ERROR:MapLib:978 - LUT6 symbol symbol, ERROR, MapLib

2464330

DDR3_SDRAM/DDR3_SDRAM/mpmc_core_0/gen_paths.mpmc_data_path_0/gen_write_fifos
   [3].gen_fifos.mpmc_write_fifo_0/next_push_is_word_rstpot2" (output
   signal=DDR3_SDRAM/DDR3_SDRAM/mpmc_core_0/gen_paths.mpmc_data_path_0/gen_write
   _fifos[3].gen_fifos.mpmc_write_fifo_0/next_push_is_word_rstpot2) has an
   equation that uses input pin I2, which no longer has a connected signal.
   Please ensure that all the pins used in the equation for this LUT have
   signals that are not trimmed (see Section 5 of the Map Report File for
   details on which signals were trimmed).


请问这是为什么啊？