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 8E34B38582AD; Thu,  4 Jan 2024 14:52:01 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8E34B38582AD
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1704379921;
	bh=RbSN/8vFGdk7oa2fAbpXYD4U66byXqTdupRPli020LI=;
	h=From:To:Subject:Date:From;
	b=gn6Bf2W3BKGwNY4NOq1k3L4uS+JJqaSjDIpqS/y6wtVeUdVhlPCVlXEWnsujqZgyR
	 e3LSBbN8GpZwd6GsR6LcqvR5yOjCZ5wqsDFco5xJwVmvHldvOs5elKOlACp9M/tLLt
	 mCSZOoV6A5LHEmsuG5nJCD8/bHrFFHtgeQfWPMSY=
From: "denis.campredon at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/113234] New: missing folding to
 builtin_isunordered if manual nan comparison is used
Date: Thu, 04 Jan 2024 14:52:01 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: denis.campredon at gmail dot com
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: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-113234-4@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=3D113234

            Bug ID: 113234
           Summary: missing folding to builtin_isunordered if manual nan
                    comparison is used
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: denis.campredon at gmail dot com
  Target Milestone: ---

Compiled with -O1, on x86-64, f1 and f2 should produce the same code than f3
and f4, but f1 and f2 use two comparisons whereas f3 and f4 only use 1.


-------------------
bool f1(float i, float j)
{
    return i !=3Di || j !=3D j;
}

bool f2(float i, float j)
{
    return i =3D=3D i && j =3D=3D j;
}

bool f3(float i, float j)
{
    return __builtin_isnan(i) || __builtin_isnan(j);
}

bool f4(float i, float j)
{
    return !__builtin_isnan(i) && !__builtin_isnan(j);
}
-------------------------------


It seems that gcc does not fold "f !=3D f" to __builtin_isnan, or too late,
leading to the missed optimisation.=