Apparatus and method for optimizing shader execution. For example, one embodiment of a graphics processing apparatus comprises: a plurality of execution units to execute shader programs; optimization detection circuitry and/or logic to identify one or more portions of shader program code to be optimized including one or more reduction operations which require read/write memory operations and associated barrier operations; and optimization circuitry and/or logic to optimize the shader program code by converting a plurality of the read/write memory operations to read/write register operations and removing one or more barrier operations to generate optimized shader program code; the execution units to execute the optimized shader program code.