The following tests hit the assert in the loom repo:

aplications/microbenchmarks/other/Test_7.java#id12
applications/microbenchmarks/other/Test_8.java#id0

The loom repo is currently sync'ed with jdk-19+9. I haven't been able to duplicate it with the main line.

One set of options that seem to trigger it reliably is: -XX:-DoEscapeAnalysis -XX:CompileThreshold=100

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/workspace/open/src/hotspot/share/opto/phaseX.hpp:134), pid=8746, tid=8841
# assert(i<_max) failed: oob
#
# JRE version: Java(TM) SE Runtime Environment (19.0) (fastdebug build 19-internal+0-2022-02-06-0741038.alan.bateman.loom-merge)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 19-internal+0-2022-02-06-0741038.alan.bateman.loom-merge, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x8e43e4] PhiNode::Ideal(PhaseGVN*, bool)+0x684
#

Current CompileTask:
C2: 4636 1515 4 jdk.jfr.DynamicEvent1::commit (77 bytes)

Stack: [0x00007fc69156d000,0x00007fc69166e000], sp=0x00007fc691669480, free space=1009k
Thread 0x00007fc66c112080 [8841]
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x8e43e4] PhiNode::Ideal(PhaseGVN*, bool)+0x684
V [libjvm.so+0x150aeb5] PhaseGVN::transform_no_reclaim(Node*)+0x25
V [libjvm.so+0x1204491] LibraryCallKit::inline_native_getEventWriter()+0x1561
V [libjvm.so+0x121042e] LibraryIntrinsic::generate(JVMState*)+0x21e
V [libjvm.so+0xbd71eb] Parse::do_call()+0x2fb
V [libjvm.so+0x14e7648] Parse::do_one_bytecode()+0x3c8
V [libjvm.so+0x14d8386] Parse::do_one_block()+0x5a6
V [libjvm.so+0x14d9233] Parse::do_all_blocks()+0xf3
V [libjvm.so+0x14dcedf] Parse::Parse(JVMState*, ciMethod*, float)+0xb9f
V [libjvm.so+0x8a2935] ParseGenerator::generate(JVMState*)+0xd5
V [libjvm.so+0xbd71eb] Parse::do_call()+0x2fb
V [libjvm.so+0x14e7648] Parse::do_one_bytecode()+0x3c8
V [libjvm.so+0x14d8386] Parse::do_one_block()+0x5a6
V [libjvm.so+0x14d9233] Parse::do_all_blocks()+0xf3
V [libjvm.so+0x14dcedf] Parse::Parse(JVMState*, ciMethod*, float)+0xb9f
V [libjvm.so+0x8a2935] ParseGenerator::generate(JVMState*)+0xd5
V [libjvm.so+0x8a4b2e] PredictedCallGenerator::generate(JVMState*)+0x27e
V [libjvm.so+0xbd71eb] Parse::do_call()+0x2fb
V [libjvm.so+0x14e7648] Parse::do_one_bytecode()+0x3c8
V [libjvm.so+0x14d8386] Parse::do_one_block()+0x5a6
V [libjvm.so+0x14d9233] Parse::do_all_blocks()+0xf3
V [libjvm.so+0x14dcedf] Parse::Parse(JVMState*, ciMethod*, float)+0xb9f
V [libjvm.so+0x8a2935] ParseGenerator::generate(JVMState*)+0xd5
V [libjvm.so+0xa15c62] Compile::Compile(ciEnv*, ciMethod*, int, Options, DirectiveSet*)+0xd82
V [libjvm.so+0x8a0058] C2Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x178
V [libjvm.so+0xa23948] CompileBroker::invoke_compiler_on_method(CompileTask*)+0xbc8
V [libjvm.so+0xa24488] CompileBroker::compiler_thread_loop()+0x408
V [libjvm.so+0x174d55a] JavaThread::thread_main_inner()+0x1ea
V [libjvm.so+0x1754b20] Thread::call_run()+0x100
V [libjvm.so+0x14929d4] thread_native_entry(Thread*)+0x104