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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/106811] GENERIC and GIMPLE IL undefined behavior needs documenting
Date: Sat, 05 Nov 2022 14:22:42 +0000	[thread overview]
Message-ID: <bug-106811-4-w8nZs20kPn@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106811-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106811

--- Comment #2 from rguenther at suse dot de <rguenther at suse dot de> ---
On Wed, 2 Nov 2022, nunoplopes at sapo dot pt wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106811
> 
> Nuno Lopes <nunoplopes at sapo dot pt> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |nunoplopes at sapo dot pt
> 
> --- Comment #1 from Nuno Lopes <nunoplopes at sapo dot pt> ---
> I suggest adopting the concept of poison that LLVM has. It allows operations to
> have undefined behavior, while still allow them to be moved freely.
> I have some slides that may serve as an introduction to the topic:
> https://web.ist.utl.pt/nuno.lopes/pres/ub-vmcai19.pdf
> 
> Happy to discuss further.

I've seen this before but I don't really see how that manages to avoid
issues when making conditional undefined behavior invoking stmts
unconditional.

  parent reply	other threads:[~2022-11-05 14:22 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-02  6:49 [Bug middle-end/106811] New: " rguenth at gcc dot gnu.org
2022-11-02  9:59 ` [Bug middle-end/106811] " nunoplopes at sapo dot pt
2022-11-05 14:22 ` rguenther at suse dot de [this message]
2022-11-07 18:07 ` nunoplopes at sapo dot pt
2022-11-07 18:17 ` rguenther at suse dot de
2023-09-15 10:22 ` rguenth at gcc dot gnu.org

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