A logic option that removes a register if it is identical to another register. If two registers generate the same logic, the second one will be deleted and the first one will be made to fan-out to the second one's destinations. Also, if the deleted register has different logic option assignments, they will be ignored. This option is recognized only if the Remove Duplicate Logic option is turned on. When turned on, the Remove Duplicate Logic option also removes duplicate registers, therefore, you should use the Remove Duplicate Registers option only if you wish to prevent the Compiler from removing duplicate registers that you used deliberately. That is, you should use this option only with the Off setting.

This option is ignored if it is assigned to anything other than an individual register or a design entity containing registers. This option is available for all Altera^® devices supported by the Quartus^® II software.