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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109546] [13/14 Regression]  Missed Dead Code
 Elimination when using __builtin_unreachable since r13-3596-ge7310e24b1c0ca
Date: Fri, 21 Apr 2023 18:55:49 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109546

--- Comment #3 from Andrew Macleod <amacleod at redhat dot com> ---
Patch in testing.

when deciding to  fold condition of builtin_unreachable, VRP is failing to
recognize that given=20

  if (ptr =3D=3D &x)
    __builtin_unreachable ()

&x is not a representable range, and thus should not be eliminated early ev=
en
though it satisfies the other criteria.

it just sees it as a symbolic value =3D=3D CONSTANT  and thinks its smart e=
nough
when it isn't.=