A data processing system for optimising a machine code instruction stream.

摘要

A method operable within an optimising compiler to move certain range check instructions out of single entry strongly connected regions or loops and into linear regions of the instruction stream whereby computational efficiency is increased with no loss of program accuracy. The method comprises placing a range check trap instruction into the head node of the SCR provided there is only one conditional exit from the SCR, modifying the conditional exit test based on the value of the induction variable v, and inserting a new check at the loop exit point(s) to insure that the induction variable has reached the value it would have obtained in the original - (unmodified) program.