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From: "guojiufu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/102131] [12 Regression] wrong code at -O1 and
 above on x86_64-linux-gnu
Date: Tue, 31 Aug 2021 09:51:16 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102131

--- Comment #3 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
The issue may come from 'iv0 cmp iv1' transform:

   if (c<b) exit-loop
-->if (c>=3Db) in-loop
-->if (b<=3Dc) in-loop

  c: {4, +, 3}
  b: {1, +, 1}

  if ({1, +, 1} <=3D {4, +, 3})
  =3D=3D> if ({1,+,-2} <=3D {4,+,0}) //// here, error occur
  =3D=3D> if ({1,+,-2} < {5,+,0}) le-->lt=