From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11513 Path: news.gmane.org!.POSTED!not-for-mail From: David Edelsohn Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH] s390x: Add single instruction math functions Date: Sun, 18 Jun 2017 13:12:15 -0400 Message-ID: References: <20170610194855.GS1627@brightrain.aerifal.cx> <20170610212801.GW9350@port70.net> <20170611022044.GV1627@brightrain.aerifal.cx> <20170611101955.GX9350@port70.net> <20170612090331.GZ9350@port70.net> <20170614234426.GI1627@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Trace: blaine.gmane.org 1497805952 17227 195.159.176.226 (18 Jun 2017 17:12:32 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 18 Jun 2017 17:12:32 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-11526-gllmg-musl=m.gmane.org@lists.openwall.com Sun Jun 18 19:12:26 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1dMdkP-00049K-Vg for gllmg-musl@m.gmane.org; Sun, 18 Jun 2017 19:12:26 +0200 Original-Received: (qmail 7575 invoked by uid 550); 18 Jun 2017 17:12:29 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 7554 invoked from network); 18 Jun 2017 17:12:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=DwhYJlZ3qosF5KjGE3aSpKcYYyG2gaVJ4DYyosxaUek=; b=lF1/iX8I9+EvR5mB62V50yIHPT1/DwW9cZNx/wvRqEKix5ThEz8bs1ReRsfV84dmgx vuhqbZqJcE8uU+tvi74OgqaunM6Wu8UGE3hwTJo5F4Gp+7b/DAR1zXWG44FwEQIT+3gE 753JdH+5USXsBqBoCV8HiNaIOx0XgTiNEw30hODxtUSYQl25pOtRqC6/tA46Bj81Sux8 p6ulTnmBzwVraDpoZA/pF8E5Q5zCo/SiN6ee5Oh1Z1ijnwL+zx/QwI1TBEs0tZHbOAPf UzFYXgVTCHtU4Ab+wNl82QqxCwTckt9k9povXSCTwxl5qnAUyErg0WzOtVT9wtMhSPzg I0BQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=DwhYJlZ3qosF5KjGE3aSpKcYYyG2gaVJ4DYyosxaUek=; b=f+6cOyKL5187Q4F4alOFxCVvoOK0sA4+O8MebHbUPlWdbIFN6lNh+AdU5VCJ5vLxsh Gx5flo156dsQm514yFCKMy6g///pmc4G7XEOEU1nw8TLePhnX6pKU8tHv/CUhrjVsSjj jQE+fzx7ed++mx6xiC8DsBBMWWgRRahl5iv4SfB+G9Yq19WkeeFrj5G9HOuVuBOfkZKS ReYuTi5WnmK6qZGRrVUMjNexjBk377V3kU2MBn8f5lDdM8BJatki3ZIJ9LWKfpS0BQme 0gUYbWRoM7agtnbpdRSqoO+ctvL8sZtFxZfE/xmH0sbU2plgPsJDBly+nxpXYLmwwUlF dKjA== X-Gm-Message-State: AKS2vOwA4RbQRMqJAibgUh8DRAYwu02/HLwb13fksOfPkbYWiS0YgiIQ u3RfjsqnjKfSAV3dTENIjxujl6z3RQ== X-Received: by 10.200.36.144 with SMTP id s16mr24896661qts.224.1497805936398; Sun, 18 Jun 2017 10:12:16 -0700 (PDT) In-Reply-To: <20170614234426.GI1627@brightrain.aerifal.cx> Xref: news.gmane.org gmane.linux.lib.musl.general:11513 Archived-At: How can we move forward with this patch? I would prefer to avoid the __ARCH__ complexity until there is a clear user requirement. Thanks, David On Wed, Jun 14, 2017 at 7:44 PM, Rich Felker wrote: > On Mon, Jun 12, 2017 at 09:28:52AM -0400, David Edelsohn wrote: >> >> The following IBM table of supported and tested systems >> >> >> >> https://www-03.ibm.com/systems/z/os/linux/resources/testedplatforms.html >> >> >> >> shows that RHEL 7 and SLES 12 require at least z196, and Ubuntu 16.04 >> >> requires at least zEC12. >> >> >> >> I can't find any official hardware requirements description for Alpine >> >> Linux. I tend to doubt that user would run it on older hardware, >> >> especially hardware no longer supported by other, modern Linux >> >> distributions. >> >> >> >> Building musl libc on older hardware is a nice accomplishment, but >> >> investing effort and complexity to maintain support probably isn't >> >> useful to any musl libc user and probably isn't a productive use of >> >> developer resources. >> >> >> >> I will continue to inquire if there is a simple technique to accomplish this. >> >> Apparently GCC 7.1 added architecture macros. >> >> As Tuan referenced, Alpine Linux also requires z196 as the minimum >> architecture level. I believe that it would be better for s390-musl >> to default to z196 ISA than musl to require GCC 7.1. > > I agree we shouldn't "require GCC 7.1", but using the macros does not > imply such a requirement. For example: > > #if __ARCH__ >= 10 > > would only use the asm on z196+ (if I got the number right) with GCC > 7.1+ (no asm on older compilers), whereas: > > #if __ARCH__ >= 10 || !defined(__ARCH__) > > would use the asm on z196+ or on compilers too old to provide __ARCH__ > (and building for a more minimal baseline ISA would not be supported > on such compilers unless you manually add -D__ARCH__=5 or whatever to > CFLAGS). > > I'm fine with waiting to add those pp conditionals until if/when > someone actually wants to use the lower baseline ISA, if you don't > want to do it now. I am hesitant to add new ISA-forcing logic to > configure, though (see the other reply on that). Would it be bad to > have the build fail with low default -march? If so, maybe the > configure logic could check for !defined(__ARCH__) and then do a > compile test to define __ARCH__ on its own, and we could use the above > logic? > > Rich