Gary Benson wrote (http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2010-August/003707.html):
This webrev contains a number of fixes for Zero and Shark:
Firstly, the two bugs 6953477 and 6730276 required changes
to be made to Zero. Secondly, an assertion that is invalid
on Shark was removed, which allows debug builds of Shark to
be built on ia32.
I don't have a bug id for this.