From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 45FB73851891; Fri, 18 Nov 2022 08:42:45 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 45FB73851891
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1668760965;
	bh=b9zAhUi5wdiGoQOA0I5p+J5ofPkOF/KgvmJ+Jzz+TTg=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=E7tC3BIrSkSki/ycZcLixQGoVyp2dh7MkQogSQTkoIFiolOXXqrR3KMhAHVroNhVj
	 NrNtFtW+ZFW5NYS5eHaF7NNZmaQEms5mkbYd6npVtVPTOofayUrP+CwrQVdbq3JCvP
	 8vgysAk7o+5976urwMJ9/f+qxjtpcJV3DFMANACI=
From: "slyfox at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/107661] [13 Regression] lambdas get merged
 incorrectly in tempaltes, cause llvm-12 miscompilation since
 r13-3358-ge0403e95689af7
Date: Fri, 18 Nov 2022 08:42:41 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: blocker
X-Bugzilla-Who: slyfox at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P1
X-Bugzilla-Assigned-To: jamborm at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 13.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-107661-4-oGwPqiWQ5h@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-107661-4@http.gcc.gnu.org/bugzilla/>
References: <bug-107661-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107661

--- Comment #8 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
(In reply to Sergei Trofimovich from comment #7)
> When debug reports unqualified `Aggregate replacements: 1[0]=3Dcallback_f=
n`
> does it mean ipa-cp does not distinguish between:
>   * static void function_ref::callback_fn(void*) [with Callable =3D
> seemingly_unused_foo(int)::L]/30.
>   * static void function_ref::callback_fn(void*) [with Callable =3D void(=
)]/29.
> ?
>=20
> I suspect it does not and that results in a wrong callback_fn inline.

That was not it. Identical names is a printing artifact.

I shrunk example a bit more to avoid any overloads and crashes. Now example
just prints different things.

// How to break:
// $ ./gcc-13-snap/bin/gcc -O1 -fipa-cp -fipa-cp-clone                 a.cc=
 -o
a && ./a
// GOOD
// BAD
// $ ./gcc-13-snap/bin/gcc -O1 -fipa-cp -fipa-cp-clone -DDISABLE_HACK a.cc =
-o a
&& ./a
// GOOD
// GOOD

// #define DISABLE_HACK 1

#include <stdio.h>

struct R {} RGood;
struct L {} LBad;

static void L_run(void) { fprintf(stderr, "BAD\n"); }
static void callback_fn_L(void) { L_run(); }
static void callback_fn_R(void) { fprintf(stderr, "GOOD\n"); }

struct function_ref {
  void (*callback)(void) =3D nullptr;

  function_ref(L * pl) { callback =3D callback_fn_L; }
  function_ref(R * pr) { callback =3D callback_fn_R; }
};

// allow one level of recursion to call callback twice
static int is_recur(void) {
    static int n =3D 0;
    switch (n++) {
      case 0: return 1;
      default: return 0;
    }
}

static void do3(volatile int * punused, function_ref Expired) {
  Expired.callback();

  if (is_recur())
      do3(punused, Expired);
}

static void do1(function_ref Expired) {
  volatile int unused =3D 42;

  do3(&unused, Expired);
}

int main(void) { do1(&RGood); }

#if defined(DISABLE_HACK)
#else
void seemingly_unused_foo(void) { do1(&LBad); }
#endif=