1. A method of controlling a processor that changes an execution sequence of instructions arranged in a program, the method comprising the steps of: executing a second instruction that is placed after a first instruction in the program, prior to execution of the first instruction; and when an address of first data to be executed by the first instruction is included in an address region of second data to be processed by the second instruction, overwriting an execution result of the first instruction on data corresponding to the address of the first data.