Honors Compilers
			 G22.3130 Spring 2000

			     Assignment 7
			     Optimization

			  Due Tuesday, May 2



Your assignment is to implement an optimization, or several
optimizations if you feel ambitious, based on global dataflow
analysis. You may choose an optimization described in the Dragon book
(e.g. CSE, Copy Propagation, Dead Code Elimination, etc.) or any other
that you like.

The dataflow information used for this optimization will have been
computed, of course, by the code you wrote for assignment 6.  Thus,
before starting assignment 6, you will need to choose an optimization.

The optimization phase will take as input a flow graph representing a
procedure and will produce a modified flow graph as output. Your
assembly code generator from assignment 5 will then be used to produce
the (hopefully) improved code.

Output to Turn In
-----------------

You will be given a Pointless program to compile. You shold turn
in:

1. A printout of the flow graph for each procedure in the program (in
   the simple format described in assignment 6), both before and after
   optimization.

2. The assembly code generated with the optimization disabled and with
   the optimization enabled.

3. The test program will contain calls to the C procedure clock(), to
   determine how long the program runs for (type "man clock" on a unix
   machine to see what it does). Submit the running times for the
   program with and without the optimization enabled.