[Bug tree-optimization/126906] back threader does not thread paths into unreachable edges but DOM does

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126906

--- Comment #11 from rguenther at suse dot de <rguenther at suse dot de> ---
On Wed, 2 Sep 2026, aldyh at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126906
> 
> --- Comment #10 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
> (In reply to Aldy Hernandez from comment #7)
> > (In reply to Richard Biener from comment #5)
> > > (In reply to Aldy Hernandez from comment #4)
> 
> > BTW, neither of these commits have tests associated with them.  How about we
> > retroactively distill tests for them, commit them independently, so whatever
> > fix we come up with does not regress those?
> 
> For example, like this.
> 
> I’ve gone back in time and made testcases for the commits that fail without the
> original patches and pass with them.  They are reduced from the original
> preprocessed sources, and also contain a further reduced minimal testcase.
> 
> I have added Assisted-by tags to both patches, as all the work was done by AI. 
> Per our policy, tests are fair game, so I assume I can contribute as is?  I
> would adjust the commit message of course, as that was entirely generated.
> 
> Would something like this be appropriate?

Sure.  Please post them to gcc-patches (ISTR I did not have small
enough testcases that I thought were "stable" enough to work, 
jump-threading testcases tend to be quite fragile)