vkd3d-shader/ir: Minimise temp usage.
Overall this is simpler, results in less verbose SPIR-V code which is easier to debug, and eliminates stuttering issues in Horizon Zero Dawn when run in an SM 6 dev branch with Gio's cfg4 structuriser branch.
Overall this is simpler, results in less verbose SPIR-V code which is easier to debug, and eliminates stuttering issues in Horizon Zero Dawn when run in an SM 6 dev branch with Gio's cfg4 structuriser branch.