| 摘要 |
The present invention eliminates redundant array range checks. A two-phased check is performed, namely a wide range check is performed by combining a plurality of array range checks, and a strict range check is unsuccessful, so as to reduce the number of range checks at execution time and allow execution at high speed. For instance, it is possible with a processor such as PowerPC, by using a flag, to invalidate a code for performing an array range check at high speed without increasing a code size. Consequently, the number of array range checks to be executed can be reduced so as to allow execution at high speed. Also, for instance, a plurality of array range checks can be combined without considering existence of instructions which cause a side effect. Consequently, the number of array range checks to be executed can be reduced so as to allow execution at high speed. In addition, a versioning is performed by using, as array access information for versioning, information of array access information for versioning information of array accesses which are always performed even if passing through any execution path in a loop so that there are fewer cases where it goes to a version with a larger number of array range checks at execution time.
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