A case has been seen where unconstrained GT components were incorrectly autoplaced next to unbonded GTPADs and then the placer errored out as though the designer had LOC'd them to these bad sites.
Phase 12.24 (Checksum:7270df4) REAL time: 1 mins
ERROR:Place:631 - The GT component
aurora_rear_panel/aurora_rear_panel/aurora_module_i/lane_0_mgt_i locked to
site GT_X0Y1 requires the GTPAD component a_rprx0n must be placed at RXNPAD2.
But the location RXNPAD2 is unbonded. Please correct this by removing the
illegal lock on the GT component or lock it down at a feasible location.
This problem was fixed in version 9.1i. The problem can be avoided in earlier revisions by locking the GT components to valid sites next to bonded GTPADs.