On Tue, Oct 9, 2018 at 11:23 AM Jakub Jelinek <ja...@redhat.com> wrote: > > On Tue, Oct 09, 2018 at 11:08:44AM +0200, Richard Biener wrote: > > On Tue, Oct 9, 2018 at 11:00 AM Alexander Monakov <amona...@ispras.ru> > > wrote: > > > > > > On Tue, 9 Oct 2018, Richard Biener wrote: > > > > > > > > then we cannot set the alignment of i_1 at/after k = *i_1 because doing > > > > so would > > > > affect the alignment test which we'd then optimize away. We'd need to > > > > introduce > > > > a SSA copy to get a new SSA name but that would be optimized away > > > > quickly. > > > > > > We preserve __builtin_assume_aligned up to pass-fold-all-builtins, so > > > would it > > > work to emit it just before the memcpy > > > > > > i_2 = __builtin_assume_aligned(i_1, 4); > > > __builtin_memcpy(j, i_2, 32); > > > > > > in theory? > > > > That's still before RTL expansion so I'm not sure that is enough. > > But we likely won't invalidate the computed SSA_NAME_INFO afterwards.
But we've propagated out the i_2 = i_1 copy, no? Richard. > Jakub
