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From: "rearnsha at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/106187] armhf: Miscompilation at O2 level (O0 / O1 are working)
Date: Mon, 25 Jul 2022 09:44:58 +0000	[thread overview]
Message-ID: <bug-106187-4-gevuK3B5v7@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106187-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106187

--- Comment #35 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
> There's no union involved here though but a memcpy used in BitCast.
Agreed, but by creating a shared stack slot, the compiler is effectively
creating a union of its own, and I think that needs to be accounted for. 
update_alias_info_with_stack_vars handles the cases where we have pointers (at
the gimple level) into a shared stack slot, but doesn't (AFAICT) cater for RTL
lowering creating additional pointers (as it must since all objects on the
stack ultimately have to be addressed).

So if we create a shared stack slot for objects of different types, why do we
not also create an alias set for the combination of such types, much as we
would do for a union?

  parent reply	other threads:[~2022-07-25  9:44 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-04 16:23 [Bug c++/106187] New: armhf: Miscompilation with -O2 mathieu.malaterre at gmail dot com
2022-07-04 16:37 ` [Bug c++/106187] " mathieu.malaterre at gmail dot com
2022-07-04 16:37 ` mathieu.malaterre at gmail dot com
2022-07-04 16:42 ` [Bug c++/106187] armhf: Miscompilation at all optimization levels mathieu.malaterre at gmail dot com
2022-07-04 20:19 ` pinskia at gcc dot gnu.org
2022-07-04 20:22 ` pinskia at gcc dot gnu.org
2022-07-05  7:18 ` [Bug target/106187] " mathieu.malaterre at gmail dot com
2022-07-05  7:46 ` [Bug target/106187] armhf: Miscompilation at O2 level (O0 / O1 are working) jan.wassenberg at gmail dot com
2022-07-05  8:00 ` mathieu.malaterre at gmail dot com
2022-07-07  7:50 ` mathieu.malaterre at gmail dot com
2022-07-07  8:00 ` mathieu.malaterre at gmail dot com
2022-07-07  9:38 ` rearnsha at gcc dot gnu.org
2022-07-08  9:01 ` mathieu.malaterre at gmail dot com
2022-07-08  9:01 ` mathieu.malaterre at gmail dot com
2022-07-08  9:03 ` mathieu.malaterre at gmail dot com
2022-07-08 13:50 ` rearnsha at gcc dot gnu.org
2022-07-08 13:59 ` malat at debian dot org
2022-07-08 14:16 ` rearnsha at gcc dot gnu.org
2022-07-08 14:18 ` malat at debian dot org
2022-07-08 14:51 ` rearnsha at gcc dot gnu.org
2022-07-08 15:03 ` malat at debian dot org
2022-07-08 17:24 ` rearnsha at gcc dot gnu.org
2022-07-08 17:31 ` rearnsha at gcc dot gnu.org
2022-07-08 19:27 ` jan.wassenberg at gmail dot com
2022-07-14 13:03 ` rearnsha at gcc dot gnu.org
2022-07-14 13:18 ` rearnsha at gcc dot gnu.org
2022-07-14 16:09 ` pinskia at gcc dot gnu.org
2022-07-18 15:45 ` rearnsha at gcc dot gnu.org
2022-07-18 15:48 ` rearnsha at gcc dot gnu.org
2022-07-19  7:27 ` rguenth at gcc dot gnu.org
2022-07-19  9:00 ` rearnsha at gcc dot gnu.org
2022-07-19  9:13 ` rguenth at gcc dot gnu.org
2022-07-21  9:25 ` rearnsha at gcc dot gnu.org
2022-07-22 12:52 ` rearnsha at gcc dot gnu.org
2022-07-22 13:24 ` rearnsha at gcc dot gnu.org
2022-07-25  6:12 ` rguenth at gcc dot gnu.org
2022-07-25  9:44 ` rearnsha at gcc dot gnu.org [this message]
2022-07-25  9:50 ` rguenther at suse dot de
2022-07-25  9:59 ` rearnsha at gcc dot gnu.org
2022-07-25 10:24 ` rguenth at gcc dot gnu.org
2022-07-25 10:26 ` [Bug rtl-optimization/106187] " rguenth at gcc dot gnu.org
2022-07-25 10:33 ` rearnsha at gcc dot gnu.org
2022-07-25 10:42 ` rguenth at gcc dot gnu.org
2022-07-25 10:48 ` rearnsha at gcc dot gnu.org
2022-07-25 11:03 ` rguenther at suse dot de
2022-07-25 11:05 ` rguenth at gcc dot gnu.org
2022-07-25 13:04 ` rearnsha at gcc dot gnu.org
2022-07-25 14:45 ` rguenther at suse dot de
2022-07-27 13:35 ` rearnsha at gcc dot gnu.org
2022-07-28 16:51 ` rearnsha at gcc dot gnu.org
2022-08-03  9:07 ` cvs-commit at gcc dot gnu.org
2022-08-03  9:16 ` rearnsha at gcc dot gnu.org
2022-08-10  7:06 ` malat at debian dot org
2022-08-10  7:11 ` pinskia at gcc dot gnu.org
2022-09-02  9:28 ` malat at debian dot org
2022-09-02 12:30 ` cvs-commit at gcc dot gnu.org
2022-09-02 12:32 ` rearnsha at gcc dot gnu.org
2022-09-02 14:07 ` cvs-commit at gcc dot gnu.org
2022-09-27 15:28 ` malat at debian dot org
2022-09-27 15:54 ` rearnsha at gcc dot gnu.org
2024-01-20 17:20 ` pinskia at gcc dot gnu.org

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