re PR middle-end/17793 (Ada bootstrap failure)

	PR middle-end/17793
	* gimplify.c (gimplify_addr_expr) <VIEW_CONVERT_EXPR>: Look
	through the operand if it is a useless type conversion.

From-SVN: r89488

gcc/ChangeLog

+2004-10-23  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	PR middle-end/17793
+	* gimplify.c (gimplify_addr_expr) <VIEW_CONVERT_EXPR>: Look
+	through the operand if it is a useless type conversion.
+
 2004-10-23  Ben Elliston  <bje@au.ibm.com>
 
 	* cfg.c (remove_edge): Use VEC_unordered_remove.

gcc/gimplify.c

@@ -3093,6 +3093,13 @@ gimplify_addr_expr (tree *expr_p, tree *pre_p, tree *post_p)
 
 	 ??? The interactions of VIEW_CONVERT_EXPR and aliasing is not at
 	 all clear.  The impact of this transformation is even less clear.  */
+
+      /* If the operand is a useless conversion, look through it.  Doing so
+	 guarantees that the ADDR_EXPR and its operand will remain of the
+	 same type.  */
+      if (tree_ssa_useless_type_conversion (TREE_OPERAND (op0, 0)))
+          op0 = TREE_OPERAND (op0, 0);
+
       *expr_p = fold_convert (TREE_TYPE (expr),
 			      build_fold_addr_expr (TREE_OPERAND (op0, 0)));
       ret = GS_OK;