RADV Lands VK_EXT_subgroup_size_control For Exposing Wave32 On Navi/GFX10

Valve open-source developer Samuel Pitoiset has landed his work enabling the Vulkan VK_EXT_subgroup_size_control extension that for GFX10/Navi is being used to expose Wave32 capabilities.

Samuel's work has landed for this Vulkan extension that allows for a varying subgroup size and allows for compute shaders to use Wave32 as supported with GFX10 hardware. Another caveat though is the current implementation only works with the AMDGPU LLVM back-end and not yet the ACO shader back-end.

This commit is the one for RADV allowing the wave-size to be changed on-demand for GFX10.

The RadeonSI Gallium3D OpenGL driver meanwhile has supported Wave32 support and the RADV driver has already provided Wave32 support for some shaders.