From patchwork Tue Jan 24 21:48:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Karcher X-Patchwork-Id: 13114812 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 DC685C54EED for ; Tue, 24 Jan 2023 21:48:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233822AbjAXVs5 (ORCPT ); Tue, 24 Jan 2023 16:48:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233564AbjAXVsy (ORCPT ); Tue, 24 Jan 2023 16:48:54 -0500 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E80449969; Tue, 24 Jan 2023 13:48:51 -0800 (PST) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.95) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1pKR9s-0049W3-LT; Tue, 24 Jan 2023 22:48:48 +0100 Received: from [185.238.219.21] (helo=[192.168.46.66]) by inpost2.zedat.fu-berlin.de (Exim 4.95) with esmtpsa (TLS1.3) tls TLS_AES_128_GCM_SHA256 (envelope-from ) id 1pKR9N-0044P4-Fd; Tue, 24 Jan 2023 22:48:48 +0100 Message-ID: <619fa552-c988-35e5-b1d7-fe256c46a272@mkarcher.dialup.fu-berlin.de> Date: Tue, 24 Jan 2023 22:48:16 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 From: Michael Karcher Subject: [PATCH v5 1/1] arch/sh: avoid spurious sizeof-pointer-div warning To: linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org, Segher Boessenkool , Rich Felker , Yoshinori Sato , John Paul Adrian Glaubitz X-Original-Sender: kernel@mkarcher.dialup.fu-berlin.de X-Originating-IP: 185.238.219.21 Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org 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 inhttps://gcc.gnu.org/bugzilla/show_bug.cgi?id=108483 by Jakub Jelinek Signed-off-by: Michael Karcher Acked-by: Randy Dunlap # build-tested --- (resend of the mail as plaintext only instead of multipart/alternative) History: v5: - Cleanly generated the patch v4: - Put the case distinction into the numerator instead of the denominator - Refactor the case disctinction into a second macro v3: - I had a stern discussion with Thunderbird about not mangling the space characters in my email, and I hope spaces get sent as standard spaces now v2: - improve title and remove mostly redundant first sentence of the description - adjust formatting of the _Generic construction diff --git a/include/linux/sh_intc.h b/include/linux/sh_intc.h index c255273b0281..37ad81058d6a 100644 --- a/include/linux/sh_intc.h +++ b/include/linux/sh_intc.h @@ -97,7 +97,10 @@ struct intc_hw_desc { unsigned int nr_subgroups; }; -#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) +#define _INTC_SIZEOF_OR_ZERO(a) (_Generic(a, \ + typeof(NULL): 0, \ + default: sizeof(a))) +#define _INTC_ARRAY(a) a, _INTC_SIZEOF_OR_ZERO(a)/sizeof(*a) #define INTC_HW_DESC(vectors, groups, mask_regs, \ prio_regs, sense_regs, ack_regs) \