[turbofan] Deferred block spilling heuristic - first step.

src/compiler/instruction.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_INSTRUCTION_H_
 #define V8_COMPILER_INSTRUCTION_H_
 
 #include <deque>
 #include <iosfwd>
 #include <map>
@@ skipping 764 matching lines @@
 
   bool IsNext(const RpoNumber other) const {
     DCHECK(IsValid());
     return other.index_ == this->index_ + 1;
   }
 
   bool operator==(RpoNumber other) const {
     return this->index_ == other.index_;
   }
 
+  bool operator<(RpoNumber other) const { return index_ < other.index_; }
+
+  bool operator>(RpoNumber other) const { return index_ > other.index_; }
+
  private:
   explicit RpoNumber(int32_t index) : index_(index) {}
   int32_t index_;
 };
 
 
 std::ostream& operator<<(std::ostream&, const RpoNumber&);
 
 
 class Constant final {
@@ skipping 408 matching lines @@
 
 
 std::ostream& operator<<(std::ostream& os,
                          const PrintableInstructionSequence& code);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_H_