set_false_path -hold - When it is used?

[tsk1979]

In some SDC files I have seen the constraint
set_false_path -hold

I am unable to figure out why would somebody set "set_false_path -hold"
Under what condition or logic design would you want to allow setup check on a path but ignore hold check?

 

[YuLongHuang]

In some SDC files I have seen the constraint
set_false_path -hold

I am unable to figure out why would somebody set "set_false_path -hold"
Under what condition or logic design would you want to allow setup check on a path but ignore hold check?

Instead of setup check, sometime we will check for maximum delay.
Even though it's false path, the path with very long long delay is undesirable.

For example:
set_max_delay 1Tb -from [get_clocks Ta] -to [get_clocks Tb]
set_false_path -hold -from [get_clocks Ta] -to [get_clocks Tb]

Anyone has another idea or real case for illustration ?
PoLo

 

[asic_service]

This will disable all the hold check.
This SDC maybe used by synthesis, not by Place&Route and PT check. This may because: hold violation are usually fixed at P&R phase, not synthesis phase.