http://mail.openjdk.java.net/pipermail/valhalla-dev/2018-August/004848.html

Current CompileTask:
C2: 5707 477 Knapsack$WatchV::equals (8 bytes)

Stack: [0x00007fd78ea7c000,0x00007fd78eb7d000], sp=0x00007fd78eb78440, free space=1009k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x6914fe] AddPNode::Value(PhaseGVN*) const+0x12e
V [libjvm.so+0x16f901c] PhaseGVN::transform_no_reclaim(Node*)+0x13c
V [libjvm.so+0x16b757c] Parse::optimize_cmp_with_klass(Node*)+0x1dc
V [libjvm.so+0x16b771a] Parse::do_acmp(BoolTest::mask&, Node*, Node*)+0x5a
V [libjvm.so+0x16beab4] Parse::do_one_bytecode()+0x2a34
V [libjvm.so+0x16abbea] Parse::do_one_block()+0x39a
V [libjvm.so+0x16ac791] Parse::do_all_blocks()+0x1d1
V [libjvm.so+0x16b02eb] Parse::Parse(JVMState*, ciMethod*, float)+0xe3b
V [libjvm.so+0x90265c] ParseGenerator::generate(JVMState*)+0x1fc
V [libjvm.so+0xce1d20] Parse::do_call()+0x4b0
V [libjvm.so+0x16beba8] Parse::do_one_bytecode()+0x2b28
V [libjvm.so+0x16abbea] Parse::do_one_block()+0x39a
V [libjvm.so+0x16ac791] Parse::do_all_blocks()+0x1d1
V [libjvm.so+0x16b02eb] Parse::Parse(JVMState*, ciMethod*, float)+0xe3b
V [libjvm.so+0x90265c] ParseGenerator::generate(JVMState*)+0x1fc
V [libjvm.so+0xce1d20] Parse::do_call()+0x4b0
V [libjvm.so+0x16beba8] Parse::do_one_bytecode()+0x2b28
V [libjvm.so+0x16abbea] Parse::do_one_block()+0x39a
V [libjvm.so+0x16ac791] Parse::do_all_blocks()+0x1d1
V [libjvm.so+0x16b02eb] Parse::Parse(JVMState*, ciMethod*, float)+0xe3b
V [libjvm.so+0x90265c] ParseGenerator::generate(JVMState*)+0x1fc
V [libjvm.so+0xce1d20] Parse::do_call()+0x4b0
V [libjvm.so+0x16beba8] Parse::do_one_bytecode()+0x2b28
V [libjvm.so+0x16abbea] Parse::do_one_block()+0x39a
V [libjvm.so+0x16ac791] Parse::do_all_blocks()+0x1d1
V [libjvm.so+0x16b02eb] Parse::Parse(JVMState*, ciMethod*, float)+0xe3b
V [libjvm.so+0x90265c] ParseGenerator::generate(JVMState*)+0x1fc
V [libjvm.so+0xce1d20] Parse::do_call()+0x4b0
V [libjvm.so+0x16beba8] Parse::do_one_bytecode()+0x2b28
V [libjvm.so+0x16abbea] Parse::do_one_block()+0x39a
V [libjvm.so+0x16ac791] Parse::do_all_blocks()+0x1d1
V [libjvm.so+0x16b02eb] Parse::Parse(JVMState*, ciMethod*, float)+0xe3b
V [libjvm.so+0x90265c] ParseGenerator::generate(JVMState*)+0x1fc
V [libjvm.so+0xb37ca7] Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool, DirectiveSet*)+0x1017
V [libjvm.so+0x900072] C2Compiler::compile_method(ciEnv*, ciMethod*, int, DirectiveSet*)+0x302
V [libjvm.so+0xb45950] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x3c0
V [libjvm.so+0xb46639] CompileBroker::compiler_thread_loop()+0x269
V [libjvm.so+0x1960617] JavaThread::thread_main_inner()+0x287
V [libjvm.so+0x1960871] JavaThread::run()+0x191
V [libjvm.so+0x164493a] thread_native_entry(Thread*)+0xfa