https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93594
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Created attachment 47789 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47789&action=edit gcc10-pr93594-2.patch Actually, thinking about it some more, rather than having a special pattern to handle UNSPEC_CAST, if we change the cast patterns so that they are a vec_concat of the operand and UNSPEC_CAST that then represents just the uninitialized higher part, simplify-rtx.c is able to deal with it on its own.
