[Bug tree-optimization/85315] missed range optimisation opportunity for derefences where index must be 0 or otherwise constrained

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85315

--- Comment #9 from Martin Sebor <msebor at gcc dot gnu.org> ---
(In reply to rguent...@suse.de from comment #8)
> > I asked Peter about that yesterday.  The access to *p in your example is 
> > still
> > meant to be undefined even under the proposed provenance rules.  Here's his
> 
> Even with -fno-provenance?

With -fno-provenance the access would be valid under the proposed rules.

> I think for the compiler "unspecified" works as well - we can still
> unconditionally optimize it to return false, correct?

Correct.