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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/111151] [12/13/14 Regression] Wrong code at -O0 on
 x86_64-pc-linux-gnu
Date: Fri, 22 Mar 2024 17:29:08 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111151

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #3)
> @@ -6970,8 +6972,11 @@ extract_muldiv_1 (tree t, tree c, enum tree_code
> code, tree wide_type,
>=20=20
>        /* MIN (a, b) / 5 -> MIN (a / 5, b / 5)  */
>        sub_strict_overflow_p =3D false;
> -      if ((t1 =3D extract_muldiv (op0, c, code, wide_type,
> -                               &sub_strict_overflow_p)) !=3D 0
> +      if ((wide_type
> +          ? TYPE_OVERFLOW_UNDEFINED (wide_type)
> +          : TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))=20
> +         && (t1 =3D extract_muldiv (op0, c, code, wide_type,
> +                                  &sub_strict_overflow_p)) !=3D 0
>           && (t2 =3D extract_muldiv (op1, c, code, wide_type,
>                                    &sub_strict_overflow_p)) !=3D 0)
>         {

Isn't it fine as is for unsigned divisions and modulos?
I'd think the only problem is TYPE_OVERFLOW_WRAPS code =3D=3D MULT_EXPR or
!TYPE_UNSIGNED && TYPE_OVERFLOW_WRAPS division/modulo (say -fwrapv MIN (a, =
b) /
-1
-> MAX (a / -1, b / -1) transformation wouldn't be correct for a INT_MIN b =
0,
because the first one is INT_MIN / -1 aka. INT_MIN, while the latter is 0
or perhaps TYPE_OVERFLOW_SANITIZED should be punted on as well.=