After lowering the derefs path to a single offset node, there was no way
of knowing the type of the referenced part of the variable. This little
modification allows to avoid having to pass the data type everywhere and
it is required for supporting instructions that reference objects
components within struct types.
Since deref->data_type allows us to retrieve the type of the deref,
deref->offset_regset is no longer necessary.
lower_narrowing_casts() currently creates a new cast calling
hlsl_new_cast(). This cast may be redundant, but it is not folded, which
is making SM1 emit an unnecessary fixme in some shaders:
Aborting due to not yet implemented feature: SM1 "cast" expression.
Other passes that call hlsl_new_cast() are lower_int_division() and
lower_int_modulus(), so the new fold_redundant_casts() pass is called
after these as well.
Non-constant vector indexing is not solved with relative addressing
in the register indexes because this indexation cannot be at the level
of register-components.
Mathematical operations must be used instead.
