Index: targhooks.c
===================================================================
--- targhooks.c	(revision 151228)
+++ targhooks.c	(working copy)
@@ -771,6 +771,22 @@ default_builtin_vector_alignment_reachab
   return true;
 }
 
+/* By default, assume that a target supports any factor of misalignment
+   memory access if it supports movmisalign patten.  */
+bool
+default_builtin_support_vector_misalignment (enum machine_mode mode,
+					     const_tree type
+					     ATTRIBUTE_UNUSED,
+					     int misalignment
+					     ATTRIBUTE_UNUSED,
+					     bool is_packed
+					     ATTRIBUTE_UNUSED)
+{
+  if (movmisalign_optab->handlers[mode].insn_code != CODE_FOR_nothing)
+    return true;
+  return false;
+}
+
 bool
 default_hard_regno_scratch_ok (unsigned int regno ATTRIBUTE_UNUSED)
 {
Index: targhooks.h
===================================================================
--- targhooks.h	(revision 151228)
+++ targhooks.h	(working copy)
@@ -77,6 +77,10 @@ extern tree default_builtin_vectorized_c
 extern tree default_builtin_reciprocal (unsigned int, bool, bool);
 
 extern bool default_builtin_vector_alignment_reachable (const_tree, bool);
+extern bool
+default_builtin_support_vector_misalignment (enum machine_mode mode,
+					     const_tree,
+					     int, bool); 
 
 /* These are here, and not in hooks.[ch], because not all users of
    hooks.h include tm.h, and thus we don't have CUMULATIVE_ARGS.  */
Index: target.h
===================================================================
--- target.h	(revision 151228)
+++ target.h	(working copy)
@@ -481,6 +481,10 @@ struct gcc_target
 
     /* Target builtin that implements vector permute.  */
     tree (* builtin_vec_perm) (tree, tree*);
+    /* Return true if the target supports misaligned store/load of a
+       specific factor denoted in the third parameter.  */
+    bool (* builtin_support_vector_misalignment) (enum machine_mode, 
+                                                  const_tree, int, bool);
   } vectorize;
 
   /* The initial value of target_flags.  */
Index: tree-vect-data-refs.c
===================================================================
--- tree-vect-data-refs.c	(revision 151228)
+++ tree-vect-data-refs.c	(working copy)
@@ -3455,6 +3455,9 @@ vect_supportable_dr_alignment (struct da
 
   if (DR_IS_READ (dr))
     {
+      bool is_packed = false;
+      tree type = (TREE_TYPE (DR_REF (dr)));
+
       if (optab_handler (vec_realign_load_optab, mode)->insn_code != 
 						   	     CODE_FOR_nothing
 	  && (!targetm.vectorize.builtin_mask_for_load
@@ -3468,18 +3471,39 @@ vect_supportable_dr_alignment (struct da
 	  else
 	    return dr_explicit_realign_optimized;
 	}
-
-      if (optab_handler (movmisalign_optab, mode)->insn_code != 
-							     CODE_FOR_nothing)
+      if (!known_alignment_for_access_p (dr))
+	{
+	  tree ba = DR_BASE_OBJECT (dr);
+	  
+	  if (ba)
+	    is_packed = contains_packed_reference (ba);
+	}
+     
+      if (targetm.vectorize.
+	  builtin_support_vector_misalignment (mode, type,
+					       DR_MISALIGNMENT (dr), is_packed))
 	/* Can't software pipeline the loads, but can at least do them.  */
 	return dr_unaligned_supported;
     }
-   else
-     {
-       if (movmisalign_optab->handlers[mode].insn_code != CODE_FOR_nothing)
-         return dr_unaligned_supported;
-     }
+  else
+    {
+      bool is_packed = false;
+      tree type = (TREE_TYPE (DR_REF (dr)));
 
+      if (!known_alignment_for_access_p (dr))
+	{
+	  tree ba = DR_BASE_OBJECT (dr);
+	  
+	  if (ba)
+	    is_packed = contains_packed_reference (ba);
+	}
+     
+     if (targetm.vectorize.
+         builtin_support_vector_misalignment (mode, type, 
+					      DR_MISALIGNMENT (dr), is_packed))
+       return dr_unaligned_supported;
+    }
+  
   /* Unsupported.  */
   return dr_unaligned_unsupported;
 }
Index: target-def.h
===================================================================
--- target-def.h	(revision 151228)
+++ target-def.h	(working copy)
@@ -388,6 +388,9 @@
 #define TARGET_VECTOR_ALIGNMENT_REACHABLE \
   default_builtin_vector_alignment_reachable
 #define TARGET_VECTORIZE_BUILTIN_VEC_PERM 0
+#define TARGET_SUPPORT_VECTOR_MISALIGNMENT \
+  default_builtin_support_vector_misalignment 
+   
 
 #define TARGET_VECTORIZE                                                \
   {									\
@@ -398,7 +401,8 @@
     TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD,				\
     TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST,			\
     TARGET_VECTOR_ALIGNMENT_REACHABLE,                                  \
-    TARGET_VECTORIZE_BUILTIN_VEC_PERM                                   \
+    TARGET_VECTORIZE_BUILTIN_VEC_PERM,					\
+    TARGET_SUPPORT_VECTOR_MISALIGNMENT				\
   }
 
 #define TARGET_DEFAULT_TARGET_FLAGS 0
Index: config/rs6000/rs6000.c
===================================================================
--- config/rs6000/rs6000.c	(revision 151228)
+++ config/rs6000/rs6000.c	(working copy)
@@ -919,6 +919,10 @@ static tree rs6000_builtin_mul_widen_eve
 static tree rs6000_builtin_mul_widen_odd (tree);
 static tree rs6000_builtin_conversion (unsigned int, tree);
 static tree rs6000_builtin_vec_perm (tree, tree *);
+static bool rs6000_builtin_support_vector_misalignment (enum
+							machine_mode,
+							const_tree,
+							int, bool);
 
 static void def_builtin (int, const char *, tree, int);
 static bool rs6000_vector_alignment_reachable (const_tree, bool);
@@ -1299,7 +1303,9 @@ static const struct attribute_spec rs600
 #define TARGET_VECTORIZE_BUILTIN_CONVERSION rs6000_builtin_conversion
 #undef TARGET_VECTORIZE_BUILTIN_VEC_PERM
 #define TARGET_VECTORIZE_BUILTIN_VEC_PERM rs6000_builtin_vec_perm
-
+#undef TARGET_SUPPORT_VECTOR_MISALIGNMENT
+#define TARGET_SUPPORT_VECTOR_MISALIGNMENT		\
+  rs6000_builtin_support_vector_misalignment
 #undef TARGET_VECTOR_ALIGNMENT_REACHABLE
 #define TARGET_VECTOR_ALIGNMENT_REACHABLE rs6000_vector_alignment_reachable
 
@@ -2891,6 +2897,36 @@ rs6000_vector_alignment_reachable (const
     }
 }
 
+/* Return true if the vector misalignment factor is supported by the
+   target.  */ 
+bool
+rs6000_builtin_support_vector_misalignment (enum machine_mode mode,
+					    const_tree type
+					    ATTRIBUTE_UNUSED,
+					    int misalignment,
+					    bool is_packed)
+{
+  if (TARGET_VSX)
+    {
+      /* Return if movmisalign pattern is not supported for this mode.  */
+      if (movmisalign_optab->handlers[mode].insn_code == CODE_FOR_nothing)
+        return false;
+
+      if (misalignment == -1)
+	{
+	  /* misalignment factor is unknown at compile time but we know
+	     it's word aligned.  */
+	  if (rs6000_vector_alignment_reachable (type, is_packed))
+	    return true;
+	  return false;
+	}
+      /* VSX supports word-aligned vector.  */
+      if (misalignment % 4 == 0)
+	return true;
+    }
+  return false;
+}
+
 /* Implement targetm.vectorize.builtin_vec_perm.  */
 tree
 rs6000_builtin_vec_perm (tree type, tree *mask_element_type)