builtins.c (PAD_VARARGS_DOWN): Define.

	* builtins.c (PAD_VARARGS_DOWN): Define.
	(std_expand_builtin_va_arg): Use the above macro.
	* config/mips/mips.c (PAD_VARARGS_DOWN): Define.
	* tm.texi (Register Arguments): Document the above macro.

From-SVN: r31421

gcc/ChangeLog

+2000-01-14  Clinton Popetz  <cpopetz@cygnus.com>
+
+	* builtins.c (PAD_VARARGS_DOWN): Define. 
+	(std_expand_builtin_va_arg): Use the above macro.
+	* config/mips/mips.c (PAD_VARARGS_DOWN): Define.
+	* tm.texi (Register Arguments): Document the above macro.
+	
 2000-01-14  Nick Clifton  <nickc@cygnus.com>
 
 	* emit-rtl.c (emit_insn): If checking is enabled, make sure

gcc/builtins.c

@@ -51,6 +51,10 @@ Boston, MA 02111-1307, USA.  */
 #define OUTGOING_REGNO(IN) (IN)
 #endif
 
+#ifndef PAD_VARARGS_DOWN
+#define PAD_VARARGS_DOWN BYTES_BIG_ENDIAN
+#endif
+
 tree (*lang_type_promotes_to) PARAMS ((tree));
 
 static int get_pointer_alignment	PARAMS ((tree, unsigned));
@@ -1967,7 +1971,7 @@ std_expand_builtin_va_arg (valist, type)
 
   /* Get AP.  */
   addr_tree = valist;
-  if (BYTES_BIG_ENDIAN)
+  if (PAD_VARARGS_DOWN)
     {
       /* Small args are padded downward.  */
 

gcc/config/mips/mips.c

 /* Subroutines for insn-output.c for MIPS
-   Copyright (C) 1989, 90, 91, 93-98, 1999 Free Software Foundation, Inc.
+   Copyright (C) 1989, 90, 91, 93-98, 1999, 2000 Free Software Foundation, Inc.
    Contributed by A. Lichnewsky, lich@inria.inria.fr.
    Changes by Michael Meissner, meissner@osf.org.
    64 bit r4000 support by Ian Lance Taylor, ian@cygnus.com, and
@@ -4045,11 +4045,10 @@ mips_va_start (stdarg_p, valist, nextarg)
      tree valist;
      rtx nextarg;
 {
-  int arg_words, fp_arg_words;
+  int arg_words;
   tree t;
 
   arg_words = current_function_args_info.arg_words;
-  fp_arg_words = current_function_args_info.fp_arg_words;
 
   if (mips_abi == ABI_EABI)
     {
@@ -4059,6 +4058,11 @@ mips_va_start (stdarg_p, valist, nextarg)
 	  tree gprv, fprv;
 	  int gpro, fpro;
 
+  	  fpro = (8 - current_function_args_info.fp_arg_words);
+
+	  if (!TARGET_64BIT)
+		fpro /= 2;
+
 	  f_fpr = TYPE_FIELDS (va_list_type_node);
 	  f_rem = TREE_CHAIN (f_fpr);
 	  f_gpr = TREE_CHAIN (f_rem);
@@ -4084,16 +4088,15 @@ mips_va_start (stdarg_p, valist, nextarg)
 	  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
 
 	  t = build (MODIFY_EXPR, integer_type_node, rem,
-		     build_int_2 (8 - fp_arg_words, 0));
+		     build_int_2 (fpro, 0));
 	  TREE_SIDE_EFFECTS (t) = 1;
 	  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
 
-	  fpro = (8 - fp_arg_words) * 8;
 	  if (fpro == 0)
 	    fprv = gprv;
 	  else
 	    fprv = fold (build (PLUS_EXPR, ptr_type_node, gprv,
-				build_int_2 (-fpro, -1)));
+				build_int_2 (-(fpro*8), -1)));
 
 	  if (! TARGET_64BIT)
 	    fprv = fold (build (BIT_AND_EXPR, ptr_type_node, fprv,
@@ -4199,6 +4202,9 @@ mips_va_arg (valist, type)
 	      if (r != addr_rtx)
 		emit_move_insn (addr_rtx, r);
 
+	      /* Ensure that the POSTINCREMENT is emitted before lab_over */
+	      emit_queue();
+
 	      emit_jump (lab_over);
 	      emit_barrier ();
 	      emit_label (lab_false);

gcc/tm.texi

@@ -2943,6 +2943,14 @@ For little-endian machines, the default is to pad upward.  For
 big-endian machines, the default is to pad downward for an argument of
 constant size shorter than an @code{int}, and upward otherwise.
 
+@findex PAD_VARARGS_DOWN
+@item PAD_VARARGS_DOWN
+If defined, a C expression which determines whether the default 
+implementation of va_arg will attempt to pad down before reading the 
+next argument, if that argument is smaller than its aligned space as
+controlled by @code{PARM_BOUNDARY}.  If this macro is not defined, all such
+arguments are padded down if @code{BYTES_BIG_ENDIAN} is true.
+
 @findex FUNCTION_ARG_BOUNDARY
 @item FUNCTION_ARG_BOUNDARY (@var{mode}, @var{type})
 If defined, a C expression that gives the alignment boundary, in bits,