After several unsuccessful tries, I haven't found a way to get opencl to work with my R7 260x using the Radeon driver on Arch. (It works great with Catalyst however).
I had a look at Lorheavy's repo and also gave a shot at the git versions of xf86-video-ati / ati-dri, to no avail.
Have some of you guys managed to get it working ?
Thanks for the help !