In this paper, intelligent reflecting surfaces (IRSs) are exploited for simultaneous wireless information and power transfer. In the considered setup, the IRS, illuminated by a power transmitter, provides power to integrated sensors through energy harvesting while simultaneously transmitting information through differential permutation-based coding. The problem of allocating the IRS elements to either information or power transmission is studied, highlighting the tradeoff between the system throughput and the harvested power. The conducted performance analysis emphasizes the suitability of using IRSs in a SWIPT scenario without the need for cabled links or channel state information.