Don't add code dependencies eagerly for HCheckMaps.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 "v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "x64/lithium-codegen-x64.h"
 #include "code-stubs.h"
@@ skipping 4995 matching lines @@
       codegen()->DoDeferredInstanceMigration(instr_, object_);
     }
     Label* check_maps() { return &check_maps_; }
     virtual LInstruction* instr() V8_OVERRIDE { return instr_; }
    private:
     LCheckMaps* instr_;
     Label check_maps_;
     Register object_;
   };
 
-  if (instr->hydrogen()->CanOmitMapChecks()) return;
+  if (instr->hydrogen()->IsStabilityCheck()) {
+    const UniqueSet<Map>* maps = instr->hydrogen()->maps();
+    for (int i = 0; i < maps->size(); ++i) {
+      AddStabilityDependency(maps->at(i).handle());
+    }
+    return;
+  }
 
   LOperand* input = instr->value();
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
 
   DeferredCheckMaps* deferred = NULL;
-  if (instr->hydrogen()->has_migration_target()) {
+  if (instr->hydrogen()->HasMigrationTarget()) {
     deferred = new(zone()) DeferredCheckMaps(this, instr, reg);
     __ bind(deferred->check_maps());
   }
 
   const UniqueSet<Map>* maps = instr->hydrogen()->maps();
   Label success;
   for (int i = 0; i < maps->size() - 1; i++) {
     Handle<Map> map = maps->at(i).handle();
     __ CompareMap(reg, map);
     __ j(equal, &success, Label::kNear);
   }
 
   Handle<Map> map = maps->at(maps->size() - 1).handle();
   __ CompareMap(reg, map);
-  if (instr->hydrogen()->has_migration_target()) {
+  if (instr->hydrogen()->HasMigrationTarget()) {
     __ j(not_equal, deferred->entry());
   } else {
     DeoptimizeIf(not_equal, instr->environment());
   }
 
   __ bind(&success);
 }
 
 
 void LCodeGen::DoClampDToUint8(LClampDToUint8* instr) {
@@ skipping 649 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64