"failed: unexpected type" assert failure in ConnectionGraph::split_unique_types() with unsafe accesses

# Internal Error (/home/roland/hs/src/hotspot/share/opto/escape.cpp:3118), pid=17688, tid=17701
# assert(tn_type == TypePtr::NULL_PTR || tn_t != __null && !tinst->klass()->is_subtype_of(tn_t->klass())) failed: unexpected type
#
# JRE version: OpenJDK Runtime Environment (13.0) (fastdebug build 13-internal+0-adhoc.roland.hs)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 13-internal+0-adhoc.roland.hs, compiled mode, sharing, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0xb8ee95] ConnectionGraph::split_unique_types(GrowableArray<Node*>&, GrowableArray<ArrayCopyNode*>&)+0x405

Test case:

import java.lang.reflect.Field;
import jdk.internal.misc.Unsafe;

public class MaybeOffHeapUnsafeAccessToNewObject {
    public volatile int f_int = -1;


    public static Unsafe unsafe = Unsafe.getUnsafe();
    public static final long f_int_off;

    static {
        Field f_int_field = null;
        try {
            f_int_field = MaybeOffHeapUnsafeAccessToNewObject.class.getField("f_int");
        } catch (Exception e) {
            System.out.println("reflection failed " + e);
            e.printStackTrace();
        }
        f_int_off = unsafe.objectFieldOffset(f_int_field);
    }

    static public void main(String[] args) {
MaybeOffHeapUnsafeAccessToNewObject o = new MaybeOffHeapUnsafeAccessToNewObject();
test1();
    }

    static Object test1_helper1(Object t) {
return t;
    }

    static long test1_helper2(long off) {
return off;
    }

    static int test1() {
        MaybeOffHeapUnsafeAccessToNewObject t = new MaybeOffHeapUnsafeAccessToNewObject();
Object o = test1_helper1(t);
long off = test1_helper2(f_int_off);
        return unsafe.getInt(o, off);
    }

}

ran with:

-XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:-TieredCompilation -Xcomp -XX:CompileOnly=MaybeOffHeapUnsafeAccessToNewObject::test1 -XX:+IgnoreUnrecognizedVMOptions -XX:+AlwaysIncrementalInline MaybeOffHeapUnsafeAccessToNewObject