Calls to HCheckFunction can be eliminated if the value is an HConstant.

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 2819 matching lines @@
     SetFlag(kUseGVN);
     target_in_new_space_ = Isolate::Current()->heap()->InNewSpace(*function);
   }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
   virtual void PrintDataTo(StringStream* stream);
   virtual HType CalculateInferredType();
 
+  virtual HValue* Canonicalize();
+
 #ifdef DEBUG
   virtual void Verify();
 #endif
 
   virtual void FinalizeUniqueValueId() {
     target_unique_id_ = UniqueValueId(target_);
   }
 
   Handle<JSFunction> target() const { return target_; }
   bool target_in_new_space() const { return target_in_new_space_; }
@@ skipping 553 matching lines @@
     }
   }
 
   virtual void FinalizeUniqueValueId() {
     if (!has_double_value_) {
       ASSERT(!handle_.is_null());
       unique_id_ = UniqueValueId(handle_);
     }
   }
 
+  bool UniqueValueIdsMatch(UniqueValueId other) {
+    if (!has_double_value_) return unique_id_ == other;

[Sven Panne, 2013/07/17 08:09:56]

return !has_double_value_ && unique_id_ == other;

[mvstanton, 2013/07/17 08:45:46]

Done.

+    return false;
+  }
+
 #ifdef DEBUG
   virtual void Verify() { }
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(Constant)
 
  protected:
   virtual Range* InferRange(Zone* zone);
 
   virtual bool DataEquals(HValue* other) {
@@ skipping 3215 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_