spirv: Add a vtn_get_mem_operands() helper

Add a vtn_get_mem_operands() helper to extract memory operand attached
to load/store operations.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6090>
1 file changed