The attached fuzzer test hits the following assertion failure.

To reproduce:
$ java -Xmx1G -Xcomp -Xbatch -XX:-TieredCompilation -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/opto/phaseX.cpp:923), pid=23357, tid=23369
# assert(no_dead_loop) failed: dead loop detected
#
# JRE version: Java(TM) SE Runtime Environment (16.0) (slowdebug build 16-internal+0-2020-07-13-1111353.christian...)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (slowdebug 16-internal+0-2020-07-13-1111353.christian..., compiled mode, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0xf02e58] PhaseGVN::dead_loop_check(Node*)+0x18e
..........
Command Line: -Xmx1G -Xcomp -Xbatch -XX:-TieredCompilation -XX:CompileOnly=Test --add-modules=ALL-DEFAULT jdk.compiler/com.sun.tools.javac.launcher.Main Test.java
..........
Current thread (0x00007f4bfc343fc0): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=23369, stack(0x00007f4bf8005000,0x00007f4bf8106000)]


Current CompileTask:
C2: 12334 93 b Test::lMeth (228 bytes)

Stack: [0x00007f4bf8005000,0x00007f4bf8106000], sp=0x00007f4bf81013c0, free space=1008k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0xf02e58] PhaseGVN::dead_loop_check(Node*)+0x18e
V [libjvm.so+0xf040c2] PhaseIterGVN::transform_old(Node*)+0x26c
V [libjvm.so+0xf03ce4] PhaseIterGVN::optimize()+0x148
V [libjvm.so+0x6d5d82] Compile::Optimize()+0x18a
V [libjvm.so+0x6cfaca] Compile::Compile(ciEnv*, ciMethod*, int, bool, bool, bool, bool, DirectiveSet*)+0x1090
V [libjvm.so+0x5ce7a7] C2Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x15b
V [libjvm.so+0x6ea926] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x88e
V [libjvm.so+0x6e95b3] CompileBroker::compiler_thread_loop()+0x3df
V [libjvm.so+0x10a0bdf] compiler_thread_entry(JavaThread*, Thread*)+0x69
V [libjvm.so+0x109bd90] JavaThread::thread_main_inner()+0x146
V [libjvm.so+0x109bc41] JavaThread::run()+0x11f
V [libjvm.so+0x1097eca] Thread::call_run()+0x180
V [libjvm.so+0xea6716] thread_native_entry(Thread*)+0x1e4