[lto] i386.c: Simplify init_cumulative_args.

[Kazu Hirata]

Hi,

Attached is a patch to simplify init_cumulative_args.

One of the things we would like to do on the LTO branch is to stop
using TREE_LIST in TYPE_ARG_TYPES.  While working on a patch to
achieve that, I've noticed a clean-up opportunity shown below in the
form of a patch, which will also make the aforementioned patch smaller
and easier to review.

Observe that the control will get to "if (!TARGET_64_BIT)" if and only
if

- fntype is non-NULL,

- the linked list pointed to by TYPE_ARG_TYPES (fntype) contains at
  least one type, and

- the linked list does not end with void_type_node.

The last two are exactly what stdarg_p does.

Tested on x86_64-pc-linux-gnu.  OK to apply to the LTO branch?

Kazu Hirata

2006-06-10  Kazu Hirata  <kazu@codesourcery.com>

	* config/gcc/i386.c (init_cumulative_args): Simplify using
	stdarg_p.

Index: config/i386/i386.c
===================================================================
*** config/i386/i386.c	(revision 114406)
--- config/i386/i386.c	(working copy)
*************** init_cumulative_args (CUMULATIVE_ARGS *c
*** 2696,2702 ****
  		      tree fndecl)
  {
    static CUMULATIVE_ARGS zero_cum;
-   tree param, next_param;
  
    if (TARGET_DEBUG_ARG)
      {
--- 2696,2701 ----
*************** init_cumulative_args (CUMULATIVE_ARGS *c
*** 2746,2772 ****
       are no variable arguments.  If there are variable arguments, then
       we won't pass anything in registers in 32-bit mode. */
  
!   if (cum->nregs || cum->mmx_nregs || cum->sse_nregs)
      {
!       for (param = (fntype) ? TYPE_ARG_TYPES (fntype) : 0;
! 	   param != 0; param = next_param)
  	{
! 	  next_param = TREE_CHAIN (param);
! 	  if (next_param == 0 && TREE_VALUE (param) != void_type_node)
! 	    {
! 	      if (!TARGET_64BIT)
! 		{
! 		  cum->nregs = 0;
! 		  cum->sse_nregs = 0;
! 		  cum->mmx_nregs = 0;
! 		  cum->warn_sse = 0;
! 		  cum->warn_mmx = 0;
! 		  cum->fastcall = 0;
! 		  cum->float_in_sse = 0;
! 		}
! 	      cum->maybe_vaarg = true;
! 	    }
  	}
      }
    if ((!fntype && !libname)
        || (fntype && !TYPE_ARG_TYPES (fntype)))
--- 2745,2764 ----
       are no variable arguments.  If there are variable arguments, then
       we won't pass anything in registers in 32-bit mode. */
  
!   if ((cum->nregs || cum->mmx_nregs || cum->sse_nregs)
!       && fntype && stdarg_p (fntype))
      {
!       if (!TARGET_64BIT)
  	{
! 	  cum->nregs = 0;
! 	  cum->sse_nregs = 0;
! 	  cum->mmx_nregs = 0;
! 	  cum->warn_sse = 0;
! 	  cum->warn_mmx = 0;
! 	  cum->fastcall = 0;
! 	  cum->float_in_sse = 0;
  	}
+       cum->maybe_vaarg = true;
      }
    if ((!fntype && !libname)
        || (fntype && !TYPE_ARG_TYPES (fntype)))