It would show up in the PAR report similar to this:


This error can be safely ignored. It is not a legitimate failure due to incorrect skew analysis by the software. This problem is being fixed and planned to be fixed in ISE 12.1.
Revision History
01/26/2010 - Initial Release
| Answer Number | Answer Title | Version Found | Version Resolved |
|---|---|---|---|
| 34019 | ISE Design Suite 11.4.1 - Known Issues for Virtex-6 FPGA Service Pack | N/A | N/A |
| Answer Number | Answer Title | Version Found | Version Resolved |
|---|---|---|---|
| 34019 | ISE Design Suite 11.4.1 - Known Issues for Virtex-6 FPGA Service Pack | N/A | N/A |