It shall likewise constitute perjury for any person, with the intent to testify falsely, to knowingly give testimony under oath as to any material matter or thing and subsequently to give conflicting testimony under oath as to the same matter or thing. In any indictment for such perjury, it shall be sufficient to allege the offense by stating that the person charged therewith did, knowingly and with the intent to testify falsely, on one occasion give testimony upon a certain matter and, on a subsequent occasion, give different testimony upon the same matter. Upon the trial on such indictment, it shall be sufficient to prove that the defendant, knowingly and with the intent to testify falsely, gave such differing testimony and that the differing testimony was given on two separate occasions.