Compilers: Principles and Practice by Pearson

Code Optimization 323

and removal of the dead code:

f1(){

int j, a[10];

... ... ...

j = a[4];

... ... ...

}

One important aspect of dead variable or code removal is that if a variable represents result of some

hardware action, e.g. a flag set or reset by a hardware device, then it can get modified due to an

Interrupt Service Routine. To deal with such situations, ANSI C provides a keyword volatile,

which declares a variable whose value may not remain constant.

10.4 Structural Optimization

In this category of optimization methods, the overall structure of the code is analyzed. Generally, such

optimization results in reduction of both Time and ...