Fix bogus deopt in BuildEmitDeepCopy for holey arrays.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 097216ef830b9660042ee31ee2bb82a618ca5e23..4cf86136bdce2d612d254b1e8b57b234c76e57de 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -11012,9 +11012,11 @@ void HOptimizedGraphBuilder::BuildEmitDeepCopy(
             AddInstruction(new(zone) HConstant(i, Representation::Integer32()));
         HInstruction* value_instruction =
             AddInstruction(new(zone) HLoadKeyed(
-                boilerplate_elements, key_constant, NULL, kind));
-        AddInstruction(new(zone) HStoreKeyed(
+                boilerplate_elements, key_constant, NULL, kind,
+                ALLOW_RETURN_HOLE));
+        HInstruction* store = AddInstruction(new(zone) HStoreKeyed(
                 object_elements, key_constant, value_instruction, kind));
+        store->ClearFlag(HValue::kDeoptimizeOnUndefined);
       }
     } else if (elements->IsFixedArray()) {
       Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
@@ -11037,7 +11039,8 @@ void HOptimizedGraphBuilder::BuildEmitDeepCopy(
         } else {
           HInstruction* value_instruction =
               AddInstruction(new(zone) HLoadKeyed(
-                  boilerplate_elements, key_constant, NULL, kind));
+                  boilerplate_elements, key_constant, NULL, kind,
+                  ALLOW_RETURN_HOLE));
           AddInstruction(new(zone) HStoreKeyed(
               object_elements, key_constant, value_instruction, kind));
         }