It's effectively unused, and struct vkd3d_shader_instruction_array is
not meant to be copied by value. If io_normaliser.instructions were to
be modified it might leave program->instructions in an inconsistent
state.
The change in vsir_program_iterator_next() is necessary to allow us to
introduce instructions before the iterator using:
vsir_program_iterator_prev(&it);
vsir_program_iterator_inset_after(&it, n);
vsir_program_iterator_next(&it);
This since (it.idx == SIZE_MAX) is equivalent to the iterator being
before the beginning of the list.
I think this is slightly nicer. It also happens to avoid a
-Warray-bounds warning on some versions of gcc that suggests the "ins"
pointer returned by vsir_program_iterator_next() may be NULL.
VK_DYNAMIC_STATE_VIEWPORT and VK_DYNAMIC_STATE_SCISSOR specify that
viewports and scissor rectangles are dynamic state, but not their
counts.
It took a while to notice this issue because the existing code seemed to
largely work as intended on hardware implementations, but tests using
the additional viewports would fail on llvmpipe.
