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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A3740C3A5A5 for ; Thu, 5 Sep 2019 13:45:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B77F20820 for ; Thu, 5 Sep 2019 13:45:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731438AbfIENpr (ORCPT ); Thu, 5 Sep 2019 09:45:47 -0400 Received: from gate.crashing.org ([63.228.1.57]:44357 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727900AbfIENpq (ORCPT ); Thu, 5 Sep 2019 09:45:46 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x85Djarb028469; Thu, 5 Sep 2019 08:45:36 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id x85DjZfR028468; Thu, 5 Sep 2019 08:45:35 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Thu, 5 Sep 2019 08:45:35 -0500 From: Segher Boessenkool To: Rasmus Villemoes Cc: Nick Desaulniers , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , LKML , Miguel Ojeda , "gcc-patches@gcc.gnu.org" Subject: Re: [PATCH v2 4/6] compiler-gcc.h: add asm_inline definition Message-ID: <20190905134535.GP9749@gate.crashing.org> References: <20190829083233.24162-1-linux@rasmusvillemoes.dk> <20190830231527.22304-1-linux@rasmusvillemoes.dk> <20190830231527.22304-5-linux@rasmusvillemoes.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rasmus, On Thu, Sep 05, 2019 at 01:07:11PM +0200, Rasmus Villemoes wrote: > On 05/09/2019 02.18, Nick Desaulniers wrote: > > Is it too late to ask for a feature test macro? Maybe one already > > exists? > > No, not as far as I know. [ That's not what a feature test macro is; a feature test macro allows the user to select some optional behaviour. Things like _GNU_SOURCE. ] > Perhaps something like below, though that > won't affect the already released gcc 9.1 and 9.2, of course. That is one reason to not want such a predefined macro. Another reason is that you usually need to compile some test programs *anyway*, to see if some bug is present for example, or to see if the exact implementation of the feature is beneficial (or harmful) to your program in some way. > gcc maintainers, WDYT? Can we add a feature test macro for asm inline()? The only comparable existing predefined macro is __PRAGMA_REDEFINE_EXTNAME it seems (no, I have no idea either). Everything else is required by some standard (a "standard standard" or a "vendor standard", I'm lumping everything together here), or shows whether some target has some feature, or how many bits there are in certain types, that kind of thing. Why would GCC want to have macros for all features it has? That would be quite a few new ones every release. And what about bug fixes, are bug fixes features as well? I think you need to solve your configuration problems in your configuration system. Segher