   0  residual_call_r_i $<* fn first_non_ascii_char>, R[%r0], <CallDescr(r) EF=4> -> %i0
   7  -live- %i0
   7  -live- %i0
   7  goto_if_not_int_lt %i0, $0, L1
  12  void_return
  13  ---
  13  L1:
  13  new_with_vtable <rpython.jit.backend.llsupport.descr.SizeDescr object at 0x000000018dd60f38> -> %r0
  17  setfield_gc_i %r0, %i0, FieldDescr<rpython.rlib.rutf8.CheckError.inst_pos>
  22  assert_not_none %r0
  24  -live- %r0
  24  guard_class %r0 -> %i0
  27  -live- %r0
  27  raise %r0
