/CHECK
       /CHECK[=([NO]UNINITIALIZED_VARIABLES)] (Alpha only)
       /NOCHECK (D)

    Use this qualifier as a debugging aid.

    Use /CHECK=UNINITIALIZED_VARIABLES to initialize all automatic
    variables to the value 0x7ff580057ff58005. This value is a
    floating NaN and, if used, causes a floating-point trap. If used
    as a pointer, this value is likely to cause an ACCVIO.

    Note that on I64 systems, /CHECK=UNINITIALIZED_VARIABLES emits a
    warning and is ignored.