Since ~ middle of (or shortly before middle of) June we see various C1 and C2 compiler crashes on windows x86_64.
These have been observed with both opt and fastdebug binaries, when running an internal test suite.
The crashes occured on both test servers (with Windows server OS) and also on Win11 based notebook.
Unfortunately we cannot easily reproduce them with externally available tests.
The stacks in hserr files differ a bit. Some examples :

1)

# Internal Error (utilities/growableArray.hpp:256), pid=7436, tid=18160
# Error: ShouldNotReachHere()
#

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

Current thread (0x000001c7c11059c0): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=18160, stack(0x0000009eba000000,0x0000009eba100000) (1024K)]


Current CompileTask:
C2:14090 13241 4 sun.font.HBShaper::store_layout_results (440 bytes)

Stack: [0x0000009eba000000,0x0000009eba100000]
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0x6fce59] os::win32::platform_print_native_stack+0xd9 (os_windows_x86.cpp:235)
V [jvm.dll+0x8eda25] VMError::report+0xd95 (vmError.cpp:1011)
V [jvm.dll+0x8efcdd] VMError::report_and_die+0x5fd (vmError.cpp:1846)
V [jvm.dll+0x8f0347] VMError::report_and_die+0x47 (vmError.cpp:1611)
V [jvm.dll+0x28d587] report_vm_error+0x57 (debug.cpp:193)
V [jvm.dll+0x28d5ac] report_vm_error+0x1c (debug.cpp:149)
V [jvm.dll+0x28d500] report_should_not_reach_here+0x10 (debug.cpp:240)
V [jvm.dll+0x260b57] Compile::remove_useless_node+0x3a7 (compile.cpp:403)
V [jvm.dll+0x724606] PhaseIterGVN::remove_globally_dead_node+0x366 (phaseX.cpp:1304)
V [jvm.dll+0x724f0a] PhaseIterGVN::subsume_node+0x2ca (phaseX.cpp:1430)
V [jvm.dll+0x7258fd] PhaseIterGVN::transform_old+0x1bd (phaseX.cpp:1284)
V [jvm.dll+0x723d12] PhaseIterGVN::optimize+0x182 (phaseX.cpp:1048)
V [jvm.dll+0x2576b1] Compile::Optimize+0x1101 (compile.cpp:2425)
V [jvm.dll+0x254d17] Compile::Compile+0xe47 (compile.cpp:853)
V [jvm.dll+0x1d06ea] C2Compiler::compile_method+0x11a (c2compiler.cpp:145)
V [jvm.dll+0x264c31] CompileBroker::invoke_compiler_on_method+0x811 (compileBroker.cpp:2306)
V [jvm.dll+0x262efb] CompileBroker::compiler_thread_loop+0x26b (compileBroker.cpp:1962)
V [jvm.dll+0x4051f6] JavaThread::run+0x116 (javaThread.cpp:742)
V [jvm.dll+0x892bf8] Thread::call_run+0xc8 (thread.cpp:235)
V [jvm.dll+0x6fb695] thread_native_entry+0x95 (os_windows.cpp:553)
C [ucrtbase.dll+0x1fb80] (no source info available)
C [KERNEL32.DLL+0x84d4] (no source info available)
C [ntdll.dll+0x51a11] (no source info available)


2)

# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007ffcf58b6202, pid=14520, tid=28428
#
# V [jvm.dll+0x156202] LIR_OpVisitState::append+0x52

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

Current thread (0x000001cff5b98820): JavaThread "C1 CompilerThread1" daemon [_thread_in_native, id=28428, stack(0x00000019a9800000,0x00000019a9900000) (1024K)]

Current CompileTask:
C1:7053 8888 ! 3 com.pietjonas.wmfwriter2d.WMFGraphics::setGDIFillBrush (231 bytes)

Stack: [0x00000019a9800000,0x00000019a9900000], sp=0x00000019a98fde40, free space=1015k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0x156202] LIR_OpVisitState::append+0x52 (c1_LIR.hpp:2488)
V [jvm.dll+0x174e83] LIR_OpVisitState::visit+0xd3 (c1_LIR.cpp:928)
V [jvm.dll+0x19dfc2] LinearScan::build_intervals+0x2e2 (c1_LinearScan.cpp:1364)
V [jvm.dll+0x19ffb4] LinearScan::do_linear_scan+0x34 (c1_LinearScan.cpp:3099)
V [jvm.dll+0x158cb2] Compilation::emit_lir+0x132 (c1_Compilation.cpp:277)
V [jvm.dll+0x1584fe] Compilation::compile_java_method+0x16e (c1_Compilation.cpp:409)
V [jvm.dll+0x1587bb] Compilation::compile_method+0x1db (c1_Compilation.cpp:484)
V [jvm.dll+0x157a61] Compilation::Compilation+0x201 (c1_Compilation.cpp:611)
V [jvm.dll+0x159911] Compiler::compile_method+0xe1 (c1_Compiler.cpp:261)
V [jvm.dll+0x264c31] CompileBroker::invoke_compiler_on_method+0x811 (compileBroker.cpp:2306)
V [jvm.dll+0x262efb] CompileBroker::compiler_thread_loop+0x26b (compileBroker.cpp:1962)
V [jvm.dll+0x4051f6] JavaThread::run+0x116 (javaThread.cpp:742)
V [jvm.dll+0x892be8] Thread::call_run+0xc8 (thread.cpp:235)
V [jvm.dll+0x6fb685] thread_native_entry+0x95 (os_windows.cpp:553)
C [ucrtbase.dll+0x2268a] (no source info available)
C [KERNEL32.DLL+0x17ac4] (no source info available)
C [ntdll.dll+0x5a8c1] (no source info available)

3)

# Internal Error (node.cpp:2955), pid=9520, tid=7900
# Error: ShouldNotReachHere()

Current thread (0x0000015428937860): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=7900, stack(0x000000336c400000,0x000000336c500000) (1024K)]

Current CompileTask:
C2:10741 8161 4 sun.font.HBShaper::get_nominal_glyph (57 bytes)

Stack: [0x000000336c400000,0x000000336c500000]
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0x6fce49] os::win32::platform_print_native_stack+0xd9 (os_windows_x86.cpp:235)
V [jvm.dll+0x8eda15] VMError::report+0xd95 (vmError.cpp:1011)
V [jvm.dll+0x8efccd] VMError::report_and_die+0x5fd (vmError.cpp:1846)
V [jvm.dll+0x8f0337] VMError::report_and_die+0x47 (vmError.cpp:1611)
V [jvm.dll+0x28d587] report_vm_error+0x57 (debug.cpp:193)
V [jvm.dll+0x28d5ac] report_vm_error+0x1c (debug.cpp:149)
V [jvm.dll+0x28d500] report_should_not_reach_here+0x10 (debug.cpp:240)
V [jvm.dll+0x6d7e15] Unique_Node_List::remove+0xc5 (node.cpp:2955)
V [jvm.dll+0x7245ea] PhaseIterGVN::remove_globally_dead_node+0x35a (phaseX.cpp:1380)
V [jvm.dll+0x724efa] PhaseIterGVN::subsume_node+0x2ca (phaseX.cpp:1430)
V [jvm.dll+0x3cc525] idealize_test+0x1c5 (ifnode.cpp:1919)
V [jvm.dll+0x3cadae] IfNode::Ideal_common+0x6e (ifnode.cpp:1479)
V [jvm.dll+0x3ca885] IfNode::Ideal+0x15 (ifnode.cpp:1494)
V [jvm.dll+0x72578e] PhaseIterGVN::transform_old+0x5e (phaseX.cpp:1198)
V [jvm.dll+0x723d02] PhaseIterGVN::optimize+0x182 (phaseX.cpp:1048)
V [jvm.dll+0x2567b4] Compile::Optimize+0x204 (compile.cpp:2239)
V [jvm.dll+0x254d17] Compile::Compile+0xe47 (compile.cpp:853)
V [jvm.dll+0x1d06ea] C2Compiler::compile_method+0x11a (c2compiler.cpp:145)
V [jvm.dll+0x264c31] CompileBroker::invoke_compiler_on_method+0x811 (compileBroker.cpp:2306)
V [jvm.dll+0x262efb] CompileBroker::compiler_thread_loop+0x26b (compileBroker.cpp:1962)
V [jvm.dll+0x4051f6] JavaThread::run+0x116 (javaThread.cpp:742)
V [jvm.dll+0x892be8] Thread::call_run+0xc8 (thread.cpp:235)
V [jvm.dll+0x6fb685] thread_native_entry+0x95 (os_windows.cpp:553)
C [ucrtbase.dll+0x1fb80] (no source info available)
C [KERNEL32.DLL+0x84d4] (no source info available)
C [ntdll.dll+0x51a11] (no source info available)