* tree-vect-loop-manip.c: New file.

	* tree-vectorizer.c: Update documentation and included files.
	(vect_loop_location): Make extern.
	(rename_use_op): Move to tree-vect-loop-manip.c
	(rename_variables_in_bb, rename_variables_in_loop, 
	slpeel_update_phis_for_duplicate_loop, 
	slpeel_update_phi_nodes_for_guard1,
	slpeel_update_phi_nodes_for_guard2, slpeel_make_loop_iterate_ntimes,
	slpeel_tree_duplicate_loop_to_edge_cfg, slpeel_add_loop_guard,
	slpeel_can_duplicate_loop_p, slpeel_verify_cfg_after_peeling,
	set_prologue_iterations, slpeel_tree_peel_loop_to_edge, 
	find_loop_location): Likewise.
	(new_stmt_vec_info): Move to tree-vect-stmts.c.
	(init_stmt_vec_info_vec, free_stmt_vec_info_vec, free_stmt_vec_info,
	get_vectype_for_scalar_type, vect_is_simple_use,
	supportable_widening_operation, supportable_narrowing_operation):
	Likewise.
	(bb_in_loop_p): Move to tree-vect-loop.c.
	(new_loop_vec_info, destroy_loop_vec_info, 
	reduction_code_for_scalar_code, report_vect_op, 
	vect_is_simple_reduction, vect_is_simple_iv_evolution): Likewise.
	(vect_can_force_dr_alignment_p): Move to tree-vect-data-refs.c.
	(vect_supportable_dr_alignment): Likewise.
	* tree-vectorizer.h (tree-data-ref.h): Include.
	(vect_loop_location): Declare.
	Reorganize function declarations according to the new file structure.
	* tree-vect-loop.c: New file.
	* tree-vect-analyze.c: Remove. Move functions to tree-vect-data-refs.c, 
	tree-vect-stmts.c, tree-vect-slp.c, tree-vect-loop.c.
	* tree-vect-data-refs.c: New file.
	* tree-vect-patterns.c (timevar.h): Don't include.
	* tree-vect-stmts.c: New file.
	* tree-vect-transform.c: Remove. Move functions to tree-vect-stmts.c, 
	tree-vect-slp.c, tree-vect-loop.c.
	* Makefile.in (OBJS-common): Remove tree-vect-analyze.o and 
	tree-vect-transform.o. Add tree-vect-data-refs.o, tree-vect-stmts.o, 
	tree-vect-loop.o, tree-vect-loop-manip.o, tree-vect-slp.o.
	(tree-vect-analyze.o): Remove.
	(tree-vect-transform.o): Likewise.
	(tree-vect-data-refs.o): Add rule.
	(tree-vect-stmts.o, tree-vect-loop.o, tree-vect-loop-manip.o, 
	tree-vect-slp.o): Likewise.
	(tree-vect-patterns.o): Remove redundant dependencies.
	(tree-vectorizer.o): Likewise.
	* tree-vect-slp.c: New file.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@145280 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 2363 insertions, 0 deletions

diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
new file mode 100644
index 00000000000..22d515fe29f
--- /dev/null
+++ b/gcc/tree-vect-loop-manip.c
@@ -0,0 +1,2363 @@
+/* Vectorizer Specific Loop Manipulations 
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software
+   Foundation, Inc.
+   Contributed by Dorit Naishlos <dorit@il.ibm.com> 
+   and Ira Rosen <irar@il.ibm.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "ggc.h"
+#include "tree.h"
+#include "basic-block.h"
+#include "diagnostic.h"
+#include "tree-flow.h"
+#include "tree-dump.h"
+#include "cfgloop.h"
+#include "cfglayout.h"
+#include "expr.h"
+#include "toplev.h"
+#include "tree-scalar-evolution.h"
+#include "tree-vectorizer.h"
+#include "langhooks.h"
+
+/*************************************************************************
+  Simple Loop Peeling Utilities
+
+  Utilities to support loop peeling for vectorization purposes.
+ *************************************************************************/
+
+
+/* Renames the use *OP_P.  */
+
+static void
+rename_use_op (use_operand_p op_p)
+{
+  tree new_name;
+
+  if (TREE_CODE (USE_FROM_PTR (op_p)) != SSA_NAME)
+    return;
+
+  new_name = get_current_def (USE_FROM_PTR (op_p));
+
+  /* Something defined outside of the loop.  */
+  if (!new_name)
+    return;
+
+  /* An ordinary ssa name defined in the loop.  */
+
+  SET_USE (op_p, new_name);
+}
+
+
+/* Renames the variables in basic block BB.  */
+
+void
+rename_variables_in_bb (basic_block bb)
+{
+  gimple_stmt_iterator gsi;
+  gimple stmt;
+  use_operand_p use_p;
+  ssa_op_iter iter;
+  edge e;
+  edge_iterator ei;
+  struct loop *loop = bb->loop_father;
+
+  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      stmt = gsi_stmt (gsi);
+      FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
+	rename_use_op (use_p);
+    }
+
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    {
+      if (!flow_bb_inside_loop_p (loop, e->dest))
+	continue;
+      for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
+        rename_use_op (PHI_ARG_DEF_PTR_FROM_EDGE (gsi_stmt (gsi), e));
+    }
+}
+
+
+/* Renames variables in new generated LOOP.  */
+
+void
+rename_variables_in_loop (struct loop *loop)
+{
+  unsigned i;
+  basic_block *bbs;
+
+  bbs = get_loop_body (loop);
+
+  for (i = 0; i < loop->num_nodes; i++)
+    rename_variables_in_bb (bbs[i]);
+
+  free (bbs);
+}
+
+
+/* Update the PHI nodes of NEW_LOOP.
+
+   NEW_LOOP is a duplicate of ORIG_LOOP.
+   AFTER indicates whether NEW_LOOP executes before or after ORIG_LOOP:
+   AFTER is true if NEW_LOOP executes after ORIG_LOOP, and false if it
+   executes before it.  */
+
+static void
+slpeel_update_phis_for_duplicate_loop (struct loop *orig_loop,
+				       struct loop *new_loop, bool after)
+{
+  tree new_ssa_name;
+  gimple phi_new, phi_orig;
+  tree def;
+  edge orig_loop_latch = loop_latch_edge (orig_loop);
+  edge orig_entry_e = loop_preheader_edge (orig_loop);
+  edge new_loop_exit_e = single_exit (new_loop);
+  edge new_loop_entry_e = loop_preheader_edge (new_loop);
+  edge entry_arg_e = (after ? orig_loop_latch : orig_entry_e);
+  gimple_stmt_iterator gsi_new, gsi_orig;
+
+  /*
+     step 1. For each loop-header-phi:
+             Add the first phi argument for the phi in NEW_LOOP
+            (the one associated with the entry of NEW_LOOP)
+
+     step 2. For each loop-header-phi:
+             Add the second phi argument for the phi in NEW_LOOP
+            (the one associated with the latch of NEW_LOOP)
+
+     step 3. Update the phis in the successor block of NEW_LOOP.
+
+        case 1: NEW_LOOP was placed before ORIG_LOOP:
+                The successor block of NEW_LOOP is the header of ORIG_LOOP.
+                Updating the phis in the successor block can therefore be done
+                along with the scanning of the loop header phis, because the
+                header blocks of ORIG_LOOP and NEW_LOOP have exactly the same
+                phi nodes, organized in the same order.
+
+        case 2: NEW_LOOP was placed after ORIG_LOOP:
+                The successor block of NEW_LOOP is the original exit block of 
+                ORIG_LOOP - the phis to be updated are the loop-closed-ssa phis.
+                We postpone updating these phis to a later stage (when
+                loop guards are added).
+   */
+
+
+  /* Scan the phis in the headers of the old and new loops
+     (they are organized in exactly the same order).  */
+
+  for (gsi_new = gsi_start_phis (new_loop->header),
+       gsi_orig = gsi_start_phis (orig_loop->header);
+       !gsi_end_p (gsi_new) && !gsi_end_p (gsi_orig);
+       gsi_next (&gsi_new), gsi_next (&gsi_orig))
+    {
+      phi_new = gsi_stmt (gsi_new);
+      phi_orig = gsi_stmt (gsi_orig);
+
+      /* step 1.  */
+      def = PHI_ARG_DEF_FROM_EDGE (phi_orig, entry_arg_e);
+      add_phi_arg (phi_new, def, new_loop_entry_e);
+
+      /* step 2.  */
+      def = PHI_ARG_DEF_FROM_EDGE (phi_orig, orig_loop_latch);
+      if (TREE_CODE (def) != SSA_NAME)
+        continue;
+
+      new_ssa_name = get_current_def (def);
+      if (!new_ssa_name)
+	{
+	  /* This only happens if there are no definitions
+	     inside the loop. use the phi_result in this case.  */
+	  new_ssa_name = PHI_RESULT (phi_new);
+	}
+
+      /* An ordinary ssa name defined in the loop.  */
+      add_phi_arg (phi_new, new_ssa_name, loop_latch_edge (new_loop));
+
+      /* step 3 (case 1).  */
+      if (!after)
+        {
+          gcc_assert (new_loop_exit_e == orig_entry_e);
+          SET_PHI_ARG_DEF (phi_orig,
+                           new_loop_exit_e->dest_idx,
+                           new_ssa_name);
+        }
+    }
+}
+
+
+/* Update PHI nodes for a guard of the LOOP.
+
+   Input:
+   - LOOP, GUARD_EDGE: LOOP is a loop for which we added guard code that
+        controls whether LOOP is to be executed.  GUARD_EDGE is the edge that
+        originates from the guard-bb, skips LOOP and reaches the (unique) exit
+        bb of LOOP.  This loop-exit-bb is an empty bb with one successor.
+        We denote this bb NEW_MERGE_BB because before the guard code was added
+        it had a single predecessor (the LOOP header), and now it became a merge
+        point of two paths - the path that ends with the LOOP exit-edge, and
+        the path that ends with GUARD_EDGE.
+   - NEW_EXIT_BB: New basic block that is added by this function between LOOP
+        and NEW_MERGE_BB. It is used to place loop-closed-ssa-form exit-phis.
+
+   ===> The CFG before the guard-code was added:
+        LOOP_header_bb:
+          loop_body
+          if (exit_loop) goto update_bb
+          else           goto LOOP_header_bb
+        update_bb:
+
+   ==> The CFG after the guard-code was added:
+        guard_bb:
+          if (LOOP_guard_condition) goto new_merge_bb
+          else                      goto LOOP_header_bb
+        LOOP_header_bb:
+          loop_body
+          if (exit_loop_condition) goto new_merge_bb
+          else                     goto LOOP_header_bb
+        new_merge_bb:
+          goto update_bb
+        update_bb:
+
+   ==> The CFG after this function:
+        guard_bb:
+          if (LOOP_guard_condition) goto new_merge_bb
+          else                      goto LOOP_header_bb
+        LOOP_header_bb:
+          loop_body
+          if (exit_loop_condition) goto new_exit_bb
+          else                     goto LOOP_header_bb
+        new_exit_bb:
+        new_merge_bb:
+          goto update_bb
+        update_bb:
+
+   This function:
+   1. creates and updates the relevant phi nodes to account for the new
+      incoming edge (GUARD_EDGE) into NEW_MERGE_BB. This involves:
+      1.1. Create phi nodes at NEW_MERGE_BB.
+      1.2. Update the phi nodes at the successor of NEW_MERGE_BB (denoted
+           UPDATE_BB).  UPDATE_BB was the exit-bb of LOOP before NEW_MERGE_BB
+   2. preserves loop-closed-ssa-form by creating the required phi nodes
+      at the exit of LOOP (i.e, in NEW_EXIT_BB).
+
+   There are two flavors to this function:
+
+   slpeel_update_phi_nodes_for_guard1:
+     Here the guard controls whether we enter or skip LOOP, where LOOP is a
+     prolog_loop (loop1 below), and the new phis created in NEW_MERGE_BB are
+     for variables that have phis in the loop header.
+
+   slpeel_update_phi_nodes_for_guard2:
+     Here the guard controls whether we enter or skip LOOP, where LOOP is an
+     epilog_loop (loop2 below), and the new phis created in NEW_MERGE_BB are
+     for variables that have phis in the loop exit.
+
+   I.E., the overall structure is:
+
+        loop1_preheader_bb:
+                guard1 (goto loop1/merge1_bb)
+        loop1
+        loop1_exit_bb:
+                guard2 (goto merge1_bb/merge2_bb)
+        merge1_bb
+        loop2
+        loop2_exit_bb
+        merge2_bb
+        next_bb
+
+   slpeel_update_phi_nodes_for_guard1 takes care of creating phis in
+   loop1_exit_bb and merge1_bb. These are entry phis (phis for the vars
+   that have phis in loop1->header).
+
+   slpeel_update_phi_nodes_for_guard2 takes care of creating phis in
+   loop2_exit_bb and merge2_bb. These are exit phis (phis for the vars
+   that have phis in next_bb). It also adds some of these phis to
+   loop1_exit_bb.
+
+   slpeel_update_phi_nodes_for_guard1 is always called before
+   slpeel_update_phi_nodes_for_guard2. They are both needed in order
+   to create correct data-flow and loop-closed-ssa-form.
+
+   Generally slpeel_update_phi_nodes_for_guard1 creates phis for variables
+   that change between iterations of a loop (and therefore have a phi-node
+   at the loop entry), whereas slpeel_update_phi_nodes_for_guard2 creates
+   phis for variables that are used out of the loop (and therefore have 
+   loop-closed exit phis). Some variables may be both updated between 
+   iterations and used after the loop. This is why in loop1_exit_bb we
+   may need both entry_phis (created by slpeel_update_phi_nodes_for_guard1)
+   and exit phis (created by slpeel_update_phi_nodes_for_guard2).
+
+   - IS_NEW_LOOP: if IS_NEW_LOOP is true, then LOOP is a newly created copy of
+     an original loop. i.e., we have:
+
+           orig_loop
+           guard_bb (goto LOOP/new_merge)
+           new_loop <-- LOOP
+           new_exit
+           new_merge
+           next_bb
+
+     If IS_NEW_LOOP is false, then LOOP is an original loop, in which case we
+     have:
+
+           new_loop
+           guard_bb (goto LOOP/new_merge)
+           orig_loop <-- LOOP
+           new_exit
+           new_merge
+           next_bb
+
+     The SSA names defined in the original loop have a current
+     reaching definition that that records the corresponding new
+     ssa-name used in the new duplicated loop copy.
+  */
+
+/* Function slpeel_update_phi_nodes_for_guard1
+   
+   Input:
+   - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above.
+   - DEFS - a bitmap of ssa names to mark new names for which we recorded
+            information. 
+   
+   In the context of the overall structure, we have:
+
+        loop1_preheader_bb: 
+                guard1 (goto loop1/merge1_bb)
+LOOP->  loop1
+        loop1_exit_bb:
+                guard2 (goto merge1_bb/merge2_bb)
+        merge1_bb
+        loop2
+        loop2_exit_bb
+        merge2_bb
+        next_bb
+
+   For each name updated between loop iterations (i.e - for each name that has
+   an entry (loop-header) phi in LOOP) we create a new phi in:
+   1. merge1_bb (to account for the edge from guard1)
+   2. loop1_exit_bb (an exit-phi to keep LOOP in loop-closed form)
+*/
+
+static void
+slpeel_update_phi_nodes_for_guard1 (edge guard_edge, struct loop *loop,
+                                    bool is_new_loop, basic_block *new_exit_bb,
+                                    bitmap *defs)
+{
+  gimple orig_phi, new_phi;
+  gimple update_phi, update_phi2;
+  tree guard_arg, loop_arg;
+  basic_block new_merge_bb = guard_edge->dest;
+  edge e = EDGE_SUCC (new_merge_bb, 0);
+  basic_block update_bb = e->dest;
+  basic_block orig_bb = loop->header;
+  edge new_exit_e;
+  tree current_new_name;
+  tree name;
+  gimple_stmt_iterator gsi_orig, gsi_update;
+
+  /* Create new bb between loop and new_merge_bb.  */
+  *new_exit_bb = split_edge (single_exit (loop));
+
+  new_exit_e = EDGE_SUCC (*new_exit_bb, 0);
+
+  for (gsi_orig = gsi_start_phis (orig_bb),
+       gsi_update = gsi_start_phis (update_bb);
+       !gsi_end_p (gsi_orig) && !gsi_end_p (gsi_update);
+       gsi_next (&gsi_orig), gsi_next (&gsi_update))
+    {
+      orig_phi = gsi_stmt (gsi_orig);
+      update_phi = gsi_stmt (gsi_update);
+
+      /* Virtual phi; Mark it for renaming. We actually want to call
+	 mar_sym_for_renaming, but since all ssa renaming datastructures
+	 are going to be freed before we get to call ssa_update, we just
+	 record this name for now in a bitmap, and will mark it for
+	 renaming later.  */
+      name = PHI_RESULT (orig_phi);
+      if (!is_gimple_reg (SSA_NAME_VAR (name)))
+        bitmap_set_bit (vect_memsyms_to_rename, DECL_UID (SSA_NAME_VAR (name)));
+
+      /** 1. Handle new-merge-point phis  **/
+
+      /* 1.1. Generate new phi node in NEW_MERGE_BB:  */
+      new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+                                 new_merge_bb);
+
+      /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge
+            of LOOP. Set the two phi args in NEW_PHI for these edges:  */
+      loop_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, EDGE_SUCC (loop->latch, 0));
+      guard_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, loop_preheader_edge (loop));
+
+      add_phi_arg (new_phi, loop_arg, new_exit_e);
+      add_phi_arg (new_phi, guard_arg, guard_edge);
+
+      /* 1.3. Update phi in successor block.  */
+      gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == loop_arg
+                  || PHI_ARG_DEF_FROM_EDGE (update_phi, e) == guard_arg);
+      SET_PHI_ARG_DEF (update_phi, e->dest_idx, PHI_RESULT (new_phi));
+      update_phi2 = new_phi;
+
+
+      /** 2. Handle loop-closed-ssa-form phis  **/
+
+      if (!is_gimple_reg (PHI_RESULT (orig_phi)))
+	continue;
+
+      /* 2.1. Generate new phi node in NEW_EXIT_BB:  */
+      new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+                                 *new_exit_bb);
+
+      /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop.  */
+      add_phi_arg (new_phi, loop_arg, single_exit (loop));
+
+      /* 2.3. Update phi in successor of NEW_EXIT_BB:  */
+      gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg);
+      SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, PHI_RESULT (new_phi));
+
+      /* 2.4. Record the newly created name with set_current_def.
+         We want to find a name such that
+                name = get_current_def (orig_loop_name)
+         and to set its current definition as follows:
+                set_current_def (name, new_phi_name)
+
+         If LOOP is a new loop then loop_arg is already the name we're
+         looking for. If LOOP is the original loop, then loop_arg is
+         the orig_loop_name and the relevant name is recorded in its
+         current reaching definition.  */
+      if (is_new_loop)
+        current_new_name = loop_arg;
+      else
+        {
+          current_new_name = get_current_def (loop_arg);
+	  /* current_def is not available only if the variable does not
+	     change inside the loop, in which case we also don't care
+	     about recording a current_def for it because we won't be
+	     trying to create loop-exit-phis for it.  */
+	  if (!current_new_name)
+	    continue;
+        }
+      gcc_assert (get_current_def (current_new_name) == NULL_TREE);
+
+      set_current_def (current_new_name, PHI_RESULT (new_phi));
+      bitmap_set_bit (*defs, SSA_NAME_VERSION (current_new_name));
+    }
+}
+
+
+/* Function slpeel_update_phi_nodes_for_guard2
+
+   Input:
+   - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above.
+
+   In the context of the overall structure, we have:
+
+        loop1_preheader_bb: 
+                guard1 (goto loop1/merge1_bb)
+        loop1
+        loop1_exit_bb: 
+                guard2 (goto merge1_bb/merge2_bb)
+        merge1_bb
+LOOP->  loop2
+        loop2_exit_bb
+        merge2_bb
+        next_bb
+
+   For each name used out side the loop (i.e - for each name that has an exit
+   phi in next_bb) we create a new phi in:
+   1. merge2_bb (to account for the edge from guard_bb) 
+   2. loop2_exit_bb (an exit-phi to keep LOOP in loop-closed form)
+   3. guard2 bb (an exit phi to keep the preceding loop in loop-closed form),
+      if needed (if it wasn't handled by slpeel_update_phis_nodes_for_phi1).
+*/
+
+static void
+slpeel_update_phi_nodes_for_guard2 (edge guard_edge, struct loop *loop,
+                                    bool is_new_loop, basic_block *new_exit_bb)
+{
+  gimple orig_phi, new_phi;
+  gimple update_phi, update_phi2;
+  tree guard_arg, loop_arg;
+  basic_block new_merge_bb = guard_edge->dest;
+  edge e = EDGE_SUCC (new_merge_bb, 0);
+  basic_block update_bb = e->dest;
+  edge new_exit_e;
+  tree orig_def, orig_def_new_name;
+  tree new_name, new_name2;
+  tree arg;
+  gimple_stmt_iterator gsi;
+
+  /* Create new bb between loop and new_merge_bb.  */
+  *new_exit_bb = split_edge (single_exit (loop));
+
+  new_exit_e = EDGE_SUCC (*new_exit_bb, 0);
+
+  for (gsi = gsi_start_phis (update_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      update_phi = gsi_stmt (gsi);
+      orig_phi = update_phi;
+      orig_def = PHI_ARG_DEF_FROM_EDGE (orig_phi, e);
+      /* This loop-closed-phi actually doesn't represent a use
+         out of the loop - the phi arg is a constant.  */ 
+      if (TREE_CODE (orig_def) != SSA_NAME)
+        continue;
+      orig_def_new_name = get_current_def (orig_def);
+      arg = NULL_TREE;
+
+      /** 1. Handle new-merge-point phis  **/
+
+      /* 1.1. Generate new phi node in NEW_MERGE_BB:  */
+      new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+                                 new_merge_bb);
+
+      /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge
+            of LOOP. Set the two PHI args in NEW_PHI for these edges:  */
+      new_name = orig_def;
+      new_name2 = NULL_TREE;
+      if (orig_def_new_name)
+        {
+          new_name = orig_def_new_name;
+	  /* Some variables have both loop-entry-phis and loop-exit-phis.
+	     Such variables were given yet newer names by phis placed in
+	     guard_bb by slpeel_update_phi_nodes_for_guard1. I.e:
+	     new_name2 = get_current_def (get_current_def (orig_name)).  */
+          new_name2 = get_current_def (new_name);
+        }
+  
+      if (is_new_loop)
+        {
+          guard_arg = orig_def;
+          loop_arg = new_name;
+        }
+      else
+        {
+          guard_arg = new_name;
+          loop_arg = orig_def;
+        }
+      if (new_name2)
+        guard_arg = new_name2;
+  
+      add_phi_arg (new_phi, loop_arg, new_exit_e);
+      add_phi_arg (new_phi, guard_arg, guard_edge);
+
+      /* 1.3. Update phi in successor block.  */
+      gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == orig_def);
+      SET_PHI_ARG_DEF (update_phi, e->dest_idx, PHI_RESULT (new_phi));
+      update_phi2 = new_phi;
+
+
+      /** 2. Handle loop-closed-ssa-form phis  **/
+
+      /* 2.1. Generate new phi node in NEW_EXIT_BB:  */
+      new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+                                 *new_exit_bb);
+
+      /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop.  */
+      add_phi_arg (new_phi, loop_arg, single_exit (loop));
+
+      /* 2.3. Update phi in successor of NEW_EXIT_BB:  */
+      gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg);
+      SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, PHI_RESULT (new_phi));
+
+
+      /** 3. Handle loop-closed-ssa-form phis for first loop  **/
+
+      /* 3.1. Find the relevant names that need an exit-phi in
+	 GUARD_BB, i.e. names for which
+	 slpeel_update_phi_nodes_for_guard1 had not already created a
+	 phi node. This is the case for names that are used outside
+	 the loop (and therefore need an exit phi) but are not updated
+	 across loop iterations (and therefore don't have a
+	 loop-header-phi).
+
+	 slpeel_update_phi_nodes_for_guard1 is responsible for
+	 creating loop-exit phis in GUARD_BB for names that have a
+	 loop-header-phi.  When such a phi is created we also record
+	 the new name in its current definition.  If this new name
+	 exists, then guard_arg was set to this new name (see 1.2
+	 above).  Therefore, if guard_arg is not this new name, this
+	 is an indication that an exit-phi in GUARD_BB was not yet
+	 created, so we take care of it here.  */
+      if (guard_arg == new_name2)
+	continue;
+      arg = guard_arg;
+
+      /* 3.2. Generate new phi node in GUARD_BB:  */
+      new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+                                 guard_edge->src);
+
+      /* 3.3. GUARD_BB has one incoming edge:  */
+      gcc_assert (EDGE_COUNT (guard_edge->src->preds) == 1);
+      add_phi_arg (new_phi, arg, EDGE_PRED (guard_edge->src, 0));
+
+      /* 3.4. Update phi in successor of GUARD_BB:  */
+      gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, guard_edge)
+                                                                == guard_arg);
+      SET_PHI_ARG_DEF (update_phi2, guard_edge->dest_idx, PHI_RESULT (new_phi));
+    }
+}
+
+
+/* Make the LOOP iterate NITERS times. This is done by adding a new IV
+   that starts at zero, increases by one and its limit is NITERS.
+
+   Assumption: the exit-condition of LOOP is the last stmt in the loop.  */
+
+void
+slpeel_make_loop_iterate_ntimes (struct loop *loop, tree niters)
+{
+  tree indx_before_incr, indx_after_incr;
+  gimple cond_stmt;
+  gimple orig_cond;
+  edge exit_edge = single_exit (loop);
+  gimple_stmt_iterator loop_cond_gsi;
+  gimple_stmt_iterator incr_gsi;
+  bool insert_after;
+  tree init = build_int_cst (TREE_TYPE (niters), 0);
+  tree step = build_int_cst (TREE_TYPE (niters), 1);
+  LOC loop_loc;
+  enum tree_code code;
+
+  orig_cond = get_loop_exit_condition (loop);
+  gcc_assert (orig_cond);
+  loop_cond_gsi = gsi_for_stmt (orig_cond);
+
+  standard_iv_increment_position (loop, &incr_gsi, &insert_after);
+  create_iv (init, step, NULL_TREE, loop,
+             &incr_gsi, insert_after, &indx_before_incr, &indx_after_incr);
+
+  indx_after_incr = force_gimple_operand_gsi (&loop_cond_gsi, indx_after_incr,
+					      true, NULL_TREE, true,
+					      GSI_SAME_STMT);
+  niters = force_gimple_operand_gsi (&loop_cond_gsi, niters, true, NULL_TREE,
+				     true, GSI_SAME_STMT);
+
+  code = (exit_edge->flags & EDGE_TRUE_VALUE) ? GE_EXPR : LT_EXPR;
+  cond_stmt = gimple_build_cond (code, indx_after_incr, niters, NULL_TREE,
+				 NULL_TREE);
+
+  gsi_insert_before (&loop_cond_gsi, cond_stmt, GSI_SAME_STMT);
+
+  /* Remove old loop exit test:  */
+  gsi_remove (&loop_cond_gsi, true);
+
+  loop_loc = find_loop_location (loop);
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      if (loop_loc != UNKNOWN_LOC)
+        fprintf (dump_file, "\nloop at %s:%d: ",
+                 LOC_FILE (loop_loc), LOC_LINE (loop_loc));
+      print_gimple_stmt (dump_file, cond_stmt, 0, TDF_SLIM);
+    }
+
+  loop->nb_iterations = niters;
+}
+
+
+/* Given LOOP this function generates a new copy of it and puts it 
+   on E which is either the entry or exit of LOOP.  */
+
+struct loop *
+slpeel_tree_duplicate_loop_to_edge_cfg (struct loop *loop, edge e)
+{
+  struct loop *new_loop;
+  basic_block *new_bbs, *bbs;
+  bool at_exit;
+  bool was_imm_dom;
+  basic_block exit_dest; 
+  gimple phi;
+  tree phi_arg;
+  edge exit, new_exit;
+  gimple_stmt_iterator gsi;
+
+  at_exit = (e == single_exit (loop)); 
+  if (!at_exit && e != loop_preheader_edge (loop))
+    return NULL;
+
+  bbs = get_loop_body (loop);
+
+  /* Check whether duplication is possible.  */
+  if (!can_copy_bbs_p (bbs, loop->num_nodes))
+    {
+      free (bbs);
+      return NULL;
+    }
+
+  /* Generate new loop structure.  */
+  new_loop = duplicate_loop (loop, loop_outer (loop));
+  if (!new_loop)
+    {
+      free (bbs);
+      return NULL;
+    }
+
+  exit_dest = single_exit (loop)->dest;
+  was_imm_dom = (get_immediate_dominator (CDI_DOMINATORS, 
+					  exit_dest) == loop->header ? 
+		 true : false);
+
+  new_bbs = XNEWVEC (basic_block, loop->num_nodes);
+
+  exit = single_exit (loop);
+  copy_bbs (bbs, loop->num_nodes, new_bbs,
+	    &exit, 1, &new_exit, NULL,
+	    e->src);
+
+  /* Duplicating phi args at exit bbs as coming 
+     also from exit of duplicated loop.  */
+  for (gsi = gsi_start_phis (exit_dest); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      phi = gsi_stmt (gsi);
+      phi_arg = PHI_ARG_DEF_FROM_EDGE (phi, single_exit (loop));
+      if (phi_arg)
+	{
+	  edge new_loop_exit_edge;
+
+	  if (EDGE_SUCC (new_loop->header, 0)->dest == new_loop->latch)
+	    new_loop_exit_edge = EDGE_SUCC (new_loop->header, 1);
+	  else
+	    new_loop_exit_edge = EDGE_SUCC (new_loop->header, 0);
+  
+	  add_phi_arg (phi, phi_arg, new_loop_exit_edge);	
+	}
+    }    
+   
+  if (at_exit) /* Add the loop copy at exit.  */
+    {
+      redirect_edge_and_branch_force (e, new_loop->header);
+      PENDING_STMT (e) = NULL;
+      set_immediate_dominator (CDI_DOMINATORS, new_loop->header, e->src);
+      if (was_imm_dom)
+	set_immediate_dominator (CDI_DOMINATORS, exit_dest, new_loop->header);
+    }
+  else /* Add the copy at entry.  */
+    {
+      edge new_exit_e;
+      edge entry_e = loop_preheader_edge (loop);
+      basic_block preheader = entry_e->src;
+           
+      if (!flow_bb_inside_loop_p (new_loop, 
+				  EDGE_SUCC (new_loop->header, 0)->dest))
+        new_exit_e = EDGE_SUCC (new_loop->header, 0);
+      else
+	new_exit_e = EDGE_SUCC (new_loop->header, 1); 
+
+      redirect_edge_and_branch_force (new_exit_e, loop->header);
+      PENDING_STMT (new_exit_e) = NULL;
+      set_immediate_dominator (CDI_DOMINATORS, loop->header,
+			       new_exit_e->src);
+
+      /* We have to add phi args to the loop->header here as coming 
+	 from new_exit_e edge.  */
+      for (gsi = gsi_start_phis (loop->header);
+           !gsi_end_p (gsi);
+           gsi_next (&gsi))
+	{
+	  phi = gsi_stmt (gsi);
+	  phi_arg = PHI_ARG_DEF_FROM_EDGE (phi, entry_e);
+	  if (phi_arg)
+	    add_phi_arg (phi, phi_arg, new_exit_e);	
+	}    
+
+      redirect_edge_and_branch_force (entry_e, new_loop->header);
+      PENDING_STMT (entry_e) = NULL;
+      set_immediate_dominator (CDI_DOMINATORS, new_loop->header, preheader);
+    }
+
+  free (new_bbs);
+  free (bbs);
+
+  return new_loop;
+}
+
+
+/* Given the condition statement COND, put it as the last statement
+   of GUARD_BB; EXIT_BB is the basic block to skip the loop;
+   Assumes that this is the single exit of the guarded loop.  
+   Returns the skip edge.  */
+
+static edge
+slpeel_add_loop_guard (basic_block guard_bb, tree cond, basic_block exit_bb,
+		       basic_block dom_bb)
+{
+  gimple_stmt_iterator gsi;
+  edge new_e, enter_e;
+  gimple cond_stmt;
+  gimple_seq gimplify_stmt_list = NULL;
+
+  enter_e = EDGE_SUCC (guard_bb, 0);
+  enter_e->flags &= ~EDGE_FALLTHRU;
+  enter_e->flags |= EDGE_FALSE_VALUE;
+  gsi = gsi_last_bb (guard_bb);
+
+  cond = force_gimple_operand (cond, &gimplify_stmt_list, true, NULL_TREE);
+  cond_stmt = gimple_build_cond (NE_EXPR,
+				 cond, build_int_cst (TREE_TYPE (cond), 0),
+				 NULL_TREE, NULL_TREE);
+  if (gimplify_stmt_list)
+    gsi_insert_seq_after (&gsi, gimplify_stmt_list, GSI_NEW_STMT);
+
+  gsi = gsi_last_bb (guard_bb);
+  gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT);
+
+  /* Add new edge to connect guard block to the merge/loop-exit block.  */
+  new_e = make_edge (guard_bb, exit_bb, EDGE_TRUE_VALUE);
+  set_immediate_dominator (CDI_DOMINATORS, exit_bb, dom_bb);
+  return new_e;
+}
+
+
+/* This function verifies that the following restrictions apply to LOOP:
+   (1) it is innermost
+   (2) it consists of exactly 2 basic blocks - header, and an empty latch.
+   (3) it is single entry, single exit
+   (4) its exit condition is the last stmt in the header
+   (5) E is the entry/exit edge of LOOP.
+ */
+
+bool
+slpeel_can_duplicate_loop_p (const struct loop *loop, const_edge e)
+{
+  edge exit_e = single_exit (loop);
+  edge entry_e = loop_preheader_edge (loop);
+  gimple orig_cond = get_loop_exit_condition (loop);
+  gimple_stmt_iterator loop_exit_gsi = gsi_last_bb (exit_e->src);
+
+  if (need_ssa_update_p ())
+    return false;
+
+  if (loop->inner
+      /* All loops have an outer scope; the only case loop->outer is NULL is for
+         the function itself.  */
+      || !loop_outer (loop)
+      || loop->num_nodes != 2
+      || !empty_block_p (loop->latch)
+      || !single_exit (loop)
+      /* Verify that new loop exit condition can be trivially modified.  */
+      || (!orig_cond || orig_cond != gsi_stmt (loop_exit_gsi))
+      || (e != exit_e && e != entry_e))
+    return false;
+
+  return true;
+}
+
+#ifdef ENABLE_CHECKING
+static void
+slpeel_verify_cfg_after_peeling (struct loop *first_loop,
+                                 struct loop *second_loop)
+{
+  basic_block loop1_exit_bb = single_exit (first_loop)->dest;
+  basic_block loop2_entry_bb = loop_preheader_edge (second_loop)->src;
+  basic_block loop1_entry_bb = loop_preheader_edge (first_loop)->src;
+
+  /* A guard that controls whether the second_loop is to be executed or skipped
+     is placed in first_loop->exit.  first_loop->exit therefore has two
+     successors - one is the preheader of second_loop, and the other is a bb
+     after second_loop.
+   */
+  gcc_assert (EDGE_COUNT (loop1_exit_bb->succs) == 2);
+   
+  /* 1. Verify that one of the successors of first_loop->exit is the preheader
+        of second_loop.  */
+   
+  /* The preheader of new_loop is expected to have two predecessors:
+     first_loop->exit and the block that precedes first_loop.  */
+
+  gcc_assert (EDGE_COUNT (loop2_entry_bb->preds) == 2 
+              && ((EDGE_PRED (loop2_entry_bb, 0)->src == loop1_exit_bb
+                   && EDGE_PRED (loop2_entry_bb, 1)->src == loop1_entry_bb)
+               || (EDGE_PRED (loop2_entry_bb, 1)->src ==  loop1_exit_bb
+                   && EDGE_PRED (loop2_entry_bb, 0)->src == loop1_entry_bb)));
+  
+  /* Verify that the other successor of first_loop->exit is after the
+     second_loop.  */
+  /* TODO */
+}
+#endif
+
+/* If the run time cost model check determines that vectorization is
+   not profitable and hence scalar loop should be generated then set
+   FIRST_NITERS to prologue peeled iterations. This will allow all the
+   iterations to be executed in the prologue peeled scalar loop.  */
+
+static void
+set_prologue_iterations (basic_block bb_before_first_loop,
+			 tree first_niters,
+			 struct loop *loop,
+			 unsigned int th)
+{
+  edge e;
+  basic_block cond_bb, then_bb;
+  tree var, prologue_after_cost_adjust_name;
+  gimple_stmt_iterator gsi;
+  gimple newphi;
+  edge e_true, e_false, e_fallthru;
+  gimple cond_stmt;
+  gimple_seq gimplify_stmt_list = NULL, stmts = NULL;
+  tree cost_pre_condition = NULL_TREE;
+  tree scalar_loop_iters = 
+    unshare_expr (LOOP_VINFO_NITERS_UNCHANGED (loop_vec_info_for_loop (loop)));
+
+  e = single_pred_edge (bb_before_first_loop);
+  cond_bb = split_edge(e);
+
+  e = single_pred_edge (bb_before_first_loop);
+  then_bb = split_edge(e);
+  set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb);
+
+  e_false = make_single_succ_edge (cond_bb, bb_before_first_loop,
+				   EDGE_FALSE_VALUE);
+  set_immediate_dominator (CDI_DOMINATORS, bb_before_first_loop, cond_bb);
+
+  e_true = EDGE_PRED (then_bb, 0);
+  e_true->flags &= ~EDGE_FALLTHRU;
+  e_true->flags |= EDGE_TRUE_VALUE;
+
+  e_fallthru = EDGE_SUCC (then_bb, 0);
+
+  cost_pre_condition =
+    fold_build2 (LE_EXPR, boolean_type_node, scalar_loop_iters, 
+	         build_int_cst (TREE_TYPE (scalar_loop_iters), th));
+  cost_pre_condition =
+    force_gimple_operand (cost_pre_condition, &gimplify_stmt_list,
+			  true, NULL_TREE);
+  cond_stmt = gimple_build_cond (NE_EXPR, cost_pre_condition,
+				 build_int_cst (TREE_TYPE (cost_pre_condition),
+						0), NULL_TREE, NULL_TREE);
+
+  gsi = gsi_last_bb (cond_bb);
+  if (gimplify_stmt_list)
+    gsi_insert_seq_after (&gsi, gimplify_stmt_list, GSI_NEW_STMT);
+
+  gsi = gsi_last_bb (cond_bb);
+  gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT);
+					  
+  var = create_tmp_var (TREE_TYPE (scalar_loop_iters),
+			"prologue_after_cost_adjust");
+  add_referenced_var (var);
+  prologue_after_cost_adjust_name = 
+    force_gimple_operand (scalar_loop_iters, &stmts, false, var);
+
+  gsi = gsi_last_bb (then_bb);
+  if (stmts)
+    gsi_insert_seq_after (&gsi, stmts, GSI_NEW_STMT);
+
+  newphi = create_phi_node (var, bb_before_first_loop);
+  add_phi_arg (newphi, prologue_after_cost_adjust_name, e_fallthru);
+  add_phi_arg (newphi, first_niters, e_false);
+
+  first_niters = PHI_RESULT (newphi);
+}
+
+
+/* Function slpeel_tree_peel_loop_to_edge.
+
+   Peel the first (last) iterations of LOOP into a new prolog (epilog) loop
+   that is placed on the entry (exit) edge E of LOOP. After this transformation
+   we have two loops one after the other - first-loop iterates FIRST_NITERS
+   times, and second-loop iterates the remainder NITERS - FIRST_NITERS times.
+   If the cost model indicates that it is profitable to emit a scalar 
+   loop instead of the vector one, then the prolog (epilog) loop will iterate
+   for the entire unchanged scalar iterations of the loop.
+
+   Input:
+   - LOOP: the loop to be peeled.
+   - E: the exit or entry edge of LOOP.
+        If it is the entry edge, we peel the first iterations of LOOP. In this
+        case first-loop is LOOP, and second-loop is the newly created loop.
+        If it is the exit edge, we peel the last iterations of LOOP. In this
+        case, first-loop is the newly created loop, and second-loop is LOOP.
+   - NITERS: the number of iterations that LOOP iterates.
+   - FIRST_NITERS: the number of iterations that the first-loop should iterate.
+   - UPDATE_FIRST_LOOP_COUNT:  specified whether this function is responsible
+        for updating the loop bound of the first-loop to FIRST_NITERS.  If it
+        is false, the caller of this function may want to take care of this
+        (this can be useful if we don't want new stmts added to first-loop).
+   - TH: cost model profitability threshold of iterations for vectorization.
+   - CHECK_PROFITABILITY: specify whether cost model check has not occurred
+                          during versioning and hence needs to occur during
+			  prologue generation or whether cost model check 
+			  has not occurred during prologue generation and hence
+			  needs to occur during epilogue generation.
+	    
+
+   Output:
+   The function returns a pointer to the new loop-copy, or NULL if it failed
+   to perform the transformation.
+
+   The function generates two if-then-else guards: one before the first loop,
+   and the other before the second loop:
+   The first guard is:
+     if (FIRST_NITERS == 0) then skip the first loop,
+     and go directly to the second loop.
+   The second guard is:
+     if (FIRST_NITERS == NITERS) then skip the second loop.
+
+   FORNOW only simple loops are supported (see slpeel_can_duplicate_loop_p).
+   FORNOW the resulting code will not be in loop-closed-ssa form.
+*/
+
+static struct loop*
+slpeel_tree_peel_loop_to_edge (struct loop *loop, 
+			       edge e, tree first_niters, 
+			       tree niters, bool update_first_loop_count,
+			       unsigned int th, bool check_profitability)
+{
+  struct loop *new_loop = NULL, *first_loop, *second_loop;
+  edge skip_e;
+  tree pre_condition = NULL_TREE;
+  bitmap definitions;
+  basic_block bb_before_second_loop, bb_after_second_loop;
+  basic_block bb_before_first_loop;
+  basic_block bb_between_loops;
+  basic_block new_exit_bb;
+  edge exit_e = single_exit (loop);
+  LOC loop_loc;
+  tree cost_pre_condition = NULL_TREE;
+  
+  if (!slpeel_can_duplicate_loop_p (loop, e))
+    return NULL;
+  
+  /* We have to initialize cfg_hooks. Then, when calling
+   cfg_hooks->split_edge, the function tree_split_edge 
+   is actually called and, when calling cfg_hooks->duplicate_block,
+   the function tree_duplicate_bb is called.  */
+  gimple_register_cfg_hooks ();
+
+
+  /* 1. Generate a copy of LOOP and put it on E (E is the entry/exit of LOOP).
+        Resulting CFG would be:
+
+        first_loop:
+        do {
+        } while ...
+
+        second_loop:
+        do {
+        } while ...
+
+        orig_exit_bb:
+   */
+  
+  if (!(new_loop = slpeel_tree_duplicate_loop_to_edge_cfg (loop, e)))
+    {
+      loop_loc = find_loop_location (loop);
+      if (dump_file && (dump_flags & TDF_DETAILS))
+        {
+          if (loop_loc != UNKNOWN_LOC)
+            fprintf (dump_file, "\n%s:%d: note: ",
+                     LOC_FILE (loop_loc), LOC_LINE (loop_loc));
+          fprintf (dump_file, "tree_duplicate_loop_to_edge_cfg failed.\n");
+        }
+      return NULL;
+    }
+  
+  if (e == exit_e)
+    {
+      /* NEW_LOOP was placed after LOOP.  */
+      first_loop = loop;
+      second_loop = new_loop;
+    }
+  else
+    {
+      /* NEW_LOOP was placed before LOOP.  */
+      first_loop = new_loop;
+      second_loop = loop;
+    }
+
+  definitions = ssa_names_to_replace ();
+  slpeel_update_phis_for_duplicate_loop (loop, new_loop, e == exit_e);
+  rename_variables_in_loop (new_loop);
+
+
+  /* 2.  Add the guard code in one of the following ways:
+
+     2.a Add the guard that controls whether the first loop is executed.
+         This occurs when this function is invoked for prologue or epilogue
+	 generation and when the cost model check can be done at compile time.
+
+         Resulting CFG would be:
+
+         bb_before_first_loop:
+         if (FIRST_NITERS == 0) GOTO bb_before_second_loop
+                                GOTO first-loop
+
+         first_loop:
+         do {
+         } while ...
+
+         bb_before_second_loop:
+
+         second_loop:
+         do {
+         } while ...
+
+         orig_exit_bb:
+
+     2.b Add the cost model check that allows the prologue
+         to iterate for the entire unchanged scalar
+         iterations of the loop in the event that the cost
+         model indicates that the scalar loop is more
+         profitable than the vector one. This occurs when
+	 this function is invoked for prologue generation
+	 and the cost model check needs to be done at run
+	 time.
+
+         Resulting CFG after prologue peeling would be:
+
+         if (scalar_loop_iterations <= th)
+           FIRST_NITERS = scalar_loop_iterations
+
+         bb_before_first_loop:
+         if (FIRST_NITERS == 0) GOTO bb_before_second_loop
+                                GOTO first-loop
+
+         first_loop:
+         do {
+         } while ...
+
+         bb_before_second_loop:
+
+         second_loop:
+         do {
+         } while ...
+
+         orig_exit_bb:
+
+     2.c Add the cost model check that allows the epilogue
+         to iterate for the entire unchanged scalar
+         iterations of the loop in the event that the cost
+         model indicates that the scalar loop is more
+         profitable than the vector one. This occurs when
+	 this function is invoked for epilogue generation
+	 and the cost model check needs to be done at run
+	 time.
+
+         Resulting CFG after prologue peeling would be:
+
+         bb_before_first_loop:
+         if ((scalar_loop_iterations <= th)
+             ||
+             FIRST_NITERS == 0) GOTO bb_before_second_loop
+                                GOTO first-loop
+
+         first_loop:
+         do {
+         } while ...
+
+         bb_before_second_loop:
+
+         second_loop:
+         do {
+         } while ...
+
+         orig_exit_bb:
+  */
+
+  bb_before_first_loop = split_edge (loop_preheader_edge (first_loop));
+  bb_before_second_loop = split_edge (single_exit (first_loop));
+
+  /* Epilogue peeling.  */
+  if (!update_first_loop_count)
+    {
+      pre_condition =
+	fold_build2 (LE_EXPR, boolean_type_node, first_niters, 
+		     build_int_cst (TREE_TYPE (first_niters), 0));
+      if (check_profitability)
+	{
+	  tree scalar_loop_iters
+	    = unshare_expr (LOOP_VINFO_NITERS_UNCHANGED
+					(loop_vec_info_for_loop (loop)));
+	  cost_pre_condition = 
+	    fold_build2 (LE_EXPR, boolean_type_node, scalar_loop_iters, 
+		         build_int_cst (TREE_TYPE (scalar_loop_iters), th));
+
+	  pre_condition = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+				       cost_pre_condition, pre_condition);
+	}
+    }
+
+  /* Prologue peeling.  */  
+  else
+    {
+      if (check_profitability)
+	set_prologue_iterations (bb_before_first_loop, first_niters,
+				 loop, th);
+
+      pre_condition =
+	fold_build2 (LE_EXPR, boolean_type_node, first_niters, 
+		     build_int_cst (TREE_TYPE (first_niters), 0));
+    }
+
+  skip_e = slpeel_add_loop_guard (bb_before_first_loop, pre_condition,
+                                  bb_before_second_loop, bb_before_first_loop);
+  slpeel_update_phi_nodes_for_guard1 (skip_e, first_loop,
+				      first_loop == new_loop,
+				      &new_exit_bb, &definitions);
+
+
+  /* 3. Add the guard that controls whether the second loop is executed.
+        Resulting CFG would be:
+
+        bb_before_first_loop:
+        if (FIRST_NITERS == 0) GOTO bb_before_second_loop (skip first loop)
+                               GOTO first-loop
+
+        first_loop:
+        do {
+        } while ...
+
+        bb_between_loops:
+        if (FIRST_NITERS == NITERS) GOTO bb_after_second_loop (skip second loop)
+                                    GOTO bb_before_second_loop
+
+        bb_before_second_loop:
+
+        second_loop:
+        do {
+        } while ...
+
+        bb_after_second_loop:
+
+        orig_exit_bb:
+   */
+
+  bb_between_loops = new_exit_bb;
+  bb_after_second_loop = split_edge (single_exit (second_loop));
+
+  pre_condition = 
+	fold_build2 (EQ_EXPR, boolean_type_node, first_niters, niters);
+  skip_e = slpeel_add_loop_guard (bb_between_loops, pre_condition,
+                                  bb_after_second_loop, bb_before_first_loop);
+  slpeel_update_phi_nodes_for_guard2 (skip_e, second_loop,
+                                     second_loop == new_loop, &new_exit_bb);
+
+  /* 4. Make first-loop iterate FIRST_NITERS times, if requested.
+   */
+  if (update_first_loop_count)
+    slpeel_make_loop_iterate_ntimes (first_loop, first_niters);
+
+  BITMAP_FREE (definitions);
+  delete_update_ssa ();
+
+  return new_loop;
+}
+
+/* Function vect_get_loop_location.
+
+   Extract the location of the loop in the source code.
+   If the loop is not well formed for vectorization, an estimated
+   location is calculated.
+   Return the loop location if succeed and NULL if not.  */
+
+LOC
+find_loop_location (struct loop *loop)
+{
+  gimple stmt = NULL;
+  basic_block bb;
+  gimple_stmt_iterator si;
+
+  if (!loop)
+    return UNKNOWN_LOC;
+
+  stmt = get_loop_exit_condition (loop);
+
+  if (stmt && gimple_location (stmt) != UNKNOWN_LOC)
+    return gimple_location (stmt);
+
+  /* If we got here the loop is probably not "well formed",
+     try to estimate the loop location */
+
+  if (!loop->header)
+    return UNKNOWN_LOC;
+
+  bb = loop->header;
+
+  for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
+    {
+      stmt = gsi_stmt (si);
+      if (gimple_location (stmt) != UNKNOWN_LOC)
+        return gimple_location (stmt);
+    }
+
+  return UNKNOWN_LOC;
+}
+
+
+/* This function builds ni_name = number of iterations loop executes
+   on the loop preheader.  */
+
+static tree
+vect_build_loop_niters (loop_vec_info loop_vinfo)
+{
+  tree ni_name, var;
+  gimple_seq stmts = NULL;
+  edge pe;
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  tree ni = unshare_expr (LOOP_VINFO_NITERS (loop_vinfo));
+
+  var = create_tmp_var (TREE_TYPE (ni), "niters");
+  add_referenced_var (var);
+  ni_name = force_gimple_operand (ni, &stmts, false, var);
+
+  pe = loop_preheader_edge (loop);
+  if (stmts)
+    {
+      basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts);
+      gcc_assert (!new_bb);
+    }
+
+  return ni_name;
+}
+
+
+/* This function generates the following statements:
+
+ ni_name = number of iterations loop executes
+ ratio = ni_name / vf
+ ratio_mult_vf_name = ratio * vf
+
+ and places them at the loop preheader edge.  */
+
+static void 
+vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo, 
+				 tree *ni_name_ptr,
+				 tree *ratio_mult_vf_name_ptr, 
+				 tree *ratio_name_ptr)
+{
+
+  edge pe;
+  basic_block new_bb;
+  gimple_seq stmts;
+  tree ni_name;
+  tree var;
+  tree ratio_name;
+  tree ratio_mult_vf_name;
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  tree ni = LOOP_VINFO_NITERS (loop_vinfo);
+  int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
+  tree log_vf;
+
+  pe = loop_preheader_edge (loop);
+
+  /* Generate temporary variable that contains 
+     number of iterations loop executes.  */
+
+  ni_name = vect_build_loop_niters (loop_vinfo);
+  log_vf = build_int_cst (TREE_TYPE (ni), exact_log2 (vf));
+
+  /* Create: ratio = ni >> log2(vf) */
+
+  ratio_name = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_name), ni_name, log_vf);
+  if (!is_gimple_val (ratio_name))
+    {
+      var = create_tmp_var (TREE_TYPE (ni), "bnd");
+      add_referenced_var (var);
+
+      stmts = NULL;
+      ratio_name = force_gimple_operand (ratio_name, &stmts, true, var);
+      pe = loop_preheader_edge (loop);
+      new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts);
+      gcc_assert (!new_bb);
+    }
+       
+  /* Create: ratio_mult_vf = ratio << log2 (vf).  */
+
+  ratio_mult_vf_name = fold_build2 (LSHIFT_EXPR, TREE_TYPE (ratio_name),
+				    ratio_name, log_vf);
+  if (!is_gimple_val (ratio_mult_vf_name))
+    {
+      var = create_tmp_var (TREE_TYPE (ni), "ratio_mult_vf");
+      add_referenced_var (var);
+
+      stmts = NULL;
+      ratio_mult_vf_name = force_gimple_operand (ratio_mult_vf_name, &stmts,
+						 true, var);
+      pe = loop_preheader_edge (loop);
+      new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts);
+      gcc_assert (!new_bb);
+    }
+
+  *ni_name_ptr = ni_name;
+  *ratio_mult_vf_name_ptr = ratio_mult_vf_name;
+  *ratio_name_ptr = ratio_name;
+    
+  return;  
+}
+
+/* Function vect_can_advance_ivs_p
+
+   In case the number of iterations that LOOP iterates is unknown at compile 
+   time, an epilog loop will be generated, and the loop induction variables 
+   (IVs) will be "advanced" to the value they are supposed to take just before 
+   the epilog loop.  Here we check that the access function of the loop IVs
+   and the expression that represents the loop bound are simple enough.
+   These restrictions will be relaxed in the future.  */
+
+bool 
+vect_can_advance_ivs_p (loop_vec_info loop_vinfo)
+{
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  basic_block bb = loop->header;
+  gimple phi;
+  gimple_stmt_iterator gsi;
+
+  /* Analyze phi functions of the loop header.  */
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "vect_can_advance_ivs_p:");
+
+  for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      tree access_fn = NULL;
+      tree evolution_part;
+
+      phi = gsi_stmt (gsi);
+      if (vect_print_dump_info (REPORT_DETAILS))
+	{
+          fprintf (vect_dump, "Analyze phi: ");
+          print_gimple_stmt (vect_dump, phi, 0, 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 (PHI_RESULT (phi))))
+	{
+	  if (vect_print_dump_info (REPORT_DETAILS))
+	    fprintf (vect_dump, "virtual phi. skip.");
+	  continue;
+	}
+
+      /* Skip reduction phis.  */
+
+      if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def)
+        {
+          if (vect_print_dump_info (REPORT_DETAILS))
+            fprintf (vect_dump, "reduc phi. skip.");
+          continue;
+        }
+
+      /* Analyze the evolution function.  */
+
+      access_fn = instantiate_parameters
+	(loop, analyze_scalar_evolution (loop, PHI_RESULT (phi)));
+
+      if (!access_fn)
+	{
+	  if (vect_print_dump_info (REPORT_DETAILS))
+	    fprintf (vect_dump, "No Access function.");
+	  return false;
+	}
+
+      if (vect_print_dump_info (REPORT_DETAILS))
+        {
+	  fprintf (vect_dump, "Access function of PHI: ");
+	  print_generic_expr (vect_dump, access_fn, TDF_SLIM);
+        }
+
+      evolution_part = evolution_part_in_loop_num (access_fn, loop->num);
+      
+      if (evolution_part == NULL_TREE)
+        {
+	  if (vect_print_dump_info (REPORT_DETAILS))
+	    fprintf (vect_dump, "No evolution.");
+	  return false;
+        }
+  
+      /* FORNOW: We do not transform initial conditions of IVs 
+	 which evolution functions are a polynomial of degree >= 2.  */
+
+      if (tree_is_chrec (evolution_part))
+	return false;  
+    }
+
+  return true;
+}
+
+
+/*   Function vect_update_ivs_after_vectorizer.
+
+     "Advance" the induction variables of LOOP to the value they should take
+     after the execution of LOOP.  This is currently necessary because the
+     vectorizer does not handle induction variables that are used after the
+     loop.  Such a situation occurs when the last iterations of LOOP are
+     peeled, because:
+     1. We introduced new uses after LOOP for IVs that were not originally used
+        after LOOP: the IVs of LOOP are now used by an epilog loop.
+     2. LOOP is going to be vectorized; this means that it will iterate N/VF
+        times, whereas the loop IVs should be bumped N times.
+
+     Input:
+     - LOOP - a loop that is going to be vectorized. The last few iterations
+              of LOOP were peeled.
+     - NITERS - the number of iterations that LOOP executes (before it is
+                vectorized). i.e, the number of times the ivs should be bumped.
+     - UPDATE_E - a successor edge of LOOP->exit that is on the (only) path
+                  coming out from LOOP on which there are uses of the LOOP ivs
+		  (this is the path from LOOP->exit to epilog_loop->preheader).
+
+                  The new definitions of the ivs are placed in LOOP->exit.
+                  The phi args associated with the edge UPDATE_E in the bb
+                  UPDATE_E->dest are updated accordingly.
+
+     Assumption 1: Like the rest of the vectorizer, this function assumes
+     a single loop exit that has a single predecessor.
+
+     Assumption 2: The phi nodes in the LOOP header and in update_bb are
+     organized in the same order.
+
+     Assumption 3: The access function of the ivs is simple enough (see
+     vect_can_advance_ivs_p).  This assumption will be relaxed in the future.
+
+     Assumption 4: Exactly one of the successors of LOOP exit-bb is on a path
+     coming out of LOOP on which the ivs of LOOP are used (this is the path 
+     that leads to the epilog loop; other paths skip the epilog loop).  This
+     path starts with the edge UPDATE_E, and its destination (denoted update_bb)
+     needs to have its phis updated.
+ */
+
+static void
+vect_update_ivs_after_vectorizer (loop_vec_info loop_vinfo, tree niters, 
+				  edge update_e)
+{
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  basic_block exit_bb = single_exit (loop)->dest;
+  gimple phi, phi1;
+  gimple_stmt_iterator gsi, gsi1;
+  basic_block update_bb = update_e->dest;
+
+  /* gcc_assert (vect_can_advance_ivs_p (loop_vinfo)); */
+
+  /* Make sure there exists a single-predecessor exit bb:  */
+  gcc_assert (single_pred_p (exit_bb));
+
+  for (gsi = gsi_start_phis (loop->header), gsi1 = gsi_start_phis (update_bb);
+       !gsi_end_p (gsi) && !gsi_end_p (gsi1);
+       gsi_next (&gsi), gsi_next (&gsi1))
+    {
+      tree access_fn = NULL;
+      tree evolution_part;
+      tree init_expr;
+      tree step_expr;
+      tree var, ni, ni_name;
+      gimple_stmt_iterator last_gsi;
+
+      phi = gsi_stmt (gsi);
+      phi1 = gsi_stmt (gsi1);
+      if (vect_print_dump_info (REPORT_DETAILS))
+        {
+          fprintf (vect_dump, "vect_update_ivs_after_vectorizer: phi: ");
+	  print_gimple_stmt (vect_dump, phi, 0, TDF_SLIM);
+        }
+
+      /* Skip virtual phi's.  */
+      if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
+	{
+	  if (vect_print_dump_info (REPORT_DETAILS))
+	    fprintf (vect_dump, "virtual phi. skip.");
+	  continue;
+	}
+
+      /* Skip reduction phis.  */
+      if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def)
+        { 
+          if (vect_print_dump_info (REPORT_DETAILS))
+            fprintf (vect_dump, "reduc phi. skip.");
+          continue;
+        } 
+
+      access_fn = analyze_scalar_evolution (loop, PHI_RESULT (phi)); 
+      gcc_assert (access_fn);
+      STRIP_NOPS (access_fn);
+      evolution_part =
+	 unshare_expr (evolution_part_in_loop_num (access_fn, loop->num));
+      gcc_assert (evolution_part != NULL_TREE);
+      
+      /* FORNOW: We do not support IVs whose evolution function is a polynomial
+         of degree >= 2 or exponential.  */
+      gcc_assert (!tree_is_chrec (evolution_part));
+
+      step_expr = evolution_part;
+      init_expr = unshare_expr (initial_condition_in_loop_num (access_fn, 
+							       loop->num));
+
+      if (POINTER_TYPE_P (TREE_TYPE (init_expr)))
+	ni = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (init_expr), 
+			  init_expr, 
+			  fold_convert (sizetype, 
+					fold_build2 (MULT_EXPR, TREE_TYPE (niters),
+						     niters, step_expr)));
+      else
+	ni = fold_build2 (PLUS_EXPR, TREE_TYPE (init_expr),
+			  fold_build2 (MULT_EXPR, TREE_TYPE (init_expr),
+				       fold_convert (TREE_TYPE (init_expr),
+						     niters),
+				       step_expr),
+			  init_expr);
+
+
+
+      var = create_tmp_var (TREE_TYPE (init_expr), "tmp");
+      add_referenced_var (var);
+
+      last_gsi = gsi_last_bb (exit_bb);
+      ni_name = force_gimple_operand_gsi (&last_gsi, ni, false, var,
+					  true, GSI_SAME_STMT);
+      
+      /* Fix phi expressions in the successor bb.  */
+      SET_PHI_ARG_DEF (phi1, update_e->dest_idx, ni_name);
+    }
+}
+
+/* Return the more conservative threshold between the
+   min_profitable_iters returned by the cost model and the user
+   specified threshold, if provided.  */
+
+static unsigned int
+conservative_cost_threshold (loop_vec_info loop_vinfo,
+			     int min_profitable_iters)
+{
+  unsigned int th;
+  int min_scalar_loop_bound;
+
+  min_scalar_loop_bound = ((PARAM_VALUE (PARAM_MIN_VECT_LOOP_BOUND)
+			    * LOOP_VINFO_VECT_FACTOR (loop_vinfo)) - 1);
+
+  /* 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 (th && vect_print_dump_info (REPORT_COST))
+    fprintf (vect_dump, "Vectorization may not be profitable.");
+
+  return th;
+}
+
+/* Function vect_do_peeling_for_loop_bound
+
+   Peel the last iterations of the loop represented by LOOP_VINFO.
+   The peeled iterations form a new epilog loop.  Given that the loop now 
+   iterates NITERS times, the new epilog loop iterates
+   NITERS % VECTORIZATION_FACTOR times.
+   
+   The original loop will later be made to iterate 
+   NITERS / VECTORIZATION_FACTOR times (this value is placed into RATIO).  */
+
+void 
+vect_do_peeling_for_loop_bound (loop_vec_info loop_vinfo, tree *ratio)
+{
+  tree ni_name, ratio_mult_vf_name;
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  struct loop *new_loop;
+  edge update_e;
+  basic_block preheader;
+  int loop_num;
+  bool check_profitability = false;
+  unsigned int th = 0;
+  int min_profitable_iters;
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "=== vect_do_peeling_for_loop_bound ===");
+
+  initialize_original_copy_tables ();
+
+  /* Generate the following variables on the preheader of original loop:
+	 
+     ni_name = number of iteration the original loop executes
+     ratio = ni_name / vf
+     ratio_mult_vf_name = ratio * vf  */
+  vect_generate_tmps_on_preheader (loop_vinfo, &ni_name,
+				   &ratio_mult_vf_name, ratio);
+
+  loop_num  = loop->num; 
+
+  /* If cost model check not done during versioning and 
+     peeling for alignment.  */
+  if (!VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo))
+      && !VEC_length (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo))
+      && !LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo))
+    {
+      check_profitability = true;
+
+      /* Get profitability threshold for vectorized loop.  */
+      min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo);
+
+      th = conservative_cost_threshold (loop_vinfo, 
+					min_profitable_iters);
+    }
+
+  new_loop = slpeel_tree_peel_loop_to_edge (loop, single_exit (loop),
+                                            ratio_mult_vf_name, ni_name, false,
+                                            th, check_profitability);
+  gcc_assert (new_loop);
+  gcc_assert (loop_num == loop->num);
+#ifdef ENABLE_CHECKING
+  slpeel_verify_cfg_after_peeling (loop, new_loop);
+#endif
+
+  /* A guard that controls whether the new_loop is to be executed or skipped
+     is placed in LOOP->exit.  LOOP->exit therefore has two successors - one
+     is the preheader of NEW_LOOP, where the IVs from LOOP are used.  The other
+     is a bb after NEW_LOOP, where these IVs are not used.  Find the edge that
+     is on the path where the LOOP IVs are used and need to be updated.  */
+
+  preheader = loop_preheader_edge (new_loop)->src;
+  if (EDGE_PRED (preheader, 0)->src == single_exit (loop)->dest)
+    update_e = EDGE_PRED (preheader, 0);
+  else
+    update_e = EDGE_PRED (preheader, 1);
+
+  /* Update IVs of original loop as if they were advanced 
+     by ratio_mult_vf_name steps.  */
+  vect_update_ivs_after_vectorizer (loop_vinfo, ratio_mult_vf_name, update_e); 
+
+  /* After peeling we have to reset scalar evolution analyzer.  */
+  scev_reset ();
+
+  free_original_copy_tables ();
+}
+
+
+/* Function vect_gen_niters_for_prolog_loop
+
+   Set the number of iterations for the loop represented by LOOP_VINFO
+   to the minimum between LOOP_NITERS (the original iteration count of the loop)
+   and the misalignment of DR - the data reference recorded in
+   LOOP_VINFO_UNALIGNED_DR (LOOP_VINFO).  As a result, after the execution of 
+   this loop, the data reference DR will refer to an aligned location.
+
+   The following computation is generated:
+
+   If the misalignment of DR is known at compile time:
+     addr_mis = int mis = DR_MISALIGNMENT (dr);
+   Else, compute address misalignment in bytes:
+     addr_mis = addr & (vectype_size - 1)
+
+   prolog_niters = min (LOOP_NITERS, ((VF - addr_mis/elem_size)&(VF-1))/step)
+
+   (elem_size = element type size; an element is the scalar element whose type
+   is the inner type of the vectype)
+
+   When the step of the data-ref in the loop is not 1 (as in interleaved data
+   and SLP), the number of iterations of the prolog must be divided by the step
+   (which is equal to the size of interleaved group).
+
+   The above formulas assume that VF == number of elements in the vector. This
+   may not hold when there are multiple-types in the loop.
+   In this case, for some data-references in the loop the VF does not represent
+   the number of elements that fit in the vector.  Therefore, instead of VF we
+   use TYPE_VECTOR_SUBPARTS.  */
+
+static tree 
+vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters)
+{
+  struct data_reference *dr = LOOP_VINFO_UNALIGNED_DR (loop_vinfo);
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  tree var;
+  gimple_seq stmts;
+  tree iters, iters_name;
+  edge pe;
+  basic_block new_bb;
+  gimple dr_stmt = DR_STMT (dr);
+  stmt_vec_info stmt_info = vinfo_for_stmt (dr_stmt);
+  tree vectype = STMT_VINFO_VECTYPE (stmt_info);
+  int vectype_align = TYPE_ALIGN (vectype) / BITS_PER_UNIT;
+  tree niters_type = TREE_TYPE (loop_niters);
+  int step = 1;
+  int element_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
+  int nelements = TYPE_VECTOR_SUBPARTS (vectype);
+
+  if (STMT_VINFO_STRIDED_ACCESS (stmt_info))
+    step = DR_GROUP_SIZE (vinfo_for_stmt (DR_GROUP_FIRST_DR (stmt_info)));
+
+  pe = loop_preheader_edge (loop); 
+
+  if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0)
+    {
+      int byte_misalign = LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo);
+      int elem_misalign = byte_misalign / element_size;
+
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "known alignment = %d.", byte_misalign);
+
+      iters = build_int_cst (niters_type,
+                     (((nelements - elem_misalign) & (nelements - 1)) / step));
+    }
+  else
+    {
+      gimple_seq new_stmts = NULL;
+      tree start_addr = vect_create_addr_base_for_vector_ref (dr_stmt, 
+						&new_stmts, NULL_TREE, loop);
+      tree ptr_type = TREE_TYPE (start_addr);
+      tree size = TYPE_SIZE (ptr_type);
+      tree type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1);
+      tree vectype_size_minus_1 = build_int_cst (type, vectype_align - 1);
+      tree elem_size_log =
+        build_int_cst (type, exact_log2 (vectype_align/nelements));
+      tree nelements_minus_1 = build_int_cst (type, nelements - 1);
+      tree nelements_tree = build_int_cst (type, nelements);
+      tree byte_misalign;
+      tree elem_misalign;
+
+      new_bb = gsi_insert_seq_on_edge_immediate (pe, new_stmts);
+      gcc_assert (!new_bb);
+  
+      /* Create:  byte_misalign = addr & (vectype_size - 1)  */
+      byte_misalign = 
+        fold_build2 (BIT_AND_EXPR, type, fold_convert (type, start_addr), vectype_size_minus_1);
+  
+      /* Create:  elem_misalign = byte_misalign / element_size  */
+      elem_misalign =
+        fold_build2 (RSHIFT_EXPR, type, byte_misalign, elem_size_log);
+
+      /* Create:  (niters_type) (nelements - elem_misalign)&(nelements - 1)  */
+      iters = fold_build2 (MINUS_EXPR, type, nelements_tree, elem_misalign);
+      iters = fold_build2 (BIT_AND_EXPR, type, iters, nelements_minus_1);
+      iters = fold_convert (niters_type, iters);
+    }
+
+  /* Create:  prolog_loop_niters = min (iters, loop_niters) */
+  /* If the loop bound is known at compile time we already verified that it is
+     greater than vf; since the misalignment ('iters') is at most vf, there's
+     no need to generate the MIN_EXPR in this case.  */
+  if (TREE_CODE (loop_niters) != INTEGER_CST)
+    iters = fold_build2 (MIN_EXPR, niters_type, iters, loop_niters);
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    {
+      fprintf (vect_dump, "niters for prolog loop: ");
+      print_generic_expr (vect_dump, iters, TDF_SLIM);
+    }
+
+  var = create_tmp_var (niters_type, "prolog_loop_niters");
+  add_referenced_var (var);
+  stmts = NULL;
+  iters_name = force_gimple_operand (iters, &stmts, false, var);
+
+  /* Insert stmt on loop preheader edge.  */
+  if (stmts)
+    {
+      basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts);
+      gcc_assert (!new_bb);
+    }
+
+  return iters_name; 
+}
+
+
+/* Function vect_update_init_of_dr
+
+   NITERS iterations were peeled from LOOP.  DR represents a data reference
+   in LOOP.  This function updates the information recorded in DR to
+   account for the fact that the first NITERS iterations had already been 
+   executed.  Specifically, it updates the OFFSET field of DR.  */
+
+static void
+vect_update_init_of_dr (struct data_reference *dr, tree niters)
+{
+  tree offset = DR_OFFSET (dr);
+      
+  niters = fold_build2 (MULT_EXPR, sizetype,
+			fold_convert (sizetype, niters),
+			fold_convert (sizetype, DR_STEP (dr)));
+  offset = fold_build2 (PLUS_EXPR, sizetype, offset, niters);
+  DR_OFFSET (dr) = offset;
+}
+
+
+/* Function vect_update_inits_of_drs
+
+   NITERS iterations were peeled from the loop represented by LOOP_VINFO.  
+   This function updates the information recorded for the data references in 
+   the loop to account for the fact that the first NITERS iterations had 
+   already been executed.  Specifically, it updates the initial_condition of
+   the access_function of all the data_references in the loop.  */
+
+static void
+vect_update_inits_of_drs (loop_vec_info loop_vinfo, tree niters)
+{
+  unsigned int i;
+  VEC (data_reference_p, heap) *datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
+  struct data_reference *dr;
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "=== vect_update_inits_of_dr ===");
+
+  for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
+    vect_update_init_of_dr (dr, niters);
+}
+
+
+/* Function vect_do_peeling_for_alignment
+
+   Peel the first 'niters' iterations of the loop represented by LOOP_VINFO.
+   'niters' is set to the misalignment of one of the data references in the
+   loop, thereby forcing it to refer to an aligned location at the beginning
+   of the execution of this loop.  The data reference for which we are
+   peeling is recorded in LOOP_VINFO_UNALIGNED_DR.  */
+
+void
+vect_do_peeling_for_alignment (loop_vec_info loop_vinfo)
+{
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  tree niters_of_prolog_loop, ni_name;
+  tree n_iters;
+  struct loop *new_loop;
+  bool check_profitability = false;
+  unsigned int th = 0;
+  int min_profitable_iters;
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "=== vect_do_peeling_for_alignment ===");
+
+  initialize_original_copy_tables ();
+
+  ni_name = vect_build_loop_niters (loop_vinfo);
+  niters_of_prolog_loop = vect_gen_niters_for_prolog_loop (loop_vinfo, ni_name);
+  
+
+  /* If cost model check not done during versioning.  */
+  if (!VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo))
+      && !VEC_length (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo)))
+    {
+      check_profitability = true;
+
+      /* Get profitability threshold for vectorized loop.  */
+      min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo);
+
+      th = conservative_cost_threshold (loop_vinfo, 
+					min_profitable_iters);
+    }
+
+  /* Peel the prolog loop and iterate it niters_of_prolog_loop.  */
+  new_loop =
+    slpeel_tree_peel_loop_to_edge (loop, loop_preheader_edge (loop),
+				   niters_of_prolog_loop, ni_name, true,
+				   th, check_profitability);
+
+  gcc_assert (new_loop);
+#ifdef ENABLE_CHECKING
+  slpeel_verify_cfg_after_peeling (new_loop, loop);
+#endif
+
+  /* Update number of times loop executes.  */
+  n_iters = LOOP_VINFO_NITERS (loop_vinfo);
+  LOOP_VINFO_NITERS (loop_vinfo) = fold_build2 (MINUS_EXPR,
+		TREE_TYPE (n_iters), n_iters, niters_of_prolog_loop);
+
+  /* Update the init conditions of the access functions of all data refs.  */
+  vect_update_inits_of_drs (loop_vinfo, niters_of_prolog_loop);
+
+  /* After peeling we have to reset scalar evolution analyzer.  */
+  scev_reset ();
+
+  free_original_copy_tables ();
+}
+
+
+/* Function vect_create_cond_for_align_checks.
+
+   Create a conditional expression that represents the alignment checks for
+   all of data references (array element references) whose alignment must be
+   checked at runtime.
+
+   Input:
+   COND_EXPR  - input conditional expression.  New conditions will be chained
+                with logical AND operation.
+   LOOP_VINFO - two fields of the loop information are used.
+                LOOP_VINFO_PTR_MASK is the mask used to check the alignment.
+                LOOP_VINFO_MAY_MISALIGN_STMTS contains the refs to be checked.
+
+   Output:
+   COND_EXPR_STMT_LIST - statements needed to construct the conditional
+                         expression.
+   The returned value is the conditional expression to be used in the if
+   statement that controls which version of the loop gets executed at runtime.
+
+   The algorithm makes two assumptions:
+     1) The number of bytes "n" in a vector is a power of 2.
+     2) An address "a" is aligned if a%n is zero and that this
+        test can be done as a&(n-1) == 0.  For example, for 16
+        byte vectors the test is a&0xf == 0.  */
+
+static void
+vect_create_cond_for_align_checks (loop_vec_info loop_vinfo,
+                                   tree *cond_expr,
+				   gimple_seq *cond_expr_stmt_list)
+{
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  VEC(gimple,heap) *may_misalign_stmts
+    = LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo);
+  gimple ref_stmt;
+  int mask = LOOP_VINFO_PTR_MASK (loop_vinfo);
+  tree mask_cst;
+  unsigned int i;
+  tree psize;
+  tree int_ptrsize_type;
+  char tmp_name[20];
+  tree or_tmp_name = NULL_TREE;
+  tree and_tmp, and_tmp_name;
+  gimple and_stmt;
+  tree ptrsize_zero;
+  tree part_cond_expr;
+
+  /* Check that mask is one less than a power of 2, i.e., mask is
+     all zeros followed by all ones.  */
+  gcc_assert ((mask != 0) && ((mask & (mask+1)) == 0));
+
+  /* CHECKME: what is the best integer or unsigned type to use to hold a
+     cast from a pointer value?  */
+  psize = TYPE_SIZE (ptr_type_node);
+  int_ptrsize_type
+    = lang_hooks.types.type_for_size (tree_low_cst (psize, 1), 0);
+
+  /* Create expression (mask & (dr_1 || ... || dr_n)) where dr_i is the address
+     of the first vector of the i'th data reference. */
+
+  for (i = 0; VEC_iterate (gimple, may_misalign_stmts, i, ref_stmt); i++)
+    {
+      gimple_seq new_stmt_list = NULL;
+      tree addr_base;
+      tree addr_tmp, addr_tmp_name;
+      tree or_tmp, new_or_tmp_name;
+      gimple addr_stmt, or_stmt;
+
+      /* create: addr_tmp = (int)(address_of_first_vector) */
+      addr_base =
+	vect_create_addr_base_for_vector_ref (ref_stmt, &new_stmt_list,
+					      NULL_TREE, loop);
+      if (new_stmt_list != NULL)
+	gimple_seq_add_seq (cond_expr_stmt_list, new_stmt_list);
+
+      sprintf (tmp_name, "%s%d", "addr2int", i);
+      addr_tmp = create_tmp_var (int_ptrsize_type, tmp_name);
+      add_referenced_var (addr_tmp);
+      addr_tmp_name = make_ssa_name (addr_tmp, NULL);
+      addr_stmt = gimple_build_assign_with_ops (NOP_EXPR, addr_tmp_name,
+						addr_base, NULL_TREE);
+      SSA_NAME_DEF_STMT (addr_tmp_name) = addr_stmt;
+      gimple_seq_add_stmt (cond_expr_stmt_list, addr_stmt);
+
+      /* The addresses are OR together.  */
+
+      if (or_tmp_name != NULL_TREE)
+        {
+          /* create: or_tmp = or_tmp | addr_tmp */
+          sprintf (tmp_name, "%s%d", "orptrs", i);
+          or_tmp = create_tmp_var (int_ptrsize_type, tmp_name);
+          add_referenced_var (or_tmp);
+	  new_or_tmp_name = make_ssa_name (or_tmp, NULL);
+	  or_stmt = gimple_build_assign_with_ops (BIT_IOR_EXPR,
+						  new_or_tmp_name,
+						  or_tmp_name, addr_tmp_name);
+          SSA_NAME_DEF_STMT (new_or_tmp_name) = or_stmt;
+	  gimple_seq_add_stmt (cond_expr_stmt_list, or_stmt);
+          or_tmp_name = new_or_tmp_name;
+        }
+      else
+        or_tmp_name = addr_tmp_name;
+
+    } /* end for i */
+
+  mask_cst = build_int_cst (int_ptrsize_type, mask);
+
+  /* create: and_tmp = or_tmp & mask  */
+  and_tmp = create_tmp_var (int_ptrsize_type, "andmask" );
+  add_referenced_var (and_tmp);
+  and_tmp_name = make_ssa_name (and_tmp, NULL);
+
+  and_stmt = gimple_build_assign_with_ops (BIT_AND_EXPR, and_tmp_name,
+					   or_tmp_name, mask_cst);
+  SSA_NAME_DEF_STMT (and_tmp_name) = and_stmt;
+  gimple_seq_add_stmt (cond_expr_stmt_list, and_stmt);
+
+  /* Make and_tmp the left operand of the conditional test against zero.
+     if and_tmp has a nonzero bit then some address is unaligned.  */
+  ptrsize_zero = build_int_cst (int_ptrsize_type, 0);
+  part_cond_expr = fold_build2 (EQ_EXPR, boolean_type_node,
+				and_tmp_name, ptrsize_zero);
+  if (*cond_expr)
+    *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
+			      *cond_expr, part_cond_expr);
+  else
+    *cond_expr = part_cond_expr;
+}
+
+
+/* Function vect_vfa_segment_size.
+
+   Create an expression that computes the size of segment
+   that will be accessed for a data reference.  The functions takes into
+   account that realignment loads may access one more vector.
+
+   Input:
+     DR: The data reference.
+     VECT_FACTOR: vectorization factor.
+
+   Return an expression whose value is the size of segment which will be
+   accessed by DR.  */
+
+static tree
+vect_vfa_segment_size (struct data_reference *dr, tree vect_factor)
+{
+  tree segment_length = fold_build2 (MULT_EXPR, integer_type_node,
+			             DR_STEP (dr), vect_factor);
+
+  if (vect_supportable_dr_alignment (dr) == dr_explicit_realign_optimized)
+    {
+      tree vector_size = TYPE_SIZE_UNIT
+			  (STMT_VINFO_VECTYPE (vinfo_for_stmt (DR_STMT (dr))));
+
+      segment_length = fold_build2 (PLUS_EXPR, integer_type_node,
+				    segment_length, vector_size);
+    }
+  return fold_convert (sizetype, segment_length);
+}
+
+
+/* Function vect_create_cond_for_alias_checks.
+
+   Create a conditional expression that represents the run-time checks for
+   overlapping of address ranges represented by a list of data references
+   relations passed as input.
+
+   Input:
+   COND_EXPR  - input conditional expression.  New conditions will be chained
+                with logical AND operation.
+   LOOP_VINFO - field LOOP_VINFO_MAY_ALIAS_STMTS contains the list of ddrs
+	        to be checked.
+
+   Output:
+   COND_EXPR - conditional expression.
+   COND_EXPR_STMT_LIST - statements needed to construct the conditional
+                         expression.
+
+
+   The returned value is the conditional expression to be used in the if
+   statement that controls which version of the loop gets executed at runtime.
+*/
+
+static void
+vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo,
+				   tree * cond_expr,
+				   gimple_seq * cond_expr_stmt_list)
+{
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  VEC (ddr_p, heap) * may_alias_ddrs =
+    LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo);
+  tree vect_factor =
+    build_int_cst (integer_type_node, LOOP_VINFO_VECT_FACTOR (loop_vinfo));
+
+  ddr_p ddr;
+  unsigned int i;
+  tree part_cond_expr;
+
+  /* Create expression
+     ((store_ptr_0 + store_segment_length_0) < load_ptr_0)
+     || (load_ptr_0 + load_segment_length_0) < store_ptr_0))
+     &&         
+     ...
+     &&
+     ((store_ptr_n + store_segment_length_n) < load_ptr_n)
+     || (load_ptr_n + load_segment_length_n) < store_ptr_n))  */
+
+  if (VEC_empty (ddr_p, may_alias_ddrs))
+    return;
+
+  for (i = 0; VEC_iterate (ddr_p, may_alias_ddrs, i, ddr); i++)
+    {
+      struct data_reference *dr_a, *dr_b;
+      gimple dr_group_first_a, dr_group_first_b;
+      tree addr_base_a, addr_base_b;
+      tree segment_length_a, segment_length_b;
+      gimple stmt_a, stmt_b;
+
+      dr_a = DDR_A (ddr);
+      stmt_a = DR_STMT (DDR_A (ddr));
+      dr_group_first_a = DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_a));
+      if (dr_group_first_a)
+        {
+	  stmt_a = dr_group_first_a;
+	  dr_a = STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt_a));
+	}
+
+      dr_b = DDR_B (ddr);
+      stmt_b = DR_STMT (DDR_B (ddr));
+      dr_group_first_b = DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_b));
+      if (dr_group_first_b)
+        {
+	  stmt_b = dr_group_first_b;
+	  dr_b = STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt_b));
+	}
+
+      addr_base_a =
+        vect_create_addr_base_for_vector_ref (stmt_a, cond_expr_stmt_list,
+					      NULL_TREE, loop);
+      addr_base_b =
+        vect_create_addr_base_for_vector_ref (stmt_b, cond_expr_stmt_list,
+					      NULL_TREE, loop);
+
+      segment_length_a = vect_vfa_segment_size (dr_a, vect_factor);
+      segment_length_b = vect_vfa_segment_size (dr_b, vect_factor);
+
+      if (vect_print_dump_info (REPORT_DR_DETAILS))
+	{
+	  fprintf (vect_dump,
+		   "create runtime check for data references ");
+	  print_generic_expr (vect_dump, DR_REF (dr_a), TDF_SLIM);
+	  fprintf (vect_dump, " and ");
+	  print_generic_expr (vect_dump, DR_REF (dr_b), TDF_SLIM);
+	}
+
+
+      part_cond_expr = 
+      	fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+	  fold_build2 (LT_EXPR, boolean_type_node,
+	    fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_a),
+	      addr_base_a,
+	      segment_length_a),
+	    addr_base_b),
+	  fold_build2 (LT_EXPR, boolean_type_node,
+	    fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_b),
+	      addr_base_b,
+	      segment_length_b),
+	    addr_base_a));
+      
+      if (*cond_expr)
+	*cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
+				  *cond_expr, part_cond_expr);
+      else
+	*cond_expr = part_cond_expr;
+    }
+    if (vect_print_dump_info (REPORT_VECTORIZED_LOOPS))
+      fprintf (vect_dump, "created %u versioning for alias checks.\n",
+               VEC_length (ddr_p, may_alias_ddrs));
+
+}
+
+
+/* Function vect_loop_versioning.
+ 
+   If the loop has data references that may or may not be aligned or/and
+   has data reference relations whose independence was not proven then
+   two versions of the loop need to be generated, one which is vectorized
+   and one which isn't.  A test is then generated to control which of the
+   loops is executed.  The test checks for the alignment of all of the
+   data references that may or may not be aligned.  An additional
+   sequence of runtime tests is generated for each pairs of DDRs whose
+   independence was not proven.  The vectorized version of loop is 
+   executed only if both alias and alignment tests are passed.  
+  
+   The test generated to check which version of loop is executed
+   is modified to also check for profitability as indicated by the 
+   cost model initially.  */
+
+void
+vect_loop_versioning (loop_vec_info loop_vinfo)
+{
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+  struct loop *nloop;
+  tree cond_expr = NULL_TREE;
+  gimple_seq cond_expr_stmt_list = NULL;
+  basic_block condition_bb;
+  gimple_stmt_iterator gsi, cond_exp_gsi;
+  basic_block merge_bb;
+  basic_block new_exit_bb;
+  edge new_exit_e, e;
+  gimple orig_phi, new_phi;
+  tree arg;
+  unsigned prob = 4 * REG_BR_PROB_BASE / 5;
+  gimple_seq gimplify_stmt_list = NULL;
+  tree scalar_loop_iters = LOOP_VINFO_NITERS (loop_vinfo);
+  int min_profitable_iters = 0;
+  unsigned int th;
+
+  /* Get profitability threshold for vectorized loop.  */
+  min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo);
+
+  th = conservative_cost_threshold (loop_vinfo,
+				    min_profitable_iters);
+
+  cond_expr =
+    fold_build2 (GT_EXPR, boolean_type_node, scalar_loop_iters, 
+ 	         build_int_cst (TREE_TYPE (scalar_loop_iters), th));
+
+  cond_expr = force_gimple_operand (cond_expr, &cond_expr_stmt_list,
+				    false, NULL_TREE);
+
+  if (VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)))
+      vect_create_cond_for_align_checks (loop_vinfo, &cond_expr,
+					 &cond_expr_stmt_list);
+
+  if (VEC_length (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo)))
+    vect_create_cond_for_alias_checks (loop_vinfo, &cond_expr, 
+				       &cond_expr_stmt_list);
+
+  cond_expr =
+    fold_build2 (NE_EXPR, boolean_type_node, cond_expr, integer_zero_node);
+  cond_expr =
+    force_gimple_operand (cond_expr, &gimplify_stmt_list, true, NULL_TREE);
+  gimple_seq_add_seq (&cond_expr_stmt_list, gimplify_stmt_list);
+
+  initialize_original_copy_tables ();
+  nloop = loop_version (loop, cond_expr, &condition_bb,
+			prob, prob, REG_BR_PROB_BASE - prob, true);
+  free_original_copy_tables();
+
+  /* Loop versioning violates an assumption we try to maintain during 
+     vectorization - that the loop exit block has a single predecessor.
+     After versioning, the exit block of both loop versions is the same
+     basic block (i.e. it has two predecessors). Just in order to simplify
+     following transformations in the vectorizer, we fix this situation
+     here by adding a new (empty) block on the exit-edge of the loop,
+     with the proper loop-exit phis to maintain loop-closed-form.  */
+  
+  merge_bb = single_exit (loop)->dest;
+  gcc_assert (EDGE_COUNT (merge_bb->preds) == 2);
+  new_exit_bb = split_edge (single_exit (loop));
+  new_exit_e = single_exit (loop);
+  e = EDGE_SUCC (new_exit_bb, 0);
+
+  for (gsi = gsi_start_phis (merge_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      orig_phi = gsi_stmt (gsi);
+      new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)),
+				  new_exit_bb);
+      arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, e);
+      add_phi_arg (new_phi, arg, new_exit_e);
+      SET_PHI_ARG_DEF (orig_phi, e->dest_idx, PHI_RESULT (new_phi));
+    } 
+
+  /* End loop-exit-fixes after versioning.  */
+
+  update_ssa (TODO_update_ssa);
+  if (cond_expr_stmt_list)
+    {
+      cond_exp_gsi = gsi_last_bb (condition_bb);
+      gsi_insert_seq_before (&cond_exp_gsi, cond_expr_stmt_list, GSI_SAME_STMT);
+    }
+}
+