re PR target/23630 (built-ins MMX regression)

        PR target/23630
        * expr.c (expand_expr_real_1) <VIEW_CONVERT_EXPR>: Use gen_lowpart
        whenever the mode sizes match.

From-SVN: r103660

gcc/ChangeLog

+2005-08-30  Richard Henderson  <rth@redhat.com>
+
+	PR target/23630
+	* expr.c (expand_expr_real_1) <VIEW_CONVERT_EXPR>: Use gen_lowpart
+	whenever the mode sizes match.
+
 2005-08-31  Alan Modra  <amodra@bigpond.net.au>
 
 	* calls.c (load_register_parameters): Fix comment typo.
@@ -84,8 +90,8 @@
 2005-08-27  David Edelsohn  <edelsohn@gnu.org>
 
 	PR target/23539
-        * config/rs6000/rs6000.c (expand_block_clear): Use HImode when
-        bytes >= 2 not bytes == 2.
+	* config/rs6000/rs6000.c (expand_block_clear): Use HImode when
+	bytes >= 2 not bytes == 2.
 	(expand_block_move): Same.
 
 2005-08-27  Richard Guenther  <rguenther@suse.de>

gcc/expr.c

@@ -7505,18 +7505,23 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
     case VIEW_CONVERT_EXPR:
       op0 = expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, mode, modifier);
 
-      /* If the input and output modes are both the same, we are done.
-	 Otherwise, if neither mode is BLKmode and both are integral and within
-	 a word, we can use gen_lowpart.  If neither is true, make sure the
-	 operand is in memory and convert the MEM to the new mode.  */
+      /* If the input and output modes are both the same, we are done.  */
       if (TYPE_MODE (type) == GET_MODE (op0))
 	;
+      /* If neither mode is BLKmode, and both modes are the same size
+	 then we can use gen_lowpart.  */
       else if (TYPE_MODE (type) != BLKmode && GET_MODE (op0) != BLKmode
-	       && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT
-	       && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT
-	       && GET_MODE_SIZE (TYPE_MODE (type)) <= UNITS_PER_WORD
-	       && GET_MODE_SIZE (GET_MODE (op0)) <= UNITS_PER_WORD)
+	       && GET_MODE_SIZE (TYPE_MODE (type))
+		   == GET_MODE_SIZE (GET_MODE (op0)))
 	op0 = gen_lowpart (TYPE_MODE (type), op0);
+      /* If both modes are integral, then we can convert from one to the
+	 other.  */
+      else if (SCALAR_INT_MODE_P (GET_MODE (op0))
+	       && SCALAR_INT_MODE_P (TYPE_MODE (type)))
+	op0 = convert_modes (TYPE_MODE (type), GET_MODE (op0), op0, 
+			     TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (exp, 0))));
+      /* As a last resort, spill op0 to memory, and reload it in a 
+	 different mode.  */
       else if (!MEM_P (op0))
 	{
 	  /* If the operand is not a MEM, force it into memory.  Since we