Simplify CheckPrototypeMaps.

src/arm/lithium-codegen-arm.cc

 // Copyright 2011 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 2492 matching lines @@
   DeoptimizeIf(ne, instr->environment());
 }
 
 
 void LCodeGen::LoadPrototype(Register result,
                              Handle<JSObject> prototype) {
   if (Heap::InNewSpace(*prototype)) {
     Handle<JSGlobalPropertyCell> cell =
         Factory::NewJSGlobalPropertyCell(prototype);
     __ mov(result, Operand(cell));
+    __ ldr(result, FieldMemOperand(result, JSGlobalPropertyCell::kValueOffset));
   } else {
     __ mov(result, Operand(prototype));
   }
 }
 
 
 void LCodeGen::DoCheckPrototypeMaps(LCheckPrototypeMaps* instr) {
   Register temp1 = ToRegister(instr->temp1());
   Register temp2 = ToRegister(instr->temp2());
 
   Handle<JSObject> holder = instr->holder();
-  Handle<Map> receiver_map = instr->receiver_map();
-  Handle<JSObject> current_prototype(JSObject::cast(receiver_map->prototype()));
+  Handle<JSObject> current_prototype = instr->prototype();
 
   // Load prototype object.
   LoadPrototype(temp1, current_prototype);
 
   // Check prototype maps up to the holder.
   while (!current_prototype.is_identical_to(holder)) {
     __ ldr(temp2, FieldMemOperand(temp1, HeapObject::kMapOffset));
     __ cmp(temp2, Operand(Handle<Map>(current_prototype->map())));
     DeoptimizeIf(ne, instr->environment());
     current_prototype =
@@ skipping 294 matching lines @@
 
 
 void LCodeGen::DoOsrEntry(LOsrEntry* instr) {
   Abort("DoOsrEntry unimplemented.");
 }
 
 
 #undef __
 
 } }  // namespace v8::internal