编译ddr模块出现如下错误是什么原因?

Error: Specified DDIO registers are not part of a legal DDIO circuit
	Error: Register "SCPU:inst|ddr_sdram_0:the_ddr_sdram_0|ddr_sdram_0_auk_ddr_sdram:ddr_sdram_0_auk_ddr_sdram_inst|ddr_sdram_0_auk_ddr_datapath:ddr_io|ddr_sdram_0_auk_ddr_dqs_group:\g_datapath:1:g_ddr_io|altddio_bidir:\g_dq_io:4:dq_io|ddio_bidir_c0l:auto_generated|output_cell_L[0]" is not part of a legal DDIO circuit
	Error: Register "SCPU:inst|ddr_sdram_0:the_ddr_sdram_0|ddr_sdram_0_auk_ddr_sdram:ddr_sdram_0_auk_ddr_sdram_inst|ddr_sdram_0_auk_ddr_datapath:ddr_io|ddr_sdram_0_auk_ddr_dqs_group:\g_datapath:1:g_ddr_io|altddio_bidir:\g_dq_io:4:dq_io|ddio_bidir_c0l:auto_generated|output_cell_H[0]" is not part of a legal DDIO circuit
	Error: Register "SCPU:inst|ddr_sdram_0:the_ddr_sdram_0|ddr_sdram_0_auk_ddr_sdram:ddr_sdram_0_auk_ddr_sdram_inst|ddr_sdram_0_auk_ddr_datapath:ddr_io|ddr_sdram_0_auk_ddr_dqs_group:\g_datapath:1:g_ddr_io|altddio_bidir:\g_dq_io:7:dq_io|ddio_bidir_c0l:auto_generated|output_cell_L[0]" is not part of a legal DDIO circuit
	Error: Register "SCPU:inst|ddr_sdram_0:the_ddr_sdram_0|ddr_sdram_0_auk_ddr_sdram:ddr_sdram_0_auk_ddr_sdram_inst|ddr_sdram_0_auk_ddr_datapath:ddr_io|ddr_sdram_0_auk_ddr_dqs_group:\g_datapath:1:g_ddr_io|altddio_bidir:\g_dq_io:7:dq_io|ddio_bidir_c0l:auto_generated|output_cell_H[0]" is not part of a legal DDIO circuit
	Error: Register "SCPU:inst|ddr_sdram_0:the_ddr_sdram_0|ddr_sdram_0_auk_ddr_sdram:ddr_sdram_0_auk_ddr_sdram_inst|ddr_sdram_0_auk_ddr_datapath:ddr_io|ddr_sdram_0_auk_ddr_dqs_group:\g_datapath:1:g_ddr_io|altddio_bidir:\g_dq_io:6:dq_io|ddio_bidir_c0l:auto_generated|output_cell_L[0]" is not part of a legal DDIO circuit
	Error: Register "SCPU:inst|ddr_sdram_0:the_ddr_sdram_0|ddr_sdram_0_auk_ddr_sdram:ddr_sdram_0_auk_ddr_sdram_inst|ddr_sdram_0_auk_ddr_datapath:ddr_io|ddr_sdram_0_auk_ddr_dqs_group:\g_datapath:1:g_ddr_io|altddio_bidir:\g_dq_io:6:dq_io|ddio_bidir_c0l:auto_generated|output_cell_H[0]" is not part of a legal DDIO circuit
	Error: Register "SCPU:inst|ddr_sdram_0:the_ddr_sdram_0|ddr_sdram_0_auk_ddr_sdram:ddr_sdram_0_auk_ddr_sdram_inst|ddr_sdram_0_auk_ddr_datapath:ddr_io|ddr_sdram_0_auk_ddr_dqs_group:\g_