re PR middle-end/21985 (miscompiled or wrong code snippet?)

	PR middle-end/21985
	* fold-const.c (split_address_to_core_and_offset): Always return
	the address of the base object.

	* gcc.dg/tree-ssa/pr21985.c: New test.

From-SVN: r100877

gcc/ChangeLog

+2005-06-13  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR middle-end/21985
+	* fold-const.c (split_address_to_core_and_offset): Always return
+	the address of the base object.
+
 2005-06-13  Bernd Schmidt  <bernd.schmidt@analog.com>
 
 	* doc/invoke.texi (Blackfin Options): Document -mlong-calls.

gcc/fold-const.c

@@ -11801,9 +11801,7 @@ split_address_to_core_and_offset (tree exp,
       core = get_inner_reference (TREE_OPERAND (exp, 0), &bitsize, pbitpos,
 				  poffset, &mode, &unsignedp, &volatilep,
 				  false);
-
-      if (TREE_CODE (core) == INDIRECT_REF)
-	core = TREE_OPERAND (core, 0);
+      core = build_fold_addr_expr (core);
     }
   else
     {

gcc/testsuite/ChangeLog

+2005-06-13  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR middle-end/21985
+	* gcc.dg/tree-ssa/pr21985.c: New test.
+
 2005-06-12  James A. Morrison  <phython@gcc.gnu.org>
 
 	* ggcc.dg/pr14796-1.c: Add tests for (X << C) >> C.

gcc/testsuite/gcc.dg/tree-ssa/pr21985.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-vars" } */
+
+struct
+{
+  struct
+    {
+      int a;
+      int b;
+    } a[100];
+} a;
+
+void foo(unsigned);
+unsigned *bar (void);
+
+int
+main (void)
+{
+  unsigned *b = bar ();
+
+  /* This should be folded.  */
+  foo (&a.a[50].a - &a.a[33].b);
+  foo ((unsigned) &a.a[50].b - (unsigned) &a);
+
+  /* And this should not.  */
+  foo ((unsigned) &b - (unsigned) b);
+  return 0;
+}
+
+/* Two of the calls to foo should be folded to just foo(constant).  */
+
+/* { dg-final { scan-tree-dump-times "foo \\(\[0-9\]*\\)" 2 "vars" } } */