From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 57167383D034 for ; Thu, 24 Jun 2021 14:40:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 57167383D034 Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-169-ygE2J7gYOUqgv4EbdCiS8g-1; Thu, 24 Jun 2021 10:40:21 -0400 X-MC-Unique: ygE2J7gYOUqgv4EbdCiS8g-1 Received: by mail-wm1-f72.google.com with SMTP id k16-20020a7bc3100000b02901d849b41038so3141784wmj.7 for ; Thu, 24 Jun 2021 07:40:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=O2eYPw07HSua3DuQvR+h/IyfPHNfL4JQrbRoVbHwkL8=; b=VMtkL1hhlEWLpC5/aovi4iCGxX5VVX/VzR6UbJdqacNmyqfe34x4XW6pBR+OerbBoq rFefItA5YCfTPZOf5oEFvany+ijHyG6GJnQMS0fHfx2Hch80IJreH8edx25NbOJGkfYf GkN335DK1Z5OGWYkg8Sc14zD+JnWprs/x7mLY0dMqo0+K/5aOIuSHqV54/aUG1w78LD6 BhTMwyQig8HXbutbaW6Ivyl9mBzI14+JDNMa04P5IffJ2/YN/OBsIKaEVBCbgdulnzEb 56qzaRm55nk8LJv9T6s6UPCFWGWrwXU1N1vSmOkYeZgvWfJJiQgmoLyk9DxWndpHQ1GB WmUw== X-Gm-Message-State: AOAM530E2mNUzPXPfcVjZd5HQJ5wbPDp7jPSXhpchz20AHpwucVpkI0G 9dukXZvR5s9NJS3Ge0kFGyOfwGgrS0hSkh7Qe+3H99rUN9HXcVqzeYh/89BqwIpAsi8pjtFmTQC VWQgitRGjegL0G6J4NPs/5F7jwvoXsRM= X-Received: by 2002:a5d:6409:: with SMTP id z9mr4808645wru.279.1624545620563; Thu, 24 Jun 2021 07:40:20 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzHZQoJeljKsRuBJIqyEPcI0X0RBzc2XHFP0fnVs210Ji/iQF0rb4+d6gRmj3ki5cUNCQq0WGOI8vQVFMZd0hI= X-Received: by 2002:a5d:6409:: with SMTP id z9mr4808635wru.279.1624545620405; Thu, 24 Jun 2021 07:40:20 -0700 (PDT) MIME-Version: 1.0 References: <270527782.u9WJ3AIrlG@excalibur> <3553838.ebMzRN9Arp@excalibur> <3315301.e9AK2G76lq@excalibur> <14392010.RDIVbhacDa@minbar> <20210624140837.GT7746@tucnak> <20210624142104.GU7746@tucnak> In-Reply-To: From: Jonathan Wakely Date: Thu, 24 Jun 2021 15:40:09 +0100 Message-ID: Subject: Re: [PATCH 04/11 v3] libstdc++: Make use of __builtin_bit_cast To: Jakub Jelinek Cc: Matthias Kretz , gcc Patches , "libstdc++" X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-6.6 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Jun 2021 14:40:24 -0000 On Thu, 24 Jun 2021 at 15:34, Jonathan Wakely wrote: > Rather than use the _GLIBCXX_HAS_BUILTIN macro more widely, I'd prefer > to not use it where it isn't needed, as in the attached (untested) > patch. My rationale for this is that I'd prefer to use standardized features like __has_include and __has_cpp_attribute where possible, instead of adding more and more configure macros. You don't need to look in c++config.h to see how the macro is defined if you just use a standard feature directly. __has_builtin obviously isn't standardized, but as long as it's available on all the compilers we care about (which it is) then the same rationale applies.