Revert r10118 from bleeding edge.

src/hydrogen-instructions.h

 // 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 1253 matching lines @@
   }
   int ast_id_;
   int pop_count_;
   ZoneList<HValue*> values_;
   ZoneList<int> assigned_indexes_;
 };
 
 
 class HStackCheck: public HTemplateInstruction<1> {
  public:
-  explicit HStackCheck(HValue* context) {
+  enum Type {
+    kFunctionEntry,
+    kBackwardsBranch
+  };
+
+  HStackCheck(HValue* context, Type type) : type_(type) {
     SetOperandAt(0, context);
   }
 
   HValue* context() { return OperandAt(0); }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
 
   void Eliminate() {
     // The stack check eliminator might try to eliminate the same stack
     // check instruction multiple times.
     if (IsLinked()) {
       DeleteFromGraph();
     }
   }
 
+  bool is_function_entry() { return type_ == kFunctionEntry; }
+  bool is_backwards_branch() { return type_ == kBackwardsBranch; }
+
   DECLARE_CONCRETE_INSTRUCTION(StackCheck)
+
+ private:
+  Type type_;
 };
 
 
 class HEnterInlined: public HTemplateInstruction<0> {
  public:
   HEnterInlined(Handle<JSFunction> closure,
                 FunctionLiteral* function,
                 CallKind call_kind)
       : closure_(closure),
         function_(function),
@@ skipping 3112 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_