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 62CE63858D39; Fri,  3 Nov 2023 09:31:52 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 62CE63858D39
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1699003912;
	bh=jF9WfyI2fa/azj2j1Lr2S/EllstSN8Mk2QGGX8UuULs=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=yXGOCrb33oFrwEUaMVZlFm+b0iB8YAmNGXCatltLOkDctqKCX38xPqtr/A9IoJAb2
	 Dq/fdnypZ2f6Kw8OXGcNEansqGg+fSzkIkimvQLv5wisxYrCo4ogwfxt5Qm3wVI3mX
	 kMeqb24Skj6kztoKc7dmU3j93yo18X+Y2oURuV0s=
From: "tschwinge at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/112363] GCN: 'FAIL:
 gcc.dg/vect/vect-cond-reduc-in-order-2-signed-zero.c execution test'
Date: Fri, 03 Nov 2023 09:31:50 +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: testsuite-fail
X-Bugzilla-Severity: normal
X-Bugzilla-Who: tschwinge at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-112363-4-8PjZFJdxII@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-112363-4@http.gcc.gnu.org/bugzilla/>
References: <bug-112363-4@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=3D112363

--- Comment #2 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
Right, that's what I suspected (see my "signed zero" comment).  And indeed,=
 the
first check in 'main' instrumented as follows:

    --- gcc/testsuite/gcc.dg/vect/vect-cond-reduc-in-order-2-signed-zero.c
    +++ gcc/testsuite/gcc.dg/vect/vect-cond-reduc-in-order-2-signed-zero.c
    @@ -74,8 +74,11 @@ main ()
       double res4 =3D reduc_minus_double (a, -0.0, cond1, n);
       double ref4 =3D reduc_minus_double_ref (a, -0.0, cond1, n);

    +  __builtin_printf("L0\n");
    +  __builtin_printf("eq %d, SBres 0x%x, SBref 0x%x\n", res1 =3D=3D ref1,
signbit (res1), signbit (ref1));
       if (res1 !=3D ref1 || signbit (res1) !=3D signbit (ref1))
         __builtin_abort ();
    +  __builtin_printf("L1\n");

..., I see:

    L0
    eq 1, SBres 0, SBref 80000000
    GCN Kernel Aborted
    Kernel aborted

..., so unexpected 'signbit' difference of '-0.0' '+' reduction, and thus
'abort'.  Thus, likely, a GCN target issue -- for Andrew/Julian to take ove=
r.=