An if statement is optional and results in no delay.

While checking for an infinite loop in an always block I missed
the case where an if statement does not have a statement. This
was resulting in a segmentation fault.

netlist.cc

@@ -2697,7 +2697,11 @@ DelayType NetCondit::delay_type() const
       } else {
 	      /* Because of the indeterminate conditional value the
 	       * best we can have for this case is a possible delay. */
+	    if (if_) {
 		  result = combine_delays(if_->delay_type(), NO_DELAY);
+	    } else {
+		  result = NO_DELAY;
+	    }
       }
 
       return result;