re PR tree-optimization/47265 (Error: SSA name in freelist but still referenced)

	PR tree-optimization/47265
	PR tree-optimization/47443
	* tree-ssa-forwprop.c (forward_propagate_addr_expr): Return false
	if name still has some uses.

	* gcc.c-torture/compile/pr47265.c: New test.
	* gcc.dg/pr47443.c: New test.

From-SVN: r169250

gcc/ChangeLog

+2011-01-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/47265
+	PR tree-optimization/47443
+	* tree-ssa-forwprop.c (forward_propagate_addr_expr): Return false
+	if name still has some uses.
+
 2011-01-25  Martin Jambor  <mjambor@suse.cz>
 
 	PR tree-optimization/47382

gcc/testsuite/ChangeLog

+2011-01-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/47265
+	PR tree-optimization/47443
+	* gcc.c-torture/compile/pr47265.c: New test.
+	* gcc.dg/pr47443.c: New test.
+
 2011-01-25  Martin Jambor  <mjambor@suse.cz>
 
 	PR tree-optimization/47382

gcc/testsuite/gcc.c-torture/compile/pr47265.c

+/* PR tree-optimization/47265 */
+
+struct S
+{
+  char a[3];
+  char b[3];
+};
+
+void
+bar (char *dst, const char *src, unsigned n)
+{
+  while (n--)
+    *dst++ = *src ? *src++ : ' ';
+}
+
+void
+foo (struct S *s)
+{
+  bar (s->a, s->b, 3);
+}

gcc/testsuite/gcc.dg/pr47443.c

+/* PR tree-optimization/47443 */
+/* { dg-do compile } */
+/* { dg-options "-O -fstack-check=generic" } */
+
+static inline bar (char *c, int i)
+{
+  return c + i > c;
+}
+
+int foo ()
+{
+  char c[100];
+  return (bar (c, 1));
+}

gcc/tree-ssa-forwprop.c

 /* Forward propagation of expressions for single use variables.
-   Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010
+   Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -1114,7 +1114,7 @@ forward_propagate_addr_expr (tree name, tree rhs)
 	}
     }
 
-  return all;
+  return all && has_zero_uses (name);
 }
 
 /* Forward propagate the comparison defined in STMT like