I ran into an assert when running lucene using a debug build of hotspot-comp. I do not get the crash every time, empirically I'd say it reproduces every 4th time or so.

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (lucene/src/share/vm/opto/phaseX.cpp:1428), pid=32214, tid=139795492837120
# assert(t->meet(t0) == t) failed: Not monotonic
#
# JRE version: Java(TM) SE Runtime Environment (8.0-b114) (build 1.8.0-ea-b114)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.0-b58-internal-debug mixed mode linux-amd64 compressed oops)
# Core dump written. Default location: lucene/lucene/trunk/lucene/build/core/test/J0/core or core.32214
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#

--------------- T H R E A D ---------------

Current thread (0x00007f24c018a000): JavaThread "C2 CompilerThread1" daemon [_thread_in_native, id=32230, stack(0x00007f24aca11000,0x00007f24acb12000)]

Stack: [0x00007f24aca11000,0x00007f24acb12000], sp=0x00007f24acb0be70, free space=1003k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0xce1ba6] VMError::report(outputStream*)+0x10ea
V [libjvm.so+0xce3066] VMError::report_and_die()+0x42c
V [libjvm.so+0x649230] report_vm_error(char const*, int, char const*, char const*)+0x93
V [libjvm.so+0xb6b7b4] ccp_type_widens(Type const*, Type const*)+0x4e
V [libjvm.so+0xb6b9cb] PhaseCCP::analyze()+0x121
V [libjvm.so+0xb6b716] PhaseCCP::PhaseCCP(PhaseIterGVN*)+0x98
V [libjvm.so+0x5d59e5] Compile::Optimize()+0x8cd
V [libjvm.so+0x5d00ac] Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool)+0x111a
V [libjvm.so+0x506c71] C2Compiler::compile_method(ciEnv*, ciMethod*, int)+0xf7
V [libjvm.so+0x5e6e95] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x459
V [libjvm.so+0x5e64fc] CompileBroker::compiler_thread_loop()+0x334
V [libjvm.so+0xc88c82] compiler_thread_entry(JavaThread*, Thread*)+0x57
V [libjvm.so+0xc842ab] JavaThread::thread_main_inner()+0x14f
V [libjvm.so+0xc8414d] JavaThread::run()+0x163
V [libjvm.so+0xb0f48e] java_start(Thread*)+0x1c2


Current CompileTask:
C2: 453919 33602 % 4 com.carrotsearch.randomizedtesting.ClassModel$ModelBuilder::build @ 43 (245 bytes)