Vivado Synthesis can be run incrementally. In this flow, the tool will have a reference run that will be referred to in later runs. It will be able to detect when the design has changed and then only re-run synthesis on sections of the design that have changed. The key advantage of this flow is that for designs with small changes, the runtime will be greatly reduced. In addition, the QoR of the design will fluctuate less when small changes are inserted into the RTL.