http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50494
--- Comment #10 from Michael Meissner <meissner at gcc dot gnu.org> 2013-02-12 19:16:56 UTC --- If -fno-merge-constants (and the default -fsection-anchors) is used, then the correct alignment for the table is set (and Altivec memory instructions are used). At a guess, it is likely be in the gimplify_init_constructor function in gimplify.c.