Abstract: An apparatus comprises processing circuitry to generate a result vector including at least one N-bit data element in response to an element size increasing instruction identifying at least a first input vector including M-bit data elements, where N>M. First and second forms of the element size increasing instruction are provided for generating the result vector using first and second subsets of data elements of the first input vector respectively. Positions of the first and second subsets of data elements in the first input vector are interleaved.