Don't pre-initialise block contexts with holes

src/compiler/js-typed-lowering.cc

 // Copyright 2014 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/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/linkage.h"
@@ skipping 2050 matching lines @@
         context, context, effect);
     AllocationBuilder a(jsgraph(), effect, control);
     STATIC_ASSERT(Context::MIN_CONTEXT_SLOTS == 4);  // Ensure fully covered.
     a.AllocateArray(context_length, factory()->block_context_map());
     a.Store(AccessBuilder::ForContextSlot(Context::CLOSURE_INDEX), closure);
     a.Store(AccessBuilder::ForContextSlot(Context::PREVIOUS_INDEX), context);
     a.Store(AccessBuilder::ForContextSlot(Context::EXTENSION_INDEX), extension);
     a.Store(AccessBuilder::ForContextSlot(Context::NATIVE_CONTEXT_INDEX),
             native_context);
     for (int i = Context::MIN_CONTEXT_SLOTS; i < context_length; ++i) {
-      a.Store(AccessBuilder::ForContextSlot(i), jsgraph()->TheHoleConstant());
+      a.Store(AccessBuilder::ForContextSlot(i), jsgraph()->UndefinedConstant());
     }
     RelaxControls(node);
     a.FinishAndChange(node);
     return Changed(node);
   }
 
   return NoChange();
 }
 
 
@@ skipping 770 matching lines @@
 }
 
 
 CompilationDependencies* JSTypedLowering::dependencies() const {
   return dependencies_;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8