CS 640 Fall 201l
HW #1
Due Sept 27 at classtime

1. For the code below, perform Local Value Numbering (including constant calculations) and show what redundancies are exposed. Do the same for DAG construction.

   a = x + y
   b = x - y
   c = a * b
   d = x + y
   e = d - c
   f = e + c
   

2. To do super-local value numbering, the extended basic blocks in a CFG must be found.
   • Give the extended basic blocks for these two CFGs.
   • How can we take advantage of the existence of exended basic blocks in a CFG?
3. For the same two CFGs as question 2, draw spanning trees and IDOM trees. Give the dominance frontiers for the nodes in the graphs.