From patchwork Tue Sep 22 14:34:34 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 521081 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 0F7BF1401AD for ; Wed, 23 Sep 2015 00:35:43 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933509AbbIVOfU (ORCPT ); Tue, 22 Sep 2015 10:35:20 -0400 Received: from 2.236.17.93.rev.sfr.net ([93.17.236.2]:55592 "EHLO mailhub1.si.c-s.fr" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933351AbbIVOeg (ORCPT ); Tue, 22 Sep 2015 10:34:36 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id C993A1C9267; Tue, 22 Sep 2015 16:34:35 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from mailhub1.si.c-s.fr ([192.168.12.234]) by localhost (mailhub1.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AjFlLlu6Itkk; Tue, 22 Sep 2015 16:34:35 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id B15B51C9236; Tue, 22 Sep 2015 16:34:35 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9D158C73C8; Tue, 22 Sep 2015 16:34:35 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id w0EauQHTcdTV; Tue, 22 Sep 2015 16:34:35 +0200 (CEST) Received: from PO10863.localdomain (unknown [192.168.232.142]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 63658C73C4; Tue, 22 Sep 2015 16:34:35 +0200 (CEST) Received: by localhost.localdomain (Postfix, from userid 0) id 24BBC1A2467; Tue, 22 Sep 2015 16:34:34 +0200 (CEST) Message-Id: <5549ecca2c921f34d076c47b5e2a91a3e78b20a7.1442876807.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH 8/9] powerpc: simplify csum_add(a, b) in case a or b is constant 0 To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , scottwood@freescale.com Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org Date: Tue, 22 Sep 2015 16:34:34 +0200 (CEST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Simplify csum_add(a, b) in case a or b is constant 0 Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/checksum.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h index 56deea8..f8a9704 100644 --- a/arch/powerpc/include/asm/checksum.h +++ b/arch/powerpc/include/asm/checksum.h @@ -119,7 +119,13 @@ static inline __wsum csum_add(__wsum csum, __wsum addend) { #ifdef __powerpc64__ u64 res = (__force u64)csum; +#endif + if (__builtin_constant_p(csum) && csum == 0) + return addend; + if (__builtin_constant_p(addend) && addend == 0) + return csum; +#ifdef __powerpc64__ res += (__force u64)addend; return (__force __wsum)((u32)res + (res >> 32)); #else