[LLVMdev] Jump Theading/GVN bug - moving discussion to llvm-dev

[Rafael Espíndola]

On 25 February 2015 at 10:58, Daniel Berlin <dberlin at dberlin.org> wrote:
>
>
> On Wed, Feb 25, 2015 at 6:26 AM, Rafael Espíndola
> <rafael.espindola at gmail.com> wrote:
>>
>> > Maybe.
>> > My view is the ideal is either no-unreachable code, or unreachable
>> > blocks
>> > only contain terminators.
>>
>> I am definitely happy with both. What worries me is introducing a
>> special dominance rule for unreachable blocks.
>>
>> >> I don't think that rejecting
>> >>
>> >>   %a = getelementptr inbounds i8* %a, i64 1
>> >>
>> >> but accepting
>> >>
>> >>   %a = getelementptr inbounds i8* %b, i64 1
>> >>   %b = getelementptr inbounds i8* %a, i64 1
>> >>
>> >
>> > Does the verifier accept the latter right now?
>>
>> Yes. %a dominates %b and %b dominates %a, so it is valid.
>>
>
> So i'm confused.
>
> How does %b dominate %a?

all the zero paths from entry to %a pass by %b.

Cheers,
Rafael