The attached fuzzer test fails with the following assertion:

To reproduce:
$ java -Xcomp -XX:TieredStopAtLevel=1 -XX:CompileOnly=Test Test.java

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/christian/jdk/open/src/hotspot/share/c1/c1_LIR.hpp:423), pid=10943, tid=10955
# assert(is_virtual()) failed: type check
#
# JRE version: Java(TM) SE Runtime Environment (16.0) (slowdebug build 16-internal+0-2020-10-16-0945385.christian...)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (slowdebug 16-internal+0-2020-10-16-0945385.christian..., compiled mode, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x5f2991] LIR_OprDesc::vreg_number() const+0x29
..........
Command Line: -Xcomp -XX:TieredStopAtLevel=1 -XX:CompileOnly=Test --add-modules=ALL-DEFAULT jdk.compiler/com.sun.tools.javac.launcher.Main Test.java
..........
Current thread (0x00007fc6d434fda0): JavaThread "C1 CompilerThread0" daemon [_thread_in_native, id=10955, stack(0x00007fc6bc228000,0x00007fc6bc329000)]


Current CompileTask:
C1: 12942 88 !b 1 Test::vMeth1 (1566 bytes)

Stack: [0x00007fc6bc228000,0x00007fc6bc329000], sp=0x00007fc6bc326710, free space=1017k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x5f2991] LIR_OprDesc::vreg_number() const+0x29
V [libjvm.so+0x636dd5] LinearScan::resolve_exception_edge(XHandler*, int, int, Phi*, MoveResolver&)+0x127
V [libjvm.so+0x63721f] LinearScan::resolve_exception_edge(XHandler*, int, MoveResolver&)+0x397
V [libjvm.so+0x637608] LinearScan::resolve_exception_handlers()+0x2fc
V [libjvm.so+0x63bd7c] LinearScan::do_linear_scan()+0x112
V [libjvm.so+0x5ade3c] Compilation::emit_lir()+0x152
V [libjvm.so+0x5ae5ac] Compilation::compile_java_method()+0x21e
V [libjvm.so+0x5ae90e] Compilation::compile_method()+0x106
V [libjvm.so+0x5af106] Compilation::Compilation(AbstractCompiler*, ciEnv*, ciMethod*, int, BufferBlob*, bool, DirectiveSet*)+0x362
V [libjvm.so+0x5b2fd7] Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0xd9
V [libjvm.so+0x7b2dd5] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x895
V [libjvm.so+0x7b1a61] CompileBroker::compiler_thread_loop()+0x3df
V [libjvm.so+0x11abcf2] compiler_thread_entry(JavaThread*, Thread*)+0x69
V [libjvm.so+0x11a7b68] JavaThread::thread_main_inner()+0x14c
V [libjvm.so+0x11a7a14] JavaThread::run()+0x11e
V [libjvm.so+0x11a3c24] Thread::call_run()+0x180
V [libjvm.so+0xfa1f7c] thread_native_entry(Thread*)+0x1e4