Don't add code dependencies eagerly for HCheckMaps.

src/x64/lithium-x64.cc

 // Copyright 2012 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 "lithium-allocator-inl.h"
 #include "x64/lithium-x64.h"
@@ skipping 1917 matching lines @@
 }
 
 
 LInstruction* LChunkBuilder::DoCheckValue(HCheckValue* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
   return AssignEnvironment(new(zone()) LCheckValue(value));
 }
 
 
 LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
-  LOperand* value = NULL;
-  if (!instr->CanOmitMapChecks()) {
-    value = UseRegisterAtStart(instr->value());
-    if (instr->has_migration_target()) info()->MarkAsDeferredCalling();
-  }
-  LInstruction* result = new(zone()) LCheckMaps(value);
-  if (!instr->CanOmitMapChecks()) {
-    result = AssignEnvironment(result);
-    if (instr->has_migration_target()) result = AssignPointerMap(result);
+  if (instr->IsStabilityCheck()) return new(zone()) LCheckMaps;
+  LOperand* value = UseRegisterAtStart(instr->value());
+  LInstruction* result = AssignEnvironment(new(zone()) LCheckMaps(value));
+  if (instr->HasMigrationTarget()) {
+    info()->MarkAsDeferredCalling();
+    result = AssignPointerMap(result);
   }
   return result;
 }
 
 
 LInstruction* LChunkBuilder::DoClampToUint8(HClampToUint8* instr) {
   HValue* value = instr->value();
   Representation input_rep = value->representation();
   LOperand* reg = UseRegister(value);
   if (input_rep.IsDouble()) {
@@ skipping 631 matching lines @@
   LOperand* index = UseTempRegister(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64