patch: teach assign_parm* about float parallels

[Aldy Hernandez <aldyh at redhat dot com>]

Hi Richard.

*digs up old emails*

Imagine this function, keeping in mind SF -> DF promotion:

        float geee;
        void alloc_float(efff)
         float efff;
        { geee = efff; }

assign_parms() tries to call emit_group_store with:
        orig_dst ==> (reg:SF)
        src      ==> (parallel:DF ...)

You can only imagine the havoc this creates.

The patch below fixes assign_parm_setup_block to do the following 
conversion:

        (parallel:DF src) -> (reg:DF temp)
        convert_mode (orig_dst, temp)   // where orig_dst was an SF

In your original email, when I showed you this, you mentioned I
should do this without the SCALAR_INT_MODE_P check, but now I'm all
paranoid because of the recent breakage.

I've also added a check for BLKmode, for good measure, but I doubt
any one is passing BLKmode's in parallels for function arguments.
(Ada?  Does Ada even have unnamed arguments?)

I don't think this affects anything else, as it only relates to non 
integer (float) hard registers in parallels, not memory like the
emit_group_* patch.

Testing currently underway on ppc-linux.

OK?

	* function.c (assign_parm_setup_block): Handle parallles of
	floats.

Index: function.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/function.c,v
retrieving revision 1.584
diff -c -p -r1.584 function.c
*** function.c	19 Oct 2004 14:43:52 -0000	1.584
--- function.c	27 Oct 2004 19:43:01 -0000
*************** assign_parm_setup_block (tree parm, stru
*** 2550,2557 ****
      {
        rtx parmreg = gen_reg_rtx (data->nominal_mode);
  
!       emit_group_store (parmreg, entry_parm, data->nominal_type,
! 			int_size_in_bytes (data->nominal_type));
        SET_DECL_RTL (parm, parmreg);
        return;
      }
--- 2550,2569 ----
      {
        rtx parmreg = gen_reg_rtx (data->nominal_mode);
  
!       /* Handle parallels of floats.  In this case we can't get at the
! 	 individual words.  */
!       if (!SCALAR_INT_MODE_P (GET_MODE (parmreg))
! 	  && GET_MODE (parmreg) != BLKmode
! 	  && data->nominal_mode != data->passed_mode)
! 	{
! 	  rtx t = gen_reg_rtx (GET_MODE (entry_parm));
! 	  emit_group_store (t, entry_parm, NULL_TREE,
! 			    GET_MODE_SIZE (GET_MODE (entry_parm)));
! 	  convert_move (parmreg, t, 0);
! 	}
!       else
! 	emit_group_store (parmreg, entry_parm, data->nominal_type,
! 			  int_size_in_bytes (data->nominal_type));
        SET_DECL_RTL (parm, parmreg);
        return;
      }