are you sure it's irrevocable? Even a trust with that term in its name can be grantor trust which may still need to file a 1041 but no k-1 is issued. Rather a grantor trust letter.
A trust is considered a grantor trust if the grantor retains certain powers12:
To change the trust’s beneficiary.
To borrow from the trust.
To change the assets in the trust by substituting assets of equal value.
To pay life insurance premiums from the trust’s income.
A reversionary interest of more than 5% of the trust property or income.
The power to revoke the trust and/or to return the trust’s corpus/principle to the grantor.
The power to distribute income to the grantor or grantor’s spouse.
A grantor trust is any trust that allows the grantor to retain full control over any investments or other assets held inside of the trust3. The grantor can make changes to the trust and the assets inside the trust as long as they are competent to do so3. A “grantor trust” is a trust in which the grantor (or some other person) retains control over the trust to such an extent that the grantor (or such other person), rather than the fiduciary or beneficiary, is treated for federal income tax purposes as the owner of all or part of the trust4. Grantor trust rules also state that a trust becomes a grantor trust if the creator of the trust has a reversionary interest greater than 5% of trust assets at the time the transfer of assets to the trust is made
