Index: tree-ssa-ccp.c
===================================================================
--- tree-ssa-ccp.c	(revision 123037)
+++ tree-ssa-ccp.c	(working copy)
@@ -1202,10 +1202,10 @@
 	 location that created the SSA_NAMEs for the virtual operands,
 	 we can propagate the value on the RHS.  */
       prop_value_t *nval = get_value_loaded_by (stmt, const_val);
-
       if (nval
-	  && nval->mem_ref
-	  && operand_equal_p (nval->mem_ref, rhs, 0))
+          && nval->mem_ref
+          && (operand_equal_p (nval->mem_ref, rhs, 0)
+              || all_vdef_have_same_lattice_const_value (nval, stmt)))
 	val = *nval;
       else
 	val = evaluate_stmt (stmt);
Index: tree-ssa-propagate.c
===================================================================
--- tree-ssa-propagate.c	(revision 123037)
+++ tree-ssa-propagate.c	(working copy)
@@ -892,7 +892,93 @@
   return replaced;
 }
 
+/* Return the defining stmt for the rhs of STMT following the virtual
+   use-def chains if all the VDEFs of this rhs up until the defining stmt
+   initialized by the same constant value as CONST_VAL.  Returns the
+   MODIFY_EXPR stmt which lhs is equal to the rhs of STMT or NULL_TREE
+   if no such stmt can be found.  */
+static tree
+get_def_of_stmt_rhs (tree stmt, tree const_val)
+{
+  /* See if we know exactly where this comes from.  */
+  tree def, rhs, def_stmt, t;
+  use_operand_p use;
 
+  if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
+    return NULL_TREE;
+
+  rhs = GIMPLE_STMT_OPERAND (stmt, 1);
+
+  /* The stmt must have a single VUSE.  */
+  use = SINGLE_SSA_USE_OPERAND (stmt, SSA_OP_VUSE);
+  if (use == NULL_USE_OPERAND_P)
+    return NULL_TREE;
+
+  do
+    {
+      /* Look at the DEF for the VUSE and see if it matches this USE
+         and if it's RHS is an SSA_NAME.  */
+      def_stmt = SSA_NAME_DEF_STMT (*use->use);
+      if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
+       return NULL_TREE;
+
+      def = GIMPLE_STMT_OPERAND (def_stmt, 0);
+      t = GIMPLE_STMT_OPERAND (def_stmt, 1);
+     
+      /* Verify that the VUSE is loaded with the same constant value.  */ 
+      if (!is_gimple_min_invariant (t) || !operand_equal_p (t, const_val, 0))
+       return NULL_TREE;
+
+      /* If def_stmt lhs is equal to the rhs of STMT then we found
+      the stmt which defines SSA_NAME of rhs.  */
+      if (operand_equal_p (def, rhs, 0))
+       return def_stmt;
+      use = SINGLE_SSA_USE_OPERAND (def_stmt, SSA_OP_VMAYUSE);
+      if (use == NULL_USE_OPERAND_P)
+       return NULL_TREE;
+    }
+  while (1);
+
+  return NULL_TREE;
+}
+
+static bool
+do_store_ccp (void)
+{
+  return (flag_tree_store_ccp != 0 && flag_tree_ccp != 0);
+}
+
+/* Return true if rhs of STMT has a known VUSE and all
+   it's VDEFs in the virtual use-def chain (up until the insn
+   which created it's SSA_NAME) have the same constant value as
+   recorded in VAL.  */
+bool
+all_vdef_have_same_lattice_const_value (prop_value_t *val, tree stmt)
+{
+  tree def_stmt;
+  tree rhs;
+  
+  if (!stmt_makes_single_load (stmt))
+    return false;
+
+  if (!is_gimple_min_invariant (val->value))
+    return false;
+
+  def_stmt = get_def_of_stmt_rhs (stmt, val->value);
+
+  if (def_stmt == NULL_TREE)
+    return false;
+
+  rhs = get_rhs (def_stmt);
+
+  if (rhs == NULL_TREE)
+    return false;
+
+  if (is_gimple_min_invariant (rhs) && operand_equal_p (rhs, val->value, 0))
+    return true;
+
+  return false;
+}
 /* Replace the VUSE references in statement STMT with the values
    stored in PROP_VALUE.  Return true if a reference was replaced.  If
    REPLACED_ADDRESSES_P is given, it will be set to true if an address
@@ -974,7 +1060,9 @@
 	  && val->value
 	  && (is_gimple_reg (val->value)
 	      || is_gimple_min_invariant (val->value))
-	  && simple_cst_equal (rhs, val->mem_ref) == 1)
+	  && ((simple_cst_equal (rhs, val->mem_ref) == 1)
+              || (do_store_ccp ()
+                  && all_vdef_have_same_lattice_const_value (val, stmt))))
 
 	{
 	  /* If we are replacing a constant address, inform our
Index: tree-ssa-propagate.h
===================================================================
--- tree-ssa-propagate.h	(revision 123037)
+++ tree-ssa-propagate.h	(working copy)
@@ -121,5 +121,5 @@
 prop_value_t *get_value_loaded_by (tree, prop_value_t *);
 bool replace_uses_in (tree, bool *, prop_value_t *);
 bool substitute_and_fold (prop_value_t *, bool);
-
+bool all_vdef_have_same_lattice_const_value (prop_value_t *, tree);
 #endif /* _TREE_SSA_PROPAGATE_H  */