Reduced fuzz test case:

public class TestBeautifyLoops_2 {

    private class X {
        public int x() {
            return -1;
        }
    }

    private int mI = 0;
    private float mF = 0;
    private boolean mZ = false;
    private X mX = new X();
    private long[] mArray = new long[331];

    private void testMethod() {
        double d = 0;

        for (int i = 0; i < 331; i++) {
            if (mZ) {
                continue;
            }

            try {
                for (int j = mArray.length - 1; j >= 0; j--) {
                    {
                        for (int k = 0; k < 331; k++) {
                            d += ((double) new Double(d));
                            switch (267) {
                                case 256:
                                default: {
                                    mF += (mX.x());
                                    break;
                                }
                            }
                        }
                    }
                }
            } catch (Exception ignore) {
            }
        }
    }

    public static void main(String[] args) {
        TestBeautifyLoops_2 obj = new TestBeautifyLoops_2();
        obj.testMethod();
    }

}

Command line: java -Xcomp -XX:-BackgroundCompilation -XX:CompileCommand=compileonly,TestBeautifyLoops_2::testMethod  TestBeautifyLoops_2

JVM crashes on x86-64 linux:
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc:  SuppressErrorAt=/loopnode.cpp:2258
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (/home/yangfei/openjdk-jdk/src/hotspot/share/opto/loopnode.cpp:2258), pid=33823, tid=33837
#  assert(_phase->is_dominator(_head, nlpt->_head)) failed: inner head dominated by outer head
#
# JRE version: OpenJDK Runtime Environment (15.0) (slowdebug build 15-internal+0-adhoc.yangfei.openjdk-jdk)
# Java VM: OpenJDK 64-Bit Server VM (slowdebug 15-internal+0-adhoc.yangfei.openjdk-jdk, compiled mode, sharing, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V  [libjvm.so+0xd24378]  IdealLoopTree::check_safepts(VectorSet&, Node_List&)+0x2f4
#
# Core dump will be written. Default location: Core dumps may be processed with "/usr/share/apport/apport %p %s %c %d %P %E" (or dumping to /home/yangfei/576/core.33823)
#
# An error report file with more information is saved as:
# /home/yangfei/576/hs_err_pid33823.log
#
# Compiler replay data is saved as:
# /home/yangfei/576/replay_pid33823.log

Call trace:
18 ---------------  S U M M A R Y ------------
 19
 20 Command Line: -Xcomp -XX:-BackgroundCompilation -XX:CompileCommand=compileonly,TestBeautifyLoops_2::testMethod TestBeautifyLoops_2
 21
 22 Host: ubuntu18, Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz, 48 cores, 377G, Ubuntu 18.04.2 LTS
 23 Time: Tue May  5 15:59:46 2020 CST elapsed time: 0.589157 seconds (0d 0h 0m 0s)
 24
 25 ---------------  T H R E A D  ---------------
 26
 27 Current thread (0x00007f9470362000):  JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=33837, stack(0x00007f93fd03c000,0x00007f93fd13d000)]
 28
 29
 30 Current CompileTask:
 31 C2:    589    3 % !b  4       TestBeautifyLoops_2::testMethod @ 38 (121 bytes)
 32
 33 Stack: [0x00007f93fd03c000,0x00007f93fd13d000],  sp=0x00007f93fd1373f0,  free space=1004k
 34 Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
 35 V  [libjvm.so+0xd24378]  IdealLoopTree::check_safepts(VectorSet&, Node_List&)+0x2f4
 36 V  [libjvm.so+0xd240cd]  IdealLoopTree::check_safepts(VectorSet&, Node_List&)+0x49
 37 V  [libjvm.so+0xd26fcd]  PhaseIdealLoop::build_and_optimize(LoopOptsMode)+0x7d9
 38 V  [libjvm.so+0x6f69a7]  PhaseIdealLoop::PhaseIdealLoop(PhaseIterGVN&, LoopOptsMode)+0xb3
 39 V  [libjvm.so+0x6f6aa2]  PhaseIdealLoop::optimize(PhaseIterGVN&, LoopOptsMode)+0x46
 40 V  [libjvm.so+0x6eae1a]  Compile::Optimize()+0x580
 41 V  [libjvm.so+0x6e4745]  Compile::Compile(ciEnv*, ciMethod*, int, bool, bool, bool, DirectiveSet*)+0x10e9
 42 V  [libjvm.so+0x5e2185]  C2Compiler::compile_method(ciEnv*, ciMethod*, int, DirectiveSet*)+0x141
 43 V  [libjvm.so+0x6fee46]  CompileBroker::invoke_compiler_on_method(CompileTask*)+0x7f0
 44 V  [libjvm.so+0x6fdb61]  CompileBroker::compiler_thread_loop()+0x3dd
 45 V  [libjvm.so+0x114c765]  compiler_thread_entry(JavaThread*, Thread*)+0x69
 46 V  [libjvm.so+0x1147985]  JavaThread::thread_main_inner()+0x149
 47 V  [libjvm.so+0x1147833]  JavaThread::run()+0x11f
 48 V  [libjvm.so+0x1143aa0]  Thread::call_run()+0x180
 49 V  [libjvm.so+0xeb4ac0]  thread_native_entry(Thread*)+0x1e4