Question about promoted_input_arg

[Momchil Velikov <velco at fadata dot bg>]

Hi,

Trying to understand what the function does ...


rtx
promoted_input_arg (regno, pmode, punsignedp)
     unsigned int regno;
     enum machine_mode *pmode;
     int *punsignedp;
{
  tree arg;

  for (arg = DECL_ARGUMENTS (current_function_decl); arg;
       arg = TREE_CHAIN (arg))
    if (GET_CODE (DECL_INCOMING_RTL (arg)) == REG
	&& REGNO (DECL_INCOMING_RTL (arg)) == regno
	&& TYPE_MODE (DECL_ARG_TYPE (arg)) == TYPE_MODE (TREE_TYPE (arg)))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Why do we check this (after the last &&) ? Isn't it possible after an
argument is promoted from TREE_TYPE (arg) to DECL_ARG_TYPE (arg), a
mode promotion to take place ?
 
      {
	enum machine_mode mode = TYPE_MODE (TREE_TYPE (arg));
	int unsignedp = TREE_UNSIGNED (TREE_TYPE (arg));

	mode = promote_mode (TREE_TYPE (arg), mode, &unsignedp, 1);
	if (mode == GET_MODE (DECL_INCOMING_RTL (arg))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
And this ?  Isn't it more like ``assert (mode == GET_MODE (DECL_INCOMING_RTL (arg))''.

	    && mode != DECL_MODE (arg))
	  {
	    *pmode = DECL_MODE (arg);
	    *punsignedp = unsignedp;
	    return DECL_INCOMING_RTL (arg);
	  }
      }

  return 0;
}

Regards,
-velco