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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/107561] [13 Regression] g++.dg/pr71488.C  and
 [g++.dg/warn/Warray-bounds-16.C -m32] regression due to -Wstringop-overflow
 problem
Date: Wed, 01 Mar 2023 14:55:17 +0000
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X-Bugzilla-Component: tree-optimization
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107561

--- Comment #18 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Does the FE really do that?
I certainly don't see it in the gimple dump:
void X::X (struct X * const this, int k)
{
  *this =3D {CLOBBER};
  {
    this->i =3D k;
    # USE =3D anything
    # CLB =3D anything
    bar ();
    _1 =3D this->i;
    _2 =3D k !=3D _1;
    _3 =3D (int) _2;
    this->j =3D _3;
  }
}
While if I compile the C variant after fixing it up:
struct X { int i, j; };
void bar (void);

void foo (struct X * restrict this, int k)
{
  this->i =3D k;
  bar ();
  this->j =3D this->i !=3D k;
}
it is there:
void foo (struct X * restrict this, int k)
{
  this->i =3D k;
  bar ();
  _1 =3D this->i;
  _2 =3D k !=3D _1;
  _3 =3D (int) _2;
  this->j =3D _3;
}=