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... Richard.
