[turbofan] Fix length in LowerJSCreateLiteralObject.

src/compiler/js-generic-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/code-stubs.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/js-generic-lowering.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 645 matching lines @@
   } else {
     node->InsertInput(zone(), 3, jsgraph()->SmiConstant(p.flags()));
     ReplaceWithRuntimeCall(node, Runtime::kCreateArrayLiteral);
   }
 }
 
 
 void JSGenericLowering::LowerJSCreateLiteralObject(Node* node) {
   CreateLiteralParameters const& p = CreateLiteralParametersOf(node->op());
   CallDescriptor::Flags flags = AdjustFrameStatesForCall(node);
-  int const length = Handle<FixedArray>::cast(p.constant())->length();
+  // Constants are pairs, see ObjectLiteral::properties_count().
+  int const length = Handle<FixedArray>::cast(p.constant())->length() / 2;
   node->InsertInput(zone(), 1, jsgraph()->SmiConstant(p.index()));
   node->InsertInput(zone(), 2, jsgraph()->HeapConstant(p.constant()));
   node->InsertInput(zone(), 3, jsgraph()->SmiConstant(p.flags()));
 
   // Use the FastCloneShallowObjectStub only for shallow boilerplates without
   // elements up to the number of properties that the stubs can handle.
   if ((p.flags() & ObjectLiteral::kShallowProperties) != 0 &&
       length <= FastCloneShallowObjectStub::kMaximumClonedProperties) {
     Callable callable = CodeFactory::FastCloneShallowObject(isolate(), length);
     ReplaceWithStubCall(node, callable, flags);
@@ skipping 186 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSGenericLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8