On Fri, Jul 07, 2017 at 01:25:14AM -0700, Christopher Li wrote:
> On Fri, Jul 7, 2017 at 12:11 AM, Luc Van Oostenryck
> <luc.vanoostenryck@xxxxxxxxx> wrote:
> >> And remove_usage() is deleting the very same list
> >> from with in the loop. That is the bug.
> >
> > Strange. kill_use_list() is only iterated via insn->phi_list
> > or insn->arguments, not p->user.
> >
> > But yes, something is surely messing with the lists here.
> >
>
> I figure it out. It is a false alarm on the checking side.
> The condition I want to check can still cause a bug,
> but this report is not one of those conditions.
>
> It is cause by this code:
>
> static int dead_insn(struct instruction *insn, pseudo_t *src1,
> pseudo_t *src2, pseudo_t *src3)
> {
> struct pseudo_user *pu;
> FOR_EACH_PTR(insn->target->users, pu) {
> if (*pu->userp != VOID)
> return 0;
> } END_FOR_EACH_PTR(pu);
>
> So the return terminate the execution flow before
> reaching to the END_FOR_EACH_PTR(pu).
> The ptr->active still think we are in the loop
> But we are not.
OK, I see.
> It is a bug in the checking side. I still think this kind
> of checking is useful, but need some special handle
> of bail out of the ptr_list loop.
Yes, some kind of optional integrity checking or the kind of
checks you're doing here should be very usefull.
> Very sorry about that.
No problem, of course.
-- Luc
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