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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/103534] [12 regression] Spurious -Wstringop-overflow warning with std::string concatencation
Date: Thu, 02 Dec 2021 21:03:21 +0000 [thread overview]
Message-ID: <bug-103534-4-VxZbUNsvzi@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-103534-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103534
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic
Last reconfirmed| |2021-12-02
Ever confirmed|0 |1
Blocks| |88443
CC| |msebor at gcc dot gnu.org
Status|UNCONFIRMED |NEW
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
The warning is for the memcpy() call in BB 12 with _73 being in the reported
excessive range:
<bb 12> [local count: 172868773]:
_209 = D.41961._M_dataplus._M_p;
_103 = _69 + 16;
__builtin_memcpy (_103, _209, _73); <<< 27->12 (T) _73 : long unsigned
int [18446744073709551600, +INF]
The range comes from BB 27:
=========== BB 27 ============
Imports: _73
Exports: _73
_73 long unsigned int [0, 0][18446744073709551600, +INF]
__size_74 const long unsigned int [0, 16]
<bb 27> [local count: 523844769]:
if (_73 != 0)
goto <bb 12>; [33.00%]
else
goto <bb 13>; [67.00%]
27->12 (T) _73 : long unsigned int [18446744073709551600, +INF]
27->12 (T) __size_74 : const long unsigned int [0, 15]
27->13 (F) _73 : long unsigned int [0, 0]
27->13 (F) __size_74 : const long unsigned int [16, 16]
The magic 16 most likely has to do with the small internal std::string buffer
that's 16 bytes big.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443
[Bug 88443] [meta-bug] bogus/missing -Wstringop-overflow warnings
next prev parent reply other threads:[~2021-12-02 21:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-02 19:47 [Bug c++/103534] New: " sss@li-snyder.org
2021-12-02 21:03 ` msebor at gcc dot gnu.org [this message]
2021-12-02 21:53 ` [Bug c++/103534] " pinskia at gcc dot gnu.org
2021-12-02 23:02 ` redi at gcc dot gnu.org
2021-12-02 23:19 ` msebor at gcc dot gnu.org
2021-12-06 8:16 ` rguenth at gcc dot gnu.org
2021-12-10 16:29 ` jason at gcc dot gnu.org
2021-12-10 16:30 ` jason at gcc dot gnu.org
2021-12-10 16:37 ` jason at gcc dot gnu.org
2021-12-10 16:53 ` msebor at gcc dot gnu.org
2021-12-10 17:04 ` jakub at gcc dot gnu.org
2021-12-11 4:58 ` cvs-commit at gcc dot gnu.org
2021-12-13 16:11 ` jason at gcc dot gnu.org
2021-12-13 16:11 ` jason at gcc dot gnu.org
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