> On Tue, 28 Nov 2023, Martin Jambor wrote: > > > On Tue, Nov 28 2023, Richard Biener wrote: > > > On Mon, 27 Nov 2023, Martin Jambor wrote: > > > > > >> Hi, > > >> > > >> The enhancement to address PR 109849 contained an importsnt thinko, > > >> and that any reference that is passed to a function and does not > > >> escape, must also not happen to be aliased by the return value of the > > >> function. This has quickly transpired as bugs PR 112711 and PR > > >> 112721. > > >> > > >> Just as IPA-modref does a good enough job to allow us to rely on the > > >> escaped set of variables, it sems to be doing well also on updating > > >> EAF_NOT_RETURNED_DIRECTLY call argument flag which happens to address > > >> exactly the situation we need to avoid. Of course, if a call > > >> statement ignores any returned value, we also do not need to check the > > >> flag. > > > > > > But what about EAF_NOT_RETURNED_INDIRECTLY? Don't you need to > > > verify the parameter doesn't escape through the return at all? > > > > > > > I thought EAF_NOT_RETURNED_INDIRECTLY prohibits things like "return > > param->next" but those are not a problem (whatever next points to cannot > > be an SRA candidate and any ADDR_EXPR storing its address there would > > trigger a disqualification or at least an assert). But I guess I am > > wrong, what is actually the exact meaning of the flag? > > I thought it's return (x.ptr = param, &x); > > so the parameter is reachable from the return value. > > But let's Honza answer... It is same difference as direct/indirect escape. so it check whether values pointed to by arg can be possibly returned. Indeed maybe we should think of better name - the other interpretation did not even occur to me, but it makes sense.
Honza > > Richard.
