When there is a PERIOD constraint used with a FROM:FFS:TO:FFS
constraint (FROM:TO overrides PERIOD constraints where there
is overlap), and there is a path covered by FROM:FFS:TO:FFS
which is slower than the slowest path covered by the PERIOD
constraint, the minimum delay and maximum frequency is
Instead of reporting the longest path covered by the FROM:TO
constraint, the longest path covered by the PERIOD constraint
is used instead.
This no longer happens in x1_5.18.