OSDN Git Service

2007-07-09 Thomas Koenig <tkoenig@gcc.gnu.org>
[pf3gnuchains/gcc-fork.git] / gcc / tree-vect-analyze.c
index 9df8ba2..2b8f318 100644 (file)
@@ -1,5 +1,5 @@
 /* Analysis Utilities for Loop Vectorization.
-   Copyright (C) 2003,2004,2005,2006 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
    Contributed by Dorit Naishlos <dorit@il.ibm.com>
 
 This file is part of GCC.
@@ -38,6 +38,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 #include "tree-data-ref.h"
 #include "tree-scalar-evolution.h"
 #include "tree-vectorizer.h"
+#include "toplev.h"
 
 /* Main analysis functions.  */
 static loop_vec_info vect_analyze_loop_form (struct loop *);
@@ -54,8 +55,6 @@ static bool vect_determine_vectorization_factor (loop_vec_info);
 
 /* Utility functions for the analyses.  */
 static bool exist_non_indexing_operands_for_use_p (tree, tree);
-static void vect_mark_relevant (VEC(tree,heap) **, tree, bool, bool);
-static bool vect_stmt_relevant_p (tree, loop_vec_info, bool *, bool *);
 static tree vect_get_loop_niters (struct loop *, tree *);
 static bool vect_analyze_data_ref_dependence
   (struct data_dependence_relation *, loop_vec_info);
@@ -64,7 +63,6 @@ static bool vect_analyze_data_ref_access (struct data_reference *);
 static bool vect_can_advance_ivs_p (loop_vec_info);
 static void vect_update_misalignment_for_peel
   (struct data_reference *, struct data_reference *, int npeel);
 
 /* Function vect_determine_vectorization_factor
 
@@ -99,8 +97,12 @@ vect_determine_vectorization_factor (loop_vec_info loop_vinfo)
   int nbbs = loop->num_nodes;
   block_stmt_iterator si;
   unsigned int vectorization_factor = 0;
-  int i;
   tree scalar_type;
+  tree phi;
+  tree vectype;
+  unsigned int nunits;
+  stmt_vec_info stmt_info;
+  int i;
 
   if (vect_print_dump_info (REPORT_DETAILS))
     fprintf (vect_dump, "=== vect_determine_vectorization_factor ===");
@@ -109,53 +111,125 @@ vect_determine_vectorization_factor (loop_vec_info loop_vinfo)
     {
       basic_block bb = bbs[i];
 
+      for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+       {
+         stmt_info = vinfo_for_stmt (phi);
+         if (vect_print_dump_info (REPORT_DETAILS))
+           {
+             fprintf (vect_dump, "==> examining phi: ");
+             print_generic_expr (vect_dump, phi, TDF_SLIM);
+           }
+
+         gcc_assert (stmt_info);
+
+         if (STMT_VINFO_RELEVANT_P (stmt_info))
+            {
+             gcc_assert (!STMT_VINFO_VECTYPE (stmt_info));
+              scalar_type = TREE_TYPE (PHI_RESULT (phi));
+
+             if (vect_print_dump_info (REPORT_DETAILS))
+               {
+                 fprintf (vect_dump, "get vectype for scalar type:  ");
+                 print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
+               }
+
+             vectype = get_vectype_for_scalar_type (scalar_type);
+             if (!vectype)
+               {
+                 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
+                   {
+                     fprintf (vect_dump,
+                              "not vectorized: unsupported data-type ");
+                     print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
+                   }
+                 return false;
+               }
+             STMT_VINFO_VECTYPE (stmt_info) = vectype;
+
+             if (vect_print_dump_info (REPORT_DETAILS))
+               {
+                 fprintf (vect_dump, "vectype: ");
+                 print_generic_expr (vect_dump, vectype, TDF_SLIM);
+               }
+
+             nunits = TYPE_VECTOR_SUBPARTS (vectype);
+             if (vect_print_dump_info (REPORT_DETAILS))
+               fprintf (vect_dump, "nunits = %d", nunits);
+
+             if (!vectorization_factor
+                 || (nunits > vectorization_factor))
+               vectorization_factor = nunits;
+           }
+       }
+
       for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
         {
-          tree stmt = bsi_stmt (si);
-          unsigned int nunits;
-          stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
-          tree vectype;
+         tree stmt = bsi_stmt (si);
+         stmt_info = vinfo_for_stmt (stmt);
 
-          if (vect_print_dump_info (REPORT_DETAILS))
-            {
-              fprintf (vect_dump, "==> examining statement: ");
-              print_generic_expr (vect_dump, stmt, TDF_SLIM);
-            }
+         if (vect_print_dump_info (REPORT_DETAILS))
+           {
+             fprintf (vect_dump, "==> examining statement: ");
+             print_generic_expr (vect_dump, stmt, TDF_SLIM);
+           }
 
-          gcc_assert (stmt_info);
-          /* skip stmts which do not need to be vectorized.  */
-          if (!STMT_VINFO_RELEVANT_P (stmt_info)
+         gcc_assert (stmt_info);
+
+         /* skip stmts which do not need to be vectorized.  */
+         if (!STMT_VINFO_RELEVANT_P (stmt_info)
              && !STMT_VINFO_LIVE_P (stmt_info))
-            {
-              if (vect_print_dump_info (REPORT_DETAILS))
-                fprintf (vect_dump, "skip.");
-              continue;
-            }
+           {
+             if (vect_print_dump_info (REPORT_DETAILS))
+               fprintf (vect_dump, "skip.");
+             continue;
+           }
 
-          if (VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))))
-            {
-              if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
-                {
-                  fprintf (vect_dump, "not vectorized: vector stmt in loop:");
-                  print_generic_expr (vect_dump, stmt, TDF_SLIM);
-                }
-              return false;
-            }
+         if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
+           {
+             if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
+               {
+                 fprintf (vect_dump, "not vectorized: irregular stmt.");
+                 print_generic_expr (vect_dump, stmt, TDF_SLIM);
+               }
+             return false;
+           }
+
+         if (!GIMPLE_STMT_P (stmt)
+             && VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))))
+           {
+             if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
+               {
+                 fprintf (vect_dump, "not vectorized: vector stmt in loop:");
+                 print_generic_expr (vect_dump, stmt, TDF_SLIM);
+               }
+             return false;
+           }
 
          if (STMT_VINFO_VECTYPE (stmt_info))
            {
+             /* The only case when a vectype had been already set is for stmts 
+                that contain a dataref, or for "pattern-stmts" (stmts generated
+                by the vectorizer to represent/replace a certain idiom).  */
+             gcc_assert (STMT_VINFO_DATA_REF (stmt_info) 
+                         || is_pattern_stmt_p (stmt_info));
              vectype = STMT_VINFO_VECTYPE (stmt_info);
-             scalar_type = TREE_TYPE (vectype);
            }
          else
            {
-             if (STMT_VINFO_DATA_REF (stmt_info))
-               scalar_type = 
-                       TREE_TYPE (DR_REF (STMT_VINFO_DATA_REF (stmt_info)));
-             else if (TREE_CODE (stmt) == MODIFY_EXPR)
-               scalar_type = TREE_TYPE (TREE_OPERAND (stmt, 0));
-             else
-               scalar_type = TREE_TYPE (stmt);
+             gcc_assert (! STMT_VINFO_DATA_REF (stmt_info)
+                         && !is_pattern_stmt_p (stmt_info));
+
+             /* We set the vectype according to the type of the result (lhs).
+                For stmts whose result-type is different than the type of the
+                arguments (e.g. demotion, promotion), vectype will be reset 
+                appropriately (later).  Note that we have to visit the smallest 
+                datatype in this function, because that determines the VF.  
+                If the smallest datatype in the loop is present only as the 
+                rhs of a promotion operation - we'd miss it here.
+                However, in such a case, that a variable of this datatype
+                does not appear in the lhs anywhere in the loop, it shouldn't
+                affect the vectorization factor.   */
+             scalar_type = TREE_TYPE (GIMPLE_STMT_OPERAND (stmt, 0));
 
              if (vect_print_dump_info (REPORT_DETAILS))
                {
@@ -177,37 +251,26 @@ vect_determine_vectorization_factor (loop_vec_info loop_vinfo)
              STMT_VINFO_VECTYPE (stmt_info) = vectype;
             }
 
-          if (vect_print_dump_info (REPORT_DETAILS))
-            {
-              fprintf (vect_dump, "vectype: ");
-              print_generic_expr (vect_dump, vectype, TDF_SLIM);
-            }
+         if (vect_print_dump_info (REPORT_DETAILS))
+           {
+             fprintf (vect_dump, "vectype: ");
+             print_generic_expr (vect_dump, vectype, TDF_SLIM);
+           }
 
-          nunits = TYPE_VECTOR_SUBPARTS (vectype);
-          if (vect_print_dump_info (REPORT_DETAILS))
-            fprintf (vect_dump, "nunits = %d", nunits);
+         nunits = TYPE_VECTOR_SUBPARTS (vectype);
+         if (vect_print_dump_info (REPORT_DETAILS))
+           fprintf (vect_dump, "nunits = %d", nunits);
 
-          if (vectorization_factor)
-            {
-              /* FORNOW: don't allow mixed units. 
-                 This restriction will be relaxed in the future.  */
-              if (nunits != vectorization_factor) 
-                {
-                  if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
-                    fprintf (vect_dump, "not vectorized: mixed data-types");
-                  return false;
-                }
-            }
-          else
-            vectorization_factor = nunits;
+         if (!vectorization_factor
+             || (nunits > vectorization_factor))
+           vectorization_factor = nunits;
 
-          gcc_assert (GET_MODE_SIZE (TYPE_MODE (scalar_type))
-                        * vectorization_factor == UNITS_PER_SIMD_WORD);
         }
     }
 
   /* TODO: Analyze cost. Decide if worth while to vectorize.  */
-
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "vectorization factor = %d", vectorization_factor);
   if (vectorization_factor <= 1)
     {
       if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
@@ -237,6 +300,9 @@ vect_analyze_operations (loop_vec_info loop_vinfo)
   tree phi;
   stmt_vec_info stmt_info;
   bool need_to_vectorize = false;
+  int min_profitable_iters;
+  int min_scalar_loop_bound;
+  unsigned int th;
 
   if (vect_print_dump_info (REPORT_DETAILS))
     fprintf (vect_dump, "=== vect_analyze_operations ===");
@@ -250,6 +316,8 @@ vect_analyze_operations (loop_vec_info loop_vinfo)
 
       for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
         {
+         ok = true;
+
          stmt_info = vinfo_for_stmt (phi);
          if (vect_print_dump_info (REPORT_DETAILS))
            {
@@ -264,16 +332,34 @@ vect_analyze_operations (loop_vec_info loop_vinfo)
              /* FORNOW: not yet supported.  */
              if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
                fprintf (vect_dump, "not vectorized: value used after loop.");
-           return false;
-         }
+             return false;
+           }
+
+         if (STMT_VINFO_RELEVANT (stmt_info) == vect_used_in_loop
+             && STMT_VINFO_DEF_TYPE (stmt_info) != vect_induction_def)
+           {
+             /* A scalar-dependence cycle that we don't support.  */
+             if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
+               fprintf (vect_dump, "not vectorized: scalar dependence cycle.");
+             return false;
+           }
 
          if (STMT_VINFO_RELEVANT_P (stmt_info))
            {
-             /* Most likely a reduction-like computation that is used
-                in the loop.  */
+             need_to_vectorize = true;
+             if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_induction_def)
+               ok = vectorizable_induction (phi, NULL, NULL);
+           }
+
+         if (!ok)
+           {
              if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
-               fprintf (vect_dump, "not vectorized: unsupported pattern.");
-            return false;
+               {
+                 fprintf (vect_dump,
+                          "not vectorized: relevant phi not supported: ");
+                 print_generic_expr (vect_dump, phi, TDF_SLIM);
+               }
+             return false;
            }
        }
 
@@ -281,6 +367,7 @@ vect_analyze_operations (loop_vec_info loop_vinfo)
        {
          tree stmt = bsi_stmt (si);
          stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+         enum vect_def_type relevance = STMT_VINFO_RELEVANT (stmt_info);
 
          if (vect_print_dump_info (REPORT_DETAILS))
            {
@@ -305,55 +392,60 @@ vect_analyze_operations (loop_vec_info loop_vinfo)
              continue;
            }
 
-          if (STMT_VINFO_RELEVANT_P (stmt_info))
-            {
-              gcc_assert (!VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))));
-              gcc_assert (STMT_VINFO_VECTYPE (stmt_info));
-
-             ok = (vectorizable_operation (stmt, NULL, NULL)
-                   || vectorizable_assignment (stmt, NULL, NULL)
-                   || vectorizable_load (stmt, NULL, NULL)
-                   || vectorizable_store (stmt, NULL, NULL)
-                   || vectorizable_condition (stmt, NULL, NULL));
+         switch (STMT_VINFO_DEF_TYPE (stmt_info))
+           {
+           case vect_loop_def:
+             break;
+       
+           case vect_reduction_def:
+             gcc_assert (relevance == vect_unused_in_loop);
+             break;    
+
+           case vect_induction_def:
+           case vect_constant_def:
+           case vect_invariant_def:
+           case vect_unknown_def_type:
+           default:
+             gcc_unreachable ();       
+           }
 
-             if (!ok)
-               {
-                 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
-                   {
-                     fprintf (vect_dump, 
-                              "not vectorized: relevant stmt not supported: ");
-                     print_generic_expr (vect_dump, stmt, TDF_SLIM);
-                   }
-                 return false;
-               }       
+         if (STMT_VINFO_RELEVANT_P (stmt_info))
+           {
+             gcc_assert (GIMPLE_STMT_P (stmt)
+                         || !VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))));
+             gcc_assert (STMT_VINFO_VECTYPE (stmt_info));
              need_to_vectorize = true;
-            }
+           }
 
-         if (STMT_VINFO_LIVE_P (stmt_info))
+         ok = (vectorizable_type_promotion (stmt, NULL, NULL)
+               || vectorizable_type_demotion (stmt, NULL, NULL)
+               || vectorizable_conversion (stmt, NULL, NULL)
+               || vectorizable_operation (stmt, NULL, NULL)
+               || vectorizable_assignment (stmt, NULL, NULL)
+               || vectorizable_load (stmt, NULL, NULL)
+               || vectorizable_call (stmt, NULL, NULL)
+               || vectorizable_store (stmt, NULL, NULL)
+               || vectorizable_condition (stmt, NULL, NULL)
+               || vectorizable_reduction (stmt, NULL, NULL));
+
+         /* Stmts that are (also) "live" (i.e. - that are used out of the loop)
+            need extra handling, except for vectorizable reductions.  */
+         if (STMT_VINFO_LIVE_P (stmt_info)
+             && STMT_VINFO_TYPE (stmt_info) != reduc_vec_info_type) 
+           ok |= vectorizable_live_operation (stmt, NULL, NULL);
+
+         if (!ok)
            {
-             ok = vectorizable_reduction (stmt, NULL, NULL);
-
-             if (ok)
-                need_to_vectorize = true;
-              else
-               ok = vectorizable_live_operation (stmt, NULL, NULL);
-
-             if (!ok)
+             if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
                {
-                 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
-                   {
-                     fprintf (vect_dump, 
-                              "not vectorized: live stmt not supported: ");
-                     print_generic_expr (vect_dump, stmt, TDF_SLIM);
-                   }
-                 return false;
+                 fprintf (vect_dump, "not vectorized: stmt not supported: ");
+                 print_generic_expr (vect_dump, stmt, TDF_SLIM);
                }
-           }
+             return false;
+           }   
        } /* stmts in bb */
     } /* bbs */
 
-  /* TODO: Analyze cost. Decide if worth while to vectorize.  */
-
   /* All operations in the loop are either irrelevant (deal with loop
      control, or dead), or only used outside the loop and can be moved
      out of the loop (e.g. invariants, inductions).  The loop can be 
@@ -377,13 +469,55 @@ vect_analyze_operations (loop_vec_info loop_vinfo)
         vectorization_factor, LOOP_VINFO_INT_NITERS (loop_vinfo));
 
   if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
-      && LOOP_VINFO_INT_NITERS (loop_vinfo) < vectorization_factor)
+      && (LOOP_VINFO_INT_NITERS (loop_vinfo) < vectorization_factor))
+    {
+      if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
+        fprintf (vect_dump, "not vectorized: iteration count too small.");
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump,"not vectorized: iteration count smaller than "
+                 "vectorization factor.");
+      return false;
+    }
+
+  /* Analyze cost. Decide if worth while to vectorize.  */
+
+  min_profitable_iters = vect_estimate_min_profitable_iters (loop_vinfo);
+  LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo) = min_profitable_iters;
+  if (min_profitable_iters < 0)
     {
       if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
-       fprintf (vect_dump, "not vectorized: iteration count too small.");
+        fprintf (vect_dump, "not vectorized: vectorization not profitable.");
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "not vectorized: vector version will never be "
+                 "profitable.");
       return false;
     }
 
+  min_scalar_loop_bound = (PARAM_VALUE (PARAM_MIN_VECT_LOOP_BOUND))
+                          * vectorization_factor;
+
+  /* Use the cost model only if it is more conservative than user specified
+     threshold.  */
+
+  th = (unsigned) min_scalar_loop_bound;
+  if (min_profitable_iters 
+      && (!min_scalar_loop_bound
+          || min_profitable_iters > min_scalar_loop_bound))
+    th = (unsigned) min_profitable_iters;
+
+  if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
+      && LOOP_VINFO_INT_NITERS (loop_vinfo) < th)
+    {
+      if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))          
+        fprintf (vect_dump, "not vectorized: vectorization not "
+                 "profitable.");
+      if (vect_print_dump_info (REPORT_DETAILS))             
+        fprintf (vect_dump, "not vectorized: iteration count smaller than "
+                 "user specified loop bound parameter or minimum "
+                 "profitable iterations (whichever is more conservative).");
+      return false;
+    }  
+
   if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
       || LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0
       || LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo))
@@ -397,7 +531,7 @@ vect_analyze_operations (loop_vec_info loop_vinfo)
                      "not vectorized: can't create epilog loop 1.");
           return false;
         }
-      if (!slpeel_can_duplicate_loop_p (loop, loop->single_exit))
+      if (!slpeel_can_duplicate_loop_p (loop, single_exit (loop)))
         {
           if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
             fprintf (vect_dump,
@@ -440,10 +574,10 @@ exist_non_indexing_operands_for_use_p (tree use, tree stmt)
      Therefore, all we need to check is if STMT falls into the
      first case, and whether var corresponds to USE.  */
  
-  if (TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME)
+  if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 0)) == SSA_NAME)
     return false;
 
-  operand = TREE_OPERAND (stmt, 1);
+  operand = GIMPLE_STMT_OPERAND (stmt, 1);
 
   if (TREE_CODE (operand) != SSA_NAME)
     return false;
@@ -500,58 +634,69 @@ vect_analyze_scalar_cycles (loop_vec_info loop_vinfo)
   tree phi;
   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
   basic_block bb = loop->header;
-  tree dummy;
+  tree dumy;
+  VEC(tree,heap) *worklist = VEC_alloc (tree, heap, 64);
 
   if (vect_print_dump_info (REPORT_DETAILS))
     fprintf (vect_dump, "=== vect_analyze_scalar_cycles ===");
 
+  /* First - identify all inductions.  */
   for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
     {
       tree access_fn = NULL;
       tree def = PHI_RESULT (phi);
       stmt_vec_info stmt_vinfo = vinfo_for_stmt (phi);
-      tree reduc_stmt;
 
       if (vect_print_dump_info (REPORT_DETAILS))
        {
-          fprintf (vect_dump, "Analyze phi: ");
-          print_generic_expr (vect_dump, phi, TDF_SLIM);
+         fprintf (vect_dump, "Analyze phi: ");
+         print_generic_expr (vect_dump, phi, TDF_SLIM);
        }
 
       /* Skip virtual phi's. The data dependences that are associated with
          virtual defs/uses (i.e., memory accesses) are analyzed elsewhere.  */
-
       if (!is_gimple_reg (SSA_NAME_VAR (def)))
-       {
-         if (vect_print_dump_info (REPORT_DETAILS))
-           fprintf (vect_dump, "virtual phi. skip.");
-         continue;
-       }
+       continue;
 
       STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_unknown_def_type;
 
       /* Analyze the evolution function.  */
-
       access_fn = analyze_scalar_evolution (loop, def);
+      if (access_fn && vect_print_dump_info (REPORT_DETAILS))
+       {
+         fprintf (vect_dump, "Access function of PHI: ");
+         print_generic_expr (vect_dump, access_fn, TDF_SLIM);
+       }
 
-      if (!access_fn)
-       continue;
+      if (!access_fn
+         || !vect_is_simple_iv_evolution (loop->num, access_fn, &dumy, &dumy)) 
+       {
+         VEC_safe_push (tree, heap, worklist, phi);      
+         continue;
+       }
 
       if (vect_print_dump_info (REPORT_DETAILS))
-        {
-           fprintf (vect_dump, "Access function of PHI: ");
-           print_generic_expr (vect_dump, access_fn, TDF_SLIM);
-        }
+       fprintf (vect_dump, "Detected induction.");
+      STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_induction_def;
+    }
 
-      if (vect_is_simple_iv_evolution (loop->num, access_fn, &dummy, &dummy))
-       {
-         if (vect_print_dump_info (REPORT_DETAILS))
-           fprintf (vect_dump, "Detected induction.");
-         STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_induction_def;
-          continue;
-       }
 
-      /* TODO: handle invariant phis  */
+  /* Second - identify all reductions.  */
+  while (VEC_length (tree, worklist) > 0)
+    {
+      tree phi = VEC_pop (tree, worklist);
+      tree def = PHI_RESULT (phi);
+      stmt_vec_info stmt_vinfo = vinfo_for_stmt (phi);
+      tree reduc_stmt;
+
+      if (vect_print_dump_info (REPORT_DETAILS))
+        { 
+          fprintf (vect_dump, "Analyze phi: ");
+          print_generic_expr (vect_dump, phi, TDF_SLIM);
+        }
+
+      gcc_assert (is_gimple_reg (SSA_NAME_VAR (def)));
+      gcc_assert (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_unknown_def_type);
 
       reduc_stmt = vect_is_simple_reduction (loop, phi);
       if (reduc_stmt)
@@ -565,13 +710,302 @@ vect_analyze_scalar_cycles (loop_vec_info loop_vinfo)
       else
         if (vect_print_dump_info (REPORT_DETAILS))
           fprintf (vect_dump, "Unknown def-use cycle pattern.");
-
     }
 
+  VEC_free (tree, heap, worklist);
   return;
 }
 
 
+/* Function vect_insert_into_interleaving_chain.
+
+   Insert DRA into the interleaving chain of DRB according to DRA's INIT.  */
+
+static void
+vect_insert_into_interleaving_chain (struct data_reference *dra,
+                                    struct data_reference *drb)
+{
+  tree prev, next, next_init;
+  stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); 
+  stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb));
+
+  prev = DR_GROUP_FIRST_DR (stmtinfo_b);
+  next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));               
+  while (next)
+    {
+      next_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (next)));
+      if (tree_int_cst_compare (next_init, DR_INIT (dra)) > 0)
+       {
+         /* Insert here.  */
+         DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = DR_STMT (dra);
+         DR_GROUP_NEXT_DR (stmtinfo_a) = next;
+         return;
+       }
+      prev = next;
+      next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));
+    }
+
+  /* We got to the end of the list. Insert here.  */
+  DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = DR_STMT (dra);
+  DR_GROUP_NEXT_DR (stmtinfo_a) = NULL_TREE;
+}
+
+
+/* Function vect_update_interleaving_chain.
+   
+   For two data-refs DRA and DRB that are a part of a chain interleaved data 
+   accesses, update the interleaving chain. DRB's INIT is smaller than DRA's.
+
+   There are four possible cases:
+   1. New stmts - both DRA and DRB are not a part of any chain:
+      FIRST_DR = DRB
+      NEXT_DR (DRB) = DRA
+   2. DRB is a part of a chain and DRA is not:
+      no need to update FIRST_DR
+      no need to insert DRB
+      insert DRA according to init
+   3. DRA is a part of a chain and DRB is not:
+      if (init of FIRST_DR > init of DRB)
+          FIRST_DR = DRB
+         NEXT(FIRST_DR) = previous FIRST_DR
+      else
+          insert DRB according to its init
+   4. both DRA and DRB are in some interleaving chains:
+      choose the chain with the smallest init of FIRST_DR
+      insert the nodes of the second chain into the first one.  */
+
+static void
+vect_update_interleaving_chain (struct data_reference *drb,
+                               struct data_reference *dra)
+{
+  stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); 
+  stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb));
+  tree next_init, init_dra_chain, init_drb_chain, first_a, first_b;
+  tree node, prev, next, node_init, first_stmt;
+
+  /* 1. New stmts - both DRA and DRB are not a part of any chain.   */
+  if (!DR_GROUP_FIRST_DR (stmtinfo_a) && !DR_GROUP_FIRST_DR (stmtinfo_b))
+    {
+      DR_GROUP_FIRST_DR (stmtinfo_a) = DR_STMT (drb);
+      DR_GROUP_FIRST_DR (stmtinfo_b) = DR_STMT (drb);
+      DR_GROUP_NEXT_DR (stmtinfo_b) = DR_STMT (dra);
+      return;
+    }
+
+  /* 2. DRB is a part of a chain and DRA is not.  */
+  if (!DR_GROUP_FIRST_DR (stmtinfo_a) && DR_GROUP_FIRST_DR (stmtinfo_b))
+    {
+      DR_GROUP_FIRST_DR (stmtinfo_a) = DR_GROUP_FIRST_DR (stmtinfo_b);
+      /* Insert DRA into the chain of DRB.  */
+      vect_insert_into_interleaving_chain (dra, drb);
+      return;
+    }
+
+  /* 3. DRA is a part of a chain and DRB is not.  */  
+  if (DR_GROUP_FIRST_DR (stmtinfo_a) && !DR_GROUP_FIRST_DR (stmtinfo_b))
+    {
+      tree old_first_stmt = DR_GROUP_FIRST_DR (stmtinfo_a);
+      tree init_old = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (
+                                                             old_first_stmt)));
+      tree tmp;
+
+      if (tree_int_cst_compare (init_old, DR_INIT (drb)) > 0)
+       {
+         /* DRB's init is smaller than the init of the stmt previously marked 
+            as the first stmt of the interleaving chain of DRA. Therefore, we 
+            update FIRST_STMT and put DRB in the head of the list.  */
+         DR_GROUP_FIRST_DR (stmtinfo_b) = DR_STMT (drb);
+         DR_GROUP_NEXT_DR (stmtinfo_b) = old_first_stmt;
+               
+         /* Update all the stmts in the list to point to the new FIRST_STMT.  */
+         tmp = old_first_stmt;
+         while (tmp)
+           {
+             DR_GROUP_FIRST_DR (vinfo_for_stmt (tmp)) = DR_STMT (drb);
+             tmp = DR_GROUP_NEXT_DR (vinfo_for_stmt (tmp));
+           }
+       }
+      else
+       {
+         /* Insert DRB in the list of DRA.  */
+         vect_insert_into_interleaving_chain (drb, dra);
+         DR_GROUP_FIRST_DR (stmtinfo_b) = DR_GROUP_FIRST_DR (stmtinfo_a);            
+       }
+      return;
+    }
+  
+  /* 4. both DRA and DRB are in some interleaving chains.  */
+  first_a = DR_GROUP_FIRST_DR (stmtinfo_a);
+  first_b = DR_GROUP_FIRST_DR (stmtinfo_b);
+  if (first_a == first_b)
+    return;
+  init_dra_chain = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (first_a)));
+  init_drb_chain = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (first_b)));
+
+  if (tree_int_cst_compare (init_dra_chain, init_drb_chain) > 0)
+    {
+      /* Insert the nodes of DRA chain into the DRB chain.  
+        After inserting a node, continue from this node of the DRB chain (don't
+         start from the beginning.  */
+      node = DR_GROUP_FIRST_DR (stmtinfo_a);
+      prev = DR_GROUP_FIRST_DR (stmtinfo_b);      
+      first_stmt = first_b;
+    }
+  else
+    {
+      /* Insert the nodes of DRB chain into the DRA chain.  
+        After inserting a node, continue from this node of the DRA chain (don't
+         start from the beginning.  */
+      node = DR_GROUP_FIRST_DR (stmtinfo_b);
+      prev = DR_GROUP_FIRST_DR (stmtinfo_a);      
+      first_stmt = first_a;
+    }
+  
+  while (node)
+    {
+      node_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (node)));
+      next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));           
+      while (next)
+       {         
+         next_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (next)));
+         if (tree_int_cst_compare (next_init, node_init) > 0)
+           {
+             /* Insert here.  */
+             DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = node;
+             DR_GROUP_NEXT_DR (vinfo_for_stmt (node)) = next;
+             prev = node;
+             break;
+           }
+         prev = next;
+         next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));
+       }
+      if (!next)
+       {
+         /* We got to the end of the list. Insert here.  */
+         DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = node;
+         DR_GROUP_NEXT_DR (vinfo_for_stmt (node)) = NULL_TREE;
+         prev = node;
+       }                       
+      DR_GROUP_FIRST_DR (vinfo_for_stmt (node)) = first_stmt;
+      node = DR_GROUP_NEXT_DR (vinfo_for_stmt (node));        
+    }
+}
+
+
+/* Function vect_equal_offsets.
+
+   Check if OFFSET1 and OFFSET2 are identical expressions.  */
+
+static bool
+vect_equal_offsets (tree offset1, tree offset2)
+{
+  bool res0, res1;
+
+  STRIP_NOPS (offset1);
+  STRIP_NOPS (offset2);
+
+  if (offset1 == offset2)
+    return true;
+
+  if (TREE_CODE (offset1) != TREE_CODE (offset2)
+      || !BINARY_CLASS_P (offset1)
+      || !BINARY_CLASS_P (offset2))    
+    return false;
+  
+  res0 = vect_equal_offsets (TREE_OPERAND (offset1, 0), 
+                            TREE_OPERAND (offset2, 0));
+  res1 = vect_equal_offsets (TREE_OPERAND (offset1, 1), 
+                            TREE_OPERAND (offset2, 1));
+
+  return (res0 && res1);
+}
+
+
+/* Function vect_check_interleaving.
+
+   Check if DRA and DRB are a part of interleaving. In case they are, insert
+   DRA and DRB in an interleaving chain.  */
+
+static void
+vect_check_interleaving (struct data_reference *dra,
+                        struct data_reference *drb)
+{
+  HOST_WIDE_INT type_size_a, type_size_b, diff_mod_size, step, init_a, init_b;
+
+  /* Check that the data-refs have same first location (except init) and they
+     are both either store or load (not load and store).  */
+  if ((DR_BASE_ADDRESS (dra) != DR_BASE_ADDRESS (drb)
+       && (TREE_CODE (DR_BASE_ADDRESS (dra)) != ADDR_EXPR 
+          || TREE_CODE (DR_BASE_ADDRESS (drb)) != ADDR_EXPR
+          || TREE_OPERAND (DR_BASE_ADDRESS (dra), 0) 
+          != TREE_OPERAND (DR_BASE_ADDRESS (drb),0)))
+      || !vect_equal_offsets (DR_OFFSET (dra), DR_OFFSET (drb))
+      || !tree_int_cst_compare (DR_INIT (dra), DR_INIT (drb)) 
+      || DR_IS_READ (dra) != DR_IS_READ (drb))
+    return;
+
+  /* Check:
+     1. data-refs are of the same type
+     2. their steps are equal
+     3. the step is greater than the difference between data-refs' inits  */
+  type_size_a = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dra))));
+  type_size_b = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (drb))));
+
+  if (type_size_a != type_size_b
+      || tree_int_cst_compare (DR_STEP (dra), DR_STEP (drb)))
+    return;
+
+  init_a = TREE_INT_CST_LOW (DR_INIT (dra));
+  init_b = TREE_INT_CST_LOW (DR_INIT (drb));
+  step = TREE_INT_CST_LOW (DR_STEP (dra));
+
+  if (init_a > init_b)
+    {
+      /* If init_a == init_b + the size of the type * k, we have an interleaving, 
+        and DRB is accessed before DRA.  */
+      diff_mod_size = (init_a - init_b) % type_size_a;
+
+      if ((init_a - init_b) > step)
+         return; 
+
+      if (diff_mod_size == 0)
+       {
+         vect_update_interleaving_chain (drb, dra);      
+         if (vect_print_dump_info (REPORT_DR_DETAILS))
+           {
+             fprintf (vect_dump, "Detected interleaving ");
+             print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
+             fprintf (vect_dump, " and ");
+             print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
+           }
+         return;
+       } 
+    }
+  else 
+    {
+      /* If init_b == init_a + the size of the type * k, we have an 
+        interleaving, and DRA is accessed before DRB.  */
+      diff_mod_size = (init_b - init_a) % type_size_a;
+
+      if ((init_b - init_a) > step)
+         return;
+
+      if (diff_mod_size == 0)
+       {
+         vect_update_interleaving_chain (dra, drb);      
+         if (vect_print_dump_info (REPORT_DR_DETAILS))
+           {
+             fprintf (vect_dump, "Detected interleaving ");
+             print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
+             fprintf (vect_dump, " and ");
+             print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
+           }
+         return;
+       } 
+    }
+}
+
+
 /* Function vect_analyze_data_ref_dependence.
 
    Return TRUE if there (might) exist a dependence between a memory-reference
@@ -588,10 +1022,19 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr,
   struct data_reference *drb = DDR_B (ddr);
   stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); 
   stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb));
+  int dra_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dra))));
+  int drb_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (drb))));
   lambda_vector dist_v;
   unsigned int loop_depth;
          
   if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
+    {
+      /* Independent data accesses.  */
+      vect_check_interleaving (dra, drb);
+      return false;
+    }
+
+  if ((DR_IS_READ (dra) && DR_IS_READ (drb)) || dra == drb)
     return false;
   
   if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
@@ -628,7 +1071,7 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr,
        fprintf (vect_dump, "dependence distance  = %d.", dist);
 
       /* Same loop iteration.  */
-      if (dist % vectorization_factor == 0)
+      if (dist % vectorization_factor == 0 && dra_size == drb_size)
        {
          /* Two references with distance zero have the same alignment.  */
          VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_a), drb);
@@ -642,7 +1085,18 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr,
              fprintf (vect_dump, " and ");
              print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
            }
-         continue;
+
+          /* For interleaving, mark that there is a read-write dependency if
+             necessary. We check before that one of the data-refs is store.  */ 
+          if (DR_IS_READ (dra))
+            DR_GROUP_READ_WRITE_DEPENDENCE (stmtinfo_a) = true;
+         else
+            {
+              if (DR_IS_READ (drb))
+                DR_GROUP_READ_WRITE_DEPENDENCE (stmtinfo_b) = true;
+           }
+         
+          continue;
        }
 
       if (abs (dist) >= vectorization_factor)
@@ -721,17 +1175,16 @@ vect_compute_data_ref_alignment (struct data_reference *dr)
     fprintf (vect_dump, "vect_compute_data_ref_alignment:");
 
   /* Initialize misalignment to unknown.  */
-  DR_MISALIGNMENT (dr) = -1;
+  SET_DR_MISALIGNMENT (dr, -1);
 
-  misalign = DR_OFFSET_MISALIGNMENT (dr);
+  misalign = DR_INIT (dr);
   aligned_to = DR_ALIGNED_TO (dr);
   base_addr = DR_BASE_ADDRESS (dr);
   base = build_fold_indirect_ref (base_addr);
   vectype = STMT_VINFO_VECTYPE (stmt_info);
   alignment = ssize_int (TYPE_ALIGN (vectype)/BITS_PER_UNIT);
 
-  if ((aligned_to && tree_int_cst_compare (aligned_to, alignment) < 0)
-      || !misalign)
+  if (tree_int_cst_compare (aligned_to, alignment) < 0)
     {
       if (vect_print_dump_info (REPORT_DETAILS))
        {
@@ -792,7 +1245,7 @@ vect_compute_data_ref_alignment (struct data_reference *dr)
       return false;
     }
 
-  DR_MISALIGNMENT (dr) = TREE_INT_CST_LOW (misalign);
+  SET_DR_MISALIGNMENT (dr, TREE_INT_CST_LOW (misalign));
 
   if (vect_print_dump_info (REPORT_DETAILS))
     {
@@ -837,16 +1290,19 @@ vect_update_misalignment_for_peel (struct data_reference *dr,
                                    struct data_reference *dr_peel, int npeel)
 {
   unsigned int i;
-  int drsize;
   VEC(dr_p,heap) *same_align_drs;
   struct data_reference *current_dr;
-
-  if (known_alignment_for_access_p (dr)
-      && DR_MISALIGNMENT (dr) == DR_MISALIGNMENT (dr_peel))
-    {
-      DR_MISALIGNMENT (dr) = 0;
-      return;
-    }
+  int dr_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
+  int dr_peel_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr_peel))));
+  stmt_vec_info stmt_info = vinfo_for_stmt (DR_STMT (dr));
+  stmt_vec_info peel_stmt_info = vinfo_for_stmt (DR_STMT (dr_peel));
+
+ /* For interleaved data accesses the step in the loop must be multiplied by
+     the size of the interleaving group.  */
+  if (DR_GROUP_FIRST_DR (stmt_info))
+    dr_size *= DR_GROUP_SIZE (vinfo_for_stmt (DR_GROUP_FIRST_DR (stmt_info)));
+  if (DR_GROUP_FIRST_DR (peel_stmt_info))
+    dr_peel_size *= DR_GROUP_SIZE (peel_stmt_info);
 
   /* It can be assumed that the data refs with the same alignment as dr_peel
      are aligned in the vector loop.  */
@@ -856,21 +1312,25 @@ vect_update_misalignment_for_peel (struct data_reference *dr,
     {
       if (current_dr != dr)
         continue;
-      gcc_assert (DR_MISALIGNMENT (dr) == DR_MISALIGNMENT (dr_peel));
-      DR_MISALIGNMENT (dr) = 0;
+      gcc_assert (DR_MISALIGNMENT (dr) / dr_size ==
+                  DR_MISALIGNMENT (dr_peel) / dr_peel_size);
+      SET_DR_MISALIGNMENT (dr, 0);
       return;
     }
 
   if (known_alignment_for_access_p (dr)
       && known_alignment_for_access_p (dr_peel))
-    {  
-      drsize = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
-      DR_MISALIGNMENT (dr) += npeel * drsize;
-      DR_MISALIGNMENT (dr) %= UNITS_PER_SIMD_WORD;
+    {
+      int misal = DR_MISALIGNMENT (dr);
+      misal += npeel * dr_size;
+      misal %= UNITS_PER_SIMD_WORD;
+      SET_DR_MISALIGNMENT (dr, misal);
       return;
     }
 
-  DR_MISALIGNMENT (dr) = -1;
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "Setting misalignment to -1.");
+  SET_DR_MISALIGNMENT (dr, -1);
 }
 
 
@@ -889,6 +1349,14 @@ vect_verify_datarefs_alignment (loop_vec_info loop_vinfo)
 
   for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
     {
+      tree stmt = DR_STMT (dr);
+      stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+
+      /* For interleaving, only the alignment of the first access matters.  */
+      if (DR_GROUP_FIRST_DR (stmt_info)
+          && DR_GROUP_FIRST_DR (stmt_info) != stmt)
+        continue;
+
       supportable_dr_alignment = vect_supportable_dr_alignment (dr);
       if (!supportable_dr_alignment)
         {
@@ -1006,6 +1474,7 @@ static bool
 vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
 {
   VEC (data_reference_p, heap) *datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
   enum dr_alignment_support supportable_dr_alignment;
   struct data_reference *dr0 = NULL;
   struct data_reference *dr;
@@ -1013,6 +1482,11 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
   bool do_peeling = false;
   bool do_versioning = false;
   bool stat;
+  tree stmt;
+  stmt_vec_info stmt_info;
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "=== vect_enhance_data_refs_alignment ===");
 
   /* While cost model enhancements are expected in the future, the high level
      view of the code at this time is as follows:
@@ -1021,7 +1495,7 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
         can make all data references satisfy vect_supportable_dr_alignment.
         If so, update data structures as needed and return true.  Note that
         at this time vect_supportable_dr_alignment is known to return false
-        for a misaligned write.
+        for a misaligned write.
 
      B) If peeling wasn't possible and there is a data reference with an
         unknown misalignment that does not satisfy vect_supportable_dr_alignment
@@ -1054,22 +1528,63 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
      TODO: Use a cost model.  */
 
   for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
-    if (!DR_IS_READ (dr) && !aligned_access_p (dr))
-      {
-       dr0 = dr;
-       do_peeling = true;
-       break;
-      }
+    {
+      stmt = DR_STMT (dr);
+      stmt_info = vinfo_for_stmt (stmt);
+
+      /* For interleaving, only the alignment of the first access
+         matters.  */
+      if (DR_GROUP_FIRST_DR (stmt_info)
+          && DR_GROUP_FIRST_DR (stmt_info) != stmt)
+        continue;
+
+      if (!DR_IS_READ (dr) && !aligned_access_p (dr))
+        {
+         if (DR_GROUP_FIRST_DR (stmt_info))
+           {
+             /* For interleaved access we peel only if number of iterations in
+                the prolog loop ({VF - misalignment}), is a multiple of the
+                number of the interleaved accesses.  */
+             int elem_size, mis_in_elements;
+             tree vectype = STMT_VINFO_VECTYPE (stmt_info);
+             int nelements = TYPE_VECTOR_SUBPARTS (vectype);
+
+             /* FORNOW: handle only known alignment.  */
+             if (!known_alignment_for_access_p (dr))
+               {
+                 do_peeling = false;
+                 break;
+               }
+
+             elem_size = UNITS_PER_SIMD_WORD / nelements;
+             mis_in_elements = DR_MISALIGNMENT (dr) / elem_size;
+
+             if ((nelements - mis_in_elements) % DR_GROUP_SIZE (stmt_info))
+               {
+                 do_peeling = false;
+                 break;
+               }
+           }
+         dr0 = dr;
+         do_peeling = true;
+         break;
+       }
+    }
 
   /* Often peeling for alignment will require peeling for loop-bound, which in 
      turn requires that we know how to adjust the loop ivs after the loop.  */
-  if (!vect_can_advance_ivs_p (loop_vinfo))
+  if (!vect_can_advance_ivs_p (loop_vinfo)
+      || !slpeel_can_duplicate_loop_p (loop, single_exit (loop)))
     do_peeling = false;
 
   if (do_peeling)
     {
       int mis;
       int npeel = 0;
+      tree stmt = DR_STMT (dr0);
+      stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+      tree vectype = STMT_VINFO_VECTYPE (stmt_info);
+      int nelements = TYPE_VECTOR_SUBPARTS (vectype);
 
       if (known_alignment_for_access_p (dr0))
         {
@@ -1079,7 +1594,17 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
              factor minus the misalignment as an element count.  */
           mis = DR_MISALIGNMENT (dr0);
           mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0))));
-          npeel = LOOP_VINFO_VECT_FACTOR (loop_vinfo) - mis;
+          npeel = nelements - mis;
+
+         /* For interleaved data access every iteration accesses all the 
+            members of the group, therefore we divide the number of iterations
+            by the group size.  */
+         stmt_info = vinfo_for_stmt (DR_STMT (dr0));     
+         if (DR_GROUP_FIRST_DR (stmt_info))
+           npeel /= DR_GROUP_SIZE (stmt_info);
+
+          if (vect_print_dump_info (REPORT_DETAILS))
+            fprintf (vect_dump, "Try peeling by %d", npeel);
         }
 
       /* Ensure that all data refs can be vectorized after the peel.  */
@@ -1090,10 +1615,18 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
          if (dr == dr0)
            continue;
 
+         stmt = DR_STMT (dr);
+         stmt_info = vinfo_for_stmt (stmt);
+         /* For interleaving, only the alignment of the first access
+            matters.  */
+         if (DR_GROUP_FIRST_DR (stmt_info)
+             && DR_GROUP_FIRST_DR (stmt_info) != stmt)
+           continue;
+
          save_misalignment = DR_MISALIGNMENT (dr);
          vect_update_misalignment_for_peel (dr, dr0, npeel);
          supportable_dr_alignment = vect_supportable_dr_alignment (dr);
-         DR_MISALIGNMENT (dr) = save_misalignment;
+         SET_DR_MISALIGNMENT (dr, save_misalignment);
          
          if (!supportable_dr_alignment)
            {
@@ -1117,7 +1650,7 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
 
           LOOP_VINFO_UNALIGNED_DR (loop_vinfo) = dr0;
           LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) = DR_MISALIGNMENT (dr0);
-          DR_MISALIGNMENT (dr0) = 0;
+         SET_DR_MISALIGNMENT (dr0, 0);
          if (vect_print_dump_info (REPORT_ALIGNMENT))
             fprintf (vect_dump, "Alignment of access forced using peeling.");
 
@@ -1147,10 +1680,17 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
     {
       for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
         {
-          if (aligned_access_p (dr))
-            continue;
+         stmt = DR_STMT (dr);
+         stmt_info = vinfo_for_stmt (stmt);
+
+         /* For interleaving, only the alignment of the first access
+            matters.  */
+         if (aligned_access_p (dr)
+             || (DR_GROUP_FIRST_DR (stmt_info)
+                 && DR_GROUP_FIRST_DR (stmt_info) != stmt))
+           continue;
 
-          supportable_dr_alignment = vect_supportable_dr_alignment (dr);
+         supportable_dr_alignment = vect_supportable_dr_alignment (dr);
 
           if (!supportable_dr_alignment)
             {
@@ -1211,7 +1751,7 @@ vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
         {
           stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
           dr = STMT_VINFO_DATA_REF (stmt_info);
-          DR_MISALIGNMENT (dr) = 0;
+         SET_DR_MISALIGNMENT (dr, 0);
          if (vect_print_dump_info (REPORT_ALIGNMENT))
             fprintf (vect_dump, "Alignment of access forced using versioning.");
         }
@@ -1267,14 +1807,183 @@ static bool
 vect_analyze_data_ref_access (struct data_reference *dr)
 {
   tree step = DR_STEP (dr);
+  HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step);
   tree scalar_type = TREE_TYPE (DR_REF (dr));
+  HOST_WIDE_INT type_size = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (scalar_type));
+  tree stmt = DR_STMT (dr);
+  /* For interleaving, STRIDE is STEP counted in elements, i.e., the size of the 
+     interleaving group (including gaps).  */
+  HOST_WIDE_INT stride = dr_step / type_size;
 
-  if (!step || tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)))
+  if (!step)
     {
       if (vect_print_dump_info (REPORT_DETAILS))
+       fprintf (vect_dump, "bad data-ref access");
+      return false;
+    }
+
+  /* Consecutive?  */
+  if (!tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)))
+    {
+      /* Mark that it is not interleaving.  */
+      DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = NULL_TREE;
+      return true;
+    }
+
+  /* Not consecutive access is possible only if it is a part of interleaving.  */
+  if (!DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)))
+    {
+      /* Check if it this DR is a part of interleaving, and is a single
+        element of the group that is accessed in the loop.  */
+      
+      /* Gaps are supported only for loads. STEP must be a multiple of the type
+        size.  The size of the group must be a power of 2.  */
+      if (DR_IS_READ (dr)
+         && (dr_step % type_size) == 0
+         && stride > 0
+         && exact_log2 (stride) != -1)
+       {
+         DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = stmt;
+         DR_GROUP_SIZE (vinfo_for_stmt (stmt)) = stride;
+         if (vect_print_dump_info (REPORT_DR_DETAILS))
+           {
+             fprintf (vect_dump, "Detected single element interleaving %d ",
+                      DR_GROUP_SIZE (vinfo_for_stmt (stmt)));
+             print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM);
+             fprintf (vect_dump, " step ");
+             print_generic_expr (vect_dump, step, TDF_SLIM);
+           }
+         return true;
+       }
+      if (vect_print_dump_info (REPORT_DETAILS))
        fprintf (vect_dump, "not consecutive access");
       return false;
     }
+
+  if (DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) == stmt)
+    {
+      /* First stmt in the interleaving chain. Check the chain.  */
+      tree next = DR_GROUP_NEXT_DR (vinfo_for_stmt (stmt));
+      struct data_reference *data_ref = dr;
+      unsigned int count = 1;
+      tree next_step;
+      tree prev_init = DR_INIT (data_ref);
+      tree prev = stmt;
+      HOST_WIDE_INT diff, count_in_bytes;
+
+      while (next)
+       {
+         /* Skip same data-refs. In case that two or more stmts share data-ref
+            (supported only for loads), we vectorize only the first stmt, and
+            the rest get their vectorized loads from the first one.  */
+         if (!tree_int_cst_compare (DR_INIT (data_ref),
+                                    DR_INIT (STMT_VINFO_DATA_REF (
+                                                     vinfo_for_stmt (next)))))
+           {
+              if (!DR_IS_READ (data_ref))
+                { 
+                  if (vect_print_dump_info (REPORT_DETAILS))
+                    fprintf (vect_dump, "Two store stmts share the same dr.");
+                  return false; 
+                }
+
+              /* Check that there is no load-store dependencies for this loads 
+                 to prevent a case of load-store-load to the same location.  */
+              if (DR_GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (next))
+                  || DR_GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (prev)))
+                {
+                  if (vect_print_dump_info (REPORT_DETAILS))
+                    fprintf (vect_dump, 
+                             "READ_WRITE dependence in interleaving.");
+                  return false;
+                }
+
+             /* For load use the same data-ref load.  */
+             DR_GROUP_SAME_DR_STMT (vinfo_for_stmt (next)) = prev;
+
+             prev = next;
+             next = DR_GROUP_NEXT_DR (vinfo_for_stmt (next));
+             continue;
+           }
+         prev = next;
+
+         /* Check that all the accesses have the same STEP.  */
+         next_step = DR_STEP (STMT_VINFO_DATA_REF (vinfo_for_stmt (next)));
+         if (tree_int_cst_compare (step, next_step))
+           {
+             if (vect_print_dump_info (REPORT_DETAILS))
+               fprintf (vect_dump, "not consecutive access in interleaving");
+             return false;
+           }
+
+         data_ref = STMT_VINFO_DATA_REF (vinfo_for_stmt (next));
+         /* Check that the distance between two accesses is equal to the type
+            size. Otherwise, we have gaps.  */
+         diff = (TREE_INT_CST_LOW (DR_INIT (data_ref)) 
+                 - TREE_INT_CST_LOW (prev_init)) / type_size;
+         if (!DR_IS_READ (data_ref) && diff != 1)
+           {
+             if (vect_print_dump_info (REPORT_DETAILS))
+               fprintf (vect_dump, "interleaved store with gaps");
+             return false;
+           }
+         /* Store the gap from the previous member of the group. If there is no
+             gap in the access, DR_GROUP_GAP is always 1.  */
+         DR_GROUP_GAP (vinfo_for_stmt (next)) = diff;
+
+         prev_init = DR_INIT (data_ref);
+         next = DR_GROUP_NEXT_DR (vinfo_for_stmt (next));
+         /* Count the number of data-refs in the chain.  */
+         count++;
+       }
+
+      /* COUNT is the number of accesses found, we multiply it by the size of 
+        the type to get COUNT_IN_BYTES.  */
+      count_in_bytes = type_size * count;
+
+      /* Check that the size of the interleaving is not greater than STEP.  */
+      if (dr_step < count_in_bytes) 
+       {
+         if (vect_print_dump_info (REPORT_DETAILS))
+           {
+             fprintf (vect_dump, "interleaving size is greater than step for ");
+             print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM); 
+           }
+         return false;
+       }
+
+      /* Check that the size of the interleaving is equal to STEP for stores, 
+         i.e., that there are no gaps.  */ 
+      if (!DR_IS_READ (dr) && dr_step != count_in_bytes) 
+       {
+         if (vect_print_dump_info (REPORT_DETAILS))
+           fprintf (vect_dump, "interleaved store with gaps");
+         return false;
+       }
+
+      /* Check that STEP is a multiple of type size.  */
+      if ((dr_step % type_size) != 0)
+       {
+         if (vect_print_dump_info (REPORT_DETAILS)) 
+            {
+              fprintf (vect_dump, "step is not a multiple of type size: step ");
+              print_generic_expr (vect_dump, step, TDF_SLIM);
+              fprintf (vect_dump, " size ");
+              print_generic_expr (vect_dump, TYPE_SIZE_UNIT (scalar_type),
+                                  TDF_SLIM);
+            }
+         return false;
+       }
+
+      /* FORNOW: we handle only interleaving that is a power of 2.  */
+      if (exact_log2 (stride) == -1)
+       {
+         if (vect_print_dump_info (REPORT_DETAILS))
+           fprintf (vect_dump, "interleaving is not a power of 2");
+         return false;
+       }
+      DR_GROUP_SIZE (vinfo_for_stmt (stmt)) = stride;
+    }
   return true;
 }
 
@@ -1334,9 +2043,9 @@ vect_analyze_data_refs (loop_vec_info loop_vinfo)
   tree scalar_type;
 
   if (vect_print_dump_info (REPORT_DETAILS))
-    fprintf (vect_dump, "=== vect_analyze_data_refs ===");
+    fprintf (vect_dump, "=== vect_analyze_data_refs ===\n");
 
-  compute_data_dependences_for_loop (loop, false,
+  compute_data_dependences_for_loop (loop, true,
                                      &LOOP_VINFO_DATAREFS (loop_vinfo),
                                      &LOOP_VINFO_DDRS (loop_vinfo));
 
@@ -1359,7 +2068,7 @@ vect_analyze_data_refs (loop_vec_info loop_vinfo)
       /* Update DR field in stmt_vec_info struct.  */
       stmt = DR_STMT (dr);
       stmt_info = vinfo_for_stmt (stmt);
-  
+
       if (STMT_VINFO_DATA_REF (stmt_info))
         {
           if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
@@ -1383,7 +2092,16 @@ vect_analyze_data_refs (loop_vec_info loop_vinfo)
             }
           return false;
         }
-      if (!DR_MEMTAG (dr))
+
+      if (TREE_CODE (DR_BASE_ADDRESS (dr)) == INTEGER_CST)
+        {
+          if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
+            fprintf (vect_dump, "not vectorized: base addr of dr is a "
+                     "constant");
+          return false;
+        }
+
+      if (!DR_SYMBOL_TAG (dr))
         {
           if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
             {
@@ -1423,14 +2141,14 @@ vect_analyze_data_refs (loop_vec_info loop_vinfo)
 
 static void
 vect_mark_relevant (VEC(tree,heap) **worklist, tree stmt,
-                   bool relevant_p, bool live_p)
+                   enum vect_relevant relevant, bool live_p)
 {
   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
-  bool save_relevant_p = STMT_VINFO_RELEVANT_P (stmt_info);
+  enum vect_relevant save_relevant = STMT_VINFO_RELEVANT (stmt_info);
   bool save_live_p = STMT_VINFO_LIVE_P (stmt_info);
 
   if (vect_print_dump_info (REPORT_DETAILS))
-    fprintf (vect_dump, "mark relevant %d, live %d.",relevant_p, live_p);
+    fprintf (vect_dump, "mark relevant %d, live %d.", relevant, live_p);
 
   if (STMT_VINFO_IN_PATTERN_P (stmt_info))
     {
@@ -1445,20 +2163,16 @@ vect_mark_relevant (VEC(tree,heap) **worklist, tree stmt,
       pattern_stmt = STMT_VINFO_RELATED_STMT (stmt_info);
       stmt_info = vinfo_for_stmt (pattern_stmt);
       gcc_assert (STMT_VINFO_RELATED_STMT (stmt_info) == stmt);
-      save_relevant_p = STMT_VINFO_RELEVANT_P (stmt_info);
+      save_relevant = STMT_VINFO_RELEVANT (stmt_info);
       save_live_p = STMT_VINFO_LIVE_P (stmt_info);
       stmt = pattern_stmt;
     }
 
   STMT_VINFO_LIVE_P (stmt_info) |= live_p;
-  STMT_VINFO_RELEVANT_P (stmt_info) |= relevant_p;
+  if (relevant > STMT_VINFO_RELEVANT (stmt_info))
+    STMT_VINFO_RELEVANT (stmt_info) = relevant;
 
-  if (TREE_CODE (stmt) == PHI_NODE)
-    /* Don't put phi-nodes in the worklist. Phis that are marked relevant
-       or live will fail vectorization later on.  */
-    return;
-
-  if (STMT_VINFO_RELEVANT_P (stmt_info) == save_relevant_p
+  if (STMT_VINFO_RELEVANT (stmt_info) == save_relevant
       && STMT_VINFO_LIVE_P (stmt_info) == save_live_p)
     {
       if (vect_print_dump_info (REPORT_DETAILS))
@@ -1484,7 +2198,7 @@ vect_mark_relevant (VEC(tree,heap) **worklist, tree stmt,
 
 static bool
 vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo,
-                     bool *relevant_p, bool *live_p)
+                     enum vect_relevant *relevant, bool *live_p)
 {
   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
   ssa_op_iter op_iter;
@@ -1492,12 +2206,12 @@ vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo,
   use_operand_p use_p;
   def_operand_p def_p;
 
-  *relevant_p = false;
+  *relevant = vect_unused_in_loop;
   *live_p = false;
 
   /* cond stmt other than loop exit cond.  */
   if (is_ctrl_stmt (stmt) && (stmt != LOOP_VINFO_EXIT_COND (loop_vinfo)))
-    *relevant_p = true;
+    *relevant = vect_used_in_loop;
 
   /* changing memory.  */
   if (TREE_CODE (stmt) != PHI_NODE)
@@ -1505,7 +2219,7 @@ vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo,
       {
        if (vect_print_dump_info (REPORT_DETAILS))
          fprintf (vect_dump, "vec_stmt_relevant_p: stmt has vdefs.");
-       *relevant_p = true;
+       *relevant = vect_used_in_loop;
       }
 
   /* uses outside the loop.  */
@@ -1522,14 +2236,89 @@ vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo,
              /* We expect all such uses to be in the loop exit phis
                 (because of loop closed form)   */
              gcc_assert (TREE_CODE (USE_STMT (use_p)) == PHI_NODE);
-             gcc_assert (bb == loop->single_exit->dest);
+             gcc_assert (bb == single_exit (loop)->dest);
 
               *live_p = true;
            }
        }
     }
 
-  return (*live_p || *relevant_p);
+  return (*live_p || *relevant);
+}
+
+
+/* 
+   Function process_use.
+
+   Inputs:
+   - a USE in STMT in a loop represented by LOOP_VINFO
+   - LIVE_P, RELEVANT - enum values to be set in the STMT_VINFO of the stmt 
+     that defined USE. This is dont by calling mark_relevant and passing it
+     the WORKLIST (to add DEF_STMT to the WORKlist in case itis relevant). 
+
+   Outputs:
+   Generally, LIVE_P and RELEVANT are used to define the liveness and
+   relevance info of the DEF_STMT of this USE:
+       STMT_VINFO_LIVE_P (DEF_STMT_info) <-- live_p
+       STMT_VINFO_RELEVANT (DEF_STMT_info) <-- relevant
+   Exceptions:
+   - case 1: If USE is used only for address computations (e.g. array indexing),
+   which does not need to be directly vectorized, then the liveness/relevance 
+   of the respective DEF_STMT is left unchanged.
+   - case 2: If STMT is a reduction phi and DEF_STMT is a reduction stmt, we 
+   skip DEF_STMT cause it had already been processed.  
+
+   Return true if everything is as expected. Return false otherwise.  */
+
+static bool
+process_use (tree stmt, tree use, loop_vec_info loop_vinfo, bool live_p, 
+            enum vect_relevant relevant, VEC(tree,heap) **worklist)
+{
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt);
+  stmt_vec_info dstmt_vinfo;
+  basic_block def_bb;
+  tree def, def_stmt;
+  enum vect_def_type dt;
+
+  /* case 1: we are only interested in uses that need to be vectorized.  Uses 
+     that are used for address computation are not considered relevant.  */
+  if (!exist_non_indexing_operands_for_use_p (use, stmt))
+     return true;
+
+  if (!vect_is_simple_use (use, loop_vinfo, &def_stmt, &def, &dt))
+    { 
+      if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
+        fprintf (vect_dump, "not vectorized: unsupported use in stmt.");
+      return false;
+    }
+
+  if (!def_stmt || IS_EMPTY_STMT (def_stmt))
+    return true;
+
+  def_bb = bb_for_stmt (def_stmt);
+  if (!flow_bb_inside_loop_p (loop, def_bb))
+    return true;
+
+  /* case 2: A reduction phi defining a reduction stmt (DEF_STMT). DEF_STMT 
+     must have already been processed, so we just check that everything is as 
+     expected, and we are done.  */
+  dstmt_vinfo = vinfo_for_stmt (def_stmt);
+  if (TREE_CODE (stmt) == PHI_NODE
+      && STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def
+      && TREE_CODE (def_stmt) != PHI_NODE
+      && STMT_VINFO_DEF_TYPE (dstmt_vinfo) == vect_reduction_def)
+    {
+      if (STMT_VINFO_IN_PATTERN_P (dstmt_vinfo))
+       dstmt_vinfo = vinfo_for_stmt (STMT_VINFO_RELATED_STMT (dstmt_vinfo));
+      gcc_assert (STMT_VINFO_RELEVANT (dstmt_vinfo) < vect_used_by_reduction);
+      gcc_assert (STMT_VINFO_LIVE_P (dstmt_vinfo) 
+                 || STMT_VINFO_RELEVANT (dstmt_vinfo) > vect_unused_in_loop);
+      return true;
+    }
+
+  vect_mark_relevant (worklist, def_stmt, relevant, live_p);
+  return true;
 }
 
 
@@ -1557,16 +2346,14 @@ vect_mark_stmts_to_be_vectorized (loop_vec_info loop_vinfo)
   basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
   unsigned int nbbs = loop->num_nodes;
   block_stmt_iterator si;
-  tree stmt, use;
+  tree stmt;
   stmt_ann_t ann;
-  ssa_op_iter iter;
   unsigned int i;
   stmt_vec_info stmt_vinfo;
   basic_block bb;
   tree phi;
-  bool relevant_p, live_p;
-  tree def, def_stmt;
-  enum vect_def_type dt;
+  bool live_p;
+  enum vect_relevant relevant;
 
   if (vect_print_dump_info (REPORT_DETAILS))
     fprintf (vect_dump, "=== vect_mark_stmts_to_be_vectorized ===");
@@ -1574,145 +2361,110 @@ vect_mark_stmts_to_be_vectorized (loop_vec_info loop_vinfo)
   worklist = VEC_alloc (tree, heap, 64);
 
   /* 1. Init worklist.  */
-
-  bb = loop->header;
-  for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
-    {
-      if (vect_print_dump_info (REPORT_DETAILS))
-        {
-          fprintf (vect_dump, "init: phi relevant? ");
-          print_generic_expr (vect_dump, phi, TDF_SLIM);
-        }
-
-      if (vect_stmt_relevant_p (phi, loop_vinfo, &relevant_p, &live_p))
-       vect_mark_relevant (&worklist, phi, relevant_p, live_p);
-    }
-
   for (i = 0; i < nbbs; i++)
     {
       bb = bbs[i];
+      for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+       { 
+         if (vect_print_dump_info (REPORT_DETAILS))
+           {
+             fprintf (vect_dump, "init: phi relevant? ");
+             print_generic_expr (vect_dump, phi, TDF_SLIM);
+           }
+
+         if (vect_stmt_relevant_p (phi, loop_vinfo, &relevant, &live_p))
+           vect_mark_relevant (&worklist, phi, relevant, live_p);
+       }
       for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
        {
          stmt = bsi_stmt (si);
-
          if (vect_print_dump_info (REPORT_DETAILS))
            {
              fprintf (vect_dump, "init: stmt relevant? ");
              print_generic_expr (vect_dump, stmt, TDF_SLIM);
            } 
 
-         if (vect_stmt_relevant_p (stmt, loop_vinfo, &relevant_p, &live_p))
-            vect_mark_relevant (&worklist, stmt, relevant_p, live_p);
+         if (vect_stmt_relevant_p (stmt, loop_vinfo, &relevant, &live_p))
+            vect_mark_relevant (&worklist, stmt, relevant, live_p);
        }
     }
 
-
   /* 2. Process_worklist */
-
   while (VEC_length (tree, worklist) > 0)
     {
-      stmt = VEC_pop (tree, worklist);
+      use_operand_p use_p;
+      ssa_op_iter iter;
 
+      stmt = VEC_pop (tree, worklist);
       if (vect_print_dump_info (REPORT_DETAILS))
        {
           fprintf (vect_dump, "worklist: examine stmt: ");
           print_generic_expr (vect_dump, stmt, TDF_SLIM);
        }
 
-      /* Examine the USEs of STMT. For each ssa-name USE thta is defined
-         in the loop, mark the stmt that defines it (DEF_STMT) as
-         relevant/irrelevant and live/dead according to the liveness and
-         relevance properties of STMT.
-       */
-
-      gcc_assert (TREE_CODE (stmt) != PHI_NODE);
-
+      /* Examine the USEs of STMT. For each USE, mark the stmt that defines it 
+        (DEF_STMT) as relevant/irrelevant and live/dead according to the 
+        liveness and relevance properties of STMT.  */
       ann = stmt_ann (stmt);
       stmt_vinfo = vinfo_for_stmt (stmt);
-
-      relevant_p = STMT_VINFO_RELEVANT_P (stmt_vinfo);
+      relevant = STMT_VINFO_RELEVANT (stmt_vinfo);
       live_p = STMT_VINFO_LIVE_P (stmt_vinfo);
 
       /* Generally, the liveness and relevance properties of STMT are
-         propagated to the DEF_STMTs of its USEs:
-             STMT_VINFO_LIVE_P (DEF_STMT_info) <-- live_p
-             STMT_VINFO_RELEVANT_P (DEF_STMT_info) <-- relevant_p
-
-         Exceptions:
-
-        (case 1)
-           If USE is used only for address computations (e.g. array indexing),
-           which does not need to be directly vectorized, then the
-           liveness/relevance of the respective DEF_STMT is left unchanged.
-
-        (case 2)
-           If STMT has been identified as defining a reduction variable, then
-          we have two cases:
-          (case 2.1)
-            The last use of STMT is the reduction-variable, which is defined
-            by a loop-header-phi. We don't want to mark the phi as live or
-            relevant (because it does not need to be vectorized, it is handled
-             as part of the vectorization of the reduction), so in this case we
-            skip the call to vect_mark_relevant.
-          (case 2.2)
-            The rest of the uses of STMT are defined in the loop body. For
-             the def_stmt of these uses we want to set liveness/relevance
-             as follows:
-               STMT_VINFO_LIVE_P (DEF_STMT_info) <-- false
-               STMT_VINFO_RELEVANT_P (DEF_STMT_info) <-- true
-             because even though STMT is classified as live (since it defines a
-             value that is used across loop iterations) and irrelevant (since it
-             is not used inside the loop), it will be vectorized, and therefore
-             the corresponding DEF_STMTs need to marked as relevant.
-       */
-
-      /* case 2.2:  */
+        propagated as is to the DEF_STMTs of its USEs:
+         live_p <-- STMT_VINFO_LIVE_P (STMT_VINFO)
+         relevant <-- STMT_VINFO_RELEVANT (STMT_VINFO)
+
+        One exception is when STMT has been identified as defining a reduction
+        variable; in this case we set the liveness/relevance as follows:
+          live_p = false
+          relevant = vect_used_by_reduction
+        This is because we distinguish between two kinds of relevant stmts -
+        those that are used by a reduction computation, and those that are 
+        (also) used by a regular computation. This allows us later on to 
+        identify stmts that are used solely by a reduction, and therefore the 
+        order of the results that they produce does not have to be kept.
+
+         Reduction phis are expected to be used by a reduction stmt;  Other 
+        reduction stmts are expected to be unused in the loop.  These are the 
+        expected values of "relevant" for reduction phis/stmts in the loop:
+
+        relevance:                             phi     stmt
+        vect_unused_in_loop                            ok
+        vect_used_by_reduction                 ok
+        vect_used_in_loop                                                */
+
       if (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def)
         {
-          gcc_assert (!relevant_p && live_p);
-          relevant_p = true;
-          live_p = false;
-        }
+         switch (relevant)
+           {
+           case vect_unused_in_loop:
+             gcc_assert (TREE_CODE (stmt) != PHI_NODE);
+             break;
+           case vect_used_by_reduction:
+             if (TREE_CODE (stmt) == PHI_NODE)
+               break;
+           case vect_used_in_loop:
+           default:
+             if (vect_print_dump_info (REPORT_DETAILS))
+               fprintf (vect_dump, "unsupported use of reduction.");
+             VEC_free (tree, heap, worklist);
+             return false;
+           }
+         relevant = vect_used_by_reduction;
+         live_p = false;       
+       }
 
-      FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
+      FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE)
        {
-         /* case 1: we are only interested in uses that need to be vectorized. 
-            Uses that are used for address computation are not considered 
-            relevant.
-          */
-         if (!exist_non_indexing_operands_for_use_p (use, stmt))
-           continue;
-
-         if (!vect_is_simple_use (use, loop_vinfo, &def_stmt, &def, &dt))
-            {
-              if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
-                fprintf (vect_dump, "not vectorized: unsupported use in stmt.");
+         tree op = USE_FROM_PTR (use_p);
+         if (!process_use (stmt, op, loop_vinfo, live_p, relevant, &worklist))
+           {
              VEC_free (tree, heap, worklist);
-              return false;
-            }
-
-         if (!def_stmt || IS_EMPTY_STMT (def_stmt))
-           continue;
-
-          if (vect_print_dump_info (REPORT_DETAILS))
-            {
-              fprintf (vect_dump, "worklist: examine use %d: ", i);
-              print_generic_expr (vect_dump, use, TDF_SLIM);
-            }
-
-         bb = bb_for_stmt (def_stmt);
-          if (!flow_bb_inside_loop_p (loop, bb))
-            continue;
-
-         /* case 2.1: the reduction-use does not mark the defining-phi
-            as relevant.  */
-         if (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def
-             && TREE_CODE (def_stmt) == PHI_NODE)
-           continue;
-
-         vect_mark_relevant (&worklist, def_stmt, relevant_p, live_p);
+             return false;
+           }
        }
-    }                          /* while worklist */
+    } /* while worklist */
 
   VEC_free (tree, heap, worklist);
   return true;
@@ -1738,7 +2490,7 @@ vect_can_advance_ivs_p (loop_vec_info loop_vinfo)
   /* Analyze phi functions of the loop header.  */
 
   if (vect_print_dump_info (REPORT_DETAILS))
-    fprintf (vect_dump, "=== vect_can_advance_ivs_p ===");
+    fprintf (vect_dump, "vect_can_advance_ivs_p:");
 
   for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
     {
@@ -1823,7 +2575,7 @@ vect_get_loop_niters (struct loop *loop, tree *number_of_iterations)
   if (vect_print_dump_info (REPORT_DETAILS))
     fprintf (vect_dump, "=== get_loop_niters ===");
 
-  niters = number_of_iterations_in_loop (loop);
+  niters = number_of_exit_cond_executions (loop);
 
   if (niters != NULL_TREE
       && niters != chrec_dont_know)
@@ -1868,13 +2620,13 @@ vect_analyze_loop_form (struct loop *loop)
       return NULL;
     }
   
-  if (!loop->single_exit 
+  if (!single_exit (loop) 
       || loop->num_nodes != 2
       || EDGE_COUNT (loop->header->preds) != 2)
     {
       if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
         {
-          if (!loop->single_exit)
+          if (!single_exit (loop))
             fprintf (vect_dump, "not vectorized: multiple exits.");
           else if (loop->num_nodes != 2)
             fprintf (vect_dump, "not vectorized: too many BBs in loop.");
@@ -1889,7 +2641,8 @@ vect_analyze_loop_form (struct loop *loop)
      that the loop is represented as a do-while (with a proper if-guard
      before the loop if needed), where the loop header contains all the
      executable statements, and the latch is empty.  */
-  if (!empty_block_p (loop->latch))
+  if (!empty_block_p (loop->latch)
+        || phi_nodes (loop->latch))
     {
       if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
         fprintf (vect_dump, "not vectorized: unexpected loop form.");
@@ -1897,9 +2650,9 @@ vect_analyze_loop_form (struct loop *loop)
     }
 
   /* Make sure there exists a single-predecessor exit bb:  */
-  if (!single_pred_p (loop->single_exit->dest))
+  if (!single_pred_p (single_exit (loop)->dest))
     {
-      edge e = loop->single_exit;
+      edge e = single_exit (loop);
       if (!(e->flags & EDGE_ABNORMAL))
        {
          split_loop_exit_edge (e);
@@ -1944,10 +2697,7 @@ vect_analyze_loop_form (struct loop *loop)
       return false;
     }
 
-  loop_vinfo = new_loop_vec_info (loop);
-  LOOP_VINFO_NITERS (loop_vinfo) = number_of_iterations;
-
-  if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
+  if (!NITERS_KNOWN_P (number_of_iterations))
     {
       if (vect_print_dump_info (REPORT_DETAILS))
         {
@@ -1955,16 +2705,19 @@ vect_analyze_loop_form (struct loop *loop)
           print_generic_expr (vect_dump, number_of_iterations, TDF_DETAILS);
         }
     }
-  else
-  if (LOOP_VINFO_INT_NITERS (loop_vinfo) == 0)
+  else if (TREE_INT_CST_LOW (number_of_iterations) == 0)
     {
       if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
         fprintf (vect_dump, "not vectorized: number of iterations = 0.");
       return NULL;
     }
 
+  loop_vinfo = new_loop_vec_info (loop);
+  LOOP_VINFO_NITERS (loop_vinfo) = number_of_iterations;
   LOOP_VINFO_EXIT_COND (loop_vinfo) = loop_cond;
 
+  gcc_assert (!loop->aux);
+  loop->aux = loop_vinfo;
   return loop_vinfo;
 }