Abstract: This invention provides a process within an optimizing compiler for transforming code to take advantage of update instructions available on some computer architectures. On architectures which implement some form of autoindexing instructions or addressing modes, this process will improve the code generated for looping constructs which manipulate arrays in memory. The process is achieved by selecting memory referencing instructions inside loops for conversion to update forms, modifying those instructions to an update form available on a particular processor, and applying an offset compensation to other memory referencing instructions in the loop so as to enable the program to still address the appropriate locations while using the available autoindexing instructions. The improved compiler and compiler process enables the compiler to convert those program instructions that would otherwise convert to autoindexing instructions not supported by the processor to autoindexing instructions that are supported.