regular tax
(1) In general For purposes of this section, the term “regular tax” means the regular tax liability for the taxable year (as defined in section 26(b) ) reduced by the foreign tax credit allowable under section 27(a). Such term shall not include any increase in tax under section 45(e)(11)(C) , 49(b) or 50(a) or subsection (j) or (k) of section 42.