GDP doesn't tell us much in the case of Ireland, because these huge companies only invest very little in the country, as is typical for a tax haven. If you look at GNP, the gross national product, the actual gains for the people in Ireland are much lower. Have a look at GDP[1] and GNP[0] numbers per inhabitant for Europe: Where for most european countries both numbers are about the same, for Ireland there's a difference of over 30%. Much of Irelands GDP growth didn't result in more income for the people.

[0] = https://en.wikipedia.org/wiki/List_of_sovereign_states_in_Eu... [1] = https://en.wikipedia.org/wiki/List_of_sovereign_states_in_Eu...