CRITICAL_SIG_OPT - 2024.2 English - UG901

Vivado Design Suite User Guide: Synthesis (UG901)

Document ID
UG901
Release Date
2024-12-11
Version
2024.2 English

CRITICAL_SIG_OPT is used to optimize sequential loops by restructuring logic in the feedback path, so that timing-critical signals travel through the smallest number of logic levels. The attribute should be placed on sequential objects such as registers, that drive critical paths to their own inputs.

The optimization improves critical path timing, but at the expense of increased logic utilization as it involves Shannon decomposition. You must mark the sequential elements (registers) with a loop which have reasonable logic levels. It can cause resource overhead due to logic replication.