A compiling system and method for optimizing binary code. The method includes the step of replacing a memory access on a stack area in order to save a value of a register with local variable access. The method further includes: giving a call number to a call instruction and an inlined code in response to an inline expansion of a code to be called by the call instruction; creating a parent-child relationship information for at least one of the call number; processing the memory accesses with an escaped stack pointer as a base address if a stack pointer has escaped; prohibiting a replacement of a prohibited memory access if the stack pointer has escaped; and replacing unprohibited memory access with the local variable access if the stack pointer has escaped.