https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90811
--- Comment #16 from Jakub Jelinek <jakub at gcc dot gnu.org> --- estimate_stack_frame_size is definitely the wrong spot to change DECL_ALIGN of variables, that is a routine for inlining heuristics and shouldn't have such side-effects. It can be done in some other pass of course, but for offloading to work properly, that needs to be after IPA.
