A processor circuit and an operation method thereof are provided. The processor circuit includes a re-order buffer (ROB) and an alias queue (AQ) module. The ROB records next sequential instruction pointer (Nsip) values of a plurality of load instructions and a plurality of store instructions. Each of a plurality of entries of the AQ module includes a first field and a plurality of second fields. When a first load instruction and a first store instruction cause a first memory violation and the ROB retires the first load instruction, the AQ module stores the Nsip value of the first load instruction into the first field of one of the entries and stores the Nsip value of the first store instruction into one of the second fields of one of the entries.