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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/108637] ASAN at -O2 misses a stack-use-after-scope
Date: Thu, 02 Feb 2023 22:06:33 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108637

Li Shaohua <shaohua.li at inf dot ethz.ch> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|INVALID                     |---
             Status|RESOLVED                    |UNCONFIRMED

--- Comment #3 from Li Shaohua <shaohua.li at inf dot ethz.ch> ---
(In reply to Li Shaohua from comment #2)
> (In reply to Andrew Pinski from comment #1)
> > PRE removes the load/stores from/to *f .
> > Basically the compiler is able to remove the use-after-scope usage with=
 -O2
> > and above.
>=20
> Well, this makes sense to me while in this case only -O2 not other opt
> levels did not report this use-after-scope usage.

I looked into this again and found that for GCC-12, it was indeed the case.=
 But
for the trunk, I indeed observed that PRE did not optimize away load/store.

Compiler explorer: https://godbolt.org/z/sb658P1cM=