COMPILE METHOD USING COPY PROPAGATION OF A VARIABLE

A compile method to be executed in a digital computer includes the step for detecting among statements in source program codes a first statement defining a first variable and including a polynomial of a plurality of other variables to define the first variable and a second statement including the first variable defined by the first statement so as to use the first variable. The method also includes the steps of judging whether or not the detected second statement satisfies a predetermined copy propagation condition and of replacing the first variable included in the second statement, when a result of the judgement indicates the condition to be satisfied by the second statement, with the polynomial and for eliminating the first statement, with the polynomial anbd for eliminating the first statement. Finally, the method includes the step of generating from a source code after the replacing step object program codes corresponding to the source code.