From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <xry111@xry111.site>
Received: from xry111.site (xry111.site [89.208.246.23])
	by sourceware.org (Postfix) with ESMTPS id 964F43858D1E
	for <gcc-patches@gcc.gnu.org>; Wed,  9 Nov 2022 08:14:40 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 964F43858D1E
Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=xry111.site
Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=xry111.site
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site;
	s=default; t=1667981679;
	bh=e6MXbgnSr+M71JeJq7O4GS7fpHHNkEdW4oAcHPHzhfc=;
	h=Subject:From:To:Cc:Date:In-Reply-To:References:From;
	b=hYBDqqvKrb0NWooAnPo8PXQbTLea0C3Z4oA+NTjl9ZfoB+ZuV7sAREBYqcxr13FHR
	 dg8e6VYZO3feRf8fLvzm6HDgUSo56t27Y3goCmmRA/ItMbPrxUmvwQqseGopqMdyu/
	 UA2FUss2jK+CQ9KCme/iYPeLOojrI57vHeCULpu8=
Received: from localhost.localdomain (xry111.site [IPv6:2001:470:683e::1])
	(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
	 key-exchange ECDHE (P-256) server-signature ECDSA (P-384))
	(Client did not present a certificate)
	(Authenticated sender: xry111@xry111.site)
	by xry111.site (Postfix) with ESMTPSA id 75B9265EC8;
	Wed,  9 Nov 2022 03:14:38 -0500 (EST)
Message-ID: <1c8436863493d9a3abfbda035f75ff35272a5358.camel@xry111.site>
Subject: Re: [PATCH 2/4] LoongArch: Add ftint{,rm,rp}.{w,l}.{s,d}
 instructions
From: Xi Ruoyao <xry111@xry111.site>
To: Lulu Cheng <chenglulu@loongson.cn>, gcc-patches@gcc.gnu.org
Cc: Wang Xuerui <i@xen0n.name>, Chenghua Xu <xuchenghua@loongson.cn>, 
	Xiaolin Tang <tangxiaolin@loongson.cn>
Date: Wed, 09 Nov 2022 16:14:37 +0800
In-Reply-To: <4c43dfab-7562-8d7a-5186-e2c1b7f181a9@loongson.cn>
References: <20221109072147.789090-1-xry111@xry111.site>
	 <20221109072147.789090-3-xry111@xry111.site>
	 <4c43dfab-7562-8d7a-5186-e2c1b7f181a9@loongson.cn>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.46.0 
MIME-Version: 1.0
X-Spam-Status: No, score=1.0 required=5.0 tests=BAYES_00,BODY_8BITS,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FROM_SUSPICIOUS_NTLD,LIKELY_SPAM_FROM,PDS_OTHER_BAD_TLD,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=no autolearn_force=no version=3.4.6
X-Spam-Level: *
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org
List-Id: <gcc-patches.gcc.gnu.org>

On Wed, 2022-11-09 at 15:46 +0800, Lulu Cheng wrote:
> There is a paragraph in the explanation information for the compile=20
> parameter '-fno-fp-int-builtin-inexact' in the gcc.pdf document:
>=20
> =C2=A0=C2=A0=C2=A0=C2=A0 "Do not allow the built-in functions ceil, floor=
, round and
> trunc,=20
> and their=E3=80=80float and long double variants,
>=20
> =C2=A0=C2=A0=C2=A0=C2=A0 to generate code that raises the =E2=80=9Cinexac=
t=E2=80=9D=E3=80=80floating-point
> exception=20
> for noninteger arguments.
>=20
> =C2=A0=C2=A0=C2=A0=C2=A0 ISO C99 and C11 allow=E3=80=80these functions to=
 raise the =E2=80=9Cinexact=E2=80=9D=20
> exception, but ISO/IEC TS 18661-1:2014,
>=20
> =C2=A0=C2=A0=C2=A0=C2=A0 the C bindings to IEEE 754-2008, as integrated i=
nto ISO C2X, does
> not allow=E3=80=80these functions to do so."
>=20
> So I think the implementation of these functions needs to be confirmed
> again.
>=20
> Or am I misinterpreting this description?:-[

You are correct, I'm wrong :(.

This patch breaks:

long x(double d)
{
	return __builtin_ceil(d);
}

The compiler then folds it into __builtin_lceil and produce
ftintrp.l.d $f0,$f0, even if -fno-fp-int-builtin-inexact is used.

I'll revise this patch to limit lceil and lfloor for -ffp-int-builtin-
inexact only.


--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University