[Bug tree-optimization/101750] [12 regression] g++.dg/vect/pr99149.cc fails on aarch64 since r12-2523

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101750

--- Comment #3 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 3 Aug 2021, tnfchris at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101750
> 
> --- Comment #2 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
> (In reply to Richard Biener from comment #1)
> > On x86_64 the testcase is optimized to the following now:
> > not sure how we conclude that 'n' is not written to anywhere.  The issue
> > persists even when I rename 'main' to 'foo' (when it's 'main' we could indeed
> > conclude so).
> 
> I think it's because it's concluding that the access of `h` must trap since `h`
> is local and uninitialized.

Hmm, but 'h' is a member of the class object 'n' which is global.

> That also explains the abort. Looks like the reducer needs some slight
> adjustment. if I declare `h` static then it works again.