RFA: reload infrastructure to fix PR target/21623

[Bernd Schmidt]

Joern RENNECKE wrote:
> +enum reg_class
> +secondary_reload_class (int in_p, enum reg_class class,
> +			enum machine_mode mode, rtx x)
> +{
> +  enum insn_code icode;

> +  icode = targetm.reload_icode (in_p, x, class, mode);

> +  if (icode > CODE_FOR_nothing)
> +    return icode - CODE_FOR_reload__NO_REGS + NO_REGS;

No way.

What's wrong with

   enum insn_code icode;
   enum reg_class secondary_class;
   enum machine_mode secondary_mode; /* if it's needed */

   if (targetm.secondary_reload_needed (in_p, x, class, mode,
				       &icode, &secondary_class,
				       &secondary_mode))
     do_stuff ();


Bernd