When running JMC (HEAD) with a slowdebug OpenJDK build (HEAD), the following assertion is hit loading a big JFR recording:
assert(init == verif_init && stride == verif_stride) failed: missed opaque node

This happens since the fix for bug JDK-8289127 was submitted (which introduced the triggering assertion).

The values of 'init' and 'stride' are 0, but the values of 'verify_init' and 'verify_stride' are 1.

The 'current compile task' is always for the same OSR compilation (for entry of the last while loop in the code):
C2: 392782 11513 % 4 org.openjdk.jmc.flightrecorder.internal.parser.v1.ChunkLoaderV1::call @ 119 (220 bytes)

Stack:
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0xe2b0c3] os::platform_print_native_stack+0x63 (os_windows_x86.cpp:234)
V [jvm.dll+0x111e145] VMError::report+0x1235 (vmError.cpp:836)
V [jvm.dll+0x11209ae] VMError::report_and_die+0x6ce (vmError.cpp:1684)
V [jvm.dll+0x1121011] VMError::report_and_die+0x81 (vmError.cpp:1469)
V [jvm.dll+0x61179d] report_vm_error+0x9d (debug.cpp:285)
V [jvm.dll+0xc69339] PhaseIdealLoop::skeleton_predicate_has_opaque+0x309 (loopTransform.cpp:1451)
V [jvm.dll+0xc59f86] PhaseIdealLoop::get_skeleton_predicates+0x1e6 (loopPredicate.cpp:385)
V [jvm.dll+0xc8bde1] PhaseIdealLoop::collect_potentially_useful_predicates+0x261 (loopnode.cpp:4067)
V [jvm.dll+0xc8be05] PhaseIdealLoop::collect_potentially_useful_predicates+0x285 (loopnode.cpp:4070)
V [jvm.dll+0xc8bbb7] PhaseIdealLoop::collect_potentially_useful_predicates+0x37 (loopnode.cpp:4038)
V [jvm.dll+0xc8bea4] PhaseIdealLoop::eliminate_useless_predicates+0x94 (loopnode.cpp:4086)
V [jvm.dll+0xc84689] PhaseIdealLoop::build_and_optimize+0xbc9 (loopnode.cpp:4419)
V [jvm.dll+0x59da2e] PhaseIdealLoop::PhaseIdealLoop+0xee (loopnode.hpp:1086)
V [jvm.dll+0x5a0089] PhaseIdealLoop::optimize+0x49 (loopnode.hpp:1166)
V [jvm.dll+0x58e553] Compile::optimize_loops+0x93 (compile.cpp:2173)
V [jvm.dll+0x592efe] Compile::Optimize+0xebe (compile.cpp:2408)
V [jvm.dll+0x58fe8e] Compile::Compile+0x142e (compile.cpp:824)
V [jvm.dll+0x498f85] C2Compiler::compile_method+0x145 (c2compiler.cpp:115)
V [jvm.dll+0x5a46d6] CompileBroker::invoke_compiler_on_method+0x7a6 (compileBroker.cpp:2314)
V [jvm.dll+0x5a7a8a] CompileBroker::compiler_thread_loop+0x35a (compileBroker.cpp:1982)
V [jvm.dll+0x5c5aa4] CompilerThread::thread_entry+0x54 (compilerThread.cpp:60)
V [jvm.dll+0x999888] JavaThread::thread_main_inner+0x138 (javaThread.cpp:700)
V [jvm.dll+0x999737] JavaThread::run+0x127 (javaThread.cpp:683)
V [jvm.dll+0x1086b6c] Thread::call_run+0x15c (thread.cpp:229)
V [jvm.dll+0xe238e8] thread_native_entry+0x108 (os_windows.cpp:546)
C [ucrtbase.dll+0x21bb2]
C [KERNEL32.DLL+0x17034]
C [ntdll.dll+0x52651]