[turbofan] optimize moves into merges

src/compiler/register-allocator-verifier.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/bit-vector.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/register-allocator-verifier.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 227 matching lines @@
 };
 
 class PhiMap : public ZoneMap<int, PhiData*>, public ZoneObject {
  public:
   explicit PhiMap(Zone* zone) : ZoneMap<int, PhiData*>(zone) {}
 };
 
 struct OperandLess {
   bool operator()(const InstructionOperand* a,
                   const InstructionOperand* b) const {
-    if (a->kind() == b->kind()) return a->index() < b->index();
-    return a->kind() < b->kind();
+    return *a < *b;
   }
 };
 
 class OperandMap : public ZoneObject {
  public:
   struct MapValue : public ZoneObject {
     MapValue()
         : incoming(nullptr),
           define_vreg(kInvalidVreg),
           use_vreg(kInvalidVreg),
@@ skipping 401 matching lines @@
         int virtual_register = op_constraints[count].virtual_register_;
         current->Define(zone(), instr->OutputAt(i), virtual_register);
       }
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8