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From: "carlosgalvezp at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/106901] [13 Regression] False positive -Warray-bounds with -O2 or higher?
Date: Tue, 11 Oct 2022 12:28:33 +0000	[thread overview]
Message-ID: <bug-106901-4-peqM0UUOCd@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106901-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106901

--- Comment #7 from Carlos Galvez <carlosgalvezp at gmail dot com> ---
I understand the reasoning, but the loop _can_ executed in other cases where
the function is called with different arguments:

bar(vec, 5, 5);  // Warray-bounds, loop not executed, no runtime OOB.
bar(vec, 5, 4);  // No Warray-bounds, loop executed,  no runtime OOB.

There is no OOB access in either case, so the compiler is incorrect in claiming
there is one. If there were, the OOB access would show up in Valgrind or ASan,
which is not the case.

Please note that the presence of False Positives in basic compiler warnings
like Wall or Wextra damages the credibility of compiler warnings. Warnings that
may have FPs should go in a different category, or as part of a separate tool,
like a static analyzer.

      parent reply	other threads:[~2022-10-11 12:28 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-10 17:06 [Bug c++/106901] New: " carlosgalvezp at gmail dot com
2022-09-10 17:15 ` [Bug c++/106901] " pinskia at gcc dot gnu.org
2022-09-10 17:28 ` carlosgalvezp at gmail dot com
2022-09-10 17:32 ` pinskia at gcc dot gnu.org
2022-09-10 18:27 ` carlosgalvezp at gmail dot com
2022-09-11  8:31 ` carlosgalvezp at gmail dot com
2022-09-12  7:57 ` [Bug tree-optimization/106901] [13 Regression] " rguenth at gcc dot gnu.org
2022-10-11 12:28 ` carlosgalvezp at gmail dot com [this message]

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