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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 c/111319] Wrong code at -O2 on x86_64-linux-gnu
Date: Thu, 07 Sep 2023 08:09:51 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111319

--- Comment #4 from Shaohua Li <shaohua.li at inf dot ethz.ch> ---
(In reply to Xi Ruoyao from comment #3)
> Please try not to create more reports with "not sure if there is UB" esp.
> this UB should be obvious, and it's also detectable with
> -fsanitize=3Dundefined:
>=20
> t.c:13:7: runtime error: load of address 0x7ffd53183020 with insufficient
> space for an object of type 'int'
> 0x7ffd53183020: note: pointer points here
>  2a 56 00 00  01 00 00 00 00 00 00 00  00 14 1a ed ca 50 d4 0e  00 00 00 =
00
> 00 00 00 00  98 31 18 53
>               ^

UBSan only detects it at -O2 level and I used `-O0
-fsanitize=3Daddress,undefined` to detect if there is any report.

https://godbolt.org/z/zvcG8znvT=