local-pure-const.c: New testcase.

	* gcc.dg/tree-ssa/local-pure-const.c: New testcase.
	* ipa-pure-const.c (check_op): Use PTA info to see if indirect_ref is
	local.

From-SVN: r149176

gcc/ChangeLog

+2009-07-02  Jan Hubicka  <jh@suse.cz>
+
+	* ipa-pure-const.c (check_op): Use PTA info to see if indirect_ref is
+	local.
+
 2009-07-02  Paolo Bonzini  <bonzini@gnu.org>
 
 	* expmed.c (emit_cstore, emit_store_flag_1): Accept target_mode

gcc/ipa-pure-const.c

@@ -213,13 +213,23 @@ check_decl (funct_state local,
 static inline void 
 check_op (funct_state local, tree t, bool checking_write)
 {
-  if (TREE_THIS_VOLATILE (t))
+  t = get_base_address (t);
+  if (t && TREE_THIS_VOLATILE (t))
     {
       local->pure_const_state = IPA_NEITHER;
       if (dump_file)
 	fprintf (dump_file, "    Volatile indirect ref is not const/pure\n");
       return;
     }
+  else if (t
+  	   && INDIRECT_REF_P (t)
+	   && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
+	   && !ptr_deref_may_alias_global_p (TREE_OPERAND (t, 0)))
+    {
+      if (dump_file)
+	fprintf (dump_file, "    Indirect ref to local memory is OK\n");
+      return;
+    }
   else if (checking_write)
     {
       local->pure_const_state = IPA_NEITHER;

gcc/testsuite/ChangeLog

+2009-07-02  Jan Hubicka  <jh@suse.cz>
+
+	* gcc.dg/tree-ssa/local-pure-const.c: New testcase.
+
 2009-07-01  Adam Nemet  <anemet@caviumnetworks.com>
 
 	* gcc.target/mips/truncate-4.c: New testcase.

gcc/testsuite/gcc.dg/tree-ssa/local-pure-const.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-local-pure-const1" } */
+t(int a, int b, int c)
+{
+  int *p;
+  if (a)
+    p = &a;
+  else
+    p = &c;
+  return *p;
+}
+/* { dg-final { scan-tree-dump-times "local memory is OK" 1 "local-pure-const1"} } */
+/* { dg-final { scan-tree-dump-times "found to be const" 1 "local-pure-const1"} } */
+/* { dg-final { cleanup-tree-dump "local-pure-const1" } } */