Design Rule Checks (DRCs) check the design and report on common issues. 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 Critical
Warning DRCs are elevated to Error-level severity and prevent bitstream generation. Review the
DRC reports early to identify areas of the design that need modification.