the cache is monomorphic (non-arrays) or megamorphic we go
+      // back to premonomorphic.
+      ASSERT_EQ(*TypeFeedbackInfo::MegamorphicSentinel(heap->isolate()),
+          heap->undefined_value());
+      if (obj->IsUndefined() || obj->IsJSFunction()) {
+        feedback_vector->set(i, premonomorphic_sentinel, SKIP_WRITE_BARRIER);
       }
     }
   }