RADV Driver Tacks On VK_AMD_gpu_shader_half_float Support In Mesa 19.1

Mesa's "RADV" Radeon Vulkan open-source driver has landed support for VK_AMD_gpu_shader_half_float.

VK_AMD_gpu_shader_half_float is the Vulkan extension indicating support for SPIR-V's SPV_AMD_gpu_shader_half_float extension to allow support for half-floats (16-bit floating point) support within extended instructions.

This Vulkan/SPIR-V AMD half-float support is modeled after OpenGL's AMD_gpu_shader_half_float extension for GLSL.

Following some NIR 16-bit changes that landed in Git, Samuel Pitoiset of Valve enabled the VK_AMD_gpu_shader_half_float support for RADV in the Mesa 19.1 code. This extension will work with AMD Volcanic Islands hardware and newer and does depend upon the LLVM 8.0 AMDGPU back-end (or newer).

Mesa 19.1 is due to be released around the end of May as the next quarterly feature update to Mesa3D.