[xsl] Suggestion for handling an endless loop

["Mark Giffin m1879@xxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

I'm getting what appears to be an endless loop while running XSLT 2.0. 
It hangs when transforming a certain XML file, and I can watch the 
memory consumption rise to as much as 9 GB, and it apparently will never 
end. I have to force it to stop. When I change it back to XSLT 1.0, it 
runs fine, and when it hits the same file it hung up on with 2.0, it 
transforms in a second or two with 1.0. The XSLT does not use any 2.0 
capabilities yet. The only change is changing 2.0 to 1.0 in 
<xsl:stylesheet version="2.0">.

I'm interested in methods to debug something like this. Where to look? I 
notice Oxygen has an XSLT profiler.

Details:
The XSLT is running under the DITA Open Toolkit version 3.3.2 (late 
model). I am converting an HTML-based publishing output from a much 
older version of the DITA OT, 1.8.5 (where the code worked). It looks 
like the 3.3.2 OT uses Saxon-HE-9.8.0-14.jar.

Thanks,
Mark