From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29487 invoked by alias); 25 Feb 2014 21:00:24 -0000 Mailing-List: contact crossgcc-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: crossgcc-owner@sourceware.org Received: (qmail 29469 invoked by uid 89); 25 Feb 2014 21:00:23 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 X-HELO: plane.gmane.org Received: from plane.gmane.org (HELO plane.gmane.org) (80.91.229.3) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Tue, 25 Feb 2014 21:00:23 +0000 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1WIP6w-0004S4-OM for crossgcc@sourceware.org; Tue, 25 Feb 2014 22:00:18 +0100 Received: from dsl.comtrol.com ([64.122.56.22]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 25 Feb 2014 22:00:18 +0100 Received: from grant.b.edwards by dsl.comtrol.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 25 Feb 2014 22:00:18 +0100 To: crossgcc@sourceware.org From: Grant Edwards Subject: Re: 32-bit host vs 64-bit host Date: Tue, 25 Feb 2014 21:00:00 -0000 Message-ID: References: <20140225134757.f955220426e7925665b5897d8ef6e12e.7871ca77e8.wbe@email02.secureserver.net> User-Agent: slrn/1.0.1 (Linux) X-IsSubscribed: yes X-SW-Source: 2014-02/txt/msg00068.txt.bz2 On 2014-02-25, wrote: >>What sort of differences did you find? > > I could not compile the standard c library with the 32 bit toolchain on > a 64 bit host, when the same library would build fine on the 32 bit > host. I have ran into this issue many times during the second stage of > the toolchain build on a 64 bit host. Same gcc/glibc sources would > compile on a 32 bit host but would fail on a 64 bit. Ah, I see. I suspect that has something to do with missing 32-bit compatibility libraries. That's not really what I'm asking about. I've got a 32-bit toolchain which has been in use for some time on both 32-bit and 64-bit hosts -- everything works fine. The last of the 32-bit machines in the development group was just changed over to 64-bit. Now everybody is running 64-bit development machines. I'm trying to decide how much testing and verification would be needed if/when we rebuild the exact same toolchain as a 64-bit hosted application. For a naively written compiler (e.g. all of the one's I've written/worked on), I would expect the exact same object code to be emitted regardless of the word-size of the host. However, gcc is far from "naive" and I wouldn't put it past the developers to write optimizer code that actually generates different output when the host's native word size changes. One of these days, I'll build a toolchain on a 64-bit host and actually compare some target program binaries to see if anything changes... -- Grant Edwards grant.b.edwards Yow! Now I'm concentrating at on a specific tank battle gmail.com toward the end of World War II! -- For unsubscribe information see http://sourceware.org/lists.html#faq