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From: "qinzhao at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/116316] incorrect code with -O2
Date: Fri, 09 Aug 2024 19:15:55 +0000 [thread overview]
Message-ID: <bug-116316-4-zjNaIwpiW3@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-116316-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116316
--- Comment #2 from qinzhao at gcc dot gnu.org ---
(In reply to Andrew Pinski from comment #1)
> <source>:13:6: warning: dereferencing type-punned pointer will break
> strict-aliasing rules [-Wstrict-aliasing]
> 13 | *(size_t *)(&(array_annotated->b)) = 10;
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> -fno-strict-aliasing fixes it.
>
> You access `array_annotated->b` via size_t (which is most likely `unsigned
> long`) and via int. Since long and int are distant types (and not signed
> versions of each other) they don't alias.
Okay, I see. thanks a lot.
I did suspect that this is a source code issue, now confirmed. -:)
prev parent reply other threads:[~2024-08-09 19:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-09 18:42 [Bug tree-optimization/116316] New: " qinzhao at gcc dot gnu.org
2024-08-09 18:51 ` [Bug tree-optimization/116316] " pinskia at gcc dot gnu.org
2024-08-09 19:15 ` qinzhao at gcc dot gnu.org [this message]
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