Always require exact maps.

src/x64/lithium-codegen-x64.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 103 matching lines @@
   void DoDeferredMathAbsTaggedHeapNumber(LUnaryMathOperation* instr);
   void DoDeferredStackCheck(LStackCheck* instr);
   void DoDeferredRandom(LRandom* instr);
   void DoDeferredStringCharCodeAt(LStringCharCodeAt* instr);
   void DoDeferredStringCharFromCode(LStringCharFromCode* instr);
   void DoDeferredAllocateObject(LAllocateObject* instr);
   void DoDeferredAllocate(LAllocate* instr);
   void DoDeferredInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr,
                                        Label* map_check);
 
-  void DoCheckMapCommon(Register reg, Handle<Map> map,
-                        CompareMapMode mode, LInstruction* instr);
+  void DoCheckMapCommon(Register reg, Handle<Map> map, LInstruction* instr);
 
 // Parallel move support.
   void DoParallelMove(LParallelMove* move);
   void DoGap(LGap* instr);
 
   // Emit frame translation commands for an environment.
   void WriteTranslation(LEnvironment* environment,
                         Translation* translation,
                         int* arguments_index,
                         int* arguments_count);
@@ skipping 304 matching lines @@
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_LITHIUM_CODEGEN_X64_H_