[U-Boot-Users] why there is __asm__ __volatile__("": : :"memory") in board_init_f(lib_mips/board.c), but not in board_init_r?

i see theres lines in board_init_f(lib_mips/board.c)

/* compiler optimization barrier needed for GCC >= 3.4 */ __asm__ __volatile__("": : :"memory");

but there is not the same lines in board_init_r? why it do not need in the board_init_r?

regards