The following test failed in the JDK20 CI:

applications/javafuzzer/MediumTest.java

Here's a snippet from the log file:

Summary of the JavaFuzzer run:
------------------------------
Host: win2016-x64-270877
Tests: 12 x 50
Args: -conf config.yml

Started at: Tue Aug 16 19:56:36 GMT 2022


r3- 50: 33 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 17 Reference Java failures
r12- 50: 33 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 17 Reference Java failures
r7- 50: 32 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 18 Reference Java failures
r8- 50: 33 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 17 Reference Java failures
r6- 50: 34 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 16 Reference Java failures
r11- 50: 29 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 21 Reference Java failures
r1- 50: 34 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 16 Reference Java failures
r9- 50: 28 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 22 Reference Java failures
r4- 50: 31 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 19 Reference Java failures
r5- 50: 30 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 20 Reference Java failures
r2- 50: 25 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 25 Reference Java failures
r10- 50: 25 passed, 2 crashes, 0 fails, 0 hangs, 0 incorrect tests, 24 Reference Java failures

Finished at: Tue Aug 16 21:21:27 GMT 2022


#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (c:\\sb\\prod\\1660600762\\workspace\\open\\src\\hotspot\\share\\opto\\block.cpp:1223), pid=11460, tid=5576
# assert(found) failed: block b is not in n's home loop or an ancestor of it
#
# JRE version: Java(TM) SE Runtime Environment (20.0+11) (fastdebug build 20-ea+11-635)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 20-ea+11-635, compiled mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, windows-amd64)
# Core dump will be written. Default location: C:\\sb\\prod\\1660679683\\testoutput\\test-support\\jtreg_closed_test_hotspot_jtreg_applications_javafuzzer_MediumTest_java\\tmp\\fuzzer.tmp.3G2vOyvHxh\\hs_err_pid11460.mdmp
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#

Command Line: -Xmx1G -Xcomp -Xbatch -XX:CompileOnly=Test -XX:CompileCommand=quiet Test

Here's the crashing thread's stack:

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

Current thread (0x000001cc37df8aa0): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=5576, stack(0x000000432d200000,0x000000432d300000)]


Current CompileTask:
C2: 1064 78 !b 4 Test::mainTest (749 bytes)

Stack: [0x000000432d200000,0x000000432d300000]
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0xc43d61] os::win32::platform_print_native_stack+0xf1 (os_windows_x86.cpp:236)
V [jvm.dll+0xe97f6e] VMError::report+0x10de (vmError.cpp:839)
V [jvm.dll+0xe9999e] VMError::report_and_die+0x65e (vmError.cpp:1687)
V [jvm.dll+0xe9a114] VMError::report_and_die+0x64 (vmError.cpp:1468)
V [jvm.dll+0x58cdc7] report_vm_error+0xb7 (debug.cpp:284)
V [jvm.dll+0x33b863] PhaseCFG::verify_memory_writer_placement+0xc3 (block.cpp:1224)
V [jvm.dll+0x730d49] PhaseCFG::hoist_to_cheaper_block+0x3c9 (gcm.cpp:1228)
V [jvm.dll+0x734ace] PhaseCFG::schedule_late+0x66e (gcm.cpp:1456)
V [jvm.dll+0x72ff4f] PhaseCFG::global_code_motion+0x31f (gcm.cpp:1521)
V [jvm.dll+0x72eb1a] PhaseCFG::do_global_code_motion+0x4a (gcm.cpp:1644)
V [jvm.dll+0x51f485] Compile::Code_Gen+0x1d5 (compile.cpp:2936)
V [jvm.dll+0x51e32a] Compile::Compile+0x15fa (compile.cpp:857)
V [jvm.dll+0x443ed5] C2Compiler::compile_method+0x145 (c2compiler.cpp:115)
V [jvm.dll+0x537f80] CompileBroker::invoke_compiler_on_method+0x980 (compileBroker.cpp:2314)
V [jvm.dll+0x53552c] CompileBroker::compiler_thread_loop+0x25c (compileBroker.cpp:1982)
V [jvm.dll+0x80262f] JavaThread::thread_main_inner+0x29f (javaThread.cpp:700)
V [jvm.dll+0xe11ba7] Thread::call_run+0x257 (thread.cpp:229)
V [jvm.dll+0xc426a8] thread_native_entry+0xb8 (os_windows.cpp:547)
C [ucrtbase.dll+0x1fb80]
C [KERNEL32.DLL+0x84d4]
C [ntdll.dll+0x51791]