The generated Vulkan calls look right and do not trigger any
validation error, but the returned timestamp is 0. A valid
timestamp is returned if the CopyResource() call is commented,
or the second EndQuery() call is moved before CopyResource(),
or the first EndQuery() call is commented. I am not seeing any
sensible pattern here, so I guess there is just a bug in
MoltenVK.
Specifically, MoltenVK seems to be able to load from stencil, but
the specific replicating swizzle (repeating the stencil value on
all the channels) is not honored. The stencil value is read only
on the red channel.
The relative-addressed case in shader_register_normalise_arrayed_addressing()
leaves the control point id in idx[0], while for constant register
indices it is placed in idx[1]. The latter case could be fixed instead,
but placing the control point count in the outer dimension is more
logical.
The FXC optimiser sometimes converts a local array of input values into
direct array addressing of the inputs, which can result in a
dcl_indexrange instruction spanning input elements with different masks.
Apparently Metal doesn't support specifying a bias directly in the
sampler, and, with "nearest" mip filtering, it doesn't switch
precisely at LOD 0.5 (though still between 0.5 and 0.6).
