You have lost all three pitot tube inputs leading to all three IRU's declaring sick.
Apologies If I am wrong, but pitot tubes provide ADR data, not Inertial Reference Data.
Unless a very strange comparison algorithm validates Inertial Data from Air Data - and not just the opposed - blocked pitot tubes cannot generate IR faults by themselves.
There is no clear indication of loss of all IRUs in the AF447 case.