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List:       openjdk-hotspot-dev
Subject:    Is i686 the minimum required for HotSpot on x86?
From:       ahughes () redhat ! com (Dr Andrew John Hughes)
Date:       2011-03-31 14:53:17
Message-ID: 20110331145317.GX6143 () rivendell ! middle-earth ! co ! uk
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On 12:27 Thu 31 Mar     , Christian Thalinger wrote:
> On Mar 30, 2011, at 10:33 AM, Christian Thalinger wrote:
> > On Mar 30, 2011, at 12:44 AM, Dr Andrew John Hughes wrote:
> > > On 17:31 Tue 29 Mar     , Christian Thalinger wrote:
> > > > On Mar 29, 2011, at 4:35 PM, Christian Thalinger wrote:
> > > > > On Mar 29, 2011, at 4:26 PM, Dr Andrew John Hughes wrote:
> > > > > > We've just had a bug report for IcedTea which suggests that
> > > > > > HotSpot fails on any x86 platform below i686.
> > > > > > 
> > > > > > The report is:
> > > > > > 
> > > > > > http://icedtea.classpath.org/bugzilla/show_bug.cgi?id=682
> > > > > > 
> > > > > > and shows a failure caused by an attempt by the JIT to emit
> > > > > > an instruction which isn't present on i586.
> > > > > > 
> > > > > > Does HotSpot require i686 as a minimum? Or is there something
> > > > > > else at fault here?
> > > > > 
> > > > > There is a switch -XX:+Use486InstrsOnly but I have an open bug for that \
> > > > > one: 
> > > > > 6808665: Use486InstrsOnly aborts 32-bit VM
> > > > 
> > > > Looking a little closer this could actually be my fault.  I added unguarded \
> > > > cmov instructions to C1 with: 
> > > > 6919934: JSR 292 needs to support x86 C1
> > > > 
> > > > http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/3cf667df43ef
> > > > 
> > > > And that was delivered in HS18b01.  I will fix that.
> > > > 
> > > > -- Christian
> > > 
> > > Ah thanks for finding the issue!  I await the fix.
> > 
> > 7032388: guarantee(VM_Version::supports_cmov()) failed: illegal instruction on \
> > i586 after 6919934
> 
> I case you haven't seen it:
> 
> http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/09f96c3ff1ad
> 
> Can you apply that patch to IcedTea and ask the bug submitter to try again?
> 

First part is already done :-)

I'll try and get it approved for the 1.10.1 release on Monday, then it can
get out in the distros.

> -- Christian

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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