--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/tree-vectorizer.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,2919 @@
+/* Loop Vectorization
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Free Software
+   Foundation, Inc.
+   Contributed by Dorit Naishlos <dorit@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/>.  */
+
+/* Loop Vectorization Pass.
+
+   This pass tries to vectorize loops. This first implementation focuses on
+   simple inner-most loops, with no conditional control flow, and a set of
+   simple operations which vector form can be expressed using existing
+   tree codes (PLUS, MULT etc).
+
+   For example, the vectorizer transforms the following simple loop:
+
+	short a[N]; short b[N]; short c[N]; int i;
+
+	for (i=0; i<N; i++){
+	  a[i] = b[i] + c[i];
+	}
+
+   as if it was manually vectorized by rewriting the source code into:
+
+	typedef int __attribute__((mode(V8HI))) v8hi;
+	short a[N];  short b[N]; short c[N];   int i;
+	v8hi *pa = (v8hi*)a, *pb = (v8hi*)b, *pc = (v8hi*)c;
+	v8hi va, vb, vc;
+
+	for (i=0; i<N/8; i++){
+	  vb = pb[i];
+	  vc = pc[i];
+	  va = vb + vc;
+	  pa[i] = va;
+	}
+
+	The main entry to this pass is vectorize_loops(), in which
+   the vectorizer applies a set of analyses on a given set of loops,
+   followed by the actual vectorization transformation for the loops that
+   had successfully passed the analysis phase.
+
+	Throughout this pass we make a distinction between two types of
+   data: scalars (which are represented by SSA_NAMES), and memory references
+   ("data-refs"). These two types of data require different handling both 
+   during analysis and transformation. The types of data-refs that the 
+   vectorizer currently supports are ARRAY_REFS which base is an array DECL 
+   (not a pointer), and INDIRECT_REFS through pointers; both array and pointer
+   accesses are required to have a  simple (consecutive) access pattern.
+
+   Analysis phase:
+   ===============
+	The driver for the analysis phase is vect_analyze_loop_nest().
+   It applies a set of analyses, some of which rely on the scalar evolution 
+   analyzer (scev) developed by Sebastian Pop.
+
+	During the analysis phase the vectorizer records some information
+   per stmt in a "stmt_vec_info" struct which is attached to each stmt in the 
+   loop, as well as general information about the loop as a whole, which is
+   recorded in a "loop_vec_info" struct attached to each loop.
+
+   Transformation phase:
+   =====================
+	The loop transformation phase scans all the stmts in the loop, and
+   creates a vector stmt (or a sequence of stmts) for each scalar stmt S in
+   the loop that needs to be vectorized. It insert the vector code sequence
+   just before the scalar stmt S, and records a pointer to the vector code
+   in STMT_VINFO_VEC_STMT (stmt_info) (stmt_info is the stmt_vec_info struct 
+   attached to S). This pointer will be used for the vectorization of following
+   stmts which use the def of stmt S. Stmt S is removed if it writes to memory;
+   otherwise, we rely on dead code elimination for removing it.
+
+	For example, say stmt S1 was vectorized into stmt VS1:
+
+   VS1: vb = px[i];
+   S1:	b = x[i];    STMT_VINFO_VEC_STMT (stmt_info (S1)) = VS1
+   S2:  a = b;
+
+   To vectorize stmt S2, the vectorizer first finds the stmt that defines
+   the operand 'b' (S1), and gets the relevant vector def 'vb' from the
+   vector stmt VS1 pointed to by STMT_VINFO_VEC_STMT (stmt_info (S1)). The
+   resulting sequence would be:
+
+   VS1: vb = px[i];
+   S1:	b = x[i];	STMT_VINFO_VEC_STMT (stmt_info (S1)) = VS1
+   VS2: va = vb;
+   S2:  a = b;          STMT_VINFO_VEC_STMT (stmt_info (S2)) = VS2
+
+	Operands that are not SSA_NAMEs, are data-refs that appear in 
+   load/store operations (like 'x[i]' in S1), and are handled differently.
+
+   Target modeling:
+   =================
+	Currently the only target specific information that is used is the
+   size of the vector (in bytes) - "UNITS_PER_SIMD_WORD". Targets that can 
+   support different sizes of vectors, for now will need to specify one value 
+   for "UNITS_PER_SIMD_WORD". More flexibility will be added in the future.
+
+	Since we only vectorize operations which vector form can be
+   expressed using existing tree codes, to verify that an operation is
+   supported, the vectorizer checks the relevant optab at the relevant
+   machine_mode (e.g, optab_handler (add_optab, V8HImode)->insn_code). If
+   the value found is CODE_FOR_nothing, then there's no target support, and
+   we can't vectorize the stmt.
+
+   For additional information on this project see:
+   http://gcc.gnu.org/projects/tree-ssa/vectorization.html
+*/
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "ggc.h"
+#include "tree.h"
+#include "target.h"
+#include "rtl.h"
+#include "basic-block.h"
+#include "diagnostic.h"
+#include "tree-flow.h"
+#include "tree-dump.h"
+#include "timevar.h"
+#include "cfgloop.h"
+#include "cfglayout.h"
+#include "expr.h"
+#include "recog.h"
+#include "optabs.h"
+#include "params.h"
+#include "toplev.h"
+#include "tree-chrec.h"
+#include "tree-data-ref.h"
+#include "tree-scalar-evolution.h"
+#include "input.h"
+#include "hashtab.h"
+#include "tree-vectorizer.h"
+#include "tree-pass.h"
+#include "langhooks.h"
+
+/*************************************************************************
+  General Vectorization Utilities
+ *************************************************************************/
+
+/* vect_dump will be set to stderr or dump_file if exist.  */
+FILE *vect_dump;
+
+/* vect_verbosity_level set to an invalid value 
+   to mark that it's uninitialized.  */
+enum verbosity_levels vect_verbosity_level = MAX_VERBOSITY_LEVEL;
+
+/* Loop location.  */
+static LOC vect_loop_location;
+
+/* Bitmap of virtual variables to be renamed.  */
+bitmap vect_memsyms_to_rename;
+
+/* Vector mapping GIMPLE stmt to stmt_vec_info. */
+VEC(vec_void_p,heap) *stmt_vec_info_vec;
+
+
+/*************************************************************************
+  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
+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.  */
+
+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.
+*/
+
+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;
+}
+
+
+/*************************************************************************
+  Vectorization Debug Information.
+ *************************************************************************/
+
+/* Function vect_set_verbosity_level.
+
+   Called from toplev.c upon detection of the
+   -ftree-vectorizer-verbose=N option.  */
+
+void
+vect_set_verbosity_level (const char *val)
+{
+   unsigned int vl;
+
+   vl = atoi (val);
+   if (vl < MAX_VERBOSITY_LEVEL)
+     vect_verbosity_level = vl;
+   else
+     vect_verbosity_level = MAX_VERBOSITY_LEVEL - 1;
+}
+
+
+/* Function vect_set_dump_settings.
+
+   Fix the verbosity level of the vectorizer if the
+   requested level was not set explicitly using the flag
+   -ftree-vectorizer-verbose=N.
+   Decide where to print the debugging information (dump_file/stderr).
+   If the user defined the verbosity level, but there is no dump file,
+   print to stderr, otherwise print to the dump file.  */
+
+static void
+vect_set_dump_settings (void)
+{
+  vect_dump = dump_file;
+
+  /* Check if the verbosity level was defined by the user:  */
+  if (vect_verbosity_level != MAX_VERBOSITY_LEVEL)
+    {
+      /* If there is no dump file, print to stderr.  */
+      if (!dump_file)
+        vect_dump = stderr;
+      return;
+    }
+
+  /* User didn't specify verbosity level:  */
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    vect_verbosity_level = REPORT_DETAILS;
+  else if (dump_file && (dump_flags & TDF_STATS))
+    vect_verbosity_level = REPORT_UNVECTORIZED_LOOPS;
+  else
+    vect_verbosity_level = REPORT_NONE;
+
+  gcc_assert (dump_file || vect_verbosity_level == REPORT_NONE);
+}
+
+
+/* Function debug_loop_details.
+
+   For vectorization debug dumps.  */
+
+bool
+vect_print_dump_info (enum verbosity_levels vl)
+{
+  if (vl > vect_verbosity_level)
+    return false;
+
+  if (!current_function_decl || !vect_dump)
+    return false;
+
+  if (vect_loop_location == UNKNOWN_LOC)
+    fprintf (vect_dump, "\n%s:%d: note: ",
+	     DECL_SOURCE_FILE (current_function_decl),
+	     DECL_SOURCE_LINE (current_function_decl));
+  else
+    fprintf (vect_dump, "\n%s:%d: note: ", 
+	     LOC_FILE (vect_loop_location), LOC_LINE (vect_loop_location));
+
+  return true;
+}
+
+
+/*************************************************************************
+  Vectorization Utilities.
+ *************************************************************************/
+
+/* Function new_stmt_vec_info.
+
+   Create and initialize a new stmt_vec_info struct for STMT.  */
+
+stmt_vec_info
+new_stmt_vec_info (gimple stmt, loop_vec_info loop_vinfo)
+{
+  stmt_vec_info res;
+  res = (stmt_vec_info) xcalloc (1, sizeof (struct _stmt_vec_info));
+
+  STMT_VINFO_TYPE (res) = undef_vec_info_type;
+  STMT_VINFO_STMT (res) = stmt;
+  STMT_VINFO_LOOP_VINFO (res) = loop_vinfo;
+  STMT_VINFO_RELEVANT (res) = 0;
+  STMT_VINFO_LIVE_P (res) = false;
+  STMT_VINFO_VECTYPE (res) = NULL;
+  STMT_VINFO_VEC_STMT (res) = NULL;
+  STMT_VINFO_IN_PATTERN_P (res) = false;
+  STMT_VINFO_RELATED_STMT (res) = NULL;
+  STMT_VINFO_DATA_REF (res) = NULL;
+
+  STMT_VINFO_DR_BASE_ADDRESS (res) = NULL;
+  STMT_VINFO_DR_OFFSET (res) = NULL;
+  STMT_VINFO_DR_INIT (res) = NULL;
+  STMT_VINFO_DR_STEP (res) = NULL;
+  STMT_VINFO_DR_ALIGNED_TO (res) = NULL;
+
+  if (gimple_code (stmt) == GIMPLE_PHI
+      && is_loop_header_bb_p (gimple_bb (stmt)))
+    STMT_VINFO_DEF_TYPE (res) = vect_unknown_def_type;
+  else
+    STMT_VINFO_DEF_TYPE (res) = vect_loop_def;
+  STMT_VINFO_SAME_ALIGN_REFS (res) = VEC_alloc (dr_p, heap, 5);
+  STMT_VINFO_INSIDE_OF_LOOP_COST (res) = 0;
+  STMT_VINFO_OUTSIDE_OF_LOOP_COST (res) = 0;
+  STMT_SLP_TYPE (res) = 0;
+  DR_GROUP_FIRST_DR (res) = NULL;
+  DR_GROUP_NEXT_DR (res) = NULL;
+  DR_GROUP_SIZE (res) = 0;
+  DR_GROUP_STORE_COUNT (res) = 0;
+  DR_GROUP_GAP (res) = 0;
+  DR_GROUP_SAME_DR_STMT (res) = NULL;
+  DR_GROUP_READ_WRITE_DEPENDENCE (res) = false;
+
+  return res;
+}
+
+/* Create a hash table for stmt_vec_info. */
+
+void
+init_stmt_vec_info_vec (void)
+{
+  gcc_assert (!stmt_vec_info_vec);
+  stmt_vec_info_vec = VEC_alloc (vec_void_p, heap, 50);
+}
+
+/* Free hash table for stmt_vec_info. */
+
+void
+free_stmt_vec_info_vec (void)
+{
+  gcc_assert (stmt_vec_info_vec);
+  VEC_free (vec_void_p, heap, stmt_vec_info_vec);
+}
+
+/* Free stmt vectorization related info.  */
+
+void
+free_stmt_vec_info (gimple stmt)
+{
+  stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+
+  if (!stmt_info)
+    return;
+
+  VEC_free (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmt_info));
+  set_vinfo_for_stmt (stmt, NULL);
+  free (stmt_info);
+}
+
+
+/* Function bb_in_loop_p
+
+   Used as predicate for dfs order traversal of the loop bbs.  */
+
+static bool
+bb_in_loop_p (const_basic_block bb, const void *data)
+{
+  const struct loop *const loop = (const struct loop *)data;
+  if (flow_bb_inside_loop_p (loop, bb))
+    return true;
+  return false;
+}
+
+
+/* Function new_loop_vec_info.
+
+   Create and initialize a new loop_vec_info struct for LOOP, as well as
+   stmt_vec_info structs for all the stmts in LOOP.  */
+
+loop_vec_info
+new_loop_vec_info (struct loop *loop)
+{
+  loop_vec_info res;
+  basic_block *bbs;
+  gimple_stmt_iterator si;
+  unsigned int i, nbbs;
+
+  res = (loop_vec_info) xcalloc (1, sizeof (struct _loop_vec_info));
+  LOOP_VINFO_LOOP (res) = loop;
+
+  bbs = get_loop_body (loop);
+
+  /* Create/Update stmt_info for all stmts in the loop.  */
+  for (i = 0; i < loop->num_nodes; i++)
+    {
+      basic_block bb = bbs[i];
+
+      /* BBs in a nested inner-loop will have been already processed (because 
+	 we will have called vect_analyze_loop_form for any nested inner-loop).
+	 Therefore, for stmts in an inner-loop we just want to update the 
+	 STMT_VINFO_LOOP_VINFO field of their stmt_info to point to the new 
+	 loop_info of the outer-loop we are currently considering to vectorize 
+	 (instead of the loop_info of the inner-loop).
+	 For stmts in other BBs we need to create a stmt_info from scratch.  */
+      if (bb->loop_father != loop)
+	{
+	  /* Inner-loop bb.  */
+	  gcc_assert (loop->inner && bb->loop_father == loop->inner);
+	  for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
+	    {
+	      gimple phi = gsi_stmt (si);
+	      stmt_vec_info stmt_info = vinfo_for_stmt (phi);
+	      loop_vec_info inner_loop_vinfo =
+		STMT_VINFO_LOOP_VINFO (stmt_info);
+	      gcc_assert (loop->inner == LOOP_VINFO_LOOP (inner_loop_vinfo));
+	      STMT_VINFO_LOOP_VINFO (stmt_info) = res;
+	    }
+	  for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
+	   {
+	      gimple stmt = gsi_stmt (si);
+	      stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+	      loop_vec_info inner_loop_vinfo =
+		 STMT_VINFO_LOOP_VINFO (stmt_info);
+	      gcc_assert (loop->inner == LOOP_VINFO_LOOP (inner_loop_vinfo));
+	      STMT_VINFO_LOOP_VINFO (stmt_info) = res;
+	   }
+	}
+      else
+	{
+	  /* bb in current nest.  */
+	  for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
+	    {
+	      gimple phi = gsi_stmt (si);
+	      gimple_set_uid (phi, 0);
+	      set_vinfo_for_stmt (phi, new_stmt_vec_info (phi, res));
+	    }
+
+	  for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
+	    {
+	      gimple stmt = gsi_stmt (si);
+	      gimple_set_uid (stmt, 0);
+	      set_vinfo_for_stmt (stmt, new_stmt_vec_info (stmt, res));
+	    }
+	}
+    }
+
+  /* CHECKME: We want to visit all BBs before their successors (except for 
+     latch blocks, for which this assertion wouldn't hold).  In the simple 
+     case of the loop forms we allow, a dfs order of the BBs would the same 
+     as reversed postorder traversal, so we are safe.  */
+
+   free (bbs);
+   bbs = XCNEWVEC (basic_block, loop->num_nodes);
+   nbbs = dfs_enumerate_from (loop->header, 0, bb_in_loop_p, 
+			      bbs, loop->num_nodes, loop);
+   gcc_assert (nbbs == loop->num_nodes);
+
+  LOOP_VINFO_BBS (res) = bbs;
+  LOOP_VINFO_NITERS (res) = NULL;
+  LOOP_VINFO_NITERS_UNCHANGED (res) = NULL;
+  LOOP_VINFO_COST_MODEL_MIN_ITERS (res) = 0;
+  LOOP_VINFO_VECTORIZABLE_P (res) = 0;
+  LOOP_PEELING_FOR_ALIGNMENT (res) = 0;
+  LOOP_VINFO_VECT_FACTOR (res) = 0;
+  LOOP_VINFO_DATAREFS (res) = VEC_alloc (data_reference_p, heap, 10);
+  LOOP_VINFO_DDRS (res) = VEC_alloc (ddr_p, heap, 10 * 10);
+  LOOP_VINFO_UNALIGNED_DR (res) = NULL;
+  LOOP_VINFO_MAY_MISALIGN_STMTS (res) =
+    VEC_alloc (gimple, heap,
+	       PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS));
+  LOOP_VINFO_MAY_ALIAS_DDRS (res) =
+    VEC_alloc (ddr_p, heap,
+	       PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS));
+  LOOP_VINFO_STRIDED_STORES (res) = VEC_alloc (gimple, heap, 10);
+  LOOP_VINFO_SLP_INSTANCES (res) = VEC_alloc (slp_instance, heap, 10);
+  LOOP_VINFO_SLP_UNROLLING_FACTOR (res) = 1;
+
+  return res;
+}
+
+
+/* Function destroy_loop_vec_info.
+ 
+   Free LOOP_VINFO struct, as well as all the stmt_vec_info structs of all the 
+   stmts in the loop.  */
+
+void
+destroy_loop_vec_info (loop_vec_info loop_vinfo, bool clean_stmts)
+{
+  struct loop *loop;
+  basic_block *bbs;
+  int nbbs;
+  gimple_stmt_iterator si;
+  int j;
+  VEC (slp_instance, heap) *slp_instances;
+  slp_instance instance;
+
+  if (!loop_vinfo)
+    return;
+
+  loop = LOOP_VINFO_LOOP (loop_vinfo);
+
+  bbs = LOOP_VINFO_BBS (loop_vinfo);
+  nbbs = loop->num_nodes;
+
+  if (!clean_stmts)
+    {
+      free (LOOP_VINFO_BBS (loop_vinfo));
+      free_data_refs (LOOP_VINFO_DATAREFS (loop_vinfo));
+      free_dependence_relations (LOOP_VINFO_DDRS (loop_vinfo));
+      VEC_free (gimple, heap, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo));
+
+      free (loop_vinfo);
+      loop->aux = NULL;
+      return;
+    }
+
+  for (j = 0; j < nbbs; j++)
+    {
+      basic_block bb = bbs[j];
+
+      for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
+        free_stmt_vec_info (gsi_stmt (si));
+
+      for (si = gsi_start_bb (bb); !gsi_end_p (si); )
+	{
+	  gimple stmt = gsi_stmt (si);
+	  stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+
+	  if (stmt_info)
+	    {
+	      /* Check if this is a "pattern stmt" (introduced by the 
+		 vectorizer during the pattern recognition pass).  */
+	      bool remove_stmt_p = false;
+	      gimple orig_stmt = STMT_VINFO_RELATED_STMT (stmt_info);
+	      if (orig_stmt)
+		{
+		  stmt_vec_info orig_stmt_info = vinfo_for_stmt (orig_stmt);
+		  if (orig_stmt_info
+		      && STMT_VINFO_IN_PATTERN_P (orig_stmt_info))
+		    remove_stmt_p = true; 
+		}
+			
+	      /* Free stmt_vec_info.  */
+	      free_stmt_vec_info (stmt);
+
+	      /* Remove dead "pattern stmts".  */
+	      if (remove_stmt_p)
+	        gsi_remove (&si, true);
+	    }
+	  gsi_next (&si);
+	}
+    }
+
+  free (LOOP_VINFO_BBS (loop_vinfo));
+  free_data_refs (LOOP_VINFO_DATAREFS (loop_vinfo));
+  free_dependence_relations (LOOP_VINFO_DDRS (loop_vinfo));
+  VEC_free (gimple, heap, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo));
+  VEC_free (ddr_p, heap, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo));
+  slp_instances = LOOP_VINFO_SLP_INSTANCES (loop_vinfo);
+  for (j = 0; VEC_iterate (slp_instance, slp_instances, j, instance); j++)
+    vect_free_slp_instance (instance);
+
+  VEC_free (slp_instance, heap, LOOP_VINFO_SLP_INSTANCES (loop_vinfo));
+  VEC_free (gimple, heap, LOOP_VINFO_STRIDED_STORES (loop_vinfo));
+
+  free (loop_vinfo);
+  loop->aux = NULL;
+}
+
+
+/* Function vect_force_dr_alignment_p.
+
+   Returns whether the alignment of a DECL can be forced to be aligned
+   on ALIGNMENT bit boundary.  */
+
+bool 
+vect_can_force_dr_alignment_p (const_tree decl, unsigned int alignment)
+{
+  if (TREE_CODE (decl) != VAR_DECL)
+    return false;
+
+  if (DECL_EXTERNAL (decl))
+    return false;
+
+  if (TREE_ASM_WRITTEN (decl))
+    return false;
+
+  if (TREE_STATIC (decl))
+    return (alignment <= MAX_OFILE_ALIGNMENT);
+  else
+    return (alignment <= MAX_STACK_ALIGNMENT);
+}
+
+
+/* Function get_vectype_for_scalar_type.
+
+   Returns the vector type corresponding to SCALAR_TYPE as supported
+   by the target.  */
+
+tree
+get_vectype_for_scalar_type (tree scalar_type)
+{
+  enum machine_mode inner_mode = TYPE_MODE (scalar_type);
+  int nbytes = GET_MODE_SIZE (inner_mode);
+  int nunits;
+  tree vectype;
+
+  if (nbytes == 0 || nbytes >= UNITS_PER_SIMD_WORD (inner_mode))
+    return NULL_TREE;
+
+  /* FORNOW: Only a single vector size per mode (UNITS_PER_SIMD_WORD)
+     is expected.  */
+  nunits = UNITS_PER_SIMD_WORD (inner_mode) / nbytes;
+
+  vectype = build_vector_type (scalar_type, nunits);
+  if (vect_print_dump_info (REPORT_DETAILS))
+    {
+      fprintf (vect_dump, "get vectype with %d units of type ", nunits);
+      print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
+    }
+
+  if (!vectype)
+    return NULL_TREE;
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    {
+      fprintf (vect_dump, "vectype: ");
+      print_generic_expr (vect_dump, vectype, TDF_SLIM);
+    }
+
+  if (!VECTOR_MODE_P (TYPE_MODE (vectype))
+      && !INTEGRAL_MODE_P (TYPE_MODE (vectype)))
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "mode not supported by target.");
+      return NULL_TREE;
+    }
+
+  return vectype;
+}
+
+
+/* Function vect_supportable_dr_alignment
+
+   Return whether the data reference DR is supported with respect to its
+   alignment.  */
+
+enum dr_alignment_support
+vect_supportable_dr_alignment (struct data_reference *dr)
+{
+  gimple stmt = DR_STMT (dr);
+  stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+  tree vectype = STMT_VINFO_VECTYPE (stmt_info);
+  enum machine_mode mode = (int) TYPE_MODE (vectype);
+  struct loop *vect_loop = LOOP_VINFO_LOOP (STMT_VINFO_LOOP_VINFO (stmt_info));
+  bool nested_in_vect_loop = nested_in_vect_loop_p (vect_loop, stmt);
+  bool invariant_in_outerloop = false;
+
+  if (aligned_access_p (dr))
+    return dr_aligned;
+
+  if (nested_in_vect_loop)
+    {
+      tree outerloop_step = STMT_VINFO_DR_STEP (stmt_info);
+      invariant_in_outerloop =
+	(tree_int_cst_compare (outerloop_step, size_zero_node) == 0);
+    }
+
+  /* Possibly unaligned access.  */
+
+  /* We can choose between using the implicit realignment scheme (generating
+     a misaligned_move stmt) and the explicit realignment scheme (generating
+     aligned loads with a REALIGN_LOAD). There are two variants to the explicit
+     realignment scheme: optimized, and unoptimized.
+     We can optimize the realignment only if the step between consecutive
+     vector loads is equal to the vector size.  Since the vector memory
+     accesses advance in steps of VS (Vector Size) in the vectorized loop, it
+     is guaranteed that the misalignment amount remains the same throughout the
+     execution of the vectorized loop.  Therefore, we can create the
+     "realignment token" (the permutation mask that is passed to REALIGN_LOAD)
+     at the loop preheader.
+
+     However, in the case of outer-loop vectorization, when vectorizing a
+     memory access in the inner-loop nested within the LOOP that is now being
+     vectorized, while it is guaranteed that the misalignment of the
+     vectorized memory access will remain the same in different outer-loop
+     iterations, it is *not* guaranteed that is will remain the same throughout
+     the execution of the inner-loop.  This is because the inner-loop advances
+     with the original scalar step (and not in steps of VS).  If the inner-loop
+     step happens to be a multiple of VS, then the misalignment remains fixed
+     and we can use the optimized realignment scheme.  For example:
+
+      for (i=0; i<N; i++)
+        for (j=0; j<M; j++)
+          s += a[i+j];
+
+     When vectorizing the i-loop in the above example, the step between
+     consecutive vector loads is 1, and so the misalignment does not remain
+     fixed across the execution of the inner-loop, and the realignment cannot
+     be optimized (as illustrated in the following pseudo vectorized loop):
+
+      for (i=0; i<N; i+=4)
+        for (j=0; j<M; j++){
+          vs += vp[i+j]; // misalignment of &vp[i+j] is {0,1,2,3,0,1,2,3,...}
+                         // when j is {0,1,2,3,4,5,6,7,...} respectively.
+                         // (assuming that we start from an aligned address).
+          }
+
+     We therefore have to use the unoptimized realignment scheme:
+
+      for (i=0; i<N; i+=4)
+          for (j=k; j<M; j+=4)
+          vs += vp[i+j]; // misalignment of &vp[i+j] is always k (assuming
+                           // that the misalignment of the initial address is
+                           // 0).
+
+     The loop can then be vectorized as follows:
+
+      for (k=0; k<4; k++){
+        rt = get_realignment_token (&vp[k]);
+        for (i=0; i<N; i+=4){
+          v1 = vp[i+k];
+          for (j=k; j<M; j+=4){
+            v2 = vp[i+j+VS-1];
+            va = REALIGN_LOAD <v1,v2,rt>;
+            vs += va;
+            v1 = v2;
+          }
+        }
+    } */
+
+  if (DR_IS_READ (dr))
+    {
+      if (optab_handler (vec_realign_load_optab, mode)->insn_code != 
+						   	     CODE_FOR_nothing
+	  && (!targetm.vectorize.builtin_mask_for_load
+	      || targetm.vectorize.builtin_mask_for_load ()))
+	{
+	  tree vectype = STMT_VINFO_VECTYPE (stmt_info);
+	  if (nested_in_vect_loop
+	      && (TREE_INT_CST_LOW (DR_STEP (dr))
+		  != GET_MODE_SIZE (TYPE_MODE (vectype))))
+	    return dr_explicit_realign;
+	  else
+	    return dr_explicit_realign_optimized;
+	}
+
+      if (optab_handler (movmisalign_optab, mode)->insn_code != 
+							     CODE_FOR_nothing)
+	/* Can't software pipeline the loads, but can at least do them.  */
+	return dr_unaligned_supported;
+    }
+
+  /* Unsupported.  */
+  return dr_unaligned_unsupported;
+}
+
+
+/* Function vect_is_simple_use.
+
+   Input:
+   LOOP - the loop that is being vectorized.
+   OPERAND - operand of a stmt in LOOP.
+   DEF - the defining stmt in case OPERAND is an SSA_NAME.
+
+   Returns whether a stmt with OPERAND can be vectorized.
+   Supportable operands are constants, loop invariants, and operands that are
+   defined by the current iteration of the loop. Unsupportable operands are 
+   those that are defined by a previous iteration of the loop (as is the case
+   in reduction/induction computations).  */
+
+bool
+vect_is_simple_use (tree operand, loop_vec_info loop_vinfo, gimple *def_stmt,
+		    tree *def, enum vect_def_type *dt)
+{ 
+  basic_block bb;
+  stmt_vec_info stmt_vinfo;
+  struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
+
+  *def_stmt = NULL;
+  *def = NULL_TREE;
+  
+  if (vect_print_dump_info (REPORT_DETAILS))
+    {
+      fprintf (vect_dump, "vect_is_simple_use: operand ");
+      print_generic_expr (vect_dump, operand, TDF_SLIM);
+    }
+    
+  if (TREE_CODE (operand) == INTEGER_CST || TREE_CODE (operand) == REAL_CST)
+    {
+      *dt = vect_constant_def;
+      return true;
+    }
+  if (is_gimple_min_invariant (operand))
+    {
+      *def = operand;
+      *dt = vect_invariant_def;
+      return true;
+    }
+
+  if (TREE_CODE (operand) == PAREN_EXPR)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "non-associatable copy.");
+      operand = TREE_OPERAND (operand, 0);
+    }
+  if (TREE_CODE (operand) != SSA_NAME)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "not ssa-name.");
+      return false;
+    }
+    
+  *def_stmt = SSA_NAME_DEF_STMT (operand);
+  if (*def_stmt == NULL)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "no def_stmt.");
+      return false;
+    }
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    {
+      fprintf (vect_dump, "def_stmt: ");
+      print_gimple_stmt (vect_dump, *def_stmt, 0, TDF_SLIM);
+    }
+
+  /* empty stmt is expected only in case of a function argument.
+     (Otherwise - we expect a phi_node or a GIMPLE_ASSIGN).  */
+  if (gimple_nop_p (*def_stmt))
+    {
+      *def = operand;
+      *dt = vect_invariant_def;
+      return true;
+    }
+
+  bb = gimple_bb (*def_stmt);
+  if (!flow_bb_inside_loop_p (loop, bb))
+    *dt = vect_invariant_def;
+  else
+    {
+      stmt_vinfo = vinfo_for_stmt (*def_stmt);
+      *dt = STMT_VINFO_DEF_TYPE (stmt_vinfo);
+    }
+
+  if (*dt == vect_unknown_def_type)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "Unsupported pattern.");
+      return false;
+    }
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    fprintf (vect_dump, "type of def: %d.",*dt);
+
+  switch (gimple_code (*def_stmt))
+    {
+    case GIMPLE_PHI:
+      *def = gimple_phi_result (*def_stmt);
+      break;
+
+    case GIMPLE_ASSIGN:
+      *def = gimple_assign_lhs (*def_stmt);
+      break;
+
+    case GIMPLE_CALL:
+      *def = gimple_call_lhs (*def_stmt);
+      if (*def != NULL)
+	break;
+      /* FALLTHRU */
+    default:
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "unsupported defining stmt: ");
+      return false;
+    }
+
+  return true;
+}
+
+
+/* Function supportable_widening_operation
+
+   Check whether an operation represented by the code CODE is a 
+   widening operation that is supported by the target platform in 
+   vector form (i.e., when operating on arguments of type VECTYPE).
+    
+   Widening operations we currently support are NOP (CONVERT), FLOAT
+   and WIDEN_MULT.  This function checks if these operations are supported
+   by the target platform either directly (via vector tree-codes), or via
+   target builtins.
+
+   Output:
+   - CODE1 and CODE2 are codes of vector operations to be used when 
+   vectorizing the operation, if available. 
+   - DECL1 and DECL2 are decls of target builtin functions to be used
+   when vectorizing the operation, if available. In this case,
+   CODE1 and CODE2 are CALL_EXPR.  
+   - MULTI_STEP_CVT determines the number of required intermediate steps in
+   case of multi-step conversion (like char->short->int - in that case
+   MULTI_STEP_CVT will be 1).
+   - INTERM_TYPES contains the intermediate type required to perform the 
+   widening operation (short in the above example).  */   
+
+bool
+supportable_widening_operation (enum tree_code code, gimple stmt, tree vectype,
+                                tree *decl1, tree *decl2,
+                                enum tree_code *code1, enum tree_code *code2,
+                                int *multi_step_cvt,
+                                VEC (tree, heap) **interm_types)
+{
+  stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+  loop_vec_info loop_info = STMT_VINFO_LOOP_VINFO (stmt_info);
+  struct loop *vect_loop = LOOP_VINFO_LOOP (loop_info);
+  bool ordered_p;
+  enum machine_mode vec_mode;
+  enum insn_code icode1 = 0, icode2 = 0;
+  optab optab1, optab2;
+  tree type = gimple_expr_type (stmt);
+  tree wide_vectype = get_vectype_for_scalar_type (type);
+  enum tree_code c1, c2;
+
+  /* The result of a vectorized widening operation usually requires two vectors
+     (because the widened results do not fit int one vector). The generated 
+     vector results would normally be expected to be generated in the same 
+     order as in the original scalar computation, i.e. if 8 results are
+     generated in each vector iteration, they are to be organized as follows:
+        vect1: [res1,res2,res3,res4], vect2: [res5,res6,res7,res8]. 
+
+     However, in the special case that the result of the widening operation is 
+     used in a reduction computation only, the order doesn't matter (because
+     when vectorizing a reduction we change the order of the computation). 
+     Some targets can take advantage of this and generate more efficient code.
+     For example, targets like Altivec, that support widen_mult using a sequence
+     of {mult_even,mult_odd} generate the following vectors:
+        vect1: [res1,res3,res5,res7], vect2: [res2,res4,res6,res8].
+
+     When vectorizing outer-loops, we execute the inner-loop sequentially
+     (each vectorized inner-loop iteration contributes to VF outer-loop 
+     iterations in parallel). We therefore don't allow to change the order 
+     of the computation in the inner-loop during outer-loop vectorization.  */
+
+   if (STMT_VINFO_RELEVANT (stmt_info) == vect_used_by_reduction
+       && !nested_in_vect_loop_p (vect_loop, stmt))
+     ordered_p = false;
+   else
+     ordered_p = true;
+
+  if (!ordered_p
+      && code == WIDEN_MULT_EXPR
+      && targetm.vectorize.builtin_mul_widen_even
+      && targetm.vectorize.builtin_mul_widen_even (vectype)
+      && targetm.vectorize.builtin_mul_widen_odd
+      && targetm.vectorize.builtin_mul_widen_odd (vectype))
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "Unordered widening operation detected.");
+
+      *code1 = *code2 = CALL_EXPR;
+      *decl1 = targetm.vectorize.builtin_mul_widen_even (vectype);
+      *decl2 = targetm.vectorize.builtin_mul_widen_odd (vectype);
+      return true;
+    }
+
+  switch (code)
+    {
+    case WIDEN_MULT_EXPR:
+      if (BYTES_BIG_ENDIAN)
+        {
+          c1 = VEC_WIDEN_MULT_HI_EXPR;
+          c2 = VEC_WIDEN_MULT_LO_EXPR;
+        }
+      else
+        {
+          c2 = VEC_WIDEN_MULT_HI_EXPR;
+          c1 = VEC_WIDEN_MULT_LO_EXPR;
+        }
+      break;
+
+    CASE_CONVERT:
+      if (BYTES_BIG_ENDIAN)
+        {
+          c1 = VEC_UNPACK_HI_EXPR;
+          c2 = VEC_UNPACK_LO_EXPR;
+        }
+      else
+        {
+          c2 = VEC_UNPACK_HI_EXPR;
+          c1 = VEC_UNPACK_LO_EXPR;
+        }
+      break;
+
+    case FLOAT_EXPR:
+      if (BYTES_BIG_ENDIAN)
+        {
+          c1 = VEC_UNPACK_FLOAT_HI_EXPR;
+          c2 = VEC_UNPACK_FLOAT_LO_EXPR;
+        }
+      else
+        {
+          c2 = VEC_UNPACK_FLOAT_HI_EXPR;
+          c1 = VEC_UNPACK_FLOAT_LO_EXPR;
+        }
+      break;
+
+    case FIX_TRUNC_EXPR:
+      /* ??? Not yet implemented due to missing VEC_UNPACK_FIX_TRUNC_HI_EXPR/
+	 VEC_UNPACK_FIX_TRUNC_LO_EXPR tree codes and optabs used for
+	 computing the operation.  */
+      return false;
+
+    default:
+      gcc_unreachable ();
+    }
+
+  if (code == FIX_TRUNC_EXPR)
+    {
+      /* The signedness is determined from output operand.  */
+      optab1 = optab_for_tree_code (c1, type, optab_default);
+      optab2 = optab_for_tree_code (c2, type, optab_default);
+    }
+  else
+    {
+      optab1 = optab_for_tree_code (c1, vectype, optab_default);
+      optab2 = optab_for_tree_code (c2, vectype, optab_default);
+    }
+
+  if (!optab1 || !optab2)
+    return false;
+
+  vec_mode = TYPE_MODE (vectype);
+  if ((icode1 = optab_handler (optab1, vec_mode)->insn_code) == CODE_FOR_nothing
+       || (icode2 = optab_handler (optab2, vec_mode)->insn_code)
+                                                       == CODE_FOR_nothing)
+    return false;
+
+  /* Check if it's a multi-step conversion that can be done using intermediate 
+     types.  */
+  if (insn_data[icode1].operand[0].mode != TYPE_MODE (wide_vectype)
+       || insn_data[icode2].operand[0].mode != TYPE_MODE (wide_vectype))
+    {
+      int i;
+      tree prev_type = vectype, intermediate_type;
+      enum machine_mode intermediate_mode, prev_mode = vec_mode;
+      optab optab3, optab4;
+
+      if (!CONVERT_EXPR_CODE_P (code))
+        return false;
+      
+      *code1 = c1;
+      *code2 = c2;
+    
+      /* We assume here that there will not be more than MAX_INTERM_CVT_STEPS
+         intermediate  steps in promotion sequence. We try MAX_INTERM_CVT_STEPS
+         to get to NARROW_VECTYPE, and fail if we do not.  */
+      *interm_types = VEC_alloc (tree, heap, MAX_INTERM_CVT_STEPS);
+      for (i = 0; i < 3; i++)
+        {
+          intermediate_mode = insn_data[icode1].operand[0].mode;
+          intermediate_type = lang_hooks.types.type_for_mode (intermediate_mode,
+                                                     TYPE_UNSIGNED (prev_type));
+          optab3 = optab_for_tree_code (c1, intermediate_type, optab_default);
+          optab4 = optab_for_tree_code (c2, intermediate_type, optab_default);
+
+          if (!optab3 || !optab4
+              || (icode1 = optab1->handlers[(int) prev_mode].insn_code)
+                                                        == CODE_FOR_nothing
+              || insn_data[icode1].operand[0].mode != intermediate_mode
+              || (icode2 = optab2->handlers[(int) prev_mode].insn_code)
+                                                        == CODE_FOR_nothing
+              || insn_data[icode2].operand[0].mode != intermediate_mode
+              || (icode1 = optab3->handlers[(int) intermediate_mode].insn_code) 
+                                                        == CODE_FOR_nothing
+              || (icode2 = optab4->handlers[(int) intermediate_mode].insn_code)
+                                                        == CODE_FOR_nothing)
+            return false;
+
+          VEC_quick_push (tree, *interm_types, intermediate_type);
+          (*multi_step_cvt)++;
+
+          if (insn_data[icode1].operand[0].mode == TYPE_MODE (wide_vectype)
+              && insn_data[icode2].operand[0].mode == TYPE_MODE (wide_vectype))
+            return true;
+
+          prev_type = intermediate_type;
+          prev_mode = intermediate_mode;
+        }
+
+       return false;
+    }
+
+  *code1 = c1;
+  *code2 = c2;
+  return true;
+}
+
+
+/* Function supportable_narrowing_operation
+
+   Check whether an operation represented by the code CODE is a 
+   narrowing operation that is supported by the target platform in 
+   vector form (i.e., when operating on arguments of type VECTYPE).
+    
+   Narrowing operations we currently support are NOP (CONVERT) and
+   FIX_TRUNC. This function checks if these operations are supported by
+   the target platform directly via vector tree-codes.
+
+   Output:
+   - CODE1 is the code of a vector operation to be used when 
+   vectorizing the operation, if available. 
+   - MULTI_STEP_CVT determines the number of required intermediate steps in
+   case of multi-step conversion (like int->short->char - in that case
+   MULTI_STEP_CVT will be 1).
+   - INTERM_TYPES contains the intermediate type required to perform the
+   narrowing operation (short in the above example).   */ 
+
+bool
+supportable_narrowing_operation (enum tree_code code,
+				 const_gimple stmt, tree vectype,
+				 enum tree_code *code1, int *multi_step_cvt,
+                                 VEC (tree, heap) **interm_types)
+{
+  enum machine_mode vec_mode;
+  enum insn_code icode1;
+  optab optab1, interm_optab;
+  tree type = gimple_expr_type (stmt);
+  tree narrow_vectype = get_vectype_for_scalar_type (type);
+  enum tree_code c1;
+  tree intermediate_type, prev_type;
+  int i;
+
+  switch (code)
+    {
+    CASE_CONVERT:
+      c1 = VEC_PACK_TRUNC_EXPR;
+      break;
+
+    case FIX_TRUNC_EXPR:
+      c1 = VEC_PACK_FIX_TRUNC_EXPR;
+      break;
+
+    case FLOAT_EXPR:
+      /* ??? Not yet implemented due to missing VEC_PACK_FLOAT_EXPR
+	 tree code and optabs used for computing the operation.  */
+      return false;
+
+    default:
+      gcc_unreachable ();
+    }
+
+  if (code == FIX_TRUNC_EXPR)
+    /* The signedness is determined from output operand.  */
+    optab1 = optab_for_tree_code (c1, type, optab_default);
+  else
+    optab1 = optab_for_tree_code (c1, vectype, optab_default);
+
+  if (!optab1)
+    return false;
+
+  vec_mode = TYPE_MODE (vectype);
+  if ((icode1 = optab_handler (optab1, vec_mode)->insn_code) 
+       == CODE_FOR_nothing)
+    return false;
+
+  /* Check if it's a multi-step conversion that can be done using intermediate
+     types.  */
+  if (insn_data[icode1].operand[0].mode != TYPE_MODE (narrow_vectype))
+    {
+      enum machine_mode intermediate_mode, prev_mode = vec_mode;
+
+      *code1 = c1;
+      prev_type = vectype;
+      /* We assume here that there will not be more than MAX_INTERM_CVT_STEPS
+         intermediate  steps in promotion sequence. We try MAX_INTERM_CVT_STEPS
+         to get to NARROW_VECTYPE, and fail if we do not.  */
+      *interm_types = VEC_alloc (tree, heap, MAX_INTERM_CVT_STEPS);
+      for (i = 0; i < 3; i++)
+        {
+          intermediate_mode = insn_data[icode1].operand[0].mode;
+          intermediate_type = lang_hooks.types.type_for_mode (intermediate_mode,
+                                                     TYPE_UNSIGNED (prev_type));
+          interm_optab = optab_for_tree_code (c1, intermediate_type, 
+                                              optab_default);
+          if (!interm_optab  
+              || (icode1 = optab1->handlers[(int) prev_mode].insn_code)
+                                                        == CODE_FOR_nothing
+              || insn_data[icode1].operand[0].mode != intermediate_mode
+              || (icode1 
+                  = interm_optab->handlers[(int) intermediate_mode].insn_code)
+                 == CODE_FOR_nothing)
+            return false;
+
+          VEC_quick_push (tree, *interm_types, intermediate_type);
+          (*multi_step_cvt)++;
+
+          if (insn_data[icode1].operand[0].mode == TYPE_MODE (narrow_vectype))
+            return true;
+
+          prev_type = intermediate_type;
+          prev_mode = intermediate_mode;
+        }
+
+      return false;
+    }
+
+  *code1 = c1;
+  return true;
+}
+
+
+/* Function reduction_code_for_scalar_code
+
+   Input:
+   CODE - tree_code of a reduction operations.
+
+   Output:
+   REDUC_CODE - the corresponding tree-code to be used to reduce the
+      vector of partial results into a single scalar result (which
+      will also reside in a vector).
+
+   Return TRUE if a corresponding REDUC_CODE was found, FALSE otherwise.  */
+
+bool
+reduction_code_for_scalar_code (enum tree_code code,
+                                enum tree_code *reduc_code)
+{
+  switch (code)
+  {
+  case MAX_EXPR:
+    *reduc_code = REDUC_MAX_EXPR;
+    return true;
+
+  case MIN_EXPR:
+    *reduc_code = REDUC_MIN_EXPR;
+    return true;
+
+  case PLUS_EXPR:
+    *reduc_code = REDUC_PLUS_EXPR;
+    return true;
+
+  default:
+    return false;
+  }
+}
+
+/* Error reporting helper for vect_is_simple_reduction below. GIMPLE statement
+   STMT is printed with a message MSG. */
+
+static void
+report_vect_op (gimple stmt, const char *msg)
+{
+  fprintf (vect_dump, "%s", msg);
+  print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
+}
+
+/* Function vect_is_simple_reduction
+
+   Detect a cross-iteration def-use cycle that represents a simple
+   reduction computation. We look for the following pattern:
+
+   loop_header:
+     a1 = phi < a0, a2 >
+     a3 = ...
+     a2 = operation (a3, a1)
+  
+   such that:
+   1. operation is commutative and associative and it is safe to 
+      change the order of the computation.
+   2. no uses for a2 in the loop (a2 is used out of the loop)
+   3. no uses of a1 in the loop besides the reduction operation.
+
+   Condition 1 is tested here.
+   Conditions 2,3 are tested in vect_mark_stmts_to_be_vectorized.  */
+
+gimple
+vect_is_simple_reduction (loop_vec_info loop_info, gimple phi)
+{
+  struct loop *loop = (gimple_bb (phi))->loop_father;
+  struct loop *vect_loop = LOOP_VINFO_LOOP (loop_info);
+  edge latch_e = loop_latch_edge (loop);
+  tree loop_arg = PHI_ARG_DEF_FROM_EDGE (phi, latch_e);
+  gimple def_stmt, def1, def2;
+  enum tree_code code;
+  tree op1, op2;
+  tree type;
+  int nloop_uses;
+  tree name;
+  imm_use_iterator imm_iter;
+  use_operand_p use_p;
+
+  gcc_assert (loop == vect_loop || flow_loop_nested_p (vect_loop, loop));
+
+  name = PHI_RESULT (phi);
+  nloop_uses = 0;
+  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, name)
+    {
+      gimple use_stmt = USE_STMT (use_p);
+      if (flow_bb_inside_loop_p (loop, gimple_bb (use_stmt))
+	  && vinfo_for_stmt (use_stmt)
+	  && !is_pattern_stmt_p (vinfo_for_stmt (use_stmt)))
+        nloop_uses++;
+      if (nloop_uses > 1)
+        {
+          if (vect_print_dump_info (REPORT_DETAILS))
+            fprintf (vect_dump, "reduction used in loop.");
+          return NULL;
+        }
+    }
+
+  if (TREE_CODE (loop_arg) != SSA_NAME)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	{
+	  fprintf (vect_dump, "reduction: not ssa_name: ");
+	  print_generic_expr (vect_dump, loop_arg, TDF_SLIM);
+	}
+      return NULL;
+    }
+
+  def_stmt = SSA_NAME_DEF_STMT (loop_arg);
+  if (!def_stmt)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	fprintf (vect_dump, "reduction: no def_stmt.");
+      return NULL;
+    }
+
+  if (!is_gimple_assign (def_stmt))
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        print_gimple_stmt (vect_dump, def_stmt, 0, TDF_SLIM);
+      return NULL;
+    }
+
+  name = gimple_assign_lhs (def_stmt);
+  nloop_uses = 0;
+  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, name)
+    {
+      gimple use_stmt = USE_STMT (use_p);
+      if (flow_bb_inside_loop_p (loop, gimple_bb (use_stmt))
+	  && vinfo_for_stmt (use_stmt)
+	  && !is_pattern_stmt_p (vinfo_for_stmt (use_stmt)))
+	nloop_uses++;
+      if (nloop_uses > 1)
+	{
+	  if (vect_print_dump_info (REPORT_DETAILS))
+	    fprintf (vect_dump, "reduction used in loop.");
+	  return NULL;
+	}
+    }
+
+  code = gimple_assign_rhs_code (def_stmt);
+
+  if (!commutative_tree_code (code) || !associative_tree_code (code))
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        report_vect_op (def_stmt, "reduction: not commutative/associative: ");
+      return NULL;
+    }
+
+  if (get_gimple_rhs_class (code) != GIMPLE_BINARY_RHS)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, "reduction: not binary operation: ");
+      return NULL;
+    }
+
+  op1 = gimple_assign_rhs1 (def_stmt);
+  op2 = gimple_assign_rhs2 (def_stmt);
+  if (TREE_CODE (op1) != SSA_NAME || TREE_CODE (op2) != SSA_NAME)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, "reduction: uses not ssa_names: ");
+      return NULL;
+    }
+
+  /* Check that it's ok to change the order of the computation.  */
+  type = TREE_TYPE (gimple_assign_lhs (def_stmt));
+  if (TYPE_MAIN_VARIANT (type) != TYPE_MAIN_VARIANT (TREE_TYPE (op1))
+      || TYPE_MAIN_VARIANT (type) != TYPE_MAIN_VARIANT (TREE_TYPE (op2)))
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+        {
+          fprintf (vect_dump, "reduction: multiple types: operation type: ");
+          print_generic_expr (vect_dump, type, TDF_SLIM);
+          fprintf (vect_dump, ", operands types: ");
+          print_generic_expr (vect_dump, TREE_TYPE (op1), TDF_SLIM);
+          fprintf (vect_dump, ",");
+          print_generic_expr (vect_dump, TREE_TYPE (op2), TDF_SLIM);
+        }
+      return NULL;
+    }
+
+  /* Generally, when vectorizing a reduction we change the order of the
+     computation.  This may change the behavior of the program in some
+     cases, so we need to check that this is ok.  One exception is when 
+     vectorizing an outer-loop: the inner-loop is executed sequentially,
+     and therefore vectorizing reductions in the inner-loop during
+     outer-loop vectorization is safe.  */
+
+  /* CHECKME: check for !flag_finite_math_only too?  */
+  if (SCALAR_FLOAT_TYPE_P (type) && !flag_associative_math
+      && !nested_in_vect_loop_p (vect_loop, def_stmt)) 
+    {
+      /* Changing the order of operations changes the semantics.  */
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, "reduction: unsafe fp math optimization: ");
+      return NULL;
+    }
+  else if (INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_TRAPS (type)
+	   && !nested_in_vect_loop_p (vect_loop, def_stmt))
+    {
+      /* Changing the order of operations changes the semantics.  */
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, "reduction: unsafe int math optimization: ");
+      return NULL;
+    }
+  else if (SAT_FIXED_POINT_TYPE_P (type))
+    {
+      /* Changing the order of operations changes the semantics.  */
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, 
+			"reduction: unsafe fixed-point math optimization: ");
+      return NULL;
+    }
+
+  /* reduction is safe. we're dealing with one of the following:
+     1) integer arithmetic and no trapv
+     2) floating point arithmetic, and special flags permit this optimization.
+   */
+  def1 = SSA_NAME_DEF_STMT (op1);
+  def2 = SSA_NAME_DEF_STMT (op2);
+  if (!def1 || !def2 || gimple_nop_p (def1) || gimple_nop_p (def2))
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, "reduction: no defs for operands: ");
+      return NULL;
+    }
+
+
+  /* Check that one def is the reduction def, defined by PHI,
+     the other def is either defined in the loop ("vect_loop_def"),
+     or it's an induction (defined by a loop-header phi-node).  */
+
+  if (def2 == phi
+      && flow_bb_inside_loop_p (loop, gimple_bb (def1))
+      && (is_gimple_assign (def1)
+	  || STMT_VINFO_DEF_TYPE (vinfo_for_stmt (def1)) == vect_induction_def
+	  || (gimple_code (def1) == GIMPLE_PHI
+	      && STMT_VINFO_DEF_TYPE (vinfo_for_stmt (def1)) == vect_loop_def
+	      && !is_loop_header_bb_p (gimple_bb (def1)))))
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, "detected reduction:");
+      return def_stmt;
+    }
+  else if (def1 == phi
+	   && flow_bb_inside_loop_p (loop, gimple_bb (def2))
+	   && (is_gimple_assign (def2)
+	       || STMT_VINFO_DEF_TYPE (vinfo_for_stmt (def2)) == vect_induction_def
+	       || (gimple_code (def2) == GIMPLE_PHI
+		   && STMT_VINFO_DEF_TYPE (vinfo_for_stmt (def2)) == vect_loop_def
+		   && !is_loop_header_bb_p (gimple_bb (def2)))))
+    {
+      /* Swap operands (just for simplicity - so that the rest of the code
+	 can assume that the reduction variable is always the last (second)
+	 argument).  */
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt ,
+		        "detected reduction: need to swap operands:");
+      swap_tree_operands (def_stmt, gimple_assign_rhs1_ptr (def_stmt),
+			  gimple_assign_rhs2_ptr (def_stmt));
+      return def_stmt;
+    }
+  else
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	report_vect_op (def_stmt, "reduction: unknown pattern.");
+      return NULL;
+    }
+}
+
+
+/* Function vect_is_simple_iv_evolution.
+
+   FORNOW: A simple evolution of an induction variables in the loop is
+   considered a polynomial evolution with constant step.  */
+
+bool
+vect_is_simple_iv_evolution (unsigned loop_nb, tree access_fn, tree * init, 
+			     tree * step)
+{
+  tree init_expr;
+  tree step_expr;
+  tree evolution_part = evolution_part_in_loop_num (access_fn, loop_nb);
+
+  /* When there is no evolution in this loop, the evolution function
+     is not "simple".  */  
+  if (evolution_part == NULL_TREE)
+    return false;
+  
+  /* When the evolution is a polynomial of degree >= 2
+     the evolution function is not "simple".  */
+  if (tree_is_chrec (evolution_part))
+    return false;
+  
+  step_expr = evolution_part;
+  init_expr = unshare_expr (initial_condition_in_loop_num (access_fn, loop_nb));
+
+  if (vect_print_dump_info (REPORT_DETAILS))
+    {
+      fprintf (vect_dump, "step: ");
+      print_generic_expr (vect_dump, step_expr, TDF_SLIM);
+      fprintf (vect_dump, ",  init: ");
+      print_generic_expr (vect_dump, init_expr, TDF_SLIM);
+    }
+
+  *init = init_expr;
+  *step = step_expr;
+
+  if (TREE_CODE (step_expr) != INTEGER_CST)
+    { 
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "step unknown.");
+      return false;
+    }
+
+  return true;
+}
+
+
+/* Function vectorize_loops.
+   
+   Entry Point to loop vectorization phase.  */
+
+unsigned
+vectorize_loops (void)
+{
+  unsigned int i;
+  unsigned int num_vectorized_loops = 0;
+  unsigned int vect_loops_num;
+  loop_iterator li;
+  struct loop *loop;
+
+  vect_loops_num = number_of_loops ();
+
+  /* Bail out if there are no loops.  */
+  if (vect_loops_num <= 1)
+    return 0;
+
+  /* Fix the verbosity level if not defined explicitly by the user.  */
+  vect_set_dump_settings ();
+
+  /* Allocate the bitmap that records which virtual variables that 
+     need to be renamed.  */
+  vect_memsyms_to_rename = BITMAP_ALLOC (NULL);
+
+  init_stmt_vec_info_vec ();
+
+  /*  ----------- Analyze loops. -----------  */
+
+  /* If some loop was duplicated, it gets bigger number 
+     than all previously defined loops. This fact allows us to run 
+     only over initial loops skipping newly generated ones.  */
+  FOR_EACH_LOOP (li, loop, 0)
+    if (optimize_loop_nest_for_speed_p (loop))
+      {
+	loop_vec_info loop_vinfo;
+
+	vect_loop_location = find_loop_location (loop);
+	loop_vinfo = vect_analyze_loop (loop);
+	loop->aux = loop_vinfo;
+
+	if (!loop_vinfo || !LOOP_VINFO_VECTORIZABLE_P (loop_vinfo))
+	  continue;
+
+	vect_transform_loop (loop_vinfo);
+	num_vectorized_loops++;
+      }
+  vect_loop_location = UNKNOWN_LOC;
+
+  statistics_counter_event (cfun, "Vectorized loops", num_vectorized_loops);
+  if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)
+      || (vect_print_dump_info (REPORT_VECTORIZED_LOOPS)
+	  && num_vectorized_loops > 0))
+    fprintf (vect_dump, "vectorized %u loops in function.\n",
+	     num_vectorized_loops);
+
+  /*  ----------- Finalize. -----------  */
+
+  BITMAP_FREE (vect_memsyms_to_rename);
+
+  for (i = 1; i < vect_loops_num; i++)
+    {
+      loop_vec_info loop_vinfo;
+
+      loop = get_loop (i);
+      if (!loop)
+	continue;
+      loop_vinfo = (loop_vec_info) loop->aux;
+      destroy_loop_vec_info (loop_vinfo, true);
+      loop->aux = NULL;
+    }
+
+  free_stmt_vec_info_vec ();
+
+  return num_vectorized_loops > 0 ? TODO_cleanup_cfg : 0;
+}
+
+/* Increase alignment of global arrays to improve vectorization potential.
+   TODO:
+   - Consider also structs that have an array field.
+   - Use ipa analysis to prune arrays that can't be vectorized?
+     This should involve global alignment analysis and in the future also
+     array padding.  */
+
+static unsigned int
+increase_alignment (void)
+{
+  struct varpool_node *vnode;
+
+  /* Increase the alignment of all global arrays for vectorization.  */
+  for (vnode = varpool_nodes_queue;
+       vnode;
+       vnode = vnode->next_needed)
+    {
+      tree vectype, decl = vnode->decl;
+      unsigned int alignment;
+
+      if (TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE)
+	continue;
+      vectype = get_vectype_for_scalar_type (TREE_TYPE (TREE_TYPE (decl)));
+      if (!vectype)
+	continue;
+      alignment = TYPE_ALIGN (vectype);
+      if (DECL_ALIGN (decl) >= alignment)
+	continue;
+
+      if (vect_can_force_dr_alignment_p (decl, alignment))
+	{ 
+	  DECL_ALIGN (decl) = TYPE_ALIGN (vectype);
+	  DECL_USER_ALIGN (decl) = 1;
+	  if (dump_file)
+	    { 
+	      fprintf (dump_file, "Increasing alignment of decl: ");
+	      print_generic_expr (dump_file, decl, TDF_SLIM);
+	    }
+	}
+    }
+  return 0;
+}
+
+static bool
+gate_increase_alignment (void)
+{
+  return flag_section_anchors && flag_tree_vectorize;
+}
+
+struct simple_ipa_opt_pass pass_ipa_increase_alignment = 
+{
+ {
+  SIMPLE_IPA_PASS,
+  "increase_alignment",			/* name */
+  gate_increase_alignment,		/* gate */
+  increase_alignment,			/* execute */
+  NULL,					/* sub */
+  NULL,					/* next */
+  0,					/* static_pass_number */
+  0,					/* tv_id */
+  0,					/* properties_required */
+  0,					/* properties_provided */
+  0,					/* properties_destroyed */
+  0,					/* todo_flags_start */
+  0 					/* todo_flags_finish */
+ }
+};