Eliminate map checks of constant values.

src/arm/lithium-codegen-arm.cc

 // 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 5212 matching lines @@
                                 Handle<Map> map,
                                 LEnvironment* env) {
   Label success;
   __ CompareMap(map_reg, map, &success);
   DeoptimizeIf(ne, env);
   __ bind(&success);
 }
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
+  if (instr->hydrogen()->CanOmitMapChecks()) return;
   Register map_reg = scratch0();
   LOperand* input = instr->value();
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
 
   Label success;
   SmallMapList* map_set = instr->hydrogen()->map_set();
   __ ldr(map_reg, FieldMemOperand(reg, HeapObject::kMapOffset));
   for (int i = 0; i < map_set->length() - 1; i++) {
     Handle<Map> map = map_set->at(i);
@@ skipping 52 matching lines @@
 
   // smi
   __ bind(&is_smi);
   __ ClampUint8(result_reg, result_reg);
 
   __ bind(&done);
 }
 
 
 void LCodeGen::DoCheckPrototypeMaps(LCheckPrototypeMaps* instr) {
+  if (instr->hydrogen()->CanOmitPrototypeChecks()) return;
+
   Register prototype_reg = ToRegister(instr->temp());
   Register map_reg = ToRegister(instr->temp2());
 
   ZoneList<Handle<JSObject> >* prototypes = instr->prototypes();
   ZoneList<Handle<Map> >* maps = instr->maps();
 
   ASSERT(prototypes->length() == maps->length());
 
-  if (!instr->hydrogen()->CanOmitPrototypeChecks()) {
-    for (int i = 0; i < prototypes->length(); i++) {
-      __ LoadHeapObject(prototype_reg, prototypes->at(i));
-      __ ldr(map_reg, FieldMemOperand(prototype_reg, HeapObject::kMapOffset));
-      DoCheckMapCommon(map_reg, maps->at(i), instr->environment());
-    }
+  for (int i = 0; i < prototypes->length(); i++) {
+    __ LoadHeapObject(prototype_reg, prototypes->at(i));
+    __ ldr(map_reg, FieldMemOperand(prototype_reg, HeapObject::kMapOffset));
+    DoCheckMapCommon(map_reg, maps->at(i), instr->environment());
   }
 }
 
 
 void LCodeGen::DoAllocate(LAllocate* instr) {
   class DeferredAllocate: public LDeferredCode {
    public:
     DeferredAllocate(LCodeGen* codegen, LAllocate* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     virtual void Generate() { codegen()->DoDeferredAllocate(instr_); }
@@ skipping 492 matching lines @@
   __ sub(scratch, result, Operand::PointerOffsetFromSmiKey(index));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal