https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116416
--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Created attachment 59834 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59834&action=edit gcc15-pr116416-opt.patch I've tried to implement a simple optimization (on top of the PR118002 fix), where we clear just a subobject that needs padding or other uninitialized bits cleared rather than the whole object. On the pr78687.C testcase, this results (in gimple dump) in: - D.10177 = {}; + D.10177._storage.D.9582.D.9163._tail.D.9221._tail.D.9280._head = {}; because as I wrote, the single byte option_2() is the only part of the object that actually needs to have padding bits cleared, rather than the rather large whole object. Though, SRA still punts even on that.
