diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dd7c384d843..549a9b786e6 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2005-09-09  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR tree-optimization/23509
+	* tree-cfg.c (replace_uses_by): Use replace_exp.
+	* tree-ssa-loop-ivopts.c (get_ref_tag): Assert that dereferenced
+	pointers have name_mem_tag or type_mem_tag set.
+
 2005-09-09  Sebastian Pop  <pop@cri.ensmp.fr>
 
 	* tree-chrec.c (evolution_function_is_invariant_rec_p): Use 
diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 37115562974..75c14f426ff 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -1237,8 +1237,7 @@ replace_uses_by (tree name, tree val)
   FOR_EACH_IMM_USE_SAFE (use, imm_iter, name)
     {
       stmt = USE_STMT (use);
-
-      SET_USE (use, val);
+      replace_exp (use, val);
 
       if (TREE_CODE (stmt) == PHI_NODE)
 	{
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index d0a186a166a..44ebc5ca28e 100644
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -5448,9 +5448,13 @@ get_ref_tag (tree ref)
     return NULL_TREE;
 
   if (TREE_CODE (var) == INDIRECT_REF)
-    var = TREE_OPERAND (var, 0);
-  if (TREE_CODE (var) == SSA_NAME)
     {
+      /* In case the base is a dereference of a pointer, first check its name
+	 mem tag, and if it does not have one, use type mem tag.  */
+      var = TREE_OPERAND (var, 0);
+      if (TREE_CODE (var) != SSA_NAME)
+	return NULL_TREE;
+
       if (SSA_NAME_PTR_INFO (var))
 	{
 	  tag = SSA_NAME_PTR_INFO (var)->name_mem_tag;
@@ -5459,18 +5463,21 @@ get_ref_tag (tree ref)
 	}
  
       var = SSA_NAME_VAR (var);
+      tag = var_ann (var)->type_mem_tag;
+      gcc_assert (tag != NULL_TREE);
+      return tag;
     }
- 
-  if (DECL_P (var))
-    {
+  else
+    { 
+      if (!DECL_P (var))
+	return NULL_TREE;
+
       tag = var_ann (var)->type_mem_tag;
       if (tag)
 	return tag;
 
       return var;
     }
-
-  return NULL_TREE;
 }
 
 /* Copies the reference information from OLD_REF to NEW_REF.  */