From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id DEF9F13832E for ; Fri, 19 Aug 2016 17:38:17 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id ACE9621C084; Fri, 19 Aug 2016 17:38:09 +0000 (UTC) Received: from smtp.gentoo.org (smtp.gentoo.org [140.211.166.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 96A7621C043 for ; Fri, 19 Aug 2016 17:38:08 +0000 (UTC) Received: from eris.local (dynamic-adsl-84-221-251-48.clienti.tiscali.it [84.221.251.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: lu_zero) by smtp.gentoo.org (Postfix) with ESMTPSA id DFA0634058A for ; Fri, 19 Aug 2016 17:38:06 +0000 (UTC) Subject: Re: [gentoo-dev] New project: LLVM To: gentoo-dev@lists.gentoo.org References: <20160816182204.61c27681.mgorny@gentoo.org> <20160819020737.5419083.98443.119986@pathscale.com> <36efd7a3-ce51-43ed-8aef-e1d6d79a4e5d@gentoo.org> From: Luca Barbato Message-ID: <3fd1f3db-1ccd-50ff-5257-4fd3db6cdfda@gentoo.org> Date: Fri, 19 Aug 2016 19:38:03 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.2 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Archives-Salt: 6bc47790-2139-4348-ae45-76d54d6ad8e7 X-Archives-Hash: 000fa893c15027332d3cecd2b56ba832 On 19/08/16 17:15, C Bergström wrote: > On Fri, Aug 19, 2016 at 11:01 PM, Luca Barbato wrote: >> BTW is pathscale ready to be used as system compiler as well? > > I wish, but no. We have known issues when building grub2, glibc and > the Linux kernel at the very least. Someone* did report a long time > ago that with their unofficial port, were able to build/boot the > NetBSD kernel. > (*A community dev we trusted with our sources and was helping us with > portability across platforms) > > The stuff with grub2 may potentially be fixed in the "near" future... > the others are more tricky. In general if clang can do it, we have a > strong chance as well. I see, it is getting quite close =) > As a philosophy - "we" aren't really trying to be the best generic > compiler in the world. We aim more on optimizing as much for known > targets. So if by system you mean, a compiler that would produce an > "OS" which only runs on a single class of hardware, then yeah it could > work at some point in the future. Specifically, on x86 we default on > host CPU optimizations. So on newer Intel hardware it's easy to get a > binary that won't run on AMD or older 64bit Intel. > > More recently on ARMv8 - we turn on processor specific tuning. So > while it may "run", the difference between APM's mustang and Cavium > ThunderX is pretty big and running binaries intended for A and ran on > B would certainly take a hit.. (this is just the tip of the iceberg) This is not a problem for Gentoo, actually sounds a good match for one of our many use-cases =) > For HPC codes or anything where you get loops or computationally > complex - the gloves are off and I could see big differences... (again > being general and maybe a bit dramatic for fun) I started to do some decoding benchmark across compiler version some time ago, I should try to put in the mix your compiler as well and eventually blog about it =) lu