Use proper type for temporary in expansion of COMPONENT_REF

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

The details are in the comments for this patch.

Tested on x86-64.

The test case is the following Ada code:

package MX is
   type Byte is range 0 .. 255;
   for Byte'size use 8;

   type Message_Data_T is record
      X, Y : Integer;
   end record;
   type Message_T is record
      M_Id   : Byte;
      M_Data : Message_Data_T;
   end record;

   for Message_T'Size use 8+64;
   for Message_T use record
      M_Id    at 0 range 0..7;
      M_Data  at 1 range 0..63;
   end record;

   Global_Message_Data : Message_Data_T;
   Data_Value : constant := 2;
   procedure Initialize_Global_Message_Data;
end MX;

package body MX is

   procedure Set_Global_Message_Data (M_Data : in Message_Data_T) is
   begin
      Global_Message_Data := M_Data;
   end;
   pragma Inline (Set_Global_Message_Data);

   procedure Initialize_Global_Message_Data is
      M : Message_T;
   begin
      M.M_Data.X := Data_Value;
      M.M_Data.Y := Data_Value;
      Set_Global_Message_Data (M.M_Data);
   end;
end MX;
with MX;

procedure MX_Run is
begin
   MX.Initialize_Global_Message_Data;
   if MX.Global_Message_Data.X /= MX.Data_Value then
      raise Program_Error;
   end if;
   if MX.Global_Message_Data.Y /= MX.Data_Value then
      raise Constraint_Error;
   end if;
end;


2004-03-04  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>

	* expr.c (expand_expr_real, case COMPONENT_REF): Get proper type of
	stack slot for temp used for result of BLKmode but in integral mode.

*** expr.c	3 Mar 2004 08:34:26 -0000	1.628
--- expr.c	3 Mar 2004 13:38:14 -0000
*************** expand_expr_real (tree exp, rtx target, 
*** 7237,7246 ****
  				  op0, 1);
  
  	    if (mode == BLKmode)
  	      {
! 		rtx new = assign_temp (build_qualified_type
! 				       ((*lang_hooks.types.type_for_mode)
! 					(ext_mode, 0),
! 					TYPE_QUAL_CONST), 0, 1, 1);
  
  		emit_move_insn (new, op0);
--- 7237,7253 ----
  				  op0, 1);
  
+ 	    /* If the result type is BLKmode, store the data into a temporary
+ 	       of the appropriate type, but with the mode corresponding to the
+ 	       mode for the data we have (op0's mode).  It's tempting to make
+ 	       this a constant type, since we know it's only being stored once,
+ 	       but that can cause problems if we are taking the address of this
+ 	       COMPONENT_REF because the MEM of any reference via that address
+ 	       will have flags corresponding to the type, which will not
+ 	       necessarily be constant.  */
  	    if (mode == BLKmode)
  	      {
! 		rtx new
! 		  = assign_stack_temp_for_type
! 		    (ext_mode, GET_MODE_BITSIZE (ext_mode), 0, type);
  
  		emit_move_insn (new, op0);