[PATCH 0/5] MR153: hlsl: Return hlsl_ir_node pointers from instruction constructors, part 1.

[Zebediah Figura (＠zfigura)]

The motivation for this is twofold.

Firstly, this makes code a little nicer to read, by virtue of removing a
ubiquitous &(...)->node.

Secondly, and more importantly, this allows for the possibility of constructors
returning a different instruction type than intended. The ultimate goal here is
to return a preallocated "error" instruction when allocation fails, instead of
returning NULL and propagating out-of-memory handling to the caller.