On Thu, May 05, 2022 at 11:44:59AM +0200, Richard Biener wrote:
> When we make stmts to execute unconditionally in ifcombine we have
> to make sure to rewrite stmts that can invoke undefined behavior
> on overflow into a form with defined overflow. That's possible
> for all but signed division for which we have to avoid the transform.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>
> This was developed as not working solution to fix PR105142 and
> I do not have a testcase that experiences wrong-code (but I only
> tried for about 10 minutes to construct one). Still the problem
> is obviously latent and we should fix it.
>
> Thus - OK for trunk?
>
> Thanks,
> Richard.
>
> 2022-04-04 Richard Biener <rguent...@suse.de>
>
> * tree-ssa-ifcombine.cc (bb_no_side_effects_p): Avoid executing
> divisions with undefined overflow unconditionally.
> (pass_tree_ifcombine::execute): Rewrite stmts with undefined
> overflow to defined.
LGTM.
Jakub
