翻译：The final optimization Genus performs is incremental optimization. Optimizations performed during IOPT improve timing and area and fix DRC violations. Optimizations performed during this phase include multibit cell mapping, incremental clock gating, incremental retiming, tie cell insertion, and assign removal. For more information on multibit cell mapping, refer to Mapping to Multibit Cells in the Genus Synthesis Flows Guide. By default, timing has the highest priority and Genus will not fix DRC violations if doing so causes timing violations. This priority can be overridden by setting the drc_first attribute to true. In this case, all violations will be fixed as well as those paths with positive slack. IOPT also includes Critical Region Resynthesis (CRR) which iterates over a small window on the critical path to improve slack. You can control CRR through the effort level argument in the syn_opt command. It is asserted by specifying the high effort level. If for some reason you need to cancel the Genus session in the middle of IOPT, press the Ctrl-c key sequence. You will be given a warning message with a particular IOPT state and brought back to the command line. Next time you enter a Genus session (with the same commands, constraints, script, etc. that preceded the ctrl-c halt) you can specify the IOPT state at which you stopped with the stop_at_iopt_state attribute. Genus will continue with the netlist it had generated at the specified state.

Genus进行的最后一个优化是增量优化。在IOPT期间执行的优化可以提高时序和面积，并修复DRC违规。此阶段执行的优化包括多位单元映射、增量时钟门控、增量重定时、连结单元插入和分配删除。有关多位单元映射的更多信息，请参阅Genus合成流程指南中的Mapping to Multibit Cells。默认情况下，时序具有最高优先级，并且如果修复DRC违规导致时序违规，Genus不会修复DRC违规。可以通过设置drc_first属性为true来覆盖此优先级。在这种情况下，将修复所有违规以及具有正余量的路径。IOPT还包括关键区域重合成（CRR），它在关键路径上的一个小窗口上进行迭代以改善余量。您可以通过syn_opt命令中的effort level参数控制CRR。通过指定高努力水平来断言它。如果出于某种原因需要在IOPT中间取消Genus会话，则按Ctrl-c键序列。您将收到一个具有特定IOPT状态的警告消息，并回到命令行。下次进入Genus会话（具有与ctrl-c停止之前相同的命令、约束、脚本等），可以使用stop_at_iopt_state属性指定停止的IOPT状态。Genus将继续使用在指定状态下生成的网表。