Elide hole checks on KeyedLoads of holey double arrays.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 1b4ed5b3b572e8b7cb17b85bddf6479496ef692b..5d9fd23bdbc6363e818a7e7bbb37bcde04fa5b7c 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4968,7 +4968,10 @@ class DependentCode: public FixedArray {
     // described by this map changes shape (and transitions to a new map),
     // possibly invalidating the assumptions embedded in the code.
     kPrototypeCheckGroup,
-    kGroupCount = kPrototypeCheckGroup + 1
+    // Group of code that depends on elements not being added to objects with
+    // this map.
+    kElementsCantBeAddedGroup,
+    kGroupCount = kElementsCantBeAddedGroup + 1
   };
 
   // Array for holding the index of the first code object of each group.
@@ -5500,6 +5503,8 @@ class Map: public HeapObject {
   inline void AddDependentCode(DependentCode::DependencyGroup group,
                                Handle<Code> code);
 
+  bool IsMapInArrayPrototypeChain();
+
   // Dispatched behavior.
   DECLARE_PRINTER(Map)
   DECLARE_VERIFIER(Map)