record_base_value (REGNO (reg), b);
emit_iv_add_mult (b, m, a, reg, insert_before)     rtx b;          /* initial value of basic induction variable */     rtx m;          /* multiplicative constant */     rtx a;          /* additive constant */     rtx reg;        /* destination register */     rtx insert_before;{  rtx seq;  rtx result;  /* Prevent unexpected sharing of these rtx.  */  a = copy_rtx (a);  b = copy_rtx (b);  /* Increase the lifetime of any invariants moved further in code. */  update_reg_last_use (a, insert_before);  update_reg_last_use (b, insert_before);  update_reg_last_use (m, insert_before);  start_sequence ();  result = expand_mult_add (b, reg, m, a, GET_MODE (reg), 0);  if (reg != result)    emit_move_insn (reg, result);  seq = gen_sequence ();  end_sequence ();  emit_insn_before (seq, insert_before);}