SAD Intrinsics from OpenCL

Does anyone know how to use the __sad and __usad intrinsics from OpenCL?
I have seen these are available from CUDA using the device_functions.h, but can not see a way to invoke them from OpenCL.
Is there an equivalent for OpenCL?
Or alternatively can the PTX instructions they be called from in-line assembler in some way?

Any help appreciated,

There is no in-line assambler in OpenCL.