METHOD AND APPARATUS FOR ELIMINATING REDUNDANT ARRAY RANGE CHECKS IN A COMPILER

Java language is, as its specification, capable of detecting an access exceeding an array range, and when there is no user-defined exception handler, moving control to an invoked method after getting out of a method in which an exception occurred, or when there is a user-defined exception handler, moving the process to the exception handler. Accordingly, an array range check is essential since occurrence of an exception may be described as a correct operation. However, an array range check slows execution speed compared with a language which does not require it. In an actual program, there is an array access to ensure that there is no access exceeding a range, and thus elimination of such redundant range checks greatly contributes to improved performance, and in addition, brings about an effect of expanding the range of optimization from the viewpoint of ensuring order of execution between occurrence of an exception and a process with a side effect such as an assignment of a value to an array.