It would be nice to have a tiny test to demonstrate the relevant behavior. We now compile the tests for d3dx9_43 as well (it probably wasn't the case the last time around) so that should work. No need to bring more d3dx9_xx tests up, I'll trust that you checked on the side the exact version where behavior changes :slight_smile:
Side note: I guess we could potentially get rid of the `#if D3DX_SDK_VERSION < 42` check and just always use `vkd3d_D3DCompile2VKD3D()`. If we start depending on vkd3d for some d3dx9_xx DLLs we might as well depend on it for all of them...