Don't MISS if you read the hole from certain FastHoley arrays.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 3244 matching lines @@
 
   // Check for the hole value.
   if (requires_hole_check) {
     if (IsFastSmiElementsKind(hinstr->elements_kind())) {
       Condition smi = __ CheckSmi(result);
       DeoptimizeIf(NegateCondition(smi), instr, Deoptimizer::kNotASmi);
     } else {
       __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
       DeoptimizeIf(equal, instr, Deoptimizer::kHole);
     }
+  } else if (hinstr->hole_mode() == CONVERT_HOLE_TO_UNDEFINED) {
+    DCHECK(hinstr->elements_kind() == FAST_HOLEY_ELEMENTS);
+    Label done;
+    __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
+    __ j(not_equal, &done);
+    if (info()->IsStub()) {
+      // A stub can safely convert the hole to undefined only if the array
+      // protector cell contains (Smi) 1. Otherwise it needs to bail out.
+      __ LoadRoot(result, Heap::kArrayProtectorRootIndex);
+      __ Cmp(FieldOperand(result, Cell::kValueOffset), Smi::FromInt(1));
+      DeoptimizeIf(not_equal, instr, Deoptimizer::kHole);
+    }
+    __ Move(result, isolate()->factory()->undefined_value());
+    __ bind(&done);
   }
 }
 
 
 void LCodeGen::DoLoadKeyed(LLoadKeyed* instr) {
   if (instr->is_typed_elements()) {
     DoLoadKeyedExternalArray(instr);
   } else if (instr->hydrogen()->representation().IsDouble()) {
     DoLoadKeyedFixedDoubleArray(instr);
   } else {
@@ skipping 2641 matching lines @@
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64