关于fpga警告的问题

Warning: Creation of Node or Bus "a[0]" failed. Duplicated nodes are not inserted. Node or bus name "a[0]" already exists.
Warning: Creation of Node or Bus "a[1]" failed. Duplicated nodes are not inserted. Node or bus name "a[1]" already exists.
Warning: Creation of Node or Bus "a[2]" failed. Duplicated nodes are not inserted. Node or bus name "a[2]" already exists.
Warning: Creation of Node or Bus "a[3]" failed. Duplicated nodes are not inserted. Node or bus name "a[3]" already exists.
Warning: Creation of Node or Bus "a[4]" failed. Duplicated nodes are not inserted. Node or bus name "a[4]" already exists.
Warning: Creation of Node or Bus "a[5]" failed. Duplicated nodes are not inserted. Node or bus name "a[5]" already exists.
Warning: Creation of Node or Bus "a[6]" failed. Duplicated nodes are not inserted. Node or bus name "a[6]" already exists.
Warning: Creation of Node or Bus "a[7]" failed. Duplicated nodes are not inserted. Node or bus name "a[7]" already exists.
Warning: Creation of Node or Bus "b[0]" failed. Duplicated nodes are not inserted. Node or bus name "b[0]" already exists.
Warning: Creation of Node or Bus "b[1]" failed. Duplicated nodes are not inserted. Node or bus name "b[1]" already exists.
Warning: Creation of Node or Bus "b[2]" failed. Duplicated nodes are not inserted. Node or bus name "b[2]" already exists.
Warning: Creation of Node or Bus "b[3]" failed. Duplicated nodes are not inserted. Node or bus name "b[3]" already exists.
Warning: Creation of Node or Bus "b[4]" failed. Duplicated nodes are not inserted. Node or bus name "b[4]" already exists.
Warning: Creation of Node or Bus "b[5]" failed. Duplicated nodes are not inserted. Node or bus name "b[5]" already exists.
Warning: Creation of Node or Bus "b[6]" failed. Duplicated nodes are not inserted. Node or bus name "b[6]" already exists.
Warning: Creation of Node or Bus "b[7]" failed. Duplicated nodes are not inserted. Node or bus name "b[7]" already exists.

俺初来咋到，懂得太少，有哪位好心人帮我看一下，这些警告信息是什么意思。。。多谢。。。