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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug sanitizer/112748] memmove(ptr, ptr, n) call optimized out even at -O0 with -fsanitize=undefined
Date: Wed, 29 Nov 2023 06:53:04 +0000	[thread overview]
Message-ID: <bug-112748-4-boPywLPIej@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-112748-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112748

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |documentation
                 CC|                            |dodji at gcc dot gnu.org,
                   |                            |dvyukov at gcc dot gnu.org,
                   |                            |jakub at gcc dot gnu.org,
                   |                            |kcc at gcc dot gnu.org,
                   |                            |marxin at gcc dot gnu.org
     Ever confirmed|0                           |1
          Component|middle-end                  |sanitizer
   Last reconfirmed|                            |2023-11-29

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  We fold all calls early after gimplification and folding is known
to also affect -O0.  This behavior is independent of sanitizing which happens
partly before and partly only after this folding takes place.

We also simplify 1 + 1 or x + 0 with -O0 or turn printf("%s", "Hello")
into puts("Hello") for example.

Documenting this behavior might be good.  Gating some of the simplifications
on optimization might be also reasonable.

  parent reply	other threads:[~2023-11-29  6:53 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-28 18:02 [Bug c/112748] New: " tavianator at gmail dot com
2023-11-28 18:08 ` [Bug middle-end/112748] " pinskia at gcc dot gnu.org
2023-11-28 18:21 ` tavianator at gmail dot com
2023-11-29  6:53 ` rguenth at gcc dot gnu.org [this message]
2023-11-30 19:31 ` [Bug sanitizer/112748] " jakub at gcc dot gnu.org

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