From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40AB5C433EF for ; Mon, 27 Jun 2022 23:35:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238701AbiF0XfM (ORCPT ); Mon, 27 Jun 2022 19:35:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236667AbiF0XfM (ORCPT ); Mon, 27 Jun 2022 19:35:12 -0400 Received: from avasout-ptp-004.plus.net (avasout-ptp-004.plus.net [84.93.230.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40297DF8B for ; Mon, 27 Jun 2022 16:35:11 -0700 (PDT) Received: from [10.0.2.15] ([147.147.167.40]) by smtp with ESMTPA id 5yD4otnqaAcBn5yD5odWkp; Tue, 28 Jun 2022 00:32:09 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=plus.com; s=042019; t=1656372729; bh=gfskdcoxvdejMan26LENbPzg1N3zOADFqAP3O7LzFfQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Ai/ubmONl1TJAO7lrlAVM/GuLR0vFbvBfvyvNrEg7uzLqtElgMThZZjJKEr7KBzLW N0utJdcxqfLr23oWIkPHGw3YSYgRMK2x9zQ+KIW3AVvQUpdySJ7vFYitbjlHMjFIQ4 1PhINL3EYw9tQ5kMpPmaJKqKGixtpcFQI69nRQQm9syMJhNSmFOa6Z7M2pAJtw6UBR AZVFv0npj/7msz1EiyjDh0EYttwQXzbWwFBsrFCoK8Yig1h+Du1ThInH8YXVeumcth T2uRHpTKUP5zyd/i3D7zaiQfeKwnXjzCrDNiGyPv0BTo251DSBDuc4rPN6DUOo5rUw tooXkdz3mJL5w== X-Clacks-Overhead: "GNU Terry Pratchett" X-CM-Score: 0.00 X-CNFS-Analysis: v=2.4 cv=JPUoDuGb c=1 sm=1 tr=0 ts=62ba3df9 a=nyqnwr6A7Kzjd6EpZhiMcA==:117 a=nyqnwr6A7Kzjd6EpZhiMcA==:17 a=IkcTkHD0fZMA:10 a=pGLkceISAAAA:8 a=9qV9x0tqV3PRz3u1FukA:9 a=QEXdDO2ut3YA:10 X-AUTH: ramsayjones@:2500 Message-ID: <1be25b6f-5065-f448-b6f0-9e6eaf077264@ramsayjones.plus.com> Date: Tue, 28 Jun 2022 00:32:02 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH 2/5] bitwise: accept all ones as non-restricted value Content-Language: en-GB To: Luc Van Oostenryck , linux-sparse@vger.kernel.org Cc: Linus Torvalds , Bart Van Assche References: <20220627190540.13358-1-luc.vanoostenryck@gmail.com> <20220627190540.13358-3-luc.vanoostenryck@gmail.com> From: Ramsay Jones In-Reply-To: <20220627190540.13358-3-luc.vanoostenryck@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4xfMSvmP/0/BJ7lDZIYaJ89Et0aDiWbQyr8iqmSU6MolnRxNyi9eNCBQ1dMomwaFipdgfFzxdA53RiqbYV8rXG3M+f1yYipOdHUYN32FAcDoCk9iOQyTJ4 +8Mxg7J3WV3FiHxgNIGv7CuVLqzXXDhDNIMDhk5SCZbsd0dF0in65goM2fPAmf6voHvc7cWnTwmRjEonCoT2cxDK46prADKEfu0= Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org On 27/06/2022 20:05, Luc Van Oostenryck wrote: > Currently, the only value bitwise types can act on is 0 > because the this value is anyway invariant for all bitwise s/the this/this/ s/anyway// ATB, Ramsay Jones > operations and endianness conversions. > > But, a bit-pattern of all ones has the same properties and > is also very often used. > > So, accept all ones as a valid value for bitwise operations. > > Signed-off-by: Luc Van Oostenryck > --- > evaluate.c | 2 +- > validation/bitwise-cast.c | 13 +++++++++++++ > 2 files changed, 14 insertions(+), 1 deletion(-) > > diff --git a/evaluate.c b/evaluate.c > index 61f59ee3908e..bcbcdf1ef0cc 100644 > --- a/evaluate.c > +++ b/evaluate.c > @@ -417,7 +417,7 @@ static int restricted_value(struct expression *v, struct symbol *type) > { > if (v->type != EXPR_VALUE) > return 1; > - if (v->value != 0) > + if (v->value != 0 && v->value != bits_mask(type->bit_size)) > return 1; > return 0; > } > diff --git a/validation/bitwise-cast.c b/validation/bitwise-cast.c > index 0583461cb745..1075a3e9410c 100644 > --- a/validation/bitwise-cast.c > +++ b/validation/bitwise-cast.c > @@ -35,6 +35,19 @@ static __be32 quuy(void) > return (__attribute__((force)) __be32) 1730; > } > > +/* Implicit casts of all ones, legal */ > +static __be32 foo1(void) > +{ > + __be32 x = 0xffffffff; > + return x; > +} > + > +/* Explicit cast of all ones, legal */ > +static __be32 bar1(void) > +{ > + return (__be32)0xffffffff; > +} > + > /* > * check-name: conversions to bitwise types > * check-command: sparse -Wbitwise $file