primetime unconstrained
For unconstrained paths you can check with prime time tool (specifically version later than 2005.12)
report_timing -exceptions
Prints user-entered timing exceptions, namely false paths, multi-cyle paths, and min/max delays, that are satisfied per timing path being reported. Also the reason of an unconstrained timing path is printed. The -exceptions options requires one and only one of the following three values: dominant, overridden, and all. Please note that the additional analysis required per path with - exceptions is non-trivial. Therefore, a report_timing with -exceptions is expected to execute slower than the exact same command without the -exceptions option. -exceptions does not work with -path_type short/end/summary option.