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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6958C5DF9D for ; Wed, 21 Oct 2020 15:20:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6564B2177B for ; Wed, 21 Oct 2020 15:20:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="j5xOpKQH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502292AbgJUPUN (ORCPT ); Wed, 21 Oct 2020 11:20:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2502345AbgJUPUB (ORCPT ); Wed, 21 Oct 2020 11:20:01 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC082C0613CE for ; Wed, 21 Oct 2020 08:20:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=e4f49MRnVPpD7CSUEkJ9LrgXd4e/746rpfTCV2uMwxQ=; b=j5xOpKQHUrsy9hC8TLJqMNKIn2 AcKw3hFvb9Y8EbmvQ9Tp7icWg7OT/jmW/pOYYFqA9Gm1JhAhVrS/IcLBx6isFSsHimVMA4PcviVXG MnGxuEJACwcz5RKOx4ApNkBYnrWApKDE7pcVgyYvEZEGDYgnUBZliRBXw4oeFXyCh6Poq54jjVCza QLqNjWIySThsTAcrEuLhBXUQLZ7fjU+ZxtIrw/4VCFlm46N3x4xGcBYg+PsRjLwUhAKGa/8DfVLM8 4whfi/+y1ueDrUksk4thXh/TK9voBBVKXEp9ueHIl0h15RWmD86bfSqSvN/m2AWzITYLymndwbVdU 2q9MsH7A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kVFu0-0002Nt-32; Wed, 21 Oct 2020 15:19:48 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 985AA3035D4; Wed, 21 Oct 2020 17:19:47 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 82B2C28B3CF7C; Wed, 21 Oct 2020 17:19:47 +0200 (CEST) Date: Wed, 21 Oct 2020 17:19:47 +0200 From: Peter Zijlstra To: Jakub Jelinek Cc: linux-toolchains@vger.kernel.org, Christophe Leroy Subject: Re: ilog2 vs. GCC inlining heuristics Message-ID: <20201021151947.GL2628@hirez.programming.kicks-ass.net> References: <20201021132718.GB2176@tucnak> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201021132718.GB2176@tucnak> Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On Wed, Oct 21, 2020 at 03:27:18PM +0200, Jakub Jelinek wrote: > Hi! > > Based on the GCC PR97445 discussions, I'd like to propose following change, > which should significantly decrease the amount of code in inline functions > that use ilog2, but as I'm already two decades out of the Linux kernel > development, I'd appreciate if some kernel developer could try that (all > I have done is check that it gives the same results as before) and if it > works submit it for inclusion into the kernel? I'll stick it in my queue and feed it to the robots.