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 AF4E0C54EAA for ; Sun, 22 Jan 2023 07:00:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229675AbjAVHAr (ORCPT ); Sun, 22 Jan 2023 02:00:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229480AbjAVHAq (ORCPT ); Sun, 22 Jan 2023 02:00:46 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC7D12197F; Sat, 21 Jan 2023 23:00:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=Zrb5LiNepXhvHeP/iXlU4FC0LzbmvuhWYAC688JzxQg=; b=qfaK9D9YSNmkicVKVPLd3xgB00 vFUlTCfCCKMETPyRIZlQ8xaNRupQLhMMYQFWsLpg8d6J3QpvM5DBulGn1Pd4HoX7hAEaPZYodAVtj 10DzHFGa93ocjwUwEAG9kWIEQ/D4f1/UG7OZk1+nxa/18ncot8Q4xIPObuVwaZXGTLT9aBSWFmQY+ W1nJ9E8jyO2I+YbI3YBzEy3tygpk9iz01RHG4e6sZl2gxG8PmPVsgBLC1UH+ojQSwFC29HFP+cN/0 YokSRmhDsbgTh9MiQ7jD5j4whREtyq3fxrfChfORFnnL25PyvwgMDD8JKllhs3HPuJNHx/6ftSnAl b6Ysj+OA==; Received: from [2601:1c2:d80:3110::9307] by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1pJULK-00EwfE-04; Sun, 22 Jan 2023 07:00:42 +0000 Message-ID: <2085aec3-796b-71c3-7cb2-d4103d3b6175@infradead.org> Date: Sat, 21 Jan 2023 23:00:38 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH: 1/1] sh4: avoid spurious gcc warning To: "Michael.Karcher" , linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org, Segher Boessenkool , Rich Felker , Yoshinori Sato , John Paul Adrian Glaubitz Cc: jakub@gcc.gnu.org References: <52952170-f1a9-89a0-e307-f974ce2b7977@fu-berlin.de> Content-Language: en-US From: Randy Dunlap In-Reply-To: <52952170-f1a9-89a0-e307-f974ce2b7977@fu-berlin.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi-- It's just sh: AFAICT. The patch fixes the build error for me on sh2, using gcc 12.1.0 from the kernel.org crosstool builds. On 1/21/23 16:15, Michael.Karcher wrote: > Prevent sizeof-pointer-div warning in SH4 intc macros > > Gcc warns about the pattern sizeof(void*)/sizeof(void), as it looks like > the abuse of a pattern to calculate the array size. This pattern appears > in the unevaluated part of the ternary operator in _INTC_ARRAY if the > parameter is NULL. > > The replacement uses an alternate approach to return 0 in case of NULL > which does not generate the pattern sizeof(void*)/sizeof(void), but still > emits the warning if _INTC_ARRAY is called with a nonarray parameter. > > This patch is required for successful compilation with -Werror enabled. > > The idea to use _Generic for type distinction is taken from Comment #7 > in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108483 by Jakub Jelinek > > Signed-off-by: Michael Karcher > --- > > diff --git a/include/linux/sh_intc.h b/include/linux/sh_intc.h > index c255273b0281..d7a7ffb60a34 100644 > --- a/include/linux/sh_intc.h > +++ b/include/linux/sh_intc.h > @@ -97,7 +97,7 @@ struct intc_hw_desc { > unsigned int nr_subgroups; > }; > > -#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) > +#define _INTC_ARRAY(a) a, sizeof(a)/(_Generic((a), typeof(NULL): 0xFFFFFFFFU, default: sizeof(*a))) s/: / : / in 2 places. Tested-by: Randy Dunlap # build-tested How far back in gcc versions does this work? Thanks. > > #define INTC_HW_DESC(vectors, groups, mask_regs, \ > prio_regs, sense_regs, ack_regs) \ > -- ~Randy