Built-in apply() performance benefits from an uninitialized IC.

src/mips/builtins-mips.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 "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
@@ skipping 1381 matching lines @@
 }
 
 
 static void Generate_PushAppliedArguments(MacroAssembler* masm,
                                           const int argumentsOffset,
                                           const int indexOffset,
                                           const int limitOffset) {
   Label entry, loop;
   Register receiver = LoadDescriptor::ReceiverRegister();
   Register key = LoadDescriptor::NameRegister();
+  Register slot = LoadDescriptor::SlotRegister();
+  Register vector = LoadWithVectorDescriptor::VectorRegister();
 
   __ lw(key, MemOperand(fp, indexOffset));
   __ Branch(&entry);
 
   // Load the current argument from the arguments array.
   __ bind(&loop);
   __ lw(receiver, MemOperand(fp, argumentsOffset));
 
   // Use inline caching to speed up access to arguments.
-  Handle<Code> ic = masm->isolate()->builtins()->KeyedLoadIC_Megamorphic();
+  FeedbackVectorSpec spec(0, Code::KEYED_LOAD_IC);
+  Handle<TypeFeedbackVector> feedback_vector =
+      masm->isolate()->factory()->NewTypeFeedbackVector(&spec);
+  int index = feedback_vector->GetIndex(FeedbackVectorICSlot(0));
+  __ li(slot, Operand(Smi::FromInt(index)));
+  __ li(vector, feedback_vector);
+  Handle<Code> ic = KeyedLoadICStub(masm->isolate()).GetCode();
   __ Call(ic, RelocInfo::CODE_TARGET);
 
   __ push(v0);
 
   // Use inline caching to access the arguments.
   __ lw(key, MemOperand(fp, indexOffset));
   __ Addu(key, key, Operand(1 << kSmiTagSize));
   __ sw(key, MemOperand(fp, indexOffset));
 
   // Test if the copy loop has finished copying all the elements from the
@@ skipping 408 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS