Date: Mon, 12 Nov 2007 19:47:36 -0000 (UTC) From: =?iso-8859-1?Q?Bj=F6rn_K=F6nig?= <bkoenig@alpha-tierchen.de> To: "Alexander Kabaev" <kabaev@gmail.com> Cc: freebsd-java@freebsd.org Subject: Re: jdk16 and -fno-tree-vrp Message-ID: <58177.192.168.1.2.1194896856.squirrel@webmail.alpha-tierchen.de>
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Alexander Kabaev wrote: > 1. jdk15 is missing from the list of jdk's you tried to build, and that > was the primary tree-vrp victim; Ok, I did that too right now and it builds without problems either. By the way, I used diablo-jdk15 for bootstrapping. > 2. You did not mention architecture you did your experiments on. i386. I plan to build the ports on amd64 too. > This particular optimization step was implicated in a number if > miscompiles reported by several developers and just taking it out of > the picture takes care of majority. This is right decision too given > where we are in the release cycle and unclear position of the project > towards GPL3. I understand the severity of this decision, but I'm a little bit in doubt. My first point is that most of these reported bugs happend during the pre-beta stage where -current was still not settled very well. From experience we know that numerous users start to test it during the BETA or even RC phase. Therefore I think that there were too less testers and too less bug reports. Furthermore I assume that somebody just tried -fno-tree-vrp, hit or miss, it seem to work more or less coincidentally and I'm not sure if this is a good solution. I think this because -fno-tree-vrp breaks the FreeBSD/arm world which is definitely a GCC bug. It is strange that it works fine again if you specify -fno-cse-follow-jumps or -fno-schedule-insns for example. I know that that FreeBSD/arm has not the same importance as i386 or other tier 1 platforms. Even the jdk ports are more important for the upcoming release. It is just an example to emphasise the quality of this bug. So in other words you closed one box of pandora and opened another one. Last but not least I found a small change the the GCC repository which unbreaks the ARM world compiled with -fno-tree-vrp and I'm curious whether the same change affects the jdk ports. So I build them first with the assumption that they will fail, but they didn't. That's also why I ask for a reproducible scenario. Björn
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