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Problem 4 Solution

(30 points)

    1. (10 points) Given the following C program, construct the dominator tree and postdominator tree.
Read A:LSR = 1 : RSR=A
SR = (LSR+RSR)/2
Repeat (
T=SR*SR:
IF (T>A) RSR =SR:
else if (LSR=SR:RSR=SR)
SR=(LSR+RSR)/2
Untill 9LSR/RSR)”
Print SR:
)

2 (10 pts) 2. Given the statement-based control graph for the program (a) construct the control-dependence graph for the program.



B1    1.    A=1

2.    B=2




B2
3.
C=A+B

4.
D=C-A







5. D=B*D
B3




T
F

B5








6.
D=A+B


8.
B=A+B
F
7.
E=E+1


9.
E=C-A








B4




T


















B6
10.
A=B*D





11.
B=A-D























    3. (10 points) Given the program from 2a, construct the program-dependence graph using data dependence and control dependence for the program.















2

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