Attached test crashes with:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (open/src/hotspot/share/opto/loopTransform.cpp:2984), pid=25022, tid=25034
# Error: assert(p_f->Opcode() == Op_IfFalse) failed
#
# JRE version: Java(TM) SE Runtime Environment (14.0+21) (fastdebug build 14-ea+21-927)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 14-ea+21-927, compiled mode, sharing, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x11f21fc] IdealLoopTree::remove_main_post_loops(CountedLoopNode*, PhaseIdealLoop*)+0x37c
#
# Core dump will be written. Default location: Core dumps may be processed with "/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t e %P %I %h" (or dumping to /tmp/fuzzer.tmp.zPS5O09UCc/core.25022)
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#

--------------- S U M M A R Y ------------

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

Host: Intel Core Processor (Broadwell), 12 cores, 28G, Oracle Linux Server release 7.5
Time: Fri Nov 1 11:46:11 2019 UTC elapsed time: 33 seconds (0d 0h 0m 33s)

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

Current thread (0x00007f5280340000): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=25034, stack(0x00007f5255cfd000,0x00007f5255dfe000)]


Current CompileTask:
C2: 33368 78 % b 4 Test::mainTest @ 131 (568 bytes)

Stack: [0x00007f5255cfd000,0x00007f5255dfe000], sp=0x00007f5255df8190, free space=1004k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x11f21fc] IdealLoopTree::remove_main_post_loops(CountedLoopNode*, PhaseIdealLoop*)+0x37c
V [libjvm.so+0x11f28aa] IdealLoopTree::do_remove_empty_loop(PhaseIdealLoop*) [clone .part.161]+0x64a
V [libjvm.so+0x11f2d62] IdealLoopTree::iteration_split_impl(PhaseIdealLoop*, Node_List&)+0x52
V [libjvm.so+0x11f4631] IdealLoopTree::iteration_split(PhaseIdealLoop*, Node_List&)+0x111
V [libjvm.so+0x11f4546] IdealLoopTree::iteration_split(PhaseIdealLoop*, Node_List&)+0x26
V [libjvm.so+0x1218f57] PhaseIdealLoop::build_and_optimize(LoopOptsMode)+0xc97
V [libjvm.so+0x9d9dda] PhaseIdealLoop::optimize(PhaseIterGVN&, LoopOptsMode)+0x2ea
V [libjvm.so+0x9d706c] Compile::Optimize()+0xadc
V [libjvm.so+0x9d8634] Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool, DirectiveSet*)+0x1094
V [libjvm.so+0x81ed30] C2Compiler::compile_method(ciEnv*, ciMethod*, int, DirectiveSet*)+0x110
V [libjvm.so+0x9e4ebc] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x2cc
V [libjvm.so+0x9e5e68] CompileBroker::compiler_thread_loop()+0x468
V [libjvm.so+0x170e3e6] JavaThread::thread_main_inner()+0x226
V [libjvm.so+0x1713af6] Thread::call_run()+0xf6
V [libjvm.so+0x1434b5e] thread_native_entry(Thread*)+0x10e

Register to memory mapping:

RAX=0x00007f52881f6000 points into unknown readable memory: 58 00 00 00 00 00 00 00
RBX=0x00007f523c5d05b0 points into unknown readable memory: 90 49 4b 87 52 7f 00 00
RCX=0x00007f528711ee59: <offset 0x0000000001a32e59> in /scratch/lmesnik/jenkins/workspace/JavaFuzzer/jdk-14/fastdebug/lib/server/libjvm.so at 0x00007f52856ec000
RDX=0x00007f52870ad9c8: <offset 0x00000000019c19c8> in /scratch/lmesnik/jenkins/workspace/JavaFuzzer/jdk-14/fastdebug/lib/server/libjvm.so at 0x00007f52856ec000
RSP=0x00007f5255df8190 is pointing into the stack for thread: 0x00007f5280340000
RBP=0x00007f5255df81d0 is pointing into the stack for thread: 0x00007f5280340000
RSI=0x0000000000000ba8 is an unknown value
RDI=0x00007f52870ac8c0: <offset 0x00000000019c08c0> in /scratch/lmesnik/jenkins/workspace/JavaFuzzer/jdk-14/fastdebug/lib/server/libjvm.so at 0x00007f52856ec000
R8 =0x00007f523c059310 points into unknown readable memory: a0 9f 4b 87 52 7f 00 00
R9 =0x00007f5255df8170 is pointing into the stack for thread: 0x00007f5280340000
R10=0x00007f523c5d4f10 points into unknown readable memory: 70 f2 4b 87 52 7f 00 00
R11=0x0000000000000003 is an unknown value
R12=0x00007f523c5d05b8 points into unknown readable memory: 08 06 5d 3c 52 7f 00 00
R13=0x00007f523c5d05cc points into unknown readable memory: 03 00 00 00
R14=0x00007f523c5d0a58 points into unknown readable memory: f0 81 4b 87 52 7f 00 00
R15=0x00007f523c57a668 points into unknown readable memory: f0 81 4b 87 52 7f 00 00


Registers:
RAX=0x00007f52881f6000, RBX=0x00007f523c5d05b0, RCX=0x00007f528711ee59, RDX=0x00007f52870ad9c8
RSP=0x00007f5255df8190, RBP=0x00007f5255df81d0, RSI=0x0000000000000ba8, RDI=0x00007f52870ac8c0
R8 =0x00007f523c059310, R9 =0x00007f5255df8170, R10=0x00007f523c5d4f10, R11=0x0000000000000003
R12=0x00007f523c5d05b8, R13=0x00007f523c5d05cc, R14=0x00007f523c5d0a58, R15=0x00007f523c57a668
RIP=0x00007f52868de1fc, EFLAGS=0x0000000000010202, CSGSFS=0x0000000000000033, ERR=0x0000000000000006
  TRAPNO=0x000000000000000e