Add Smi::Zero and replace all Smi::FromInt(0) calls

src/interpreter/interpreter.cc

 // Copyright 2015 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/interpreter/interpreter.h"
 
 #include <fstream>
 #include <memory>
 
 #include "src/ast/prettyprinter.h"
@@ skipping 2382 matching lines @@
 // Returns state for for..in loop execution based on the object in the register
 // |receiver|. The object must not be null or undefined and must have been
 // converted to a receiver already.
 // The result is output in registers |cache_info_triple| to
 // |cache_info_triple + 2|, with the registers holding cache_type, cache_array,
 // and cache_length respectively.
 void Interpreter::DoForInPrepare(InterpreterAssembler* assembler) {
   Node* object_reg = __ BytecodeOperandReg(0);
   Node* receiver = __ LoadRegister(object_reg);
   Node* context = __ GetContext();
-  Node* const zero_smi = __ SmiConstant(Smi::FromInt(0));
+  Node* const zero_smi = __ SmiConstant(Smi::kZero);
 
   Label nothing_to_iterate(assembler, Label::kDeferred),
       use_enum_cache(assembler), use_runtime(assembler, Label::kDeferred);
 
   if (FLAG_debug_code) {
     Label already_receiver(assembler), abort(assembler);
     Node* instance_type = __ LoadInstanceType(receiver);
     __ Branch(__ IsJSReceiverInstanceType(instance_type), &already_receiver,
               &abort);
     __ Bind(&abort);
@@ skipping 221 matching lines @@
   __ StoreObjectField(generator, JSGeneratorObject::kContinuationOffset,
       __ SmiTag(new_state));
   __ SetAccumulator(old_state);
 
   __ Dispatch();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8