Reland of r19102: Check elimination improvement: propagation of state through phis is supported, Che

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 2633 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 
   const Heap::RootListIndex index_;
 };
 
 
 class HCheckMaps V8_FINAL : public HTemplateInstruction<2> {
  public:
   static HCheckMaps* New(Zone* zone, HValue* context, HValue* value,
                          Handle<Map> map, CompilationInfo* info,
-                         HValue *typecheck = NULL);
+                         HValue* typecheck = NULL);
   static HCheckMaps* New(Zone* zone, HValue* context,
                          HValue* value, SmallMapList* maps,
-                         HValue *typecheck = NULL) {
+                         HValue* typecheck = NULL) {
     HCheckMaps* check_map = new(zone) HCheckMaps(value, zone, typecheck);
     for (int i = 0; i < maps->length(); i++) {
       check_map->Add(maps->at(i), zone);
     }
     return check_map;
   }
 
   bool CanOmitMapChecks() { return omit_; }
 
   virtual bool HasEscapingOperandAt(int index) V8_OVERRIDE { return false; }
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::Tagged();
   }
   virtual bool HandleSideEffectDominator(GVNFlag side_effect,
                                          HValue* dominator) V8_OVERRIDE;
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
   HValue* value() { return OperandAt(0); }
+  HValue* typecheck() { return OperandAt(1); }
 
   Unique<Map> first_map() const { return map_set_.at(0); }
   UniqueSet<Map> map_set() const { return map_set_; }
 
+  void set_map_set(UniqueSet<Map>* maps, Zone *zone) {
+    map_set_.Clear();
+    for (int i = 0; i < maps->size(); i++) {
+      map_set_.Add(maps->at(i), zone);
+    }
+  }
+
   bool has_migration_target() const {
     return has_migration_target_;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckMaps)
 
  protected:
   virtual bool DataEquals(HValue* other) V8_OVERRIDE {
     return this->map_set_.Equals(&HCheckMaps::cast(other)->map_set_);
   }
@@ skipping 4738 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_