   0  -live- %r1
   0  guard_class %r1 -> %i0
   3  getfield_raw_i %i0, FieldDescr<pypy.interpreter.baseobjspace.W_Root_vtable.cls_typecode> -> %i0
   8  newstr $1 -> %r0
  11  strsetitem %r0, $0, %i0
  15  new_with_vtable <rpython.jit.backend.llsupport.descr.SizeDescr object at 0x0000000174027cc8> -> %r1
  19  setfield_gc_r %r1, %r0, FieldDescr<pypy.objspace.std.bytesobject.W_BytesObject.inst__value>
  24  ref_return %r1
