assert(is_Loop(),"invalid node class")

While testing G1 I'm hitting the following assert:

# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/node.hpp:721
==============================================================================
Unexpected Error
------------------------------------------------------------------------------
Internal Error at node.hpp:721, pid=12290, tid=29
Error: assert(is_Loop(),"invalid node class")

Do you want to debug the problem?

To debug, run 'dbx - 12290'; then switch to thread 29
Enter 'yes' to launch dbx automatically (PATH must include dbx)
Otherwise, press RETURN to abort...
==============================================================================

I can reproduce it with a sparcv9 / solaris / 64-bit / fastdebug / server build running the dacapo eclipse. Here's the command line:

java -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+VerifyBeforeGC -XX:+VerifyDuringGC -XX:+VerifyAfterGC -d64 -XX:+PrintGCTimeStamps -XX:+PrintGCDetails -XX:+ShowMessageBoxOnError -jar dacapo-2006-10.jar -s default eclipse