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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/112335] missed optimization on reset and assign unique_ptr
Date: Wed, 01 Nov 2023 15:51:32 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112335

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
  __old_p_6 =3D MEM[(struct s * &)ps1_2(D)];
  MEM[(struct s * &)ps1_2(D)] =3D 0B;
  if (__old_p_6 !=3D 0B)
    goto <bb 3>; [53.47%]
  else
    goto <bb 4>; [46.53%]

  <bb 3> [local count: 574129752]:
  s::~s (__old_p_6);
  operator delete (__old_p_6, 1);

  <bb 4> [local count: 1073741824]:
  __p_4 =3D MEM[(struct s * &)ps2_3(D)];
  MEM[(struct s * &)ps2_3(D)] =3D 0B;
  __old_p_5 =3D MEM[(struct s * &)ps1_2(D)];

Well s::~s could touch the reference std::unique_ptr<s> (ps1).

So this could in theory be an invalid optimization.

I am not sure if that is the only issue here though.=