spirv: Handle all OpenCL conversion ops with full rounding

This is done for kernels via the new convert_alu_types intrinsic.  For
Vulkan and OpenGL, we maintain the old path so that drivers don't have
to add that lowering pass.

Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6945>
2 files changed