Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 2312 insertions, 0 deletions

diff --git a/gcc-4.9/gcc/tree-parloops.c b/gcc-4.9/gcc/tree-parloops.c
new file mode 100644
index 000000000..47179a967
--- /dev/null
+++ b/gcc-4.9/gcc/tree-parloops.c
@@ -0,0 +1,2312 @@
+/* Loop autoparallelization.
+   Copyright (C) 2006-2014 Free Software Foundation, Inc.
+   Contributed by Sebastian Pop <pop@cri.ensmp.fr> 
+   Zdenek Dvorak <dvorakz@suse.cz> and Razya Ladelsky <razya@il.ibm.com>.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "basic-block.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "gimple-expr.h"
+#include "is-a.h"
+#include "gimple.h"
+#include "gimplify.h"
+#include "gimple-iterator.h"
+#include "gimplify-me.h"
+#include "gimple-walk.h"
+#include "stor-layout.h"
+#include "tree-nested.h"
+#include "gimple-ssa.h"
+#include "tree-cfg.h"
+#include "tree-phinodes.h"
+#include "ssa-iterators.h"
+#include "stringpool.h"
+#include "tree-ssanames.h"
+#include "tree-ssa-loop-ivopts.h"
+#include "tree-ssa-loop-manip.h"
+#include "tree-ssa-loop-niter.h"
+#include "tree-ssa-loop.h"
+#include "tree-into-ssa.h"
+#include "cfgloop.h"
+#include "tree-data-ref.h"
+#include "tree-scalar-evolution.h"
+#include "gimple-pretty-print.h"
+#include "tree-pass.h"
+#include "langhooks.h"
+#include "tree-vectorizer.h"
+#include "tree-hasher.h"
+#include "tree-parloops.h"
+#include "omp-low.h"
+#include "tree-nested.h"
+
+/* This pass tries to distribute iterations of loops into several threads.
+   The implementation is straightforward -- for each loop we test whether its
+   iterations are independent, and if it is the case (and some additional
+   conditions regarding profitability and correctness are satisfied), we
+   add GIMPLE_OMP_PARALLEL and GIMPLE_OMP_FOR codes and let omp expansion
+   machinery do its job.
+
+   The most of the complexity is in bringing the code into shape expected
+   by the omp expanders:
+   -- for GIMPLE_OMP_FOR, ensuring that the loop has only one induction
+      variable and that the exit test is at the start of the loop body
+   -- for GIMPLE_OMP_PARALLEL, replacing the references to local addressable
+      variables by accesses through pointers, and breaking up ssa chains
+      by storing the values incoming to the parallelized loop to a structure
+      passed to the new function as an argument (something similar is done
+      in omp gimplification, unfortunately only a small part of the code
+      can be shared).
+
+   TODO:
+   -- if there are several parallelizable loops in a function, it may be
+      possible to generate the threads just once (using synchronization to
+      ensure that cross-loop dependences are obeyed).
+   -- handling of common reduction patterns for outer loops.  
+    
+   More info can also be found at http://gcc.gnu.org/wiki/AutoParInGCC  */
+/*
+  Reduction handling:
+  currently we use vect_force_simple_reduction() to detect reduction patterns.
+  The code transformation will be introduced by an example.
+
+
+parloop
+{
+  int sum=1;
+
+  for (i = 0; i < N; i++)
+   {
+    x[i] = i + 3;
+    sum+=x[i];
+   }
+}
+
+gimple-like code:
+header_bb:
+
+  # sum_29 = PHI <sum_11(5), 1(3)>
+  # i_28 = PHI <i_12(5), 0(3)>
+  D.1795_8 = i_28 + 3;
+  x[i_28] = D.1795_8;
+  sum_11 = D.1795_8 + sum_29;
+  i_12 = i_28 + 1;
+  if (N_6(D) > i_12)
+    goto header_bb;
+
+
+exit_bb:
+
+  # sum_21 = PHI <sum_11(4)>
+  printf (&"%d"[0], sum_21);
+
+
+after reduction transformation (only relevant parts):
+
+parloop
+{
+
+....
+
+
+  # Storing the initial value given by the user.  #
+
+  .paral_data_store.32.sum.27 = 1;
+
+  #pragma omp parallel num_threads(4)
+
+  #pragma omp for schedule(static)
+
+  # The neutral element corresponding to the particular
+  reduction's operation, e.g. 0 for PLUS_EXPR,
+  1 for MULT_EXPR, etc. replaces the user's initial value.  #
+
+  # sum.27_29 = PHI <sum.27_11, 0>
+
+  sum.27_11 = D.1827_8 + sum.27_29;
+
+  GIMPLE_OMP_CONTINUE
+
+  # Adding this reduction phi is done at create_phi_for_local_result() #
+  # sum.27_56 = PHI <sum.27_11, 0>
+  GIMPLE_OMP_RETURN
+
+  # Creating the atomic operation is done at
+  create_call_for_reduction_1()  #
+
+  #pragma omp atomic_load
+  D.1839_59 = *&.paral_data_load.33_51->reduction.23;
+  D.1840_60 = sum.27_56 + D.1839_59;
+  #pragma omp atomic_store (D.1840_60);
+
+  GIMPLE_OMP_RETURN
+
+ # collecting the result after the join of the threads is done at
+  create_loads_for_reductions().
+  The value computed by the threads is loaded from the
+  shared struct.  #
+
+
+  .paral_data_load.33_52 = &.paral_data_store.32;
+  sum_37 =  .paral_data_load.33_52->sum.27;
+  sum_43 = D.1795_41 + sum_37;
+
+  exit bb:
+  # sum_21 = PHI <sum_43, sum_26>
+  printf (&"%d"[0], sum_21);
+
+...
+
+}
+
+*/
+
+/* Minimal number of iterations of a loop that should be executed in each
+   thread.  */
+#define MIN_PER_THREAD 100
+
+/* Element of the hashtable, representing a
+   reduction in the current loop.  */
+struct reduction_info
+{
+  gimple reduc_stmt;		/* reduction statement.  */
+  gimple reduc_phi;		/* The phi node defining the reduction.  */
+  enum tree_code reduction_code;/* code for the reduction operation.  */
+  unsigned reduc_version;	/* SSA_NAME_VERSION of original reduc_phi
+				   result.  */
+  gimple keep_res;		/* The PHI_RESULT of this phi is the resulting value
+				   of the reduction variable when existing the loop. */
+  tree initial_value;		/* The initial value of the reduction var before entering the loop.  */
+  tree field;			/*  the name of the field in the parloop data structure intended for reduction.  */
+  tree init;			/* reduction initialization value.  */
+  gimple new_phi;		/* (helper field) Newly created phi node whose result
+				   will be passed to the atomic operation.  Represents
+				   the local result each thread computed for the reduction
+				   operation.  */
+};
+
+/* Reduction info hashtable helpers.  */
+
+struct reduction_hasher : typed_free_remove <reduction_info>
+{
+  typedef reduction_info value_type;
+  typedef reduction_info compare_type;
+  static inline hashval_t hash (const value_type *);
+  static inline bool equal (const value_type *, const compare_type *);
+};
+
+/* Equality and hash functions for hashtab code.  */
+
+inline bool
+reduction_hasher::equal (const value_type *a, const compare_type *b)
+{
+  return (a->reduc_phi == b->reduc_phi);
+}
+
+inline hashval_t
+reduction_hasher::hash (const value_type *a)
+{
+  return a->reduc_version;
+}
+
+typedef hash_table <reduction_hasher> reduction_info_table_type;
+
+
+static struct reduction_info *
+reduction_phi (reduction_info_table_type reduction_list, gimple phi)
+{
+  struct reduction_info tmpred, *red;
+
+  if (reduction_list.elements () == 0 || phi == NULL)
+    return NULL;
+
+  tmpred.reduc_phi = phi;
+  tmpred.reduc_version = gimple_uid (phi);
+  red = reduction_list.find (&tmpred);
+
+  return red;
+}
+
+/* Element of hashtable of names to copy.  */
+
+struct name_to_copy_elt
+{
+  unsigned version;	/* The version of the name to copy.  */
+  tree new_name;	/* The new name used in the copy.  */
+  tree field;		/* The field of the structure used to pass the
+			   value.  */
+};
+
+/* Name copies hashtable helpers.  */
+
+struct name_to_copy_hasher : typed_free_remove <name_to_copy_elt>
+{
+  typedef name_to_copy_elt value_type;
+  typedef name_to_copy_elt compare_type;
+  static inline hashval_t hash (const value_type *);
+  static inline bool equal (const value_type *, const compare_type *);
+};
+
+/* Equality and hash functions for hashtab code.  */
+
+inline bool
+name_to_copy_hasher::equal (const value_type *a, const compare_type *b)
+{
+  return a->version == b->version;
+}
+
+inline hashval_t
+name_to_copy_hasher::hash (const value_type *a)
+{
+  return (hashval_t) a->version;
+}
+
+typedef hash_table <name_to_copy_hasher> name_to_copy_table_type;
+
+/* A transformation matrix, which is a self-contained ROWSIZE x COLSIZE
+   matrix.  Rather than use floats, we simply keep a single DENOMINATOR that
+   represents the denominator for every element in the matrix.  */
+typedef struct lambda_trans_matrix_s
+{
+  lambda_matrix matrix;
+  int rowsize;
+  int colsize;
+  int denominator;
+} *lambda_trans_matrix;
+#define LTM_MATRIX(T) ((T)->matrix)
+#define LTM_ROWSIZE(T) ((T)->rowsize)
+#define LTM_COLSIZE(T) ((T)->colsize)
+#define LTM_DENOMINATOR(T) ((T)->denominator)
+
+/* Allocate a new transformation matrix.  */
+
+static lambda_trans_matrix
+lambda_trans_matrix_new (int colsize, int rowsize,
+			 struct obstack * lambda_obstack)
+{
+  lambda_trans_matrix ret;
+
+  ret = (lambda_trans_matrix)
+    obstack_alloc (lambda_obstack, sizeof (struct lambda_trans_matrix_s));
+  LTM_MATRIX (ret) = lambda_matrix_new (rowsize, colsize, lambda_obstack);
+  LTM_ROWSIZE (ret) = rowsize;
+  LTM_COLSIZE (ret) = colsize;
+  LTM_DENOMINATOR (ret) = 1;
+  return ret;
+}
+
+/* Multiply a vector VEC by a matrix MAT.
+   MAT is an M*N matrix, and VEC is a vector with length N.  The result
+   is stored in DEST which must be a vector of length M.  */
+
+static void
+lambda_matrix_vector_mult (lambda_matrix matrix, int m, int n,
+			   lambda_vector vec, lambda_vector dest)
+{
+  int i, j;
+
+  lambda_vector_clear (dest, m);
+  for (i = 0; i < m; i++)
+    for (j = 0; j < n; j++)
+      dest[i] += matrix[i][j] * vec[j];
+}
+
+/* Return true if TRANS is a legal transformation matrix that respects
+   the dependence vectors in DISTS and DIRS.  The conservative answer
+   is false.
+
+   "Wolfe proves that a unimodular transformation represented by the
+   matrix T is legal when applied to a loop nest with a set of
+   lexicographically non-negative distance vectors RDG if and only if
+   for each vector d in RDG, (T.d >= 0) is lexicographically positive.
+   i.e.: if and only if it transforms the lexicographically positive
+   distance vectors to lexicographically positive vectors.  Note that
+   a unimodular matrix must transform the zero vector (and only it) to
+   the zero vector." S.Muchnick.  */
+
+static bool
+lambda_transform_legal_p (lambda_trans_matrix trans,
+			  int nb_loops,
+			  vec<ddr_p> dependence_relations)
+{
+  unsigned int i, j;
+  lambda_vector distres;
+  struct data_dependence_relation *ddr;
+
+  gcc_assert (LTM_COLSIZE (trans) == nb_loops
+	      && LTM_ROWSIZE (trans) == nb_loops);
+
+  /* When there are no dependences, the transformation is correct.  */
+  if (dependence_relations.length () == 0)
+    return true;
+
+  ddr = dependence_relations[0];
+  if (ddr == NULL)
+    return true;
+
+  /* When there is an unknown relation in the dependence_relations, we
+     know that it is no worth looking at this loop nest: give up.  */
+  if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
+    return false;
+
+  distres = lambda_vector_new (nb_loops);
+
+  /* For each distance vector in the dependence graph.  */
+  FOR_EACH_VEC_ELT (dependence_relations, i, ddr)
+    {
+      /* Don't care about relations for which we know that there is no
+	 dependence, nor about read-read (aka. output-dependences):
+	 these data accesses can happen in any order.  */
+      if (DDR_ARE_DEPENDENT (ddr) == chrec_known
+	  || (DR_IS_READ (DDR_A (ddr)) && DR_IS_READ (DDR_B (ddr))))
+	continue;
+
+      /* Conservatively answer: "this transformation is not valid".  */
+      if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
+	return false;
+
+      /* If the dependence could not be captured by a distance vector,
+	 conservatively answer that the transform is not valid.  */
+      if (DDR_NUM_DIST_VECTS (ddr) == 0)
+	return false;
+
+      /* Compute trans.dist_vect */
+      for (j = 0; j < DDR_NUM_DIST_VECTS (ddr); j++)
+	{
+	  lambda_matrix_vector_mult (LTM_MATRIX (trans), nb_loops, nb_loops,
+				     DDR_DIST_VECT (ddr, j), distres);
+
+	  if (!lambda_vector_lexico_pos (distres, nb_loops))
+	    return false;
+	}
+    }
+  return true;
+}
+
+/* Data dependency analysis. Returns true if the iterations of LOOP
+   are independent on each other (that is, if we can execute them
+   in parallel).  */
+
+static bool
+loop_parallel_p (struct loop *loop, struct obstack * parloop_obstack)
+{
+  vec<ddr_p> dependence_relations;
+  vec<data_reference_p> datarefs;
+  lambda_trans_matrix trans;
+  bool ret = false;
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+  {
+    fprintf (dump_file, "Considering loop %d\n", loop->num);
+    if (!loop->inner)
+      fprintf (dump_file, "loop is innermost\n");
+    else
+      fprintf (dump_file, "loop NOT innermost\n");
+   }
+
+  /* Check for problems with dependences.  If the loop can be reversed,
+     the iterations are independent.  */
+  auto_vec<loop_p, 3> loop_nest;
+  datarefs.create (10);
+  dependence_relations.create (100);
+  if (! compute_data_dependences_for_loop (loop, true, &loop_nest, &datarefs,
+					   &dependence_relations))
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "  FAILED: cannot analyze data dependencies\n");
+      ret = false;
+      goto end;
+    }
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    dump_data_dependence_relations (dump_file, dependence_relations);
+
+  trans = lambda_trans_matrix_new (1, 1, parloop_obstack);
+  LTM_MATRIX (trans)[0][0] = -1;
+
+  if (lambda_transform_legal_p (trans, 1, dependence_relations))
+    {
+      ret = true;
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "  SUCCESS: may be parallelized\n");
+    }
+  else if (dump_file && (dump_flags & TDF_DETAILS))
+    fprintf (dump_file,
+	     "  FAILED: data dependencies exist across iterations\n");
+
+ end:
+  free_dependence_relations (dependence_relations);
+  free_data_refs (datarefs);
+
+  return ret;
+}
+
+/* Return true when LOOP contains basic blocks marked with the
+   BB_IRREDUCIBLE_LOOP flag.  */
+
+static inline bool
+loop_has_blocks_with_irreducible_flag (struct loop *loop)
+{
+  unsigned i;
+  basic_block *bbs = get_loop_body_in_dom_order (loop);
+  bool res = true;
+
+  for (i = 0; i < loop->num_nodes; i++)
+    if (bbs[i]->flags & BB_IRREDUCIBLE_LOOP)
+      goto end;
+
+  res = false;
+ end:
+  free (bbs);
+  return res;
+}
+
+/* Assigns the address of OBJ in TYPE to an ssa name, and returns this name.
+   The assignment statement is placed on edge ENTRY.  DECL_ADDRESS maps decls
+   to their addresses that can be reused.  The address of OBJ is known to
+   be invariant in the whole function.  Other needed statements are placed
+   right before GSI.  */
+
+static tree
+take_address_of (tree obj, tree type, edge entry,
+		 int_tree_htab_type decl_address, gimple_stmt_iterator *gsi)
+{
+  int uid;
+  int_tree_map **dslot;
+  struct int_tree_map ielt, *nielt;
+  tree *var_p, name, addr;
+  gimple stmt;
+  gimple_seq stmts;
+
+  /* Since the address of OBJ is invariant, the trees may be shared.
+     Avoid rewriting unrelated parts of the code.  */
+  obj = unshare_expr (obj);
+  for (var_p = &obj;
+       handled_component_p (*var_p);
+       var_p = &TREE_OPERAND (*var_p, 0))
+    continue;
+
+  /* Canonicalize the access to base on a MEM_REF.  */
+  if (DECL_P (*var_p))
+    *var_p = build_simple_mem_ref (build_fold_addr_expr (*var_p));
+
+  /* Assign a canonical SSA name to the address of the base decl used
+     in the address and share it for all accesses and addresses based
+     on it.  */
+  uid = DECL_UID (TREE_OPERAND (TREE_OPERAND (*var_p, 0), 0));
+  ielt.uid = uid;
+  dslot = decl_address.find_slot_with_hash (&ielt, uid, INSERT);
+  if (!*dslot)
+    {
+      if (gsi == NULL)
+	return NULL;
+      addr = TREE_OPERAND (*var_p, 0);
+      const char *obj_name
+	= get_name (TREE_OPERAND (TREE_OPERAND (*var_p, 0), 0));
+      if (obj_name)
+	name = make_temp_ssa_name (TREE_TYPE (addr), NULL, obj_name);
+      else
+	name = make_ssa_name (TREE_TYPE (addr), NULL);
+      stmt = gimple_build_assign (name, addr);
+      gsi_insert_on_edge_immediate (entry, stmt);
+
+      nielt = XNEW (struct int_tree_map);
+      nielt->uid = uid;
+      nielt->to = name;
+      *dslot = nielt;
+    }
+  else
+    name = (*dslot)->to;
+
+  /* Express the address in terms of the canonical SSA name.  */
+  TREE_OPERAND (*var_p, 0) = name;
+  if (gsi == NULL)
+    return build_fold_addr_expr_with_type (obj, type);
+
+  name = force_gimple_operand (build_addr (obj, current_function_decl),
+			       &stmts, true, NULL_TREE);
+  if (!gimple_seq_empty_p (stmts))
+    gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+
+  if (!useless_type_conversion_p (type, TREE_TYPE (name)))
+    {
+      name = force_gimple_operand (fold_convert (type, name), &stmts, true,
+				   NULL_TREE);
+      if (!gimple_seq_empty_p (stmts))
+	gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+    }
+
+  return name;
+}
+
+/* Callback for htab_traverse.  Create the initialization statement
+   for reduction described in SLOT, and place it at the preheader of
+   the loop described in DATA.  */
+
+int
+initialize_reductions (reduction_info **slot, struct loop *loop)
+{
+  tree init, c;
+  tree bvar, type, arg;
+  edge e;
+
+  struct reduction_info *const reduc = *slot;
+
+  /* Create initialization in preheader:
+     reduction_variable = initialization value of reduction.  */
+
+  /* In the phi node at the header, replace the argument coming
+     from the preheader with the reduction initialization value.  */
+
+  /* Create a new variable to initialize the reduction.  */
+  type = TREE_TYPE (PHI_RESULT (reduc->reduc_phi));
+  bvar = create_tmp_var (type, "reduction");
+
+  c = build_omp_clause (gimple_location (reduc->reduc_stmt),
+			OMP_CLAUSE_REDUCTION);
+  OMP_CLAUSE_REDUCTION_CODE (c) = reduc->reduction_code;
+  OMP_CLAUSE_DECL (c) = SSA_NAME_VAR (gimple_assign_lhs (reduc->reduc_stmt));
+
+  init = omp_reduction_init (c, TREE_TYPE (bvar));
+  reduc->init = init;
+
+  /* Replace the argument representing the initialization value
+     with the initialization value for the reduction (neutral
+     element for the particular operation, e.g. 0 for PLUS_EXPR,
+     1 for MULT_EXPR, etc).
+     Keep the old value in a new variable "reduction_initial",
+     that will be taken in consideration after the parallel
+     computing is done.  */
+
+  e = loop_preheader_edge (loop);
+  arg = PHI_ARG_DEF_FROM_EDGE (reduc->reduc_phi, e);
+  /* Create new variable to hold the initial value.  */
+
+  SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE
+	   (reduc->reduc_phi, loop_preheader_edge (loop)), init);
+  reduc->initial_value = arg;
+  return 1;
+}
+
+struct elv_data
+{
+  struct walk_stmt_info info;
+  edge entry;
+  int_tree_htab_type decl_address;
+  gimple_stmt_iterator *gsi;
+  bool changed;
+  bool reset;
+};
+
+/* Eliminates references to local variables in *TP out of the single
+   entry single exit region starting at DTA->ENTRY.
+   DECL_ADDRESS contains addresses of the references that had their
+   address taken already.  If the expression is changed, CHANGED is
+   set to true.  Callback for walk_tree.  */
+
+static tree
+eliminate_local_variables_1 (tree *tp, int *walk_subtrees, void *data)
+{
+  struct elv_data *const dta = (struct elv_data *) data;
+  tree t = *tp, var, addr, addr_type, type, obj;
+
+  if (DECL_P (t))
+    {
+      *walk_subtrees = 0;
+
+      if (!SSA_VAR_P (t) || DECL_EXTERNAL (t))
+	return NULL_TREE;
+
+      type = TREE_TYPE (t);
+      addr_type = build_pointer_type (type);
+      addr = take_address_of (t, addr_type, dta->entry, dta->decl_address,
+			      dta->gsi);
+      if (dta->gsi == NULL && addr == NULL_TREE)
+	{
+	  dta->reset = true;
+	  return NULL_TREE;
+	}
+
+      *tp = build_simple_mem_ref (addr);
+
+      dta->changed = true;
+      return NULL_TREE;
+    }
+
+  if (TREE_CODE (t) == ADDR_EXPR)
+    {
+      /* ADDR_EXPR may appear in two contexts:
+	 -- as a gimple operand, when the address taken is a function invariant
+	 -- as gimple rhs, when the resulting address in not a function
+	    invariant
+	 We do not need to do anything special in the latter case (the base of
+	 the memory reference whose address is taken may be replaced in the
+	 DECL_P case).  The former case is more complicated, as we need to
+	 ensure that the new address is still a gimple operand.  Thus, it
+	 is not sufficient to replace just the base of the memory reference --
+	 we need to move the whole computation of the address out of the
+	 loop.  */
+      if (!is_gimple_val (t))
+	return NULL_TREE;
+
+      *walk_subtrees = 0;
+      obj = TREE_OPERAND (t, 0);
+      var = get_base_address (obj);
+      if (!var || !SSA_VAR_P (var) || DECL_EXTERNAL (var))
+	return NULL_TREE;
+
+      addr_type = TREE_TYPE (t);
+      addr = take_address_of (obj, addr_type, dta->entry, dta->decl_address,
+			      dta->gsi);
+      if (dta->gsi == NULL && addr == NULL_TREE)
+	{
+	  dta->reset = true;
+	  return NULL_TREE;
+	}
+      *tp = addr;
+
+      dta->changed = true;
+      return NULL_TREE;
+    }
+
+  if (!EXPR_P (t))
+    *walk_subtrees = 0;
+
+  return NULL_TREE;
+}
+
+/* Moves the references to local variables in STMT at *GSI out of the single
+   entry single exit region starting at ENTRY.  DECL_ADDRESS contains
+   addresses of the references that had their address taken
+   already.  */
+
+static void
+eliminate_local_variables_stmt (edge entry, gimple_stmt_iterator *gsi,
+				int_tree_htab_type decl_address)
+{
+  struct elv_data dta;
+  gimple stmt = gsi_stmt (*gsi);
+
+  memset (&dta.info, '\0', sizeof (dta.info));
+  dta.entry = entry;
+  dta.decl_address = decl_address;
+  dta.changed = false;
+  dta.reset = false;
+
+  if (gimple_debug_bind_p (stmt))
+    {
+      dta.gsi = NULL;
+      walk_tree (gimple_debug_bind_get_value_ptr (stmt),
+		 eliminate_local_variables_1, &dta.info, NULL);
+      if (dta.reset)
+	{
+	  gimple_debug_bind_reset_value (stmt);
+	  dta.changed = true;
+	}
+    }
+  else if (gimple_clobber_p (stmt))
+    {
+      stmt = gimple_build_nop ();
+      gsi_replace (gsi, stmt, false);
+      dta.changed = true;
+    }
+  else
+    {
+      dta.gsi = gsi;
+      walk_gimple_op (stmt, eliminate_local_variables_1, &dta.info);
+    }
+
+  if (dta.changed)
+    update_stmt (stmt);
+}
+
+/* Eliminates the references to local variables from the single entry
+   single exit region between the ENTRY and EXIT edges.
+
+   This includes:
+   1) Taking address of a local variable -- these are moved out of the
+   region (and temporary variable is created to hold the address if
+   necessary).
+
+   2) Dereferencing a local variable -- these are replaced with indirect
+   references.  */
+
+static void
+eliminate_local_variables (edge entry, edge exit)
+{
+  basic_block bb;
+  auto_vec<basic_block, 3> body;
+  unsigned i;
+  gimple_stmt_iterator gsi;
+  bool has_debug_stmt = false;
+  int_tree_htab_type decl_address;
+  decl_address.create (10);
+  basic_block entry_bb = entry->src;
+  basic_block exit_bb = exit->dest;
+
+  gather_blocks_in_sese_region (entry_bb, exit_bb, &body);
+
+  FOR_EACH_VEC_ELT (body, i, bb)
+    if (bb != entry_bb && bb != exit_bb)
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	if (is_gimple_debug (gsi_stmt (gsi)))
+	  {
+	    if (gimple_debug_bind_p (gsi_stmt (gsi)))
+	      has_debug_stmt = true;
+	  }
+	else
+	  eliminate_local_variables_stmt (entry, &gsi, decl_address);
+
+  if (has_debug_stmt)
+    FOR_EACH_VEC_ELT (body, i, bb)
+      if (bb != entry_bb && bb != exit_bb)
+	for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	  if (gimple_debug_bind_p (gsi_stmt (gsi)))
+	    eliminate_local_variables_stmt (entry, &gsi, decl_address);
+
+  decl_address.dispose ();
+}
+
+/* Returns true if expression EXPR is not defined between ENTRY and
+   EXIT, i.e. if all its operands are defined outside of the region.  */
+
+static bool
+expr_invariant_in_region_p (edge entry, edge exit, tree expr)
+{
+  basic_block entry_bb = entry->src;
+  basic_block exit_bb = exit->dest;
+  basic_block def_bb;
+
+  if (is_gimple_min_invariant (expr))
+    return true;
+
+  if (TREE_CODE (expr) == SSA_NAME)
+    {
+      def_bb = gimple_bb (SSA_NAME_DEF_STMT (expr));
+      if (def_bb
+	  && dominated_by_p (CDI_DOMINATORS, def_bb, entry_bb)
+	  && !dominated_by_p (CDI_DOMINATORS, def_bb, exit_bb))
+	return false;
+
+      return true;
+    }
+
+  return false;
+}
+
+/* If COPY_NAME_P is true, creates and returns a duplicate of NAME.
+   The copies are stored to NAME_COPIES, if NAME was already duplicated,
+   its duplicate stored in NAME_COPIES is returned.
+
+   Regardless of COPY_NAME_P, the decl used as a base of the ssa name is also
+   duplicated, storing the copies in DECL_COPIES.  */
+
+static tree
+separate_decls_in_region_name (tree name, name_to_copy_table_type name_copies,
+			       int_tree_htab_type decl_copies, bool copy_name_p)
+{
+  tree copy, var, var_copy;
+  unsigned idx, uid, nuid;
+  struct int_tree_map ielt, *nielt;
+  struct name_to_copy_elt elt, *nelt;
+  name_to_copy_elt **slot;
+  int_tree_map **dslot;
+
+  if (TREE_CODE (name) != SSA_NAME)
+    return name;
+
+  idx = SSA_NAME_VERSION (name);
+  elt.version = idx;
+  slot = name_copies.find_slot_with_hash (&elt, idx,
+					  copy_name_p ? INSERT : NO_INSERT);
+  if (slot && *slot)
+    return (*slot)->new_name;
+
+  if (copy_name_p)
+    {
+      copy = duplicate_ssa_name (name, NULL);
+      nelt = XNEW (struct name_to_copy_elt);
+      nelt->version = idx;
+      nelt->new_name = copy;
+      nelt->field = NULL_TREE;
+      *slot = nelt;
+    }
+  else
+    {
+      gcc_assert (!slot);
+      copy = name;
+    }
+
+  var = SSA_NAME_VAR (name);
+  if (!var)
+    return copy;
+
+  uid = DECL_UID (var);
+  ielt.uid = uid;
+  dslot = decl_copies.find_slot_with_hash (&ielt, uid, INSERT);
+  if (!*dslot)
+    {
+      var_copy = create_tmp_var (TREE_TYPE (var), get_name (var));
+      DECL_GIMPLE_REG_P (var_copy) = DECL_GIMPLE_REG_P (var);
+      nielt = XNEW (struct int_tree_map);
+      nielt->uid = uid;
+      nielt->to = var_copy;
+      *dslot = nielt;
+
+      /* Ensure that when we meet this decl next time, we won't duplicate
+         it again.  */
+      nuid = DECL_UID (var_copy);
+      ielt.uid = nuid;
+      dslot = decl_copies.find_slot_with_hash (&ielt, nuid, INSERT);
+      gcc_assert (!*dslot);
+      nielt = XNEW (struct int_tree_map);
+      nielt->uid = nuid;
+      nielt->to = var_copy;
+      *dslot = nielt;
+    }
+  else
+    var_copy = ((struct int_tree_map *) *dslot)->to;
+
+  replace_ssa_name_symbol (copy, var_copy);
+  return copy;
+}
+
+/* Finds the ssa names used in STMT that are defined outside the
+   region between ENTRY and EXIT and replaces such ssa names with
+   their duplicates.  The duplicates are stored to NAME_COPIES.  Base
+   decls of all ssa names used in STMT (including those defined in
+   LOOP) are replaced with the new temporary variables; the
+   replacement decls are stored in DECL_COPIES.  */
+
+static void
+separate_decls_in_region_stmt (edge entry, edge exit, gimple stmt,
+			       name_to_copy_table_type name_copies,
+			       int_tree_htab_type decl_copies)
+{
+  use_operand_p use;
+  def_operand_p def;
+  ssa_op_iter oi;
+  tree name, copy;
+  bool copy_name_p;
+
+  FOR_EACH_PHI_OR_STMT_DEF (def, stmt, oi, SSA_OP_DEF)
+  {
+    name = DEF_FROM_PTR (def);
+    gcc_assert (TREE_CODE (name) == SSA_NAME);
+    copy = separate_decls_in_region_name (name, name_copies, decl_copies,
+					  false);
+    gcc_assert (copy == name);
+  }
+
+  FOR_EACH_PHI_OR_STMT_USE (use, stmt, oi, SSA_OP_USE)
+  {
+    name = USE_FROM_PTR (use);
+    if (TREE_CODE (name) != SSA_NAME)
+      continue;
+
+    copy_name_p = expr_invariant_in_region_p (entry, exit, name);
+    copy = separate_decls_in_region_name (name, name_copies, decl_copies,
+					  copy_name_p);
+    SET_USE (use, copy);
+  }
+}
+
+/* Finds the ssa names used in STMT that are defined outside the
+   region between ENTRY and EXIT and replaces such ssa names with
+   their duplicates.  The duplicates are stored to NAME_COPIES.  Base
+   decls of all ssa names used in STMT (including those defined in
+   LOOP) are replaced with the new temporary variables; the
+   replacement decls are stored in DECL_COPIES.  */
+
+static bool
+separate_decls_in_region_debug (gimple stmt,
+				name_to_copy_table_type name_copies,
+				int_tree_htab_type decl_copies)
+{
+  use_operand_p use;
+  ssa_op_iter oi;
+  tree var, name;
+  struct int_tree_map ielt;
+  struct name_to_copy_elt elt;
+  name_to_copy_elt **slot;
+  int_tree_map **dslot;
+
+  if (gimple_debug_bind_p (stmt))
+    var = gimple_debug_bind_get_var (stmt);
+  else if (gimple_debug_source_bind_p (stmt))
+    var = gimple_debug_source_bind_get_var (stmt);
+  else
+    return true;
+  if (TREE_CODE (var) == DEBUG_EXPR_DECL || TREE_CODE (var) == LABEL_DECL)
+    return true;
+  gcc_assert (DECL_P (var) && SSA_VAR_P (var));
+  ielt.uid = DECL_UID (var);
+  dslot = decl_copies.find_slot_with_hash (&ielt, ielt.uid, NO_INSERT);
+  if (!dslot)
+    return true;
+  if (gimple_debug_bind_p (stmt))
+    gimple_debug_bind_set_var (stmt, ((struct int_tree_map *) *dslot)->to);
+  else if (gimple_debug_source_bind_p (stmt))
+    gimple_debug_source_bind_set_var (stmt, ((struct int_tree_map *) *dslot)->to);
+
+  FOR_EACH_PHI_OR_STMT_USE (use, stmt, oi, SSA_OP_USE)
+  {
+    name = USE_FROM_PTR (use);
+    if (TREE_CODE (name) != SSA_NAME)
+      continue;
+
+    elt.version = SSA_NAME_VERSION (name);
+    slot = name_copies.find_slot_with_hash (&elt, elt.version, NO_INSERT);
+    if (!slot)
+      {
+	gimple_debug_bind_reset_value (stmt);
+	update_stmt (stmt);
+	break;
+      }
+
+    SET_USE (use, (*slot)->new_name);
+  }
+
+  return false;
+}
+
+/* Callback for htab_traverse.  Adds a field corresponding to the reduction
+   specified in SLOT. The type is passed in DATA.  */
+
+int
+add_field_for_reduction (reduction_info **slot, tree type)
+{
+
+  struct reduction_info *const red = *slot;
+  tree var = gimple_assign_lhs (red->reduc_stmt);
+  tree field = build_decl (gimple_location (red->reduc_stmt), FIELD_DECL,
+			   SSA_NAME_IDENTIFIER (var), TREE_TYPE (var));
+
+  insert_field_into_struct (type, field);
+
+  red->field = field;
+
+  return 1;
+}
+
+/* Callback for htab_traverse.  Adds a field corresponding to a ssa name
+   described in SLOT. The type is passed in DATA.  */
+
+int
+add_field_for_name (name_to_copy_elt **slot, tree type)
+{
+  struct name_to_copy_elt *const elt = *slot;
+  tree name = ssa_name (elt->version);
+  tree field = build_decl (UNKNOWN_LOCATION,
+			   FIELD_DECL, SSA_NAME_IDENTIFIER (name),
+			   TREE_TYPE (name));
+
+  insert_field_into_struct (type, field);
+  elt->field = field;
+
+  return 1;
+}
+
+/* Callback for htab_traverse.  A local result is the intermediate result
+   computed by a single
+   thread, or the initial value in case no iteration was executed.
+   This function creates a phi node reflecting these values.
+   The phi's result will be stored in NEW_PHI field of the
+   reduction's data structure.  */
+
+int
+create_phi_for_local_result (reduction_info **slot, struct loop *loop)
+{
+  struct reduction_info *const reduc = *slot;
+  edge e;
+  gimple new_phi;
+  basic_block store_bb;
+  tree local_res;
+  source_location locus;
+
+  /* STORE_BB is the block where the phi
+     should be stored.  It is the destination of the loop exit.
+     (Find the fallthru edge from GIMPLE_OMP_CONTINUE).  */
+  store_bb = FALLTHRU_EDGE (loop->latch)->dest;
+
+  /* STORE_BB has two predecessors.  One coming from  the loop
+     (the reduction's result is computed at the loop),
+     and another coming from a block preceding the loop,
+     when no iterations
+     are executed (the initial value should be taken).  */
+  if (EDGE_PRED (store_bb, 0) == FALLTHRU_EDGE (loop->latch))
+    e = EDGE_PRED (store_bb, 1);
+  else
+    e = EDGE_PRED (store_bb, 0);
+  local_res = copy_ssa_name (gimple_assign_lhs (reduc->reduc_stmt), NULL);
+  locus = gimple_location (reduc->reduc_stmt);
+  new_phi = create_phi_node (local_res, store_bb);
+  add_phi_arg (new_phi, reduc->init, e, locus);
+  add_phi_arg (new_phi, gimple_assign_lhs (reduc->reduc_stmt),
+	       FALLTHRU_EDGE (loop->latch), locus);
+  reduc->new_phi = new_phi;
+
+  return 1;
+}
+
+struct clsn_data
+{
+  tree store;
+  tree load;
+
+  basic_block store_bb;
+  basic_block load_bb;
+};
+
+/* Callback for htab_traverse.  Create an atomic instruction for the
+   reduction described in SLOT.
+   DATA annotates the place in memory the atomic operation relates to,
+   and the basic block it needs to be generated in.  */
+
+int
+create_call_for_reduction_1 (reduction_info **slot, struct clsn_data *clsn_data)
+{
+  struct reduction_info *const reduc = *slot;
+  gimple_stmt_iterator gsi;
+  tree type = TREE_TYPE (PHI_RESULT (reduc->reduc_phi));
+  tree load_struct;
+  basic_block bb;
+  basic_block new_bb;
+  edge e;
+  tree t, addr, ref, x;
+  tree tmp_load, name;
+  gimple load;
+
+  load_struct = build_simple_mem_ref (clsn_data->load);
+  t = build3 (COMPONENT_REF, type, load_struct, reduc->field, NULL_TREE);
+
+  addr = build_addr (t, current_function_decl);
+
+  /* Create phi node.  */
+  bb = clsn_data->load_bb;
+
+  e = split_block (bb, t);
+  new_bb = e->dest;
+
+  tmp_load = create_tmp_var (TREE_TYPE (TREE_TYPE (addr)), NULL);
+  tmp_load = make_ssa_name (tmp_load, NULL);
+  load = gimple_build_omp_atomic_load (tmp_load, addr);
+  SSA_NAME_DEF_STMT (tmp_load) = load;
+  gsi = gsi_start_bb (new_bb);
+  gsi_insert_after (&gsi, load, GSI_NEW_STMT);
+
+  e = split_block (new_bb, load);
+  new_bb = e->dest;
+  gsi = gsi_start_bb (new_bb);
+  ref = tmp_load;
+  x = fold_build2 (reduc->reduction_code,
+		   TREE_TYPE (PHI_RESULT (reduc->new_phi)), ref,
+		   PHI_RESULT (reduc->new_phi));
+
+  name = force_gimple_operand_gsi (&gsi, x, true, NULL_TREE, true,
+				   GSI_CONTINUE_LINKING);
+
+  gsi_insert_after (&gsi, gimple_build_omp_atomic_store (name), GSI_NEW_STMT);
+  return 1;
+}
+
+/* Create the atomic operation at the join point of the threads.
+   REDUCTION_LIST describes the reductions in the LOOP.
+   LD_ST_DATA describes the shared data structure where
+   shared data is stored in and loaded from.  */
+static void
+create_call_for_reduction (struct loop *loop,
+			   reduction_info_table_type reduction_list,
+			   struct clsn_data *ld_st_data)
+{
+  reduction_list.traverse <struct loop *, create_phi_for_local_result> (loop);
+  /* Find the fallthru edge from GIMPLE_OMP_CONTINUE.  */
+  ld_st_data->load_bb = FALLTHRU_EDGE (loop->latch)->dest;
+  reduction_list
+    .traverse <struct clsn_data *, create_call_for_reduction_1> (ld_st_data);
+}
+
+/* Callback for htab_traverse.  Loads the final reduction value at the
+   join point of all threads, and inserts it in the right place.  */
+
+int
+create_loads_for_reductions (reduction_info **slot, struct clsn_data *clsn_data)
+{
+  struct reduction_info *const red = *slot;
+  gimple stmt;
+  gimple_stmt_iterator gsi;
+  tree type = TREE_TYPE (gimple_assign_lhs (red->reduc_stmt));
+  tree load_struct;
+  tree name;
+  tree x;
+
+  gsi = gsi_after_labels (clsn_data->load_bb);
+  load_struct = build_simple_mem_ref (clsn_data->load);
+  load_struct = build3 (COMPONENT_REF, type, load_struct, red->field,
+			NULL_TREE);
+
+  x = load_struct;
+  name = PHI_RESULT (red->keep_res);
+  stmt = gimple_build_assign (name, x);
+
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+
+  for (gsi = gsi_start_phis (gimple_bb (red->keep_res));
+       !gsi_end_p (gsi); gsi_next (&gsi))
+    if (gsi_stmt (gsi) == red->keep_res)
+      {
+	remove_phi_node (&gsi, false);
+	return 1;
+      }
+  gcc_unreachable ();
+}
+
+/* Load the reduction result that was stored in LD_ST_DATA.
+   REDUCTION_LIST describes the list of reductions that the
+   loads should be generated for.  */
+static void
+create_final_loads_for_reduction (reduction_info_table_type reduction_list,
+				  struct clsn_data *ld_st_data)
+{
+  gimple_stmt_iterator gsi;
+  tree t;
+  gimple stmt;
+
+  gsi = gsi_after_labels (ld_st_data->load_bb);
+  t = build_fold_addr_expr (ld_st_data->store);
+  stmt = gimple_build_assign (ld_st_data->load, t);
+
+  gsi_insert_before (&gsi, stmt, GSI_NEW_STMT);
+
+  reduction_list
+    .traverse <struct clsn_data *, create_loads_for_reductions> (ld_st_data);
+
+}
+
+/* Callback for htab_traverse.  Store the neutral value for the
+  particular reduction's operation, e.g. 0 for PLUS_EXPR,
+  1 for MULT_EXPR, etc. into the reduction field.
+  The reduction is specified in SLOT. The store information is
+  passed in DATA.  */
+
+int
+create_stores_for_reduction (reduction_info **slot, struct clsn_data *clsn_data)
+{
+  struct reduction_info *const red = *slot;
+  tree t;
+  gimple stmt;
+  gimple_stmt_iterator gsi;
+  tree type = TREE_TYPE (gimple_assign_lhs (red->reduc_stmt));
+
+  gsi = gsi_last_bb (clsn_data->store_bb);
+  t = build3 (COMPONENT_REF, type, clsn_data->store, red->field, NULL_TREE);
+  stmt = gimple_build_assign (t, red->initial_value);
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+
+  return 1;
+}
+
+/* Callback for htab_traverse.  Creates loads to a field of LOAD in LOAD_BB and
+   store to a field of STORE in STORE_BB for the ssa name and its duplicate
+   specified in SLOT.  */
+
+int
+create_loads_and_stores_for_name (name_to_copy_elt **slot,
+				  struct clsn_data *clsn_data)
+{
+  struct name_to_copy_elt *const elt = *slot;
+  tree t;
+  gimple stmt;
+  gimple_stmt_iterator gsi;
+  tree type = TREE_TYPE (elt->new_name);
+  tree load_struct;
+
+  gsi = gsi_last_bb (clsn_data->store_bb);
+  t = build3 (COMPONENT_REF, type, clsn_data->store, elt->field, NULL_TREE);
+  stmt = gimple_build_assign (t, ssa_name (elt->version));
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+
+  gsi = gsi_last_bb (clsn_data->load_bb);
+  load_struct = build_simple_mem_ref (clsn_data->load);
+  t = build3 (COMPONENT_REF, type, load_struct, elt->field, NULL_TREE);
+  stmt = gimple_build_assign (elt->new_name, t);
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+
+  return 1;
+}
+
+/* Moves all the variables used in LOOP and defined outside of it (including
+   the initial values of loop phi nodes, and *PER_THREAD if it is a ssa
+   name) to a structure created for this purpose.  The code
+
+   while (1)
+     {
+       use (a);
+       use (b);
+     }
+
+   is transformed this way:
+
+   bb0:
+   old.a = a;
+   old.b = b;
+
+   bb1:
+   a' = new->a;
+   b' = new->b;
+   while (1)
+     {
+       use (a');
+       use (b');
+     }
+
+   `old' is stored to *ARG_STRUCT and `new' is stored to NEW_ARG_STRUCT.  The
+   pointer `new' is intentionally not initialized (the loop will be split to a
+   separate function later, and `new' will be initialized from its arguments).
+   LD_ST_DATA holds information about the shared data structure used to pass
+   information among the threads.  It is initialized here, and
+   gen_parallel_loop will pass it to create_call_for_reduction that
+   needs this information.  REDUCTION_LIST describes the reductions
+   in LOOP.  */
+
+static void
+separate_decls_in_region (edge entry, edge exit,
+			  reduction_info_table_type reduction_list,
+			  tree *arg_struct, tree *new_arg_struct,
+			  struct clsn_data *ld_st_data)
+
+{
+  basic_block bb1 = split_edge (entry);
+  basic_block bb0 = single_pred (bb1);
+  name_to_copy_table_type name_copies;
+  name_copies.create (10);
+  int_tree_htab_type decl_copies;
+  decl_copies.create (10);
+  unsigned i;
+  tree type, type_name, nvar;
+  gimple_stmt_iterator gsi;
+  struct clsn_data clsn_data;
+  auto_vec<basic_block, 3> body;
+  basic_block bb;
+  basic_block entry_bb = bb1;
+  basic_block exit_bb = exit->dest;
+  bool has_debug_stmt = false;
+
+  entry = single_succ_edge (entry_bb);
+  gather_blocks_in_sese_region (entry_bb, exit_bb, &body);
+
+  FOR_EACH_VEC_ELT (body, i, bb)
+    {
+      if (bb != entry_bb && bb != exit_bb)
+	{
+	  for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	    separate_decls_in_region_stmt (entry, exit, gsi_stmt (gsi),
+					   name_copies, decl_copies);
+
+	  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	    {
+	      gimple stmt = gsi_stmt (gsi);
+
+	      if (is_gimple_debug (stmt))
+		has_debug_stmt = true;
+	      else
+		separate_decls_in_region_stmt (entry, exit, stmt,
+					       name_copies, decl_copies);
+	    }
+	}
+    }
+
+  /* Now process debug bind stmts.  We must not create decls while
+     processing debug stmts, so we defer their processing so as to
+     make sure we will have debug info for as many variables as
+     possible (all of those that were dealt with in the loop above),
+     and discard those for which we know there's nothing we can
+     do.  */
+  if (has_debug_stmt)
+    FOR_EACH_VEC_ELT (body, i, bb)
+      if (bb != entry_bb && bb != exit_bb)
+	{
+	  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
+	    {
+	      gimple stmt = gsi_stmt (gsi);
+
+	      if (is_gimple_debug (stmt))
+		{
+		  if (separate_decls_in_region_debug (stmt, name_copies,
+						      decl_copies))
+		    {
+		      gsi_remove (&gsi, true);
+		      continue;
+		    }
+		}
+
+	      gsi_next (&gsi);
+	    }
+	}
+
+  if (name_copies.elements () == 0 && reduction_list.elements () == 0)
+    {
+      /* It may happen that there is nothing to copy (if there are only
+         loop carried and external variables in the loop).  */
+      *arg_struct = NULL;
+      *new_arg_struct = NULL;
+    }
+  else
+    {
+      /* Create the type for the structure to store the ssa names to.  */
+      type = lang_hooks.types.make_type (RECORD_TYPE);
+      type_name = build_decl (UNKNOWN_LOCATION,
+			      TYPE_DECL, create_tmp_var_name (".paral_data"),
+			      type);
+      TYPE_NAME (type) = type_name;
+
+      name_copies.traverse <tree, add_field_for_name> (type);
+      if (reduction_list.is_created () && reduction_list.elements () > 0)
+	{
+	  /* Create the fields for reductions.  */
+	  reduction_list.traverse <tree, add_field_for_reduction> (type);
+	}
+      layout_type (type);
+
+      /* Create the loads and stores.  */
+      *arg_struct = create_tmp_var (type, ".paral_data_store");
+      nvar = create_tmp_var (build_pointer_type (type), ".paral_data_load");
+      *new_arg_struct = make_ssa_name (nvar, NULL);
+
+      ld_st_data->store = *arg_struct;
+      ld_st_data->load = *new_arg_struct;
+      ld_st_data->store_bb = bb0;
+      ld_st_data->load_bb = bb1;
+
+      name_copies
+	.traverse <struct clsn_data *, create_loads_and_stores_for_name>
+		  (ld_st_data);
+
+      /* Load the calculation from memory (after the join of the threads).  */
+
+      if (reduction_list.is_created () && reduction_list.elements () > 0)
+	{
+	  reduction_list
+	    .traverse <struct clsn_data *, create_stores_for_reduction>
+		      (ld_st_data);
+	  clsn_data.load = make_ssa_name (nvar, NULL);
+	  clsn_data.load_bb = exit->dest;
+	  clsn_data.store = ld_st_data->store;
+	  create_final_loads_for_reduction (reduction_list, &clsn_data);
+	}
+    }
+
+  decl_copies.dispose ();
+  name_copies.dispose ();
+}
+
+/* Bitmap containing uids of functions created by parallelization.  We cannot
+   allocate it from the default obstack, as it must live across compilation
+   of several functions; we make it gc allocated instead.  */
+
+static GTY(()) bitmap parallelized_functions;
+
+/* Returns true if FN was created by create_loop_fn.  */
+
+bool
+parallelized_function_p (tree fn)
+{
+  if (!parallelized_functions || !DECL_ARTIFICIAL (fn))
+    return false;
+
+  return bitmap_bit_p (parallelized_functions, DECL_UID (fn));
+}
+
+/* Creates and returns an empty function that will receive the body of
+   a parallelized loop.  */
+
+static tree
+create_loop_fn (location_t loc)
+{
+  char buf[100];
+  char *tname;
+  tree decl, type, name, t;
+  struct function *act_cfun = cfun;
+  static unsigned loopfn_num;
+
+  loc = LOCATION_LOCUS (loc);
+  snprintf (buf, 100, "%s.$loopfn", current_function_name ());
+  ASM_FORMAT_PRIVATE_NAME (tname, buf, loopfn_num++);
+  clean_symbol_name (tname);
+  name = get_identifier (tname);
+  type = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);
+
+  decl = build_decl (loc, FUNCTION_DECL, name, type);
+  if (!parallelized_functions)
+    parallelized_functions = BITMAP_GGC_ALLOC ();
+  bitmap_set_bit (parallelized_functions, DECL_UID (decl));
+
+  TREE_STATIC (decl) = 1;
+  TREE_USED (decl) = 1;
+  DECL_ARTIFICIAL (decl) = 1;
+  DECL_IGNORED_P (decl) = 0;
+  TREE_PUBLIC (decl) = 0;
+  DECL_UNINLINABLE (decl) = 1;
+  DECL_EXTERNAL (decl) = 0;
+  DECL_CONTEXT (decl) = NULL_TREE;
+  DECL_INITIAL (decl) = make_node (BLOCK);
+
+  t = build_decl (loc, RESULT_DECL, NULL_TREE, void_type_node);
+  DECL_ARTIFICIAL (t) = 1;
+  DECL_IGNORED_P (t) = 1;
+  DECL_RESULT (decl) = t;
+
+  t = build_decl (loc, PARM_DECL, get_identifier (".paral_data_param"),
+		  ptr_type_node);
+  DECL_ARTIFICIAL (t) = 1;
+  DECL_ARG_TYPE (t) = ptr_type_node;
+  DECL_CONTEXT (t) = decl;
+  TREE_USED (t) = 1;
+  DECL_ARGUMENTS (decl) = t;
+
+  allocate_struct_function (decl, false);
+
+  /* The call to allocate_struct_function clobbers CFUN, so we need to restore
+     it.  */
+  set_cfun (act_cfun);
+
+  return decl;
+}
+
+/* Moves the exit condition of LOOP to the beginning of its header, and
+   duplicates the part of the last iteration that gets disabled to the
+   exit of the loop.  NIT is the number of iterations of the loop
+   (used to initialize the variables in the duplicated part).
+
+   TODO: the common case is that latch of the loop is empty and immediately
+   follows the loop exit.  In this case, it would be better not to copy the
+   body of the loop, but only move the entry of the loop directly before the
+   exit check and increase the number of iterations of the loop by one.
+   This may need some additional preconditioning in case NIT = ~0.
+   REDUCTION_LIST describes the reductions in LOOP.  */
+
+static void
+transform_to_exit_first_loop (struct loop *loop,
+			      reduction_info_table_type reduction_list,
+			      tree nit)
+{
+  basic_block *bbs, *nbbs, ex_bb, orig_header;
+  unsigned n;
+  bool ok;
+  edge exit = single_dom_exit (loop), hpred;
+  tree control, control_name, res, t;
+  gimple phi, nphi, cond_stmt, stmt, cond_nit;
+  gimple_stmt_iterator gsi;
+  tree nit_1;
+
+  split_block_after_labels (loop->header);
+  orig_header = single_succ (loop->header);
+  hpred = single_succ_edge (loop->header);
+
+  cond_stmt = last_stmt (exit->src);
+  control = gimple_cond_lhs (cond_stmt);
+  gcc_assert (gimple_cond_rhs (cond_stmt) == nit);
+
+  /* Make sure that we have phi nodes on exit for all loop header phis
+     (create_parallel_loop requires that).  */
+  for (gsi = gsi_start_phis (loop->header); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      phi = gsi_stmt (gsi);
+      res = PHI_RESULT (phi);
+      t = copy_ssa_name (res, phi);
+      SET_PHI_RESULT (phi, t);
+      nphi = create_phi_node (res, orig_header);
+      add_phi_arg (nphi, t, hpred, UNKNOWN_LOCATION);
+
+      if (res == control)
+	{
+	  gimple_cond_set_lhs (cond_stmt, t);
+	  update_stmt (cond_stmt);
+	  control = t;
+	}
+    }
+
+  bbs = get_loop_body_in_dom_order (loop);
+
+  for (n = 0; bbs[n] != exit->src; n++)
+   continue;
+  nbbs = XNEWVEC (basic_block, n);
+  ok = gimple_duplicate_sese_tail (single_succ_edge (loop->header), exit,
+				   bbs + 1, n, nbbs);
+  gcc_assert (ok);
+  free (bbs);
+  ex_bb = nbbs[0];
+  free (nbbs);
+
+  /* Other than reductions, the only gimple reg that should be copied
+     out of the loop is the control variable.  */
+  exit = single_dom_exit (loop);
+  control_name = NULL_TREE;
+  for (gsi = gsi_start_phis (ex_bb); !gsi_end_p (gsi); )
+    {
+      phi = gsi_stmt (gsi);
+      res = PHI_RESULT (phi);
+      if (virtual_operand_p (res))
+	{
+	  gsi_next (&gsi);
+	  continue;
+	}
+
+      /* Check if it is a part of reduction.  If it is,
+         keep the phi at the reduction's keep_res field.  The
+         PHI_RESULT of this phi is the resulting value of the reduction
+         variable when exiting the loop.  */
+
+      if (reduction_list.elements () > 0)
+	{
+	  struct reduction_info *red;
+
+	  tree val = PHI_ARG_DEF_FROM_EDGE (phi, exit);
+	  red = reduction_phi (reduction_list, SSA_NAME_DEF_STMT (val));
+	  if (red)
+	    {
+	      red->keep_res = phi;
+	      gsi_next (&gsi);
+	      continue;
+	    }
+	}
+      gcc_assert (control_name == NULL_TREE
+		  && SSA_NAME_VAR (res) == SSA_NAME_VAR (control));
+      control_name = res;
+      remove_phi_node (&gsi, false);
+    }
+  gcc_assert (control_name != NULL_TREE);
+
+  /* Initialize the control variable to number of iterations
+     according to the rhs of the exit condition.  */
+  gsi = gsi_after_labels (ex_bb);
+  cond_nit = last_stmt (exit->src);
+  nit_1 =  gimple_cond_rhs (cond_nit);
+  nit_1 = force_gimple_operand_gsi (&gsi,
+				  fold_convert (TREE_TYPE (control_name), nit_1),
+				  false, NULL_TREE, false, GSI_SAME_STMT);
+  stmt = gimple_build_assign (control_name, nit_1);
+  gsi_insert_before (&gsi, stmt, GSI_NEW_STMT);
+}
+
+/* Create the parallel constructs for LOOP as described in gen_parallel_loop.
+   LOOP_FN and DATA are the arguments of GIMPLE_OMP_PARALLEL.
+   NEW_DATA is the variable that should be initialized from the argument
+   of LOOP_FN.  N_THREADS is the requested number of threads.  Returns the
+   basic block containing GIMPLE_OMP_PARALLEL tree.  */
+
+static basic_block
+create_parallel_loop (struct loop *loop, tree loop_fn, tree data,
+		      tree new_data, unsigned n_threads, location_t loc)
+{
+  gimple_stmt_iterator gsi;
+  basic_block bb, paral_bb, for_bb, ex_bb;
+  tree t, param;
+  gimple stmt, for_stmt, phi, cond_stmt;
+  tree cvar, cvar_init, initvar, cvar_next, cvar_base, type;
+  edge exit, nexit, guard, end, e;
+
+  /* Prepare the GIMPLE_OMP_PARALLEL statement.  */
+  bb = loop_preheader_edge (loop)->src;
+  paral_bb = single_pred (bb);
+  gsi = gsi_last_bb (paral_bb);
+
+  t = build_omp_clause (loc, OMP_CLAUSE_NUM_THREADS);
+  OMP_CLAUSE_NUM_THREADS_EXPR (t)
+    = build_int_cst (integer_type_node, n_threads);
+  stmt = gimple_build_omp_parallel (NULL, t, loop_fn, data);
+  gimple_set_location (stmt, loc);
+
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+
+  /* Initialize NEW_DATA.  */
+  if (data)
+    {
+      gsi = gsi_after_labels (bb);
+
+      param = make_ssa_name (DECL_ARGUMENTS (loop_fn), NULL);
+      stmt = gimple_build_assign (param, build_fold_addr_expr (data));
+      gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
+
+      stmt = gimple_build_assign (new_data,
+				  fold_convert (TREE_TYPE (new_data), param));
+      gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
+    }
+
+  /* Emit GIMPLE_OMP_RETURN for GIMPLE_OMP_PARALLEL.  */
+  bb = split_loop_exit_edge (single_dom_exit (loop));
+  gsi = gsi_last_bb (bb);
+  stmt = gimple_build_omp_return (false);
+  gimple_set_location (stmt, loc);
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+
+  /* Extract data for GIMPLE_OMP_FOR.  */
+  gcc_assert (loop->header == single_dom_exit (loop)->src);
+  cond_stmt = last_stmt (loop->header);
+
+  cvar = gimple_cond_lhs (cond_stmt);
+  cvar_base = SSA_NAME_VAR (cvar);
+  phi = SSA_NAME_DEF_STMT (cvar);
+  cvar_init = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
+  initvar = copy_ssa_name (cvar, NULL);
+  SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (phi, loop_preheader_edge (loop)),
+	   initvar);
+  cvar_next = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop));
+
+  gsi = gsi_last_nondebug_bb (loop->latch);
+  gcc_assert (gsi_stmt (gsi) == SSA_NAME_DEF_STMT (cvar_next));
+  gsi_remove (&gsi, true);
+
+  /* Prepare cfg.  */
+  for_bb = split_edge (loop_preheader_edge (loop));
+  ex_bb = split_loop_exit_edge (single_dom_exit (loop));
+  extract_true_false_edges_from_block (loop->header, &nexit, &exit);
+  gcc_assert (exit == single_dom_exit (loop));
+
+  guard = make_edge (for_bb, ex_bb, 0);
+  single_succ_edge (loop->latch)->flags = 0;
+  end = make_edge (loop->latch, ex_bb, EDGE_FALLTHRU);
+  for (gsi = gsi_start_phis (ex_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      source_location locus;
+      tree def;
+      phi = gsi_stmt (gsi);
+      stmt = SSA_NAME_DEF_STMT (PHI_ARG_DEF_FROM_EDGE (phi, exit));
+
+      def = PHI_ARG_DEF_FROM_EDGE (stmt, loop_preheader_edge (loop));
+      locus = gimple_phi_arg_location_from_edge (stmt,
+						 loop_preheader_edge (loop));
+      add_phi_arg (phi, def, guard, locus);
+
+      def = PHI_ARG_DEF_FROM_EDGE (stmt, loop_latch_edge (loop));
+      locus = gimple_phi_arg_location_from_edge (stmt, loop_latch_edge (loop));
+      add_phi_arg (phi, def, end, locus);
+    }
+  e = redirect_edge_and_branch (exit, nexit->dest);
+  PENDING_STMT (e) = NULL;
+
+  /* Emit GIMPLE_OMP_FOR.  */
+  gimple_cond_set_lhs (cond_stmt, cvar_base);
+  type = TREE_TYPE (cvar);
+  t = build_omp_clause (loc, OMP_CLAUSE_SCHEDULE);
+  OMP_CLAUSE_SCHEDULE_KIND (t) = OMP_CLAUSE_SCHEDULE_STATIC;
+
+  for_stmt = gimple_build_omp_for (NULL, GF_OMP_FOR_KIND_FOR, t, 1, NULL);
+  gimple_set_location (for_stmt, loc);
+  gimple_omp_for_set_index (for_stmt, 0, initvar);
+  gimple_omp_for_set_initial (for_stmt, 0, cvar_init);
+  gimple_omp_for_set_final (for_stmt, 0, gimple_cond_rhs (cond_stmt));
+  gimple_omp_for_set_cond (for_stmt, 0, gimple_cond_code (cond_stmt));
+  gimple_omp_for_set_incr (for_stmt, 0, build2 (PLUS_EXPR, type,
+						cvar_base,
+						build_int_cst (type, 1)));
+
+  gsi = gsi_last_bb (for_bb);
+  gsi_insert_after (&gsi, for_stmt, GSI_NEW_STMT);
+  SSA_NAME_DEF_STMT (initvar) = for_stmt;
+
+  /* Emit GIMPLE_OMP_CONTINUE.  */
+  gsi = gsi_last_bb (loop->latch);
+  stmt = gimple_build_omp_continue (cvar_next, cvar);
+  gimple_set_location (stmt, loc);
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+  SSA_NAME_DEF_STMT (cvar_next) = stmt;
+
+  /* Emit GIMPLE_OMP_RETURN for GIMPLE_OMP_FOR.  */
+  gsi = gsi_last_bb (ex_bb);
+  stmt = gimple_build_omp_return (true);
+  gimple_set_location (stmt, loc);
+  gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
+
+  /* After the above dom info is hosed.  Re-compute it.  */
+  free_dominance_info (CDI_DOMINATORS);
+  calculate_dominance_info (CDI_DOMINATORS);
+
+  return paral_bb;
+}
+
+/* Generates code to execute the iterations of LOOP in N_THREADS
+   threads in parallel.
+
+   NITER describes number of iterations of LOOP.
+   REDUCTION_LIST describes the reductions existent in the LOOP.  */
+
+static void
+gen_parallel_loop (struct loop *loop, reduction_info_table_type reduction_list,
+		   unsigned n_threads, struct tree_niter_desc *niter)
+{
+  tree many_iterations_cond, type, nit;
+  tree arg_struct, new_arg_struct;
+  gimple_seq stmts;
+  basic_block parallel_head;
+  edge entry, exit;
+  struct clsn_data clsn_data;
+  unsigned prob;
+  location_t loc;
+  gimple cond_stmt;
+  unsigned int m_p_thread=2;
+
+  /* From
+
+     ---------------------------------------------------------------------
+     loop
+       {
+	 IV = phi (INIT, IV + STEP)
+	 BODY1;
+	 if (COND)
+	   break;
+	 BODY2;
+       }
+     ---------------------------------------------------------------------
+
+     with # of iterations NITER (possibly with MAY_BE_ZERO assumption),
+     we generate the following code:
+
+     ---------------------------------------------------------------------
+
+     if (MAY_BE_ZERO
+     || NITER < MIN_PER_THREAD * N_THREADS)
+     goto original;
+
+     BODY1;
+     store all local loop-invariant variables used in body of the loop to DATA.
+     GIMPLE_OMP_PARALLEL (OMP_CLAUSE_NUM_THREADS (N_THREADS), LOOPFN, DATA);
+     load the variables from DATA.
+     GIMPLE_OMP_FOR (IV = INIT; COND; IV += STEP) (OMP_CLAUSE_SCHEDULE (static))
+     BODY2;
+     BODY1;
+     GIMPLE_OMP_CONTINUE;
+     GIMPLE_OMP_RETURN         -- GIMPLE_OMP_FOR
+     GIMPLE_OMP_RETURN         -- GIMPLE_OMP_PARALLEL
+     goto end;
+
+     original:
+     loop
+       {
+	 IV = phi (INIT, IV + STEP)
+	 BODY1;
+	 if (COND)
+	   break;
+	 BODY2;
+       }
+
+     end:
+
+   */
+
+  /* Create two versions of the loop -- in the old one, we know that the
+     number of iterations is large enough, and we will transform it into the
+     loop that will be split to loop_fn, the new one will be used for the
+     remaining iterations.  */
+
+  /* We should compute a better number-of-iterations value for outer loops.
+     That is, if we have
+ 
+    for (i = 0; i < n; ++i)
+      for (j = 0; j < m; ++j)
+        ...
+
+    we should compute nit = n * m, not nit = n.  
+    Also may_be_zero handling would need to be adjusted.  */
+
+  type = TREE_TYPE (niter->niter);
+  nit = force_gimple_operand (unshare_expr (niter->niter), &stmts, true,
+			      NULL_TREE);
+  if (stmts)
+    gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
+
+  if (loop->inner)
+    m_p_thread=2;
+  else
+    m_p_thread=MIN_PER_THREAD;
+
+   many_iterations_cond =
+     fold_build2 (GE_EXPR, boolean_type_node,
+                nit, build_int_cst (type, m_p_thread * n_threads));
+
+  many_iterations_cond
+    = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
+		   invert_truthvalue (unshare_expr (niter->may_be_zero)),
+		   many_iterations_cond);
+  many_iterations_cond
+    = force_gimple_operand (many_iterations_cond, &stmts, false, NULL_TREE);
+  if (stmts)
+    gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
+  if (!is_gimple_condexpr (many_iterations_cond))
+    {
+      many_iterations_cond
+	= force_gimple_operand (many_iterations_cond, &stmts,
+				true, NULL_TREE);
+      if (stmts)
+	gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
+    }
+
+  initialize_original_copy_tables ();
+
+  /* We assume that the loop usually iterates a lot.  */
+  prob = 4 * REG_BR_PROB_BASE / 5;
+  loop_version (loop, many_iterations_cond, NULL,
+		prob, prob, REG_BR_PROB_BASE - prob, true);
+  update_ssa (TODO_update_ssa);
+  free_original_copy_tables ();
+
+  /* Base all the induction variables in LOOP on a single control one.  */
+  canonicalize_loop_ivs (loop, &nit, true);
+
+  /* Ensure that the exit condition is the first statement in the loop.  */
+  transform_to_exit_first_loop (loop, reduction_list, nit);
+
+  /* Generate initializations for reductions.  */
+  if (reduction_list.elements () > 0)
+    reduction_list.traverse <struct loop *, initialize_reductions> (loop);
+
+  /* Eliminate the references to local variables from the loop.  */
+  gcc_assert (single_exit (loop));
+  entry = loop_preheader_edge (loop);
+  exit = single_dom_exit (loop);
+
+  eliminate_local_variables (entry, exit);
+  /* In the old loop, move all variables non-local to the loop to a structure
+     and back, and create separate decls for the variables used in loop.  */
+  separate_decls_in_region (entry, exit, reduction_list, &arg_struct,
+			    &new_arg_struct, &clsn_data);
+
+  /* Create the parallel constructs.  */
+  loc = UNKNOWN_LOCATION;
+  cond_stmt = last_stmt (loop->header);
+  if (cond_stmt)
+    loc = gimple_location (cond_stmt);
+  parallel_head = create_parallel_loop (loop, create_loop_fn (loc), arg_struct,
+					new_arg_struct, n_threads, loc);
+  if (reduction_list.elements () > 0)
+    create_call_for_reduction (loop, reduction_list, &clsn_data);
+
+  scev_reset ();
+
+  /* Cancel the loop (it is simpler to do it here rather than to teach the
+     expander to do it).  */
+  cancel_loop_tree (loop);
+
+  /* Free loop bound estimations that could contain references to
+     removed statements.  */
+  FOR_EACH_LOOP (loop, 0)
+    free_numbers_of_iterations_estimates_loop (loop);
+
+  /* Expand the parallel constructs.  We do it directly here instead of running
+     a separate expand_omp pass, since it is more efficient, and less likely to
+     cause troubles with further analyses not being able to deal with the
+     OMP trees.  */
+
+  omp_expand_local (parallel_head);
+}
+
+/* Returns true when LOOP contains vector phi nodes.  */
+
+static bool
+loop_has_vector_phi_nodes (struct loop *loop ATTRIBUTE_UNUSED)
+{
+  unsigned i;
+  basic_block *bbs = get_loop_body_in_dom_order (loop);
+  gimple_stmt_iterator gsi;
+  bool res = true;
+
+  for (i = 0; i < loop->num_nodes; i++)
+    for (gsi = gsi_start_phis (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi))
+      if (TREE_CODE (TREE_TYPE (PHI_RESULT (gsi_stmt (gsi)))) == VECTOR_TYPE)
+	goto end;
+
+  res = false;
+ end:
+  free (bbs);
+  return res;
+}
+
+/* Create a reduction_info struct, initialize it with REDUC_STMT
+   and PHI, insert it to the REDUCTION_LIST.  */
+
+static void
+build_new_reduction (reduction_info_table_type reduction_list,
+		     gimple reduc_stmt, gimple phi)
+{
+  reduction_info **slot;
+  struct reduction_info *new_reduction;
+
+  gcc_assert (reduc_stmt);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file,
+	       "Detected reduction. reduction stmt is: \n");
+      print_gimple_stmt (dump_file, reduc_stmt, 0, 0);
+      fprintf (dump_file, "\n");
+    }
+
+  new_reduction = XCNEW (struct reduction_info);
+
+  new_reduction->reduc_stmt = reduc_stmt;
+  new_reduction->reduc_phi = phi;
+  new_reduction->reduc_version = SSA_NAME_VERSION (gimple_phi_result (phi));
+  new_reduction->reduction_code = gimple_assign_rhs_code (reduc_stmt);
+  slot = reduction_list.find_slot (new_reduction, INSERT);
+  *slot = new_reduction;
+}
+
+/* Callback for htab_traverse.  Sets gimple_uid of reduc_phi stmts.  */
+
+int
+set_reduc_phi_uids (reduction_info **slot, void *data ATTRIBUTE_UNUSED)
+{
+  struct reduction_info *const red = *slot;
+  gimple_set_uid (red->reduc_phi, red->reduc_version);
+  return 1;
+}
+
+/* Detect all reductions in the LOOP, insert them into REDUCTION_LIST.  */
+
+static void
+gather_scalar_reductions (loop_p loop, reduction_info_table_type reduction_list)
+{
+  gimple_stmt_iterator gsi;
+  loop_vec_info simple_loop_info;
+
+  simple_loop_info = vect_analyze_loop_form (loop);
+
+  for (gsi = gsi_start_phis (loop->header); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gimple phi = gsi_stmt (gsi);
+      affine_iv iv;
+      tree res = PHI_RESULT (phi);
+      bool double_reduc;
+
+      if (virtual_operand_p (res))
+	continue;
+
+      if (!simple_iv (loop, loop, res, &iv, true)
+	&& simple_loop_info)
+	{
+           gimple reduc_stmt = vect_force_simple_reduction (simple_loop_info,
+							    phi, true,
+							    &double_reduc);
+	   if (reduc_stmt && !double_reduc)
+              build_new_reduction (reduction_list, reduc_stmt, phi);
+        }
+    }
+  destroy_loop_vec_info (simple_loop_info, true);
+
+  /* As gimple_uid is used by the vectorizer in between vect_analyze_loop_form
+     and destroy_loop_vec_info, we can set gimple_uid of reduc_phi stmts
+     only now.  */
+  reduction_list.traverse <void *, set_reduc_phi_uids> (NULL);
+}
+
+/* Try to initialize NITER for code generation part.  */
+
+static bool
+try_get_loop_niter (loop_p loop, struct tree_niter_desc *niter)
+{
+  edge exit = single_dom_exit (loop);
+
+  gcc_assert (exit);
+
+  /* We need to know # of iterations, and there should be no uses of values
+     defined inside loop outside of it, unless the values are invariants of
+     the loop.  */
+  if (!number_of_iterations_exit (loop, exit, niter, false))
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "  FAILED: number of iterations not known\n");
+      return false;
+    }
+
+  return true;
+}
+
+/* Try to initialize REDUCTION_LIST for code generation part.
+   REDUCTION_LIST describes the reductions.  */
+
+static bool
+try_create_reduction_list (loop_p loop,
+			   reduction_info_table_type reduction_list)
+{
+  edge exit = single_dom_exit (loop);
+  gimple_stmt_iterator gsi;
+
+  gcc_assert (exit);
+
+  gather_scalar_reductions (loop, reduction_list);
+
+
+  for (gsi = gsi_start_phis (exit->dest); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gimple phi = gsi_stmt (gsi);
+      struct reduction_info *red;
+      imm_use_iterator imm_iter;
+      use_operand_p use_p;
+      gimple reduc_phi;
+      tree val = PHI_ARG_DEF_FROM_EDGE (phi, exit);
+
+      if (!virtual_operand_p (val))
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "phi is ");
+	      print_gimple_stmt (dump_file, phi, 0, 0);
+	      fprintf (dump_file, "arg of phi to exit:   value ");
+	      print_generic_expr (dump_file, val, 0);
+	      fprintf (dump_file, " used outside loop\n");
+	      fprintf (dump_file,
+		       "  checking if it a part of reduction pattern:  \n");
+	    }
+	  if (reduction_list.elements () == 0)
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file,
+			 "  FAILED: it is not a part of reduction.\n");
+	      return false;
+	    }
+	  reduc_phi = NULL;
+	  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, val)
+	    {
+	      if (!gimple_debug_bind_p (USE_STMT (use_p))
+		  && flow_bb_inside_loop_p (loop, gimple_bb (USE_STMT (use_p))))
+		{
+		  reduc_phi = USE_STMT (use_p);
+		  break;
+		}
+	    }
+	  red = reduction_phi (reduction_list, reduc_phi);
+	  if (red == NULL)
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file,
+			 "  FAILED: it is not a part of reduction.\n");
+	      return false;
+	    }
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "reduction phi is  ");
+	      print_gimple_stmt (dump_file, red->reduc_phi, 0, 0);
+	      fprintf (dump_file, "reduction stmt is  ");
+	      print_gimple_stmt (dump_file, red->reduc_stmt, 0, 0);
+	    }
+	}
+    }
+
+  /* The iterations of the loop may communicate only through bivs whose
+     iteration space can be distributed efficiently.  */
+  for (gsi = gsi_start_phis (loop->header); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gimple phi = gsi_stmt (gsi);
+      tree def = PHI_RESULT (phi);
+      affine_iv iv;
+
+      if (!virtual_operand_p (def) && !simple_iv (loop, loop, def, &iv, true))
+	{
+	  struct reduction_info *red;
+
+	  red = reduction_phi (reduction_list, phi);
+	  if (red == NULL)
+	    {
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file,
+			 "  FAILED: scalar dependency between iterations\n");
+	      return false;
+	    }
+	}
+    }
+
+
+  return true;
+}
+
+/* Detect parallel loops and generate parallel code using libgomp
+   primitives.  Returns true if some loop was parallelized, false
+   otherwise.  */
+
+bool
+parallelize_loops (void)
+{
+  unsigned n_threads = flag_tree_parallelize_loops;
+  bool changed = false;
+  struct loop *loop;
+  struct tree_niter_desc niter_desc;
+  reduction_info_table_type reduction_list;
+  struct obstack parloop_obstack;
+  HOST_WIDE_INT estimated;
+  source_location loop_loc;
+
+  /* Do not parallelize loops in the functions created by parallelization.  */
+  if (parallelized_function_p (cfun->decl))
+    return false;
+  if (cfun->has_nonlocal_label)
+    return false;
+
+  gcc_obstack_init (&parloop_obstack);
+  reduction_list.create (10);
+  init_stmt_vec_info_vec ();
+
+  FOR_EACH_LOOP (loop, 0)
+    {
+      reduction_list.empty ();
+      if (dump_file && (dump_flags & TDF_DETAILS))
+      {
+        fprintf (dump_file, "Trying loop %d as candidate\n",loop->num);
+	if (loop->inner)
+	  fprintf (dump_file, "loop %d is not innermost\n",loop->num);
+	else
+	  fprintf (dump_file, "loop %d is innermost\n",loop->num);
+      }
+
+      /* If we use autopar in graphite pass, we use its marked dependency
+      checking results.  */
+      if (flag_loop_parallelize_all && !loop->can_be_parallel)
+      {
+        if (dump_file && (dump_flags & TDF_DETAILS))
+	   fprintf (dump_file, "loop is not parallel according to graphite\n");
+	continue;
+      }
+
+      if (!single_dom_exit (loop))
+      {
+
+        if (dump_file && (dump_flags & TDF_DETAILS))
+	  fprintf (dump_file, "loop is !single_dom_exit\n");
+
+	continue;
+      }
+
+      if (/* And of course, the loop must be parallelizable.  */
+	  !can_duplicate_loop_p (loop)
+	  || loop_has_blocks_with_irreducible_flag (loop)
+	  || (loop_preheader_edge (loop)->src->flags & BB_IRREDUCIBLE_LOOP)
+	  /* FIXME: the check for vector phi nodes could be removed.  */
+	  || loop_has_vector_phi_nodes (loop))
+	continue;
+
+      estimated = estimated_stmt_executions_int (loop);
+      if (estimated == -1)
+	estimated = max_stmt_executions_int (loop);
+      /* FIXME: Bypass this check as graphite doesn't update the
+	 count and frequency correctly now.  */
+      if (!flag_loop_parallelize_all
+	  && ((estimated != -1
+	       && estimated <= (HOST_WIDE_INT) n_threads * MIN_PER_THREAD)
+	      /* Do not bother with loops in cold areas.  */
+	      || optimize_loop_nest_for_size_p (loop)))
+	continue;
+
+      if (!try_get_loop_niter (loop, &niter_desc))
+	continue;
+
+      if (!try_create_reduction_list (loop, reduction_list))
+	continue;
+
+      if (!flag_loop_parallelize_all
+	  && !loop_parallel_p (loop, &parloop_obstack))
+	continue;
+
+      changed = true;
+      if (dump_file && (dump_flags & TDF_DETAILS))
+      {
+	if (loop->inner)
+	  fprintf (dump_file, "parallelizing outer loop %d\n",loop->header->index);
+	else
+	  fprintf (dump_file, "parallelizing inner loop %d\n",loop->header->index);
+	loop_loc = find_loop_location (loop);
+	if (loop_loc != UNKNOWN_LOCATION)
+	  fprintf (dump_file, "\nloop at %s:%d: ",
+		   LOCATION_FILE (loop_loc), LOCATION_LINE (loop_loc));
+      }
+      gen_parallel_loop (loop, reduction_list,
+			 n_threads, &niter_desc);
+    }
+
+  free_stmt_vec_info_vec ();
+  reduction_list.dispose ();
+  obstack_free (&parloop_obstack, NULL);
+
+  /* Parallelization will cause new function calls to be inserted through
+     which local variables will escape.  Reset the points-to solution
+     for ESCAPED.  */
+  if (changed)
+    pt_solution_reset (&cfun->gimple_df->escaped);
+
+  return changed;
+}
+
+/* Parallelization.  */
+
+static bool
+gate_tree_parallelize_loops (void)
+{
+  return flag_tree_parallelize_loops > 1;
+}
+
+static unsigned
+tree_parallelize_loops (void)
+{
+  if (number_of_loops (cfun) <= 1)
+    return 0;
+
+  if (parallelize_loops ())
+    return TODO_cleanup_cfg | TODO_rebuild_alias;
+  return 0;
+}
+
+namespace {
+
+const pass_data pass_data_parallelize_loops =
+{
+  GIMPLE_PASS, /* type */
+  "parloops", /* name */
+  OPTGROUP_LOOP, /* optinfo_flags */
+  true, /* has_gate */
+  true, /* has_execute */
+  TV_TREE_PARALLELIZE_LOOPS, /* tv_id */
+  ( PROP_cfg | PROP_ssa ), /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  TODO_verify_flow, /* todo_flags_finish */
+};
+
+class pass_parallelize_loops : public gimple_opt_pass
+{
+public:
+  pass_parallelize_loops (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_parallelize_loops, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  bool gate () { return gate_tree_parallelize_loops (); }
+  unsigned int execute () { return tree_parallelize_loops (); }
+
+}; // class pass_parallelize_loops
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_parallelize_loops (gcc::context *ctxt)
+{
+  return new pass_parallelize_loops (ctxt);
+}
+
+
+#include "gt-tree-parloops.h"