The CACHE_ZERO directive invokes the machine instruction, data cache block set to zero (dcbz). This instruction sets the data cache block corresponding to the variables you specify to zero. Use this directive with discretion.
In the following example, assume that array ARRA has already been loaded into a cache block that you want to set to zero. The data in the cache block is then set to zero.
real(4) :: arrA(2**5)
! ....
!IBM* CACHE_ZERO(arrA(1)) ! set data in cache block to zero