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 E5A2C3854810; Tue,  7 Mar 2023 13:58:55 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E5A2C3854810
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1678197535;
	bh=OEdEzVL3X65naLD30/7sCyXmSvr37oMX0JkjFCH8C7Y=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=PORIpHYhh6hX/DzT0N7cDIlPiftmh/2bLLzELjqpWMbpaf+WzLp1sYRcfjk2l+mIY
	 Svcpy0hvtW8ezdq0Bjh2IiQ4nZW4BE0JKeY1bP8UJJGckguS9UmO9BDtnjcK5EOGtf
	 Q0z5lULf11ms9xaafw2bNdyxgNbn0ImyW03vPjes=
From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/109052] Unnecessary reload with -mfpmath=both
Date: Tue, 07 Mar 2023 13:58:55 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: ra
X-Bugzilla-Severity: normal
X-Bugzilla-Who: ubizjak 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: 
Message-ID: <bug-109052-4-vz4yNTmnsD@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-109052-4@http.gcc.gnu.org/bugzilla/>
References: <bug-109052-4@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=3D109052

--- Comment #2 from Uro=C5=A1 Bizjak <ubizjak at gmail dot com> ---
The original testcase is:

double foo (double a, double b)
{
  double z =3D __builtin_fmod (a, 3.14);
  return z * b;
}

-O2 -fno-math-errno:

foo:
        fldl    .LC0(%rip)
        movsd   %xmm0, -8(%rsp)
        fldl    -8(%rsp)
.L2:
        fprem
        fnstsw  %ax
        testb   $4, %ah
        jne     .L2
        fstp    %st(1)
        fstpl   -8(%rsp)
-->     movsd   -8(%rsp), %xmm0
        mulsd   %xmm1, %xmm0
        ret

and with -mavx:

foo:
        fldl    .LC0(%rip)
        vmovsd  %xmm0, -8(%rsp)
        fldl    -8(%rsp)
.L2:
        fprem
        fnstsw  %ax
        testb   $4, %ah
        jne     .L2
        fstp    %st(1)
        fstpl   -8(%rsp)
-->     vmovsd  -8(%rsp), %xmm0
        vmulsd  %xmm1, %xmm0, %xmm0
        ret=