[compiler] Initial TurboFan code stubs for abstract relational comparison.

src/compiler/raw-machine-assembler.h

 // 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.
 
 #ifndef V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 #define V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 
 #include "src/assembler.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
@@ skipping 682 matching lines @@
   CallDescriptor* call_descriptor_;
   NodeVector parameters_;
   BasicBlock* current_block_;
 
   DISALLOW_COPY_AND_ASSIGN(RawMachineAssembler);
 };
 
 
 class RawMachineLabel final {
  public:
-  RawMachineLabel();
+  enum Type { kDeferred, kNonDeferred };
+
+  explicit RawMachineLabel(Type type = kNonDeferred)
+      : deferred_(type == kDeferred) {}
   ~RawMachineLabel();
 
  private:
-  BasicBlock* block_;
-  bool used_;
-  bool bound_;
+  BasicBlock* block_ = nullptr;
+  bool used_ = false;
+  bool bound_ = false;
+  bool deferred_;
   friend class RawMachineAssembler;
   DISALLOW_COPY_AND_ASSIGN(RawMachineLabel);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_