Vivado 2015.3 and 2015.4 - There is a known issue where Tandem designs will hang during the routing phase due to a bug in the DRC checks that are run during that phase.
Patches have been made available for Vivado 2015.3 and 2015.4 and are attached to this Article.
Please select the appropriate patch.
Method 1: (Vivado 2014.4 and later only)
a. Navigate to the $XILINX_VIVADO/patches directory (create this directory if it does not exist).
b. Extract the contents of the ".zip" archive to a directory starting with the name AR66007.
Note: most extraction tools will allow you to automatically create a directory with the same name as the zip file.
c. Run Vivado software tools from the original install location.
a. Creating a separate directory containing patched files.
b. Extract the contents of the ".zip" archive to the desired patch directory location.
c. Set the MYVIVADO environment variable to point to the Vivado directory under this patch directory
d. Run Vivado software tools from the original install location.