INTRODUCTION TO COMPILER DESIGN
OVERVIEW OF COMPILERS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Strength reduction
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Copy propagation
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Constant folding
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Dead code elimination
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Detailed explanation-1: -In software engineering, strength reduction is a compiler optimization where expensive operations are replaced with equivalent but less expensive operations.
Detailed explanation-2: -Strength reduction : There are expressions that consume more CPU cycles, time, and memory. These expressions should be replaced with cheaper expressions without compromising the output of expression. For example, multiplication (x * 2) is expensive in terms of CPU cycles than (x « 1) and yields the same result.
Detailed explanation-3: -Replace P * 32 by P < < 5 => Strength reduction as shifting is faster than multiplication. So B is correct.
Detailed explanation-4: -removing loop invariant computation. replacing run-time computation by compile time computation. replacing a costly operation by a relatively cheaper one. removing common sub-expressions.