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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114425] wrong code with _BitInt()
 __builtin_add_overflow_p() and __builtin_mul_overflow_p() at -O2
Date: Fri, 22 Mar 2024 14:18:23 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114425

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Though, guess it would help if evrp avoided undesirable propagation here:
It is changing:
   <bb 2> :
   # DEBUG BEGIN_STMT
   _8 =3D .ADD_OVERFLOW (d_7(D), 0);
   _1 =3D IMAGPART_EXPR <_8>;
   _2 =3D (_Bool) _1;
   # DEBUG o =3D> (int) _2
   # DEBUG BEGIN_STMT
   a.0_3 =3D a;
   _4 =3D (_BitInt(2000)) a.0_3;
   c.1_5 =3D c;
   m_11 =3D _4 * c.1_5;
   # DEBUG m =3D> m_11
   # DEBUG BEGIN_STMT
   u_12 =3D (unsigned int) m_11;
   # DEBUG u =3D> u_12
   # DEBUG BEGIN_STMT
-  o.2_6 =3D (unsigned int) _2;
+  o.2_6 =3D (unsigned int) _1;
   _13 =3D o.2_6 + u_12;
   return _13;

 }
which is surely possible because IMAGPART_EXPR of .{ADD,SUB,MUL}_OVERFLOW h=
as
[0, 1]
range, but for such large/huge _BitInt IMAGPART_EXPR it extends the lifetim=
e of
an expensive large variable rather than just being a boolean.=