Integrated circuit and data processing system supporting address aliasing in an accelerator

An integrated circuit includes a first communication interface for communicatively coupling the integrated circuit with a coherent data processing system, a second communication interface for communicatively coupling the integrated circuit with an accelerator unit including an effective address-based accelerator cache for buffering copies of data from a system memory, and a real address-based directory inclusive of contents of the accelerator cache. The real address-based directory assigns entries based on real addresses utilized to identify storage locations in the system memory. The integrated circuit further includes request logic that communicates memory access requests and request responses with the accelerator unit. The request logic, responsive to receipt from the accelerator unit of a read-type request specifying an aliased second effective address of a target cache line, provides a request response including a host tag indicating that the accelerator unit has associated a different first effective address with the target cache line.