# Internal Error (/oracle/jdk/open/src/hotspot/share/c1/c1_LIR.hpp:732), pid=1190650, tid=1190664
# assert(res->vreg_number() == index) failed: conversion check

Current CompileTask:
C1: 7731 24 b 3 org.jaxen.saxpath.base.Verifier::isXMLLetter (7327 bytes)

Stack: [0x00007fca88036000,0x00007fca88137000], sp=0x00007fca88133e40, free space=1015k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x79b9ed] LIR_OprFact::virtual_register(int, BasicType)+0x8d
V [libjvm.so+0x7ba68b] MoveResolver::insert_move(Interval*, Interval*)+0xeb
V [libjvm.so+0x7cd2d9] MoveResolver::resolve_mappings()+0x1c9
V [libjvm.so+0x7cda27] MoveResolver::move_insert_position(LIR_List*, int)+0x67
V [libjvm.so+0x7d616c] LinearScanWalker::insert_move(int, Interval*, Interval*)+0x30c
V [libjvm.so+0x7d686d] LinearScanWalker::split_for_spilling(Interval*)+0x63d
V [libjvm.so+0x7d6c52] LinearScanWalker::split_and_spill_intersecting_intervals(int, int)+0x62
V [libjvm.so+0x7d73b2] LinearScanWalker::alloc_locked_reg(Interval*)+0x672
V [libjvm.so+0x7d7828] LinearScanWalker::activate_current()+0x278
V [libjvm.so+0x7be80b] IntervalWalker::walk_to(int)+0x3bb
V [libjvm.so+0x7cde47] LinearScan::allocate_registers()+0x287
V [libjvm.so+0x7da802] LinearScan::do_linear_scan()+0x142
V [libjvm.so+0x6fd790] Compilation::emit_lir()+0xba0
V [libjvm.so+0x70016b] Compilation::compile_java_method()+0x43b
V [libjvm.so+0x700d00] Compilation::compile_method()+0x1d0
V [libjvm.so+0x70171b] Compilation::Compilation(AbstractCompiler*, ciEnv*, ciMethod*, int, BufferBlob*, bool, DirectiveSet*)+0x36b
V [libjvm.so+0x702b43] Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x1a3
V [libjvm.so+0xa1dbc1] CompileBroker::invoke_compiler_on_method(CompileTask*)+0xea1
V [libjvm.so+0xa1e848] CompileBroker::compiler_thread_loop()+0x5a8
V [libjvm.so+0x1840a56] JavaThread::thread_main_inner()+0x256
V [libjvm.so+0x1846ed0] Thread::call_run()+0x100
V [libjvm.so+0x1533196] thread_native_entry(Thread*)+0x116

Reported by Eirik Bjørsnøs:
https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2021-February/044006.html