PT问题，跑不下去了，求助 (RC-005) (RC-008)

用PT做post-layout分析时，运行check_timing -verbose时，出现如下警告，一晚上了还是停在RC-008的警告上，没有结果！
运行了man (RC-005) (RC-008)，也看不出啥原因，在线等高手。

Warning: Failed to compute the rising RCnetwork delay from the pin 'sys_clk' to the pin 'sys_clk__L1_I0/A' in the network 'sys_clk'. (RC-005)

Warning: The type of RC delay calculationproblem(s) that have occured prevents the max results from bounding the correct values. (RC-008)

could you please check this path is constrained or unconstrainedfirstly ?
then Could you check the variable" timing_slew_propagation_mode" value ?
best regards

timing_slew_propagation_mode is worst slew，有影响吗?