ise综合时，报Unable to place this RPM这个错误！

报错如下：
   Unable to place this RPM. Due to its
   structure a packed grid cannot be constructed, hence its group cannot be
   created and placed.    Process will terminate. For technical support on this
   issue, please open a WebCase with this project attached at
   http://www.xilinx.com/support.
   谢谢！

http://www.xilinx.com/support/answers/35546.htm 上面的答案
Regenerating the core while targeting the correct device enables the design to successfully run through the tools.