A Warp or Wavefront are implementation specifics of two Khoronos members and they have no mention in the OCL standard.
There is no high level way to access predicate results of all threads of a Wavefront.
If you write GCN ISA code you can access the VCC flag which holds the results of the most recent predicate for all threads. It is a 64 bit flag , one bit per thread.
Thanks, Tzachi. It looks like OpenCL 2.0 has these methods:
So, I will wait until the 2.0 release.
On Sat, Jun 14, 2014 at 2:54 PM, tzachi.cohen <firstname.lastname@example.org>