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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/109071] -Warray-bounds warning when array
 index checked via inline
Date: Thu, 09 Mar 2023 10:18:35 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109071

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-03-09

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Yep, so we produce

<bb 2> [local count: 1073741824]:
if (index_3(D) > 3)
  goto <bb 4>; [33.00%]
else
  goto <bb 3>; [67.00%]

<bb 4> [local count: 354334800]:
warn ();
*ptr_5(D) =3D 0;
_17 =3D MEM <struct nums> [(int *)sg_2(D)].vals[index_3(D)];
warn ();

<bb 5> [local count: 1073741824]:
# _18 =3D PHI <_14(3), _17(4)>
*ptr_5(D) =3D _18;
return;

(and BB 3 with a BB4 duplicate w/o warn () calls).  If warn () were
noreturn this wouldn't happen.

And yes, we do have (plenty?) duplicates.=