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 548893858C53; Sat,  8 Jul 2023 17:41:52 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 548893858C53
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1688838112;
	bh=puISQ8G6GG+7i2ii7OVqx6ppZwC8LaLq6tkAeA7wXmo=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=jb91Cr/DemGTQ+LYwuEYm93OanPfphlBKQsKvxVwXM1Ae+j1gknGs5aOfvhzW36qg
	 ETZJ1Rap7+8nvHz3qkWbIsijkPSfOH0Ho4HtZYbz+JRbCYkkWQTL0YlDn6/k+PAfju
	 B1jquiKgMeRG9ICD1HdUZfvZ6Wqbsn863LByHa9w=
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/110598] [14 Regression] wrong code on llvm-14.0.6 due to
 memcmp being miscompiled
Date: Sat, 08 Jul 2023 17:41:52 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: pinskia at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 14.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-110598-4-YXJeLgvoMz@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-110598-4@http.gcc.gnu.org/bugzilla/>
References: <bug-110598-4@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=3D110598

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is a C testcase:
```
#include <stdbool.h>

typedef unsigned long long u64;

#define MAX_SUBTARGET_WORDS 4

//[[gnu::noipa]]
int notequal(const void *a, const void *b)
{
        return __builtin_memcmp(a,b,MAX_SUBTARGET_WORDS*sizeof(u64)) !=3D 0;
}
typedef struct FeatureBitset {
  u64 Bits[MAX_SUBTARGET_WORDS];
}FeatureBitset;

__attribute__((noipa))
bool is_eq_buggy (const FeatureBitset * lf, const FeatureBitset * rf) {
        u64 Bits_l[MAX_SUBTARGET_WORDS];
        Bits_l[0] =3D lf->Bits[0]&1;
        Bits_l[1] =3D 0;
        Bits_l[2] =3D 0;
        Bits_l[3] =3D 0;
        u64 Bits_r[MAX_SUBTARGET_WORDS];
        Bits_r[0] =3D rf->Bits[0]&1;
        Bits_r[1] =3D 0;
        Bits_r[2] =3D 0;
        Bits_r[3] =3D 0;
        return !notequal(Bits_l, Bits_r);
}

__attribute__((noipa))
void bug(void) {
    FeatureBitset lf, rf;
    lf.Bits[0] =3D rf.Bits[0] =3D 1;
    lf.Bits[1] =3D rf.Bits[1] =3D 1;
    lf.Bits[2] =3D rf.Bits[2] =3D 1;
    lf.Bits[3] =3D rf.Bits[3] =3D 1;

    bool r =3D is_eq_buggy (&lf, &rf);
    if (!r) __builtin_trap();
}

__attribute__((noipa))
int main(void) {
    bug();
}
```

Again uncomment the attribute on notequal, if you want to see it works with=
out
inlining of memcmp here ...=