From: Jakub Jelinek <jakub@redhat.com>
To: Richard Biener <rguenther@suse.de>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] rewrite undefined overflow to defined in ifcombine
Date: Thu, 5 May 2022 11:46:42 +0200 [thread overview]
Message-ID: <YnOdAqWemrkkOTCD@tucnak> (raw)
In-Reply-To: <20220505094459.912A313A65@imap2.suse-dmz.suse.de>
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 <rguenther@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
prev parent reply other threads:[~2022-05-05 9:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-05 9:44 Richard Biener
2022-05-05 9:46 ` Jakub Jelinek [this message]
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