https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87691
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- What happens if you make the attribute work for a MODE_INT union with a MODE_PARTIAL_INT first field that has MODE_SIZE of the union mode? Is there a generic way to query SImode for PSImode as defined in PARTIAL_INT_MODE (SI, 20, PSI); ? Or does one need to compare MODE_SIZE? Can there be multiple non-partial integer modes with the same size? Thus I suggest to patch handle_transparent_union_attribute according to the above.
