In the Intel® Quartus® Prime Pro Edition Software version 20.2, you can control the synthesis implementation of inferred barrel shifters for better area/speed. This is controlled by the setting “BARRELSHIFTER_CARRY_CHAIN_PACKING” in the.qsf (Intel® Quartus® Prime Settings File).
You can insert either setting into the .qsf by the following syntax:
set_global_assignment -name BARRELSHIFTER_CARRY_CHAIN_PACKING <on/off/auto>
Setting to “on” will let Synthesis optimize for better area saving.
Setting to “off” will let Synthesis optimize for better speed.
Setting to “auto” will let Synthesis to decide the trade-off between area and speed.
set_instance_assignment -name BARRELSHIFTER_CARRY_CHAIN_PACKING -to <barrel shifter name> -entity <entity name> <on/off/auto>
For more information, please refer to Intel® Quartus® Prime Pro Edition Settings File Reference Manual entry for this assignment.