Hi, On Tue, Nov 28 2023, Jan Hubicka wrote: >> 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. >
Is my patch OK then? (Apart from making one of the testcases x86_64-only, as Andrew pointed out, which I wanted to do but the line somehow got lost. Making the testcase more general is fairly low on my contested TODO list and the testing depends on a specific instruction trapping.) Thanks, Martin
