From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 84219 invoked by alias); 15 Aug 2019 00:02:20 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 84211 invoked by uid 89); 15 Aug 2019 00:02:20 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 spammy=HX-Languages-Length:863 X-HELO: gate.crashing.org Received: from gate.crashing.org (HELO gate.crashing.org) (63.228.1.57) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 15 Aug 2019 00:02:18 +0000 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x7F02GWj021393; Wed, 14 Aug 2019 19:02:16 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id x7F02FEY021392; Wed, 14 Aug 2019 19:02:15 -0500 Date: Thu, 15 Aug 2019 04:05:00 -0000 From: Segher Boessenkool To: Michael Meissner , gcc-patches@gcc.gnu.org, dje.gcc@gmail.com, Alan Modra Subject: Re: PowerPC 'future' patches introduction Message-ID: <20190815000215.GK31406@gate.crashing.org> References: <20190814205732.GA11956@ibm-toto.the-meissners.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190814205732.GA11956@ibm-toto.the-meissners.org> User-Agent: Mutt/1.4.2.3i X-IsSubscribed: yes X-SW-Source: 2019-08/txt/msg01050.txt.bz2 Hi Mike, On Wed, Aug 14, 2019 at 04:57:32PM -0400, Michael Meissner wrote: > to the current location instead of a base register, giving pc-relative > addressing. Pc-relative addressing will be supported in the next ABI (3.1) as > an alternative to the current TOC based addressing. That's not an ABI version, that's an ISA version. But it will be in a future ELFv2 ABI version, yes. > The fifth patch switches the default when you use -mcpu=future to use > pc-relative instructions instead of using the TOC by default. As David reminded me, you should only do this on OSes where this works. Only for ABIs that support PCREL, even? Or both. > The seventh patch adds a new RTL pass to implement the PCREL_OPT relocations > that will be part of the ISA 3.1 specification. Some version of the ELFv2 ABI again? Segher