https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85052
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Note, I've posted in the meantime a newer version of the patch that should handle the 2x narrowing or 2x widening cases better, see https://gcc.gnu.org/ml/gcc-patches/2019-01/msg00129.html
