Prevent Register Retiming
Enable the Prevent register retiming option if you want to globally prevent automatic
retiming of registers for design performance improvement. When disabled, the Compiler
automatically performs register retiming optimizations that move combinational logic across
register boundaries. The Compiler maintains the overall logic of the design component, and
also balances the datapath delays between each register.
Optionally, assign
Allow Register Retiming to any design entity or
instance to override Prevent register retiming for
specific portions of the design. Click to specify entity- and instance-level assignments, or use the following syntax
to make the assignment in the .qsf directly.
Disable register retiming for entity abc
set_global_assignment –name ALLOW_REGISTER_RETIMING ON set_instance_assignment –name ALLOW_REGISTER_RETIMING OFF –to “abc|” set_instance_assignment –name ALLOW_REGISTER_RETIMING ON –to “abc|def|”
Disable register retiming for the whole design, except for registers in entity abc
set_global_assignment –name ALLOW_REGISTER_RETIMING OFF set_instance_assignment –name ALLOW_REGISTER_RETIMING ON –to “abc|” set_instance_assignment –name ALLOW_REGISTER_RETIMING OFF –to “abc|def|”