Remove prototype checks for leaf maps in optimized code.

src/hydrogen-instructions.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 2549 matching lines @@
     // Dereferencing to use the object's raw address for hashing is safe.
     AllowHandleDereference allow_handle_deref;
     intptr_t hash = 0;
     for (int i = 0; i < prototypes_.length(); i++) {
       hash = 17 * hash + reinterpret_cast<intptr_t>(*prototypes_[i]);
       hash = 17 * hash + reinterpret_cast<intptr_t>(*maps_[i]);
     }
     return hash;
   }
 
+  bool CanOmitPrototypeChecks() {
+    for (int i = 0; i < maps()->length(); i++) {
+      if (!maps()->at(i)->CanOmitPrototypeChecks()) return false;
+    }
+    return true;
+  }
+
  protected:
   virtual bool DataEquals(HValue* other) {
     HCheckPrototypeMaps* b = HCheckPrototypeMaps::cast(other);
 #ifdef DEBUG
     if (prototypes_.length() != b->prototypes()->length()) return false;
     for (int i = 0; i < prototypes_.length(); i++) {
       if (!prototypes_[i].is_identical_to(b->prototypes()->at(i))) return false;
       if (!maps_[i].is_identical_to(b->maps()->at(i))) return false;
     }
     return true;
@@ skipping 3163 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_