(synopsis is provisional, please change as you see fit).

Found by fuzzing. Test bundle is attached. Crashes every time for me:

$ ~/trunks/jdk-jdk/build/linux-x86_64-server-fastdebug/images/jdk/bin/java Test

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/shade/trunks/jdk-jdk/src/hotspot/share/opto/loopnode.hpp:1410), pid=22965, tid=22976
# assert(C->live_nodes() - live_at_begin <= 2 * _nodes_required) failed: Bad node estimate: actual = 768 >> request = 166
#
# JRE version: OpenJDK Runtime Environment (14.0) (fastdebug build 14-internal+0-adhoc.shade.jdk-jdk)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 14-internal+0-adhoc.shade.jdk-jdk, mixed mode, sharing, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x11e762a] AutoNodeBudget::~AutoNodeBudget()+0x1ba
#
# Core dump will be written. Default location: Core dumps may be processed with "/usr/share/apport/apport %p %s %c %d %P" (or dumping to /home/shade/trunks/JavaFuzzer/tests/08508/core.22965)
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
#

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

Command Line: Test

Host: shade-desktop, Intel(R) Core(TM) i7-7820X CPU @ 3.60GHz, 16 cores, 125G, Ubuntu 18.04.3 LTS
Time: Tue Aug 13 21:39:29 2019 CEST elapsed time: 0 seconds (0d 0h 0m 0s)

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

Current thread (0x00007f2708596000): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=22976, stack(0x00007f26a815e000,0x00007f26a825f000)]


Current CompileTask:
C2: 245 65 ! 4 Test::iMeth (538 bytes)