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.
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=56162
Storing to a vector component using a non-constant index is not allowed
on profiles lower than 6.0. Unless this happens inside a loop that can be
unrolled, which we are not doing yet.
For this reason, a validate_nonconstant_vector_store_derefs pass is
added to detect these cases.
Ideally we would want to emit an hlsl_error on this pass, but before
implementing loop unrolling, we could reach this point on valid HLSL.
Also, as pointed out by Nikolay in the mentioned bug, currently
new_offset_from_path_index() fails an assertion when this happens,
because it expects an hlsl_ir_constant, so a check is added.
It also felt correct to emit an hlsl_fixme there, despite the
redundancy.
