diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0818b493467f34865068be53078ec1a4b13de784..beb69e756cb83f4efde5cadda4a418fd91581b0e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2005-04-11  Daniel Berlin  <dberlin@dberlin.org>
+
+	Fix PR tree-optimization/20926
+	
+	* tree-ssa-alias.c (add_type_alias): Handle subvars.
+	
 2005-04-11  Devang Patel  <dpatel@apple.com>
 
 	* config/rs6000.c (rs6000_emit_vector_select): Fix vector select
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 0f7001757c5f436539fb8042b2e699069881776c..7d8e783174e8f68b4d2714d0855bb1ef3d128aca 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -2704,6 +2704,7 @@ add_type_alias (tree ptr, tree var)
   varray_type aliases;
   tree tag;
   var_ann_t ann = var_ann (ptr);
+  subvar_t svars;
 
   if (ann->type_mem_tag == NULL_TREE)
     {
@@ -2748,7 +2749,18 @@ found_tag:
      for PTR's type tag.  */
   gcc_assert (var_ann (var)->type_mem_tag == NOT_A_TAG);
   tag = ann->type_mem_tag;
-  add_may_alias (tag, var);
+
+  /* If VAR has subvars, add the subvars to the tag instead of the
+     actual var.  */
+  if (var_can_have_subvars (var)
+      && (svars = get_subvars_for_var (var)))
+    {
+      subvar_t sv;      
+      for (sv = svars; sv; sv = sv->next)
+	add_may_alias (tag, sv->var);
+    }
+  else
+    add_may_alias (tag, var);
 
   /* TAG and its set of aliases need to be marked for renaming.  */
   mark_sym_for_renaming (tag);