DC综合的时候会出现很多这种warning，求助
时间：10-02
整理：3721RD
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DC综合的时候，时序slack为负，综合的信息会出现很多这种warning，
Warning: The following cells only drive
asynchronous pins of sequential cells which have no
timing constraint. Therefore retiming will not optimize
delay through them:
digital2/mult13/*cell*63670 (CLKBUFX20TF)
digital2/mult13/*cell*63667 (CLKBUFX20TF)
digital2/mult13/*cell*63668 (CLKBUFX20TF)
需要怎么修改约束或设置啊，谢谢
Warning: The following cells only drive
asynchronous pins of sequential cells which have no
timing constraint. Therefore retiming will not optimize
delay through them:
digital2/mult13/*cell*63670 (CLKBUFX20TF)
digital2/mult13/*cell*63667 (CLKBUFX20TF)
digital2/mult13/*cell*63668 (CLKBUFX20TF)
需要怎么修改约束或设置啊，谢谢
CLKBUFX20TF接到了DFF的异步时钟pin
false path或许是你需要设置的
3# zh123456789 谢谢这位大虾，能不能再详细的讲讲，怎么设置false path吧