A compiler device includes: a processor configured to: when a first register is allocated to first and second spill instructions, which refer to same data in a memory, of an instruction sequence and to a first section between the first and second spill instructions, search for a second register that is a candidate allocated to the first section instead of the first register; when a second section allocated with the second register and the first section do not overlap, allocate the second register to the first section instead of the first register; when the first and second sections overlap, allocate a third register to the second section instead of the second register, and then allocate the second register to the first section instead of the first register; and thereafter, delete an instruction executed later than the other instruction of the first and second spill instructions.