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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
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106811

--- 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=3D106811
>=20
> Nuno Lopes <nunoplopes at sapo dot pt> changed:
>=20
>            What    |Removed                     |Added
> -------------------------------------------------------------------------=
---
>                  CC|                            |nunoplopes at sapo dot pt
>=20
> --- Comment #1 from Nuno Lopes <nunoplopes at sapo dot pt> ---
> I suggest adopting the concept of poison that LLVM has. It allows operati=
ons 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
>=20
> 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.=