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From: "amacleod at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/104986] [12 Regression] bogus writing 1 byte into a
 region of size 0 with -fwrapv and -O2 -fpeel-loops since
 r12-4698-gf6d012338bf87f42
Date: Wed, 23 Mar 2022 14:58:53 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104986

--- Comment #7 from Andrew Macleod <amacleod at redhat dot com> ---
and I forgot to show to dom3 output which did the transformation:

j.c.195t.dom3:Match-and-simplified (sizetype) nb_66 to 18446744073709551615
j.c.195t.dom3:Optimizing statement _2 =3D (sizetype) nb_66;
j.c.195t.dom3:  Replaced 'nb_66' with constant '-1'
j.c.195t.dom3:  nb_66 =3D -1;

but for whatever reason it could not reduce nb_58 to anything better than [=
-1,
0]

nb_58 =3D prephitmp_30 + -5;
Intersecting
  int [-1, 0]
and
  int [-1, 4]
to
  int [-1, 0]=