A case has been seen where a design that successfully implemented in Vivado 2014.4, now fails with the following error in the Placer in Vivado 2015.1.
Is this a known issue?
Is there a work-around?
This error can be due to a known issue in the placer.
If no IODELAY_GROUP has been defined, the placer will build one automatically.
The issue is that this default group can be built incorrectly.
This has been fixed for Vivado 2015.3.
In the meantime, the work-around is to define a valid IODELAY_GROUP with XDC constraints to prevent the placer from building the incorrect group.