A "data verified", or DV, bit is included in an instruction to indicate if
the instruction or a dependent instruction may be associated with the
retrieved data as soon as the data is available or should instead be
associated with the data after verification. If the DV bit is in a first
state, e.g., not set, the system may issue instructions that use
associated data as soon as the data is available. If the DV bit is in a
second state, e.g., set, the system does not issue the instructions that
use the data until the data is verified. The system or user sets the DV
bit based on an analysis of an instruction set that includes the
instruction and/or accumulated profile data from previous use or uses of
the software. The DV bit is set in a LOAD instruction if the dependent
user instruction is close enough in the instruction set that the user
instruction is likely to issue before the data is verified and/or if the
LOAD instruction is part of a relatively long chain of instructions. The
DV bit may instead be set if past uses of the software indicate a
complicated or time-consuming reissue operation is associated with a
particular cache miss.
