Trying the APP SDK samples on a Radeon 290X with Catalyst Omega, they reported that there's no OpenCL 2.0 support. I compared the device info to what clinfo was giving me, and there were slight differences, such as "address bits" giving 32 bits instead of 64, and in particular the version string has "OpenCL 1.2". Switching Visual Studio (2010) to compile the x64 version, I had no problem getting an OpenCL 2.0 sample to run.
So does OpenCL 2.0 only work for 64-bit programs or is there a way to get this to work in 32-bit executables? I'd rather use 32-bit because I never quite got debugging 64-bit programs to work well in VS2010.