spirv: don't generate union tag type if it doesnt exist
Previously the tag type was generated even if it was nonexistant,
triggering an assertion that an integer type should never have
zero bits. Now its only generated when the tag type is actually emitted.
d7ddaf64a2Robin Voetter committed on 5/20/2023, 3:48:38 PM· committed by Ali Chraghiparentfedc9a1