From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from xry111.site (xry111.site [89.208.246.23]) by sourceware.org (Postfix) with ESMTPS id 35A9F3858D35; Tue, 14 Nov 2023 21:14:32 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 35A9F3858D35 Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=xry111.site Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=xry111.site ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 35A9F3858D35 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=89.208.246.23 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1699996473; cv=none; b=QAY1xeSNtFYTG1yviTF4on6TNRMkwAZsu5tmb/GlY/RzrE4cAL2qtAQ2jPYmP1Sh17xELtolasUIN0Giq2YW+NSP8qEUno1gkvWOk+/kqcJxC6t1kmKYi6bu1ISbwpVNdDArk8mrytqqiLvhHlWe2DKvjrHNdLBrCzXGzoByaSI= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1699996473; c=relaxed/simple; bh=R42eTKKTLNVN/hqpdWFsP16U+cRiiE6bMIIsRWpMAxQ=; h=DKIM-Signature:Message-ID:Subject:From:To:Date:MIME-Version; b=G/oKvlx0dEMxoMcr06jpUyPvy9SkFeY0Sc0XYP0hgNuGT0Y4QSB/jtSIDWa1eXL1wCkuZx/Khpjfy7lEfYAVfZ7KLgV49T+SrDWD3WMyy/WhpgKr+xt5u7HCPhEQDqDz+D9Oc2EvZQtG2x7BtJe4a+URZIiyS1GRFX+QE11sNuQ= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xry111.site; s=default; t=1699996466; bh=R42eTKKTLNVN/hqpdWFsP16U+cRiiE6bMIIsRWpMAxQ=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=MBQiXPZUrw83rGTI+M8pbJvVLGCjsE5FkIWmUjuhw7HZuTiDQxCLCm5/NdVtQanhY 1JVPi4T9vwJmbeqN33tGcqzZ7BlUHzLWQdclCGlXpsWocqS2Xm9QmkwN8VdLIgpM1s pLxeev918OvBCSGuSHSFwTy1bMpiiuxn4N5me5Qw= Received: from [IPv6:240e:358:11dd:4400:dc73:854d:832e:2] (unknown [IPv6:240e:358:11dd:4400:dc73:854d:832e:2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-384) server-digest SHA384) (Client did not present a certificate) (Authenticated sender: xry111@xry111.site) by xry111.site (Postfix) with ESMTPSA id 85E0866A03; Tue, 14 Nov 2023 16:14:22 -0500 (EST) Message-ID: Subject: Re: [PATCH] Only allow (copysign x, NEG_CONST) -> (fneg (fabs x)) simplification for constant folding [PR112483] From: Xi Ruoyao To: Richard Biener Cc: gcc-patches@gcc.gnu.org, chenglulu , i@xen0n.name, xuchenghua@loongson.cn, Tamar Christina , tschwinge@gcc.gnu.org, Roger Sayle , Andrew Pinski Date: Wed, 15 Nov 2023 05:14:17 +0800 In-Reply-To: References: <20231114100320.47373-1-xry111@xry111.site> Autocrypt: addr=xry111@xry111.site; prefer-encrypt=mutual; keydata=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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.1 MIME-Version: 1.0 X-Spam-Status: No, score=-7.3 required=5.0 tests=BAYES_00,BODY_8BITS,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,LIKELY_SPAM_FROM,SPF_HELO_PASS,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Tue, 2023-11-14 at 11:44 +0100, Richard Biener wrote: > > diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc > > index 2d2e5a3c1ca..f3745d86aea 100644 > > --- a/gcc/simplify-rtx.cc > > +++ b/gcc/simplify-rtx.cc > > @@ -4392,7 +4392,7 @@ simplify_ashift: > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 real_conve= rt (&f1, mode, CONST_DOUBLE_REAL_VALUE (trueop1)); > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 rtx tmp = =3D simplify_gen_unary (ABS, mode, op0, mode); > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (REAL_V= ALUE_NEGATIVE (f1)) > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 tmp =3D s= implify_gen_unary (NEG, mode, tmp, mode); > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 tmp =3D s= implify_unary_operation (NEG, mode, tmp, mode); > > return tmp; > > } >=20 > shouldn't that be when either the ABS or the NEG simplify? Simplify (copysign x, POSTIVE_CONST) to (abs x) is an optimization. So for a positive f1, tmp will just be (abs x) and we return it. > And I wonder when that happens - I suppose when op0 is CONST_DOUBLE only? Yes, it's Andrew's intention. --=20 Xi Ruoyao School of Aerospace Science and Technology, Xidian University