From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9795 invoked by alias); 17 Feb 2020 15:46:43 -0000 Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org Received: (qmail 9772 invoked by uid 89); 17 Feb 2020 15:46:43 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-4.4 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.1 spammy=noise X-HELO: mx2.suse.de Received: from mx2.suse.de (HELO mx2.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 17 Feb 2020 15:46:42 +0000 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id F29F0AE62; Mon, 17 Feb 2020 15:46:38 +0000 (UTC) Subject: Re: [PATCH] x86: Replace CpuABM with CpuPOPCNT To: "H.J. Lu" Cc: Binutils References: <20200217152740.GA270001@gmail.com> From: Jan Beulich Message-ID: <0c6ac813-e0f2-3d7f-040d-b94409f7f837@suse.com> Date: Mon, 17 Feb 2020 15:46:00 -0000 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2020-02/txt/msg00404.txt.bz2 On 17.02.2020 16:42, H.J. Lu wrote: > On Mon, Feb 17, 2020 at 7:40 AM Jan Beulich wrote: >> >> On 17.02.2020 16:27, H.J. Lu wrote: >>> AMD ABM has 2 instructions: popcnt and lzcnt. ABM CPUID feature bit has >>> been reused for lzcnt and a POPCNT CPUID feature bit is added for popcnt. >>> This patch removes CpuABM and adds CpuPOPCNT. It changes ABM to enable >>> both lzcnt and popcnt, changes SSE4.2 to also enable popcnt. >> >> I don't think removing support for something may have in active and >> working use is a good idea. Adding some better mechanism as >> _suggested_ replacement is of course fine, but people would better >> not be forced to change their _correct_ code because of gas side >> change. > > No assembly code changes are needed. The .abm directive still works > as before. My patch only changes assembler internal implementation. Oh, I'm sorry for the noise then. I apparently didn't look closely enough. Jan