VectorICs: megamorphic keyed loads in crankshaft don't need a vector.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 64a05167218c7d4f2cd599e2ea07cec495f1d83b..28b8e8e34b3fc163bb6fcbb0e27cdf2679131cfa 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -6716,7 +6716,11 @@ class HLoadKeyedGeneric FINAL : public HTemplateInstruction<3> {
   Handle<TypeFeedbackVector> feedback_vector() const {
     return feedback_vector_;
   }
-  bool HasVectorAndSlot() const { return FLAG_vector_ics; }
+  bool HasVectorAndSlot() const {
+    DCHECK(!FLAG_vector_ics || initialization_state_ == MEGAMORPHIC ||
+           feedback_vector_.is_null());
+    return !feedback_vector_.is_null();
+  }
   void SetVectorAndSlot(Handle<TypeFeedbackVector> vector,
                         FeedbackVectorICSlot slot) {
     DCHECK(FLAG_vector_ics);