(Followup from #6873, #8078) SIMILAR TO does not work with wildcard combined with OR operator

[infpmandin]

Hello,

I have a company table with zip code:

C_CP
95450
97008

If I select using

where c_cp similar to '95450|97008' -- works ok

where c_cp similar to '9545_|97008' -- does not find 97008

where c_cp similar to '95450|9700_' -- ok

where c_cp similar to '95_+|97008' -- does not find 97008

where c_cp similar to '95[[:digit:]]+|97008' -- does not find 97008

I tested with Firebird from 5.0.2 to 5.0.4

[aafemt]

As a workaround try similar to '(9545_)|(97008)' or similar to '(9545_|97008)'.