tree.h (maybe_fold_offset_to_component_ref): Declare.

	* tree.h (maybe_fold_offset_to_component_ref): Declare.
	* tree-ssa-ccp.c (maybe_fold_offset_to_component_ref): Export.
	* fold-const.c (fold_unary): Use it.

	* gcc.dg/tree-ssa/foldaddr-2.c: New file.

From-SVN: r123664

gcc/ChangeLog

+2007-04-08  Jan Hubicka  <jh@suse.cz>
+
+	* tree.h (maybe_fold_offset_to_component_ref): Declare.
+	* tree-ssa-ccp.c (maybe_fold_offset_to_component_ref): Export.
+	* fold-const.c (fold_unary): Use it.
+
 2007-04-08  Andrew Pinski  <andrew_pinski@playstation.sony.com>
 
 	* varasm.c (assemble_variable): Remove call to

gcc/fold-const.c

@@ -7735,6 +7735,13 @@ fold_unary (enum tree_code code, tree type, tree op0)
 	    return fold_convert (type, build_fold_addr_expr (base));
         }
 
+      /* Convert (type *)&A into &A->field_of_type_and_offset_0.  */
+      if (TREE_CODE (op0) == ADDR_EXPR && POINTER_TYPE_P (type)
+	  && (tem = maybe_fold_offset_to_component_ref
+		      (TREE_TYPE (TREE_OPERAND (op0, 0)), TREE_OPERAND (op0, 0),
+		       integer_zero_node, TREE_TYPE (type), false)))
+        return build_fold_addr_expr_with_type (tem, type);
+
       if ((TREE_CODE (op0) == MODIFY_EXPR
 	   || TREE_CODE (op0) == GIMPLE_MODIFY_STMT)
 	  && TREE_CONSTANT (GENERIC_TREE_OPERAND (op0, 1))

gcc/testsuite/ChangeLog

+2007-04-08  Jan Hubicka  <jh@suse.cz>
+
+	* gcc.dg/tree-ssa/foldaddr-2.c: New file.
+
 2007-04-07  Paul Thomas  <pault@gcc.gnu.org>
 
 	PR fortran/31257

gcc/testsuite/gcc.dg/tree-ssa/foldaddr-2.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+struct a{
+	int a;
+	int b;
+} a;
+int *
+t()
+{
+	return (int *)&a;
+}
+/* { dg-final { scan-tree-dump "a.a" "optimized"} } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/tree-ssa-ccp.c

@@ -1643,7 +1643,7 @@ maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type)
    is the desired result type.  */
 /* ??? This doesn't handle class inheritance.  */
 
-static tree
+tree
 maybe_fold_offset_to_component_ref (tree record_type, tree base, tree offset,
 				    tree orig_type, bool base_is_ptr)
 {

gcc/tree.h

@@ -4412,6 +4412,8 @@ extern void fold_defer_overflow_warnings (void);
 extern void fold_undefer_overflow_warnings (bool, tree, int);
 extern void fold_undefer_and_ignore_overflow_warnings (void);
 extern bool fold_deferring_overflow_warnings_p (void);
+extern tree maybe_fold_offset_to_component_ref (tree, tree, tree,
+				                tree, bool);
 
 extern tree force_fit_type_double (tree, unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 				   int, bool);