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From: "rguenth at gcc dot gnu.org" <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: Mon, 12 Sep 2022 07:57:21 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
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X-Bugzilla-Status: RESOLVED
X-Bugzilla-Resolution: INVALID
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106901

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
            Summary|False positive              |[13 Regression] False
                   |-Warray-bounds with -O2 or  |positive -Warray-bounds
                   |higher?                     |with -O2 or higher?
          Component|c++                         |tree-optimization
      Known to work|                            |12.2.0
             Blocks|                            |56456
         Resolution|---                         |INVALID
   Target Milestone|---                         |13.0

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think this is invalid.  We inline bar into foo and see

 if  (size < 5)
  return false;
 for (i =3D 5; i < size; ++i)
   if (vec[i] !=3D 0)
   ....

so we know that vec[5] is accessed when the loop is executed which is out of
bounds and we diagnose that.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D56456
[Bug 56456] [meta-bug] bogus/missing -Warray-bounds=