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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/110228] [14 Regression] llvm-16 miscompiled due to
 an maybe uninitialized and optimizations saying that the uninitialized has a
 nonzero bits of 1.
Date: Thu, 15 Jun 2023 04:50:39 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110228

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
That is these exports:
2->3  (T) c.5_7 :       [irange] int [1334323000, +INF] NONZERO 0x7fffffff
2->3  (T) _8 :  [irange] long unsigned int [1334323000, 2147483647] NONZERO
0x7fffffff
2->3  (T) b.6_9 :       [irange] int [1334323000, +INF] NONZERO 0x7fffffff
2->3  (T) _10 :         [irange] long unsigned int [1334323000, 2147483647]
NONZERO 0x7fffffff
2->3  (T) _11 :         [irange] long unsigned int [3481806647, 3481806649]
NONZERO 0xcf88273f
2->3  (T) _12 :         [irange] long unsigned int [0, 2] NONZERO 0x3

seems wrong.
We originally had:
    c.5_7 =3D c;
    _8 =3D (long unsigned int) c.5_7;
    b.6_9 =3D b;
    _10 =3D (long unsigned int) b.6_9;
    _11 =3D _8 + _10;
    _12 =3D _11 + 18446744070227744969;
    if (_12 <=3D 2)

so _11 export seems correct but _8 and _10 added together needs to be make =
_11.
Since it is unsigned, the whole range for both numbers can make _11's range;
that is we can't say anything about _8 or _10. Even if _11 is signed, I don=
't
see how _8 and _10 could be described at all ... since _8 could be 0 and _10
could be 3481806647 and the range that is exported for _8 does not even inc=
lude
0.

Unless I am missing something obvious here.=