A few days ago the latest patches were published and today the work, which was done by SUSE under contract with AMD, is now in the mainline GCC code-base.
As mentioned in that earlier article, The patches provide an HSA libgomp plug-in for run-time with hooking into GCC's OpenMP library, an HSA register allocator, and the necessary changes for providing HSA offload support. New GCC options relating to HSA are: --with-hsa-runtime, --with-hsa-runtime-include, --with-hsa-runtime-lib and --with-hsa-kmt-lib. Besides a supported compiler, you also need to be using a recent kernel that's equipped with the AMDKFD driver and on your system have the new HSAKMT library.
The work landed this morning and now makes it another nice feature for the upcoming GCC 6 release.