Dead code elimination in Compiler Design - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify dead code by checking if a statement's result is {{BLANK_1}}.

Compiler Design

if statement.result == [1]:
    print("Dead code detected")

Drag options to blanks, or click blank then click option'

Anull

Bused

Cactive

Dunused

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing 'used' with 'unused' when checking code usage.

Dead code is code whose result is never used, so checking for unused results helps identify it.

2fill in blank

medium

Complete the code to remove dead code by deleting statements that have no side effect.

Compiler Design

for stmt in program.statements:
    if not stmt.has_side_effect and stmt.result == None:
        program.statements.remove([1])

Drag options to blanks, or click blank then click option'

Aprogram

Bresult

Cstmt

Dside_effect

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to remove the whole program or unrelated attributes.

To remove dead code, we delete the statement itself, so stmt is the correct choice.

3fill in blank

hard

Fix the error in the code that checks if a variable is dead by comparing its use count.

Compiler Design

if variable.[1] == 0:
    mark_as_dead(variable)

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Ause_count

Bdefinition

Cvalue

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Checking variable name or value instead of usage count.

A variable is dead if it is never used, so checking use_count equals zero is correct.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps variables to their usage count only if the count is zero.

Compiler Design

dead_vars = {var: var.[1] for var in variables if var.[2] == 0}

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Ause_count

Bvalue

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names or values instead of usage count.

The dictionary maps variables to their use_count if the use_count is zero, indicating dead variables.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps variable names in uppercase to their usage count, but only if the usage count is zero.

Compiler Design

dead_vars = { [1]: [2] for var in variables if var.[3] == 0}

Drag options to blanks, or click blank then click option'

Avar.name.upper()

Bvar.use_count

Cuse_count

Dvar.name

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names without uppercase or wrong property names.

The comprehension uses var.name.upper() as keys, var.use_count as values, and filters where use_count is zero.