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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/105562] std::function<bool(char)>::_M_invoker may be used uninitialized in std::regex move with -fno-strict-aliasing
Date: Thu, 12 May 2022 09:54:12 +0000 [thread overview]
Message-ID: <bug-105562-4-OMAccDQp4a@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-105562-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105562
--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #9)
> Perhaps with -fno-strict-aliasing we think the store to *this might alias
> with it? Though, that shouldn't be about TBAA but simple points-to
> analysis, where obviously this as function argument can't point to a local
> var in the function.
It's the
MEM[(long unsigned int *)_12 + -8B] ={v} {CLOBBER};
store, __tmp escapes in the indirect call
_48 (&MEM[(struct _Function_base *)&__tmp + 16B]._M_functor,
&MEM[(struct _Function_base *)&__tmp + 16B]._M_functor, 3);
and _12 points to escaped (its loaded from this).
I guess since a CLOBBER isn't technically a "store" we could ignore it
and continue looking for data to load. If it would alias then we'd
access (partly) 'uninitialized' memory which would invoke undefined
behavior.
next prev parent reply other threads:[~2022-05-12 9:54 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-11 10:48 [Bug libstdc++/105562] New: [12 Regression] std::function<bool(char)>::_M_invoker may be used uninitialized in std:regex " andrey.vihrov at gmail dot com
2022-05-11 10:55 ` [Bug libstdc++/105562] [12/13 Regression] std::function<bool(char)>::_M_invoker may be used uninitialized in std::regex move with -fno-strict-aliasing since r12-6216-g5a431b60d1f22199 marxin at gcc dot gnu.org
2022-05-11 11:05 ` rguenth at gcc dot gnu.org
2022-05-11 11:32 ` andrey.vihrov at gmail dot com
2022-05-11 11:54 ` redi at gcc dot gnu.org
2022-05-11 12:44 ` [Bug libstdc++/105562] std::function<bool(char)>::_M_invoker may be used uninitialized in std::regex move with -fno-strict-aliasing redi at gcc dot gnu.org
2022-05-11 12:56 ` redi at gcc dot gnu.org
2022-05-11 12:57 ` redi at gcc dot gnu.org
2022-05-11 12:59 ` redi at gcc dot gnu.org
2022-05-12 9:27 ` jakub at gcc dot gnu.org
2022-05-12 9:35 ` jakub at gcc dot gnu.org
2022-05-12 9:54 ` rguenth at gcc dot gnu.org [this message]
2022-05-12 9:57 ` rguenth at gcc dot gnu.org
2022-05-12 10:07 ` rguenth at gcc dot gnu.org
2022-05-12 11:27 ` cvs-commit at gcc dot gnu.org
2022-05-12 11:28 ` [Bug libstdc++/105562] [12 Regression] " rguenth at gcc dot gnu.org
2022-05-19 12:47 ` cvs-commit at gcc dot gnu.org
2022-05-19 12:50 ` rguenth at gcc dot gnu.org
2022-10-22 0:50 ` pinskia at gcc dot gnu.org
2023-05-26 21:40 ` urisimchoni at gmail dot com
2023-09-12 12:04 ` jakub1miernik at gmail dot com
2023-12-06 10:03 ` romain.geissler at amadeus dot com
2023-12-06 10:26 ` rguenth at gcc dot gnu.org
2023-12-06 10:35 ` romain.geissler at amadeus dot com
2023-12-06 10:43 ` rguenther at suse dot de
2023-12-06 10:50 ` jakub at gcc dot gnu.org
2023-12-06 11:13 ` romain.geissler at amadeus dot com
2023-12-06 11:16 ` sjames at gcc dot gnu.org
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