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From: "shaohua.li at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug sanitizer/107893] gcc trunk at -O0 (UBSan) misses a Null-pointer-dereference
Date: Mon, 28 Nov 2022 09:05:25 +0000	[thread overview]
Message-ID: <bug-107893-4-0ZQ4ubBkY1@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107893-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107893

--- Comment #4 from Li Shaohua <shaohua.li at inf dot ethz.ch> ---
(In reply to Richard Biener from comment #3)
> That is,
> 
> int main() {
>   int *a = 0;
>    (a[0] | a[1]) >> 056;
> }
> 
> works at -O0:
> 
> t.c:3:6: runtime error: load of null pointer of type 'int'

Yes, the a[1] access caused the segfault. For clang's UBsan, it emits an error
message for a[1]:

a.c:3:5: runtime error: applying non-zero offset 4 to null pointer
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior a.c:3:5 in


Is there a way for gcc's UBsan to warn such errors?

      parent reply	other threads:[~2022-11-28  9:05 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-28  8:40 [Bug sanitizer/107893] New: " shaohua.li at inf dot ethz.ch
2022-11-28  8:49 ` [Bug sanitizer/107893] " jakub at gcc dot gnu.org
2022-11-28  8:57 ` rguenth at gcc dot gnu.org
2022-11-28  8:58 ` rguenth at gcc dot gnu.org
2022-11-28  9:05 ` shaohua.li at inf dot ethz.ch [this message]

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