Experimental: begin using the register allocator for switch statements...

src/virtual-frame-ia32.h

 // Copyright 2008 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 333 matching lines @@
   void CallCodeObject(Handle<Code> ic,
                       RelocInfo::Mode rmode,
                       int frame_arg_count);
 
   // Drop a number of elements from the top of the expression stack.  May
   // emit code to affect the physical frame.  Does not clobber any registers
   // excepting possibly the stack pointer.
   void Drop(int count);
 
   // Drop one element.
-  void Drop();
+  void Drop() { Drop(1); }
+
+  // Duplicate the top element of the frame.
+  void Dup() { LoadFrameSlotAt(elements_.length() - 1); }
 
   // Pop an element from the top of the expression stack.
   // Returns a Result, which may be a constant or a register.
   Result Pop();
 
   // Pop and save an element from the top of the expression stack and emit a
   // corresponding pop instruction.
   void EmitPop(Register reg);
   void EmitPop(Operand operand);
 
@@ skipping 143 matching lines @@
   // Called after all register-to-memory and register-to-register
   // moves have been made.  After this function returns, the frames
   // should be equal.
   void MergeMoveMemoryToRegisters(VirtualFrame *expected);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_VIRTUAL_FRAME_IA32_H_