On Mon, 22 Feb 2016, Richard Biener wrote:
> On Mon, 22 Feb 2016, Jakub Jelinek wrote:
>
> > On Mon, Feb 22, 2016 at 01:44:09PM +0100, Richard Biener wrote:
> > > --- 1079,1086 ----
> > > || !dominated_by_p (CDI_DOMINATORS,
> > > loop->latch, gimple_bb (stmt)))
> > > return;
> > > + if (cgraph_node::get (cfun->decl)->aliases (BUILT_IN_MEMSET))
> > > + return;
> >
> > Perhaps also punt here for:
> > BUILT_IN_MEMSET_CHK
> > BUILT_IN_TM_MEMSET
> > BUILT_IN_BZERO
> > ?
> >
> > > partition->kind = PKIND_MEMSET;
> > > partition->main_dr = single_store;
> > > partition->niter = nb_iter;
> > > *************** classify_partition (loop_p loop, struct
> > > *** 1135,1140 ****
> > > --- 1138,1146 ----
> > > }
> > > free_dependence_relation (ddr);
> > > loops.release ();
> > > + if (cgraph_node::get (cfun->decl)->aliases (BUILT_IN_MEMCPY)
> > > + || cgraph_node::get (cfun->decl)->aliases (BUILT_IN_MEMMOVE))
> > > + return;
> >
> > And here for
> > BUILT_IN_MEMCPY_CHK
> > BUILT_IN_TM_MEMCPY
> > BUILT_IN_TM_MEMCPY_RNWT
> > BUILT_IN_TM_MEMCPY_RTWN
> > BUILT_IN_MEMPCPY
> > BUILT_IN_MEMPCPY_CHK
> > BUILT_IN_MEMMOVE_CHK
> > BUILT_IN_TM_MEMMOVE
> > BUILT_IN_BCOPY
> > ?
>
> I'm going to wait for Honzas feedback. Testing all of the above
> looks expensive - if those are implemented in terms of memcpy/memset
> then hopefully in libc itself which hopefully always does local
> calls.
>
> It's not going to be an exhaustive check anyway, just a QOI one
> covering those cases we've seen in the wild. Esp. as indirection
> will break the detection (so does using asm(".alias XXX") which glibc
> does).
Ok, so maybe a better question to symtab would be if there is an
actual definition for what __builtin_FOO will call. Not really
whether that definition is cfun. Of course all the fortify
always-inline wrappers should not count as such (just in case
the symtab code is confused about those).
So,
bool symbol_table::have_definition (enum built_in_fn);
? Not sure how to best implement that either. asmname lookups are
expensive ...
Richard.
