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 7EFDDC433FE for ; Sun, 9 Oct 2022 15:46:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230108AbiJIPp6 (ORCPT ); Sun, 9 Oct 2022 11:45:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230017AbiJIPpy (ORCPT ); Sun, 9 Oct 2022 11:45:54 -0400 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D4592408B; Sun, 9 Oct 2022 08:45:53 -0700 (PDT) Received: by mail-wm1-x334.google.com with SMTP id v130-20020a1cac88000000b003bcde03bd44so7184335wme.5; Sun, 09 Oct 2022 08:45:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=7nRMSkb+ml96yYY9w8KKx8b1cTDJi6bovEKWdF0d+9Y=; b=JmbKkz1Jw/pgnvrZOmgP0Zo9MWwwLNmpJN3+e+pwC16qEybYFCiblKveHxpz26pSr+ Phc9sspbhuEayA2+LLZn8C4hvexpN7Qa2isk4KwF3GS4ED+F/vTTkLFvYy0FbTiSY91g H0rVInXMz1wyaxjwPhimc1mGKPgRGpHoogueQLf09MhLlFAz8G1MRzy3BhGcTGyqAlZS 5X3Efit43XbkAGKayC+SNPPmgLmgIy3eXe7yzWy/qX+3Fm3yN9P/ILlrP8oaE33v3m3y MVu0LPGV/qh9rN/sYl/aCmhPRx962Ca5esEOVTTPLc9IuBbO0g030lVviamMDXaIGqpU Vr8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7nRMSkb+ml96yYY9w8KKx8b1cTDJi6bovEKWdF0d+9Y=; b=oQ5QbJnpXLaBcLFOL+90cp90B0xxJ6L3+z+fTtyetRiDl/S1ND+wUzADEdfPEqOFu1 /iu4kNyJYkgKP7WqyX+pkcuIxA5bvtx7OwvqCbimcPQHXhXD369t2GzegZCRhfxceRx9 s+zcZoIz6TNXtT4HKpJWu6QJZ5Isp7kOWyL6zl+KOTDV44VYUY2cAVpZ5qauWBn4YJLS WIm0yWGi6dqPU1CR06Q/VE0kzXS+tEi/xvACW83V88oZs871I3OTNaJJQieQ2ZicBnMY YxdNfH9kt2euLkBS92zsC16KsbGh/crCz0qQD5kl2zIsfslHxAmsjyp4xCzs84JxROfT yb7w== X-Gm-Message-State: ACrzQf1usqlsqNH+gokWf5ssrPkWx5pDg2VQsFeqmsXeTshm7P0B1xnA 0buShlBunO4zTUTsUwZGwA== X-Google-Smtp-Source: AMsMyM5nP+6EqILdWCc6sT8s+AghPUti03O0i9dwrZeR+eVOpjGG8ZUOIxy6j14O27uc3GNzkTAyjg== X-Received: by 2002:a05:600c:b47:b0:3b4:8604:410c with SMTP id k7-20020a05600c0b4700b003b48604410cmr9919564wmr.51.1665330351733; Sun, 09 Oct 2022 08:45:51 -0700 (PDT) Received: from localhost.localdomain ([46.53.253.37]) by smtp.gmail.com with ESMTPSA id q8-20020adffec8000000b0022afce9ea93sm6797658wrs.40.2022.10.09.08.45.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 09 Oct 2022 08:45:51 -0700 (PDT) Date: Sun, 9 Oct 2022 18:45:49 +0300 From: Alexey Dobriyan To: Willy Tarreau Cc: lkp@intel.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, "Paul E. McKenney" Subject: Re: tools/nolibc: fix missing strlen() definition and infinite loop with gcc-12 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Willy Tarreau wrote: > +#if defined(__GNUC__) && (__GNUC__ >= 12) > +__attribute__((optimize("no-tree-loop-distribute-patterns"))) > +#endif > static __attribute__((unused)) > -size_t nolibc_strlen(const char *str I'd suggest to use asm("") in the loop body. It worked in the past to prevent folding division loop back into division instruction. Or switch to size_t f(const char *s) { const char *s0 = s; while (*s++) ; return s - s0 - 1; } which compiles to 1 branch, not 2. But of course they could recognise this pattern too.