I recently attempted to try OpenCL rendering in Cycles once more, using a recent nightly build of Blender 2.79 (2.78.5). Unlike previous attempts, recent versions of Blender seem to get a lot further with my GPU: The Kernel appears to be successfully compiled, however Blender crashes immediately after that and before rendering.
Notice: It's possible that my GPU might not be officially supported, I have not recently found the list of supported cards. However I still considered this a problem worth reporting, as the cause of the crash might be unrelated whereas fixing support for any video card (especially one that appears close to working) seems like a valid proposal. By default I don't get a GPU device listed, and need to launch Blender with the following variables which then lists it:
CYCLES_OPENCL_TEST=all CYCLES_OPENCL_SPLIT_KERNEL_TEST=1 ./blender
My video card is a Radeon R7 370 from Gigabyte (RadeonSI, GCN 1.0, AMD Pitcairn Islands). My OS is Linux openSUSE Tumbleweed x64. I have the following relevant system components: Kernel 4.11.6, Mesa 17.1.3, DRM 2.49.0, LLVM 4.0.0. Logs will be attached to this report soon.