Along something of the same lines as Gio's comment, is VKD3D_SHADER_SPIRV_ENVIRONMENT_VULKAN_1_1 actually doing anything? We need VKD3D_SHADER_COMPILE_OPTION_FEATURE_WAVE_OPS anyway; should we just set the SPIRV version and Vulkan environment based on that?
Note for review: I did double check, and this functionality is core in Vulkan 1.1 without having gone through an extension first.