def _compute_mod_regs(self, regs_init, regs_fini):
        """Compute modified registers.
        """
        assert regs_init.keys() == regs_fini.keys()

        modified_regs = []

        for reg in regs_init:
            if regs_init[reg] != regs_fini[reg]:
                modified_regs.append(reg)

        return modified_regs
Compute modified registers.