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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/102216] False positive warray-bounds with -O2
Date: Mon, 06 Sep 2021 20:46:14 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102216

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> The problem is dead code:
>   language_names_p_9 =3D &MEM <const char *> [(void *)_4 + 24B];
>   MEM[(const char * *)_4 + 24B] =3D "";
>   MEM[(const char * *)_4 + 32B] =3D "";
>   MEM[(const char * *)_4 + 40B] =3D 0B;
>   _2 =3D _4 + 40;
>   D.50907._M_comp =3D compare_cstrings;
>   __comp =3D D.50907;
>   if (_2 !=3D language_names_p_9)
>     goto <bb 3>; [53.47%]
>   else
>     goto <bb 12>; [46.53%]
>=20
>   <bb 3> [local count: 574129759]:
>   _15 =3D _2 - language_names_p_9;
>   _16 =3D _15 /[ex] 8;
>=20
> ...
>  _22 =3D _2 - language_names_p_9;


I have a (hack) patch which removes the first if statement but still does n=
ot
fold _15 and _22.=