Structural Optimization

Question 1

What is the first optimization?

Answer 1

Strength Reduction

Question 2

What is the second optimization?

Answer 2

Loop Unwinding

Question 3

What is the third optimization?

Answer 3

Loop-Invariant Code Motion

Question 4

What is the fourth optimization?

Answer 4

Copy Propagation

Question 5

What is the fifth optimization?

Answer 5

Tail-Recursion Removal

Question 6

What is an example of strength reduction?

Answer 6

Simplifying mathematical operations, such as:
- changing multiplication by powers of 2 to bit shift
- changing small multiplication values to several addition functions

Question 7

What is an example of loop unwinding?

Answer 7

Reducing the number of iterations a loop needs to complete, such as:
- if a loop executes twice, remove the loop and add the body twice
- if a loop has only a method calling using the declared variable, and has a significant number of iterations to complete, reduce the number of iterations by calling the method several times with the updated value as needed

Question 8

What is an example of loop-invariant code motion?

Answer 8

Moving constant operations that never change outside of the loop, so that they are only calculated once

Question 9

What is an example of copy propagation?

Answer 9

When a variable is assigned a value, but the variable is never used, ignore the variable and in its place you the assigned value

Question 10

What is an example of tail-recursion removal?

Answer 10

Converting the function using tail-recursion to a loop, where the needed variables are declared outside the loop