Properties without accessors are generated as

IrGetBackingField / IrSetBackingField expressions.

compiler/testData/ir/irText/expressions/jvmInstanceFieldReference.kt

@@ -0,0 +1,19 @@
+// FILE: Derived.kt
+// IR_FILE: jvmInstanceFieldReference.txt
+class Derived: Base() {
+    init {
+        value = 0
+    }
+
+    fun getValue() = value
+
+    fun setValue(value: Int) {
+        this.value = value
+    }
+}
+
+// FILE: Base.java
+public class Base {
+    public int value;
+}
+