```
ERROR:Place:1108 - A clock IOB / BUFGMUX clock component pair have been found
   that are not placed at an optimal clock IOB / BUFGMUX site pair. The clock
   IOB component <clk> is placed at site <D9>. The corresponding BUFG component
   <$auto$clkbufmap.cc:261:execute$6514> is placed at site <BUFGMUX_X2Y3>. There
   is only a select set of IOBs that can use the fast path to the Clocker
   buffer, and they are not being used. You may want to analyze why this problem
   exists and correct it. If this sub optimal condition is acceptable for this
   design, you may use the CLOCK_DEDICATED_ROUTE constraint in the .ucf file to
   demote this message to a WARNING and allow your design to continue. However,
   the use of this override is highly discouraged as it may lead to very poor
   timing results. It is recommended that this error condition be corrected in
   the design. A list of all the COMP.PINs used in this clock placement rule is
   listed below. These examples can be used directly in the .ucf file to
   override this clock rule.
   < NET "clk" CLOCK_DEDICATED_ROUTE = FALSE; >
```