From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Andrea Corallo via "Emacs development discussions." Newsgroups: gmane.emacs.devel Subject: Re: Q: What is default architecture for code produced by native compiler? Date: Wed, 25 Aug 2021 07:36:59 +0000 Message-ID: References: Reply-To: Andrea Corallo Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="35391"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: emacs-devel@gnu.org To: Arthur Miller Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Aug 25 09:40:36 2021 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mInWW-0008v0-6X for ged-emacs-devel@m.gmane-mx.org; Wed, 25 Aug 2021 09:40:36 +0200 Original-Received: from localhost ([::1]:41494 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mInWU-0002wK-NF for ged-emacs-devel@m.gmane-mx.org; Wed, 25 Aug 2021 03:40:34 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40648) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mInT7-0004cf-5E for emacs-devel@gnu.org; Wed, 25 Aug 2021 03:37:05 -0400 Original-Received: from mx.sdf.org ([205.166.94.24]:60094) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mInT4-00060a-Vj for emacs-devel@gnu.org; Wed, 25 Aug 2021 03:37:04 -0400 Original-Received: from mab (ma.sdf.org [205.166.94.33]) by mx.sdf.org (8.15.2/8.14.5) with ESMTPS id 17P7ax71004566 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits) verified NO); Wed, 25 Aug 2021 07:36:59 GMT In-Reply-To: (Arthur Miller's message of "Wed, 25 Aug 2021 04:49:57 +0200") Received-SPF: pass client-ip=205.166.94.24; envelope-from=akrl@sdf.org; helo=mx.sdf.org X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:272946 Archived-At: Arthur Miller writes: > Andrea Corallo writes: > >> Arthur Miller writes: >> >>> Just wonder, is it generic x86 or something later or does it uses >>> native for architecture and cpu flags (-march=native and -mcpu=native)? >> >> I'd say is GCC's default. >> >>> If it is generic, do we have option to pass in arch and cpu flags? >> >> No we don't, even if we could expose it using >> 'gcc_jit_context_add_command_line_option' for non obsolete versions of >> GCC. >> >> Regards >> >> Andrea > I am sorry to bother, but I have just seen: > > (defcustom native-comp-driver-options nil > "Options passed verbatim to the native compiler's back-end driver. > Note that not all options are meaningful; typically only the options > affecting the assembler and linker are likely to be useful. > > Passing these options is only available in libgccjit version 9 > and above." > :type '(repeat string) ; FIXME is this right? > :version "28.1") > > I have tested with: > > (setq native-comp-driver-options '("-march=native" "-mcpu=native")) > > but I see no difference in emitted code when I dissaemble produced binaries. Driver options are not for the compiler but rather linker and assembler, infact `native-comp-driver-options' relies on 'gcc_jit_context_add_driver_option' [1]. That said for most of the code we generate ATM I doubt would make much difference to specify a different -march and/or -mcpu. Regards Andrea [1]