https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92819
--- Comment #3 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- I guess the issue is specific to 2-element vectors: { 0, 3 } can be seen as inserting element 1 of the second vector into the first, of the first element of the second vector into the second.