COMPUTER SCIENCE AND ENGINEERING
COMPILER DESIGN
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A basic block is a sequence of instructions where control enters the sequence at the beginning and exits at the end.
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Available expression analysis can be used for common subexpression elimination
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Live variable analysis can be used for dead code elimination.
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x = 4 ∗ 5 => x = 20 is an example of common subexpression elimination
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Detailed explanation-1: -x = 4 × 5 ⇒ x = 20 ‘is an example of common subexpression elimination.] is False. is called the “constant folding” technique of compiler optimization.
Detailed explanation-2: -(D) x = 4 ∗ 5 => x = 20 is an example of common subexpression elimination. Explanation: (A) A basic block is a sequence of instructions where control enters the sequence at the beginning and exits at the end is TRUE.
Detailed explanation-3: -Common Sub-expression elimination. Dead code elimination. Code movement. Strength reduction.
Detailed explanation-4: -Common Subexpression Elimination is an optimization that searches for instances of identical expressions, and replaces them with a single variable holding the computed value.
Detailed explanation-5: -Dead code elimination is a compiler optimization to remove code which does not affect the program results. Live variable analysis is a classic data-flow analysis to calculate the variables that are live at each point in the program. Hence, is efficient for Dead code elimination.