RADV+ACO Lands FP16 Features - One Step Closer To Making ACO The Default

The Mesa Radeon Vulkan "RADV" driver's ACO shader compiler back-end has merged its FP16 related bits and in turn putting the ACO back-end very close to being enabled by default for this open-source AMD Vulkan driver.

VK_AMD_gpu_shader_half_float, VK_AMD_gpu_shader_int16, and shaderFloat16 are now working and enabled when using the ACO back-end. The work was merged on Wednesday for Mesa 20.2.

Having the FP16 support in place was one of the last feature milestones for hitting parity to the AMDGPU LLVM back-end that is currently used by default and used elsewhere throughout the open-source AMD graphics stack.

This just leaves SMEM support being flipped on as the last major feature before ACO can meet parity with the LLVM back-end. Code there is written but not yet merged - when that happens, we will likely see RADV having ACO enabled by default rather than hidden behind an environment variable option.