Can't get AREA_GROUP to work

Just to answer my own question. I needed to use a wildcard with the instance. So instead of INST "fpu_inst" AREA_GROUP="fpu_group";

I needed to do

INST "fpu_inst/*" AREA_GROUP="fpu_group";

Hopefully this will save someone else some trouble in the future.

I am trying to use area_group in my constraints file, but I keep getting the error

ERROR:NgdBuild:753 - "constraints.ucf" Line 5: Could not find instance(s) 'gclockInst' in the design. To suppress this error specify the correct instance name or remove the constraint. ERROR:Parsers:11 - Encountered unrecognized constraint while parsing. ERROR:NgdBuild:19 - Errors found while parsing constraint file "constraints.ucf".

I have tried this with several of the instances in my design, but I am having no success. I am running ISE Webpack 9.1.03i

The instance is present and is not getting optimized away. I can see it in the floorplanner.

Any suggestions on what I may be doing wrong?