Date: Sun, 28 Jul 2002 21:10:29 -0700 (PDT) From: Archie Cobbs <archie@dellroad.org> To: Clifton Royston <cliftonr@lava.net> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: Is use of -O2 still deprecated for buildworld in -stable? Message-ID: <200207290410.g6T4AU910168@arch20m.dellroad.org> In-Reply-To: <20020727191945.A10231@lava.net> "from Clifton Royston at Jul 27, 2002 07:19:45 pm"
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Clifton Royston writes: > My understanding is that whether or not -O2 *should* produce exactly > equivalent code to -O, there are recurrent reports of people having > trouble doing a buildworld with -O2 in -stable or in 4.x release > trains, where their problems go away when they revert back to -O. In > this case, we simply shouldn't be using it on production servers. I'm > using it on my home machines (-O2 for world, -O for kernel) but they > has altogether different needs for reliability. I've wondered about this a lot myself and never seen a clear answer. My best guess as to what's going on is that the FreeBSD kernel contains some (broken?) asm() statements that cause incorrect code to be generated when -O2 is used, but not when -O is used. This would explain how -O2 could cause FreeBSD to not work without there actually being a bug in gcc causing it. -Archie __________________________________________________________________________ Archie Cobbs * Packet Design * http://www.packetdesign.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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