Design Rule Checks (DRCs) check the design and report on common issues. Since the 2016.1 release, DRCs are split into two different commands. The methodology DRCs have been moved to the
report_methodology command, while all other DRCs are in the
report_drc command. Run non-methodology DRCs using the
report_drc command. During implementation, the tools also run DRCS. The DRCs become more complete and comprehensive with placement and routing.
Review the DRC messages, Critical Warnings, and Warnings early in the flow to prevent issues later.
Critical Warnings in early design stages become Errors later during the implementation flow and prevent bitstream creation. In the above example generated from a post Synthesized Design, the optional Report DRC step reports a Critical Warning for the unconstrained I/Os. The post-route design DRC report also reports these Critical Warnings. You must review the report because at
write_bitstream the DRC is elevated to an Error. Review the DRC reports early to identify areas of the design that need modification.