Eliminate map checks of constant values.

src/ia32/lithium-codegen-ia32.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 5784 matching lines @@
                                 Handle<Map> map,
                                 LInstruction* instr) {
   Label success;
   __ CompareMap(reg, map, &success);
   DeoptimizeIf(not_equal, instr->environment());
   __ bind(&success);
 }
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
+  if (instr->hydrogen()->CanOmitMapChecks()) return;
   LOperand* input = instr->value();
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
 
   Label success;
   SmallMapList* map_set = instr->hydrogen()->map_set();
   for (int i = 0; i < map_set->length() - 1; i++) {
     Handle<Map> map = map_set->at(i);
     __ CompareMap(reg, map, &success);
     __ j(equal, &success);
@@ skipping 170 matching lines @@
   if (!input_reg.is(result_reg)) {
     __ mov(result_reg, input_reg);
   }
   __ SmiUntag(result_reg);
   __ ClampUint8(result_reg);
   __ bind(&done);
 }
 
 
 void LCodeGen::DoCheckPrototypeMaps(LCheckPrototypeMaps* instr) {
+  if (instr->hydrogen()->CanOmitPrototypeChecks()) return;
   Register reg = ToRegister(instr->temp());
 
   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(reg, prototypes->at(i));
-      DoCheckMapCommon(reg, maps->at(i), instr);
-    }
+  for (int i = 0; i < prototypes->length(); i++) {
+    __ LoadHeapObject(reg, prototypes->at(i));
+    DoCheckMapCommon(reg, maps->at(i), instr);
   }
 }
 
 
 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 484 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32