WAR

``Write after read'': The register must only be written to after previous instructions read it:

If R6 is only read when the STORE instr is ready to execute, it could already have been overwritten by a later instruction.

WAR hazards cannot occur in DLX even extended with long-latency FP operations:

• In DLX, registers are always read in order in ID
• Copies of the operands are held when the instruction is stalled

WAR hazards become a serious concern with scoreboarding, as we see shortly.