Compilers: Principles and Practice by Pearson

Introduction 19

1.6.5 Optimization

What we have done above is Optimization. There are two types of optimization – machine-

independent and machine-dependent optimizations. There are several possibilities of optimization:

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register allocation,

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taking invariant code outside loops,

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operator rank reduction (e.g. add instead of mult),

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constant expression calculation (e.g. a = 3.142 * 56, RHS done at compile time),

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removal of dead code,

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rolling out a loop, etc.

Several types and levels of optimization are available in GNU C compiler, as briefly indicated in

Section. 1.7.

1.6.6 How to Develop Optimized Code?

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First get your code working ...