Merge from trunk revision 8dc2499aa62f768c6395c9754b8cabc1ce25c494

1 files changed, 0 insertions, 3516 deletions

diff --git a/gcc/tree-predcom.c b/gcc/tree-predcom.c
deleted file mode 100644
index 208e755..0000000
--- a/gcc/tree-predcom.c
+++ /dev/null
@@ -1,3516 +0,0 @@
-/* Predictive commoning.
-   Copyright (C) 2005-2021 Free Software Foundation, Inc.
-
-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/>.  */
-
-/* This file implements the predictive commoning optimization.  Predictive
-   commoning can be viewed as CSE around a loop, and with some improvements,
-   as generalized strength reduction-- i.e., reusing values computed in
-   earlier iterations of a loop in the later ones.  So far, the pass only
-   handles the most useful case, that is, reusing values of memory references.
-   If you think this is all just a special case of PRE, you are sort of right;
-   however, concentrating on loops is simpler, and makes it possible to
-   incorporate data dependence analysis to detect the opportunities, perform
-   loop unrolling to avoid copies together with renaming immediately,
-   and if needed, we could also take register pressure into account.
-
-   Let us demonstrate what is done on an example:
-
-   for (i = 0; i < 100; i++)
-     {
-       a[i+2] = a[i] + a[i+1];
-       b[10] = b[10] + i;
-       c[i] = c[99 - i];
-       d[i] = d[i + 1];
-     }
-
-   1) We find data references in the loop, and split them to mutually
-      independent groups (i.e., we find components of a data dependence
-      graph).  We ignore read-read dependences whose distance is not constant.
-      (TODO -- we could also ignore antidependences).  In this example, we
-      find the following groups:
-
-      a[i]{read}, a[i+1]{read}, a[i+2]{write}
-      b[10]{read}, b[10]{write}
-      c[99 - i]{read}, c[i]{write}
-      d[i + 1]{read}, d[i]{write}
-
-   2) Inside each of the group, we verify several conditions:
-      a) all the references must differ in indices only, and the indices
-	 must all have the same step
-      b) the references must dominate loop latch (and thus, they must be
-	 ordered by dominance relation).
-      c) the distance of the indices must be a small multiple of the step
-      We are then able to compute the difference of the references (# of
-      iterations before they point to the same place as the first of them).
-      Also, in case there are writes in the loop, we split the groups into
-      chains whose head is the write whose values are used by the reads in
-      the same chain.  The chains are then processed independently,
-      making the further transformations simpler.  Also, the shorter chains
-      need the same number of registers, but may require lower unrolling
-      factor in order to get rid of the copies on the loop latch.
-
-      In our example, we get the following chains (the chain for c is invalid).
-
-      a[i]{read,+0}, a[i+1]{read,-1}, a[i+2]{write,-2}
-      b[10]{read,+0}, b[10]{write,+0}
-      d[i + 1]{read,+0}, d[i]{write,+1}
-
-   3) For each read, we determine the read or write whose value it reuses,
-      together with the distance of this reuse.  I.e. we take the last
-      reference before it with distance 0, or the last of the references
-      with the smallest positive distance to the read.  Then, we remove
-      the references that are not used in any of these chains, discard the
-      empty groups, and propagate all the links so that they point to the
-      single root reference of the chain (adjusting their distance
-      appropriately).  Some extra care needs to be taken for references with
-      step 0.  In our example (the numbers indicate the distance of the
-      reuse),
-
-      a[i] --> (*) 2, a[i+1] --> (*) 1, a[i+2] (*)
-      b[10] --> (*) 1, b[10] (*)
-
-   4) The chains are combined together if possible.  If the corresponding
-      elements of two chains are always combined together with the same
-      operator, we remember just the result of this combination, instead
-      of remembering the values separately.  We may need to perform
-      reassociation to enable combining, for example
-
-      e[i] + f[i+1] + e[i+1] + f[i]
-
-      can be reassociated as
-
-      (e[i] + f[i]) + (e[i+1] + f[i+1])
-
-      and we can combine the chains for e and f into one chain.
-
-   5) For each root reference (end of the chain) R, let N be maximum distance
-      of a reference reusing its value.  Variables R0 up to RN are created,
-      together with phi nodes that transfer values from R1 .. RN to
-      R0 .. R(N-1).
-      Initial values are loaded to R0..R(N-1) (in case not all references
-      must necessarily be accessed and they may trap, we may fail here;
-      TODO sometimes, the loads could be guarded by a check for the number
-      of iterations).  Values loaded/stored in roots are also copied to
-      RN.  Other reads are replaced with the appropriate variable Ri.
-      Everything is put to SSA form.
-
-      As a small improvement, if R0 is dead after the root (i.e., all uses of
-      the value with the maximum distance dominate the root), we can avoid
-      creating RN and use R0 instead of it.
-
-      In our example, we get (only the parts concerning a and b are shown):
-      for (i = 0; i < 100; i++)
-	{
-	  f = phi (a[0], s);
-	  s = phi (a[1], f);
-	  x = phi (b[10], x);
-
-	  f = f + s;
-	  a[i+2] = f;
-	  x = x + i;
-	  b[10] = x;
-	}
-
-   6) Factor F for unrolling is determined as the smallest common multiple of
-      (N + 1) for each root reference (N for references for that we avoided
-      creating RN).  If F and the loop is small enough, loop is unrolled F
-      times.  The stores to RN (R0) in the copies of the loop body are
-      periodically replaced with R0, R1, ... (R1, R2, ...), so that they can
-      be coalesced and the copies can be eliminated.
-
-      TODO -- copy propagation and other optimizations may change the live
-      ranges of the temporary registers and prevent them from being coalesced;
-      this may increase the register pressure.
-
-      In our case, F = 2 and the (main loop of the) result is
-
-      for (i = 0; i < ...; i += 2)
-        {
-          f = phi (a[0], f);
-          s = phi (a[1], s);
-          x = phi (b[10], x);
-
-          f = f + s;
-          a[i+2] = f;
-          x = x + i;
-          b[10] = x;
-
-          s = s + f;
-          a[i+3] = s;
-          x = x + i;
-          b[10] = x;
-       }
-
-   Apart from predictive commoning on Load-Load and Store-Load chains, we
-   also support Store-Store chains -- stores killed by other store can be
-   eliminated.  Given below example:
-
-     for (i = 0; i < n; i++)
-       {
-	 a[i] = 1;
-	 a[i+2] = 2;
-       }
-
-   It can be replaced with:
-
-     t0 = a[0];
-     t1 = a[1];
-     for (i = 0; i < n; i++)
-       {
-	 a[i] = 1;
-	 t2 = 2;
-	 t0 = t1;
-	 t1 = t2;
-       }
-     a[n] = t0;
-     a[n+1] = t1;
-
-   If the loop runs more than 1 iterations, it can be further simplified into:
-
-     for (i = 0; i < n; i++)
-       {
-	 a[i] = 1;
-       }
-     a[n] = 2;
-     a[n+1] = 2;
-
-   The interesting part is this can be viewed either as general store motion
-   or general dead store elimination in either intra/inter-iterations way.
-
-   With trivial effort, we also support load inside Store-Store chains if the
-   load is dominated by a store statement in the same iteration of loop.  You
-   can see this as a restricted Store-Mixed-Load-Store chain.
-
-   TODO: For now, we don't support store-store chains in multi-exit loops.  We
-   force to not unroll in case of store-store chain even if other chains might
-   ask for unroll.
-
-   Predictive commoning can be generalized for arbitrary computations (not
-   just memory loads), and also nontrivial transfer functions (e.g., replacing
-   i * i with ii_last + 2 * i + 1), to generalize strength reduction.  */
-
-#include "config.h"
-#include "system.h"
-#include "coretypes.h"
-#include "backend.h"
-#include "rtl.h"
-#include "tree.h"
-#include "gimple.h"
-#include "predict.h"
-#include "tree-pass.h"
-#include "ssa.h"
-#include "gimple-pretty-print.h"
-#include "alias.h"
-#include "fold-const.h"
-#include "cfgloop.h"
-#include "tree-eh.h"
-#include "gimplify.h"
-#include "gimple-iterator.h"
-#include "gimplify-me.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 "tree-dfa.h"
-#include "tree-ssa.h"
-#include "tree-data-ref.h"
-#include "tree-scalar-evolution.h"
-#include "tree-affine.h"
-#include "builtins.h"
-#include "opts.h"
-
-/* The maximum number of iterations between the considered memory
-   references.  */
-
-#define MAX_DISTANCE (target_avail_regs < 16 ? 4 : 8)
-
-/* Data references (or phi nodes that carry data reference values across
-   loop iterations).  */
-
-typedef class dref_d
-{
-public:
-  /* The reference itself.  */
-  struct data_reference *ref;
-
-  /* The statement in that the reference appears.  */
-  gimple *stmt;
-
-  /* In case that STMT is a phi node, this field is set to the SSA name
-     defined by it in replace_phis_by_defined_names (in order to avoid
-     pointing to phi node that got reallocated in the meantime).  */
-  tree name_defined_by_phi;
-
-  /* Distance of the reference from the root of the chain (in number of
-     iterations of the loop).  */
-  unsigned distance;
-
-  /* Number of iterations offset from the first reference in the component.  */
-  widest_int offset;
-
-  /* Number of the reference in a component, in dominance ordering.  */
-  unsigned pos;
-
-  /* True if the memory reference is always accessed when the loop is
-     entered.  */
-  unsigned always_accessed : 1;
-} *dref;
-
-
-/* Type of the chain of the references.  */
-
-enum chain_type
-{
-  /* The addresses of the references in the chain are constant.  */
-  CT_INVARIANT,
-
-  /* There are only loads in the chain.  */
-  CT_LOAD,
-
-  /* Root of the chain is store, the rest are loads.  */
-  CT_STORE_LOAD,
-
-  /* There are only stores in the chain.  */
-  CT_STORE_STORE,
-
-  /* A combination of two chains.  */
-  CT_COMBINATION
-};
-
-/* Chains of data references.  */
-
-typedef struct chain
-{
-  /* Type of the chain.  */
-  enum chain_type type;
-
-  /* For combination chains, the operator and the two chains that are
-     combined, and the type of the result.  */
-  enum tree_code op;
-  tree rslt_type;
-  struct chain *ch1, *ch2;
-
-  /* The references in the chain.  */
-  auto_vec<dref> refs;
-
-  /* The maximum distance of the reference in the chain from the root.  */
-  unsigned length;
-
-  /* The variables used to copy the value throughout iterations.  */
-  auto_vec<tree> vars;
-
-  /* Initializers for the variables.  */
-  auto_vec<tree> inits;
-
-  /* Finalizers for the eliminated stores.  */
-  auto_vec<tree> finis;
-
-  /* gimple stmts intializing the initial variables of the chain.  */
-  gimple_seq init_seq;
-
-  /* gimple stmts finalizing the eliminated stores of the chain.  */
-  gimple_seq fini_seq;
-
-  /* True if there is a use of a variable with the maximal distance
-     that comes after the root in the loop.  */
-  unsigned has_max_use_after : 1;
-
-  /* True if all the memory references in the chain are always accessed.  */
-  unsigned all_always_accessed : 1;
-
-  /* True if this chain was combined together with some other chain.  */
-  unsigned combined : 1;
-
-  /* True if this is store elimination chain and eliminated stores store
-     loop invariant value into memory.  */
-  unsigned inv_store_elimination : 1;
-} *chain_p;
-
-
-/* Describes the knowledge about the step of the memory references in
-   the component.  */
-
-enum ref_step_type
-{
-  /* The step is zero.  */
-  RS_INVARIANT,
-
-  /* The step is nonzero.  */
-  RS_NONZERO,
-
-  /* The step may or may not be nonzero.  */
-  RS_ANY
-};
-
-/* Components of the data dependence graph.  */
-
-struct component
-{
-  /* The references in the component.  */
-  auto_vec<dref> refs;
-
-  /* What we know about the step of the references in the component.  */
-  enum ref_step_type comp_step;
-
-  /* True if all references in component are stores and we try to do
-     intra/inter loop iteration dead store elimination.  */
-  bool eliminate_store_p;
-
-  /* Next component in the list.  */
-  struct component *next;
-};
-
-/* A class to encapsulate the global states used for predictive
-   commoning work on top of one given LOOP.  */
-
-class pcom_worker
-{
-public:
-  pcom_worker (loop_p l) : m_loop (l), m_cache (NULL) {}
-
-  ~pcom_worker ()
-  {
-    free_data_refs (m_datarefs);
-    free_dependence_relations (m_dependences);
-    free_affine_expand_cache (&m_cache);
-    release_chains ();
-  }
-
-  pcom_worker (const pcom_worker &) = delete;
-  pcom_worker &operator= (const pcom_worker &) = delete;
-
-  /* Performs predictive commoning.  */
-  unsigned tree_predictive_commoning_loop (bool allow_unroll_p);
-
-  /* Perform the predictive commoning optimization for chains, make this
-     public for being called in callback execute_pred_commoning_cbck.  */
-  void execute_pred_commoning (bitmap tmp_vars);
-
-private:
-  /* The pointer to the given loop.  */
-  loop_p m_loop;
-
-  /* All data references.  */
-  auto_vec<data_reference_p, 10> m_datarefs;
-
-  /* All data dependences.  */
-  auto_vec<ddr_p, 10> m_dependences;
-
-  /* All chains.  */
-  auto_vec<chain_p> m_chains;
-
-  /* Bitmap of ssa names defined by looparound phi nodes covered by chains.  */
-  auto_bitmap m_looparound_phis;
-
-  typedef hash_map<tree, name_expansion *> tree_expand_map_t;
-  /* Cache used by tree_to_aff_combination_expand.  */
-  tree_expand_map_t *m_cache;
-
-  /* Splits dependence graph to components.  */
-  struct component *split_data_refs_to_components ();
-
-  /* Check the conditions on references inside each of components COMPS,
-     and remove the unsuitable components from the list.  */
-  struct component *filter_suitable_components (struct component *comps);
-
-  /* Find roots of the values and determine distances in components COMPS,
-     and separates the references to chains.  */
-  void determine_roots (struct component *comps);
-
-  /* Prepare initializers for chains, and free chains that cannot
-     be used because the initializers might trap.  */
-  void prepare_initializers ();
-
-  /* Generates finalizer memory reference for chains.  Returns true if
-     finalizer code generation for chains breaks loop closed ssa form.  */
-  bool prepare_finalizers ();
-
-  /* Try to combine the chains.  */
-  void try_combine_chains ();
-
-  /* Frees CHAINS.  */
-  void release_chains ();
-
-  /* Frees a chain CHAIN.  */
-  void release_chain (chain_p chain);
-
-  /* Prepare initializers for CHAIN.  Returns false if this is impossible
-     because one of these initializers may trap, true otherwise.  */
-  bool prepare_initializers_chain (chain_p chain);
-
-  /* Generates finalizer memory references for CHAIN.  Returns true
-     if finalizer code for CHAIN can be generated, otherwise false.  */
-  bool prepare_finalizers_chain (chain_p chain);
-
-  /* Stores DR_OFFSET (DR) + DR_INIT (DR) to OFFSET.  */
-  void aff_combination_dr_offset (struct data_reference *dr, aff_tree *offset);
-
-  /* Determines number of iterations of the innermost enclosing loop before
-     B refers to exactly the same location as A and stores it to OFF.  */
-  bool determine_offset (struct data_reference *a, struct data_reference *b,
-			 poly_widest_int *off);
-
-  /* Returns true if the component COMP satisfies the conditions
-     described in 2) at the beginning of this file.  */
-  bool suitable_component_p (struct component *comp);
-
-  /* Returns true if REF is a valid initializer for ROOT with given
-     DISTANCE (in iterations of the innermost enclosing loop).  */
-  bool valid_initializer_p (struct data_reference *ref, unsigned distance,
-			    struct data_reference *root);
-
-  /* Finds looparound phi node of loop that copies the value of REF.  */
-  gphi *find_looparound_phi (dref ref, dref root);
-
-  /* Find roots of the values and determine distances in the component
-     COMP.  The references are redistributed into chains.  */
-  void determine_roots_comp (struct component *comp);
-
-  /* For references in CHAIN that are copied around the loop, add the
-     results of such copies to the chain.  */
-  void add_looparound_copies (chain_p chain);
-
-  /* Returns the single statement in that NAME is used, excepting
-     the looparound phi nodes contained in one of the chains.  */
-  gimple *single_nonlooparound_use (tree name);
-
-  /* Remove statement STMT, as well as the chain of assignments in that
-     it is used.  */
-  void remove_stmt (gimple *stmt);
-
-  /* Perform the predictive commoning optimization for a chain CHAIN.  */
-  void execute_pred_commoning_chain (chain_p chain, bitmap tmp_vars);
-
-  /* Returns the modify statement that uses NAME.  */
-  gimple *find_use_stmt (tree *name);
-
-  /* If the operation used in STMT is associative and commutative, go
-     through the tree of the same operations and returns its root.  */
-  gimple *find_associative_operation_root (gimple *stmt, unsigned *distance);
-
-  /* Returns the common statement in that NAME1 and NAME2 have a use.  */
-  gimple *find_common_use_stmt (tree *name1, tree *name2);
-
-  /* Checks whether R1 and R2 are combined together using CODE, with the
-     result in RSLT_TYPE, in order R1 CODE R2 if SWAP is false and in order
-     R2 CODE R1 if it is true.  */
-  bool combinable_refs_p (dref r1, dref r2, enum tree_code *code, bool *swap,
-			  tree *rslt_type);
-
-  /* Reassociates the expression in that NAME1 and NAME2 are used so that
-     they are combined in a single statement, and returns this statement.  */
-  gimple *reassociate_to_the_same_stmt (tree name1, tree name2);
-
-  /* Returns the statement that combines references R1 and R2.  */
-  gimple *stmt_combining_refs (dref r1, dref r2);
-
-  /* Tries to combine chains CH1 and CH2 together.  */
-  chain_p combine_chains (chain_p ch1, chain_p ch2);
-};
-
-/* Dumps data reference REF to FILE.  */
-
-extern void dump_dref (FILE *, dref);
-void
-dump_dref (FILE *file, dref ref)
-{
-  if (ref->ref)
-    {
-      fprintf (file, "    ");
-      print_generic_expr (file, DR_REF (ref->ref), TDF_SLIM);
-      fprintf (file, " (id %u%s)\n", ref->pos,
-	       DR_IS_READ (ref->ref) ? "" : ", write");
-
-      fprintf (file, "      offset ");
-      print_decs (ref->offset, file);
-      fprintf (file, "\n");
-
-      fprintf (file, "      distance %u\n", ref->distance);
-    }
-  else
-    {
-      if (gimple_code (ref->stmt) == GIMPLE_PHI)
-	fprintf (file, "    looparound ref\n");
-      else
-	fprintf (file, "    combination ref\n");
-      fprintf (file, "      in statement ");
-      print_gimple_stmt (file, ref->stmt, 0, TDF_SLIM);
-      fprintf (file, "\n");
-      fprintf (file, "      distance %u\n", ref->distance);
-    }
-
-}
-
-/* Dumps CHAIN to FILE.  */
-
-extern void dump_chain (FILE *, chain_p);
-void
-dump_chain (FILE *file, chain_p chain)
-{
-  dref a;
-  const char *chain_type;
-  unsigned i;
-  tree var;
-
-  switch (chain->type)
-    {
-    case CT_INVARIANT:
-      chain_type = "Load motion";
-      break;
-
-    case CT_LOAD:
-      chain_type = "Loads-only";
-      break;
-
-    case CT_STORE_LOAD:
-      chain_type = "Store-loads";
-      break;
-
-    case CT_STORE_STORE:
-      chain_type = "Store-stores";
-      break;
-
-    case CT_COMBINATION:
-      chain_type = "Combination";
-      break;
-
-    default:
-      gcc_unreachable ();
-    }
-
-  fprintf (file, "%s chain %p%s\n", chain_type, (void *) chain,
-	   chain->combined ? " (combined)" : "");
-  if (chain->type != CT_INVARIANT)
-    fprintf (file, "  max distance %u%s\n", chain->length,
-	     chain->has_max_use_after ? "" : ", may reuse first");
-
-  if (chain->type == CT_COMBINATION)
-    {
-      fprintf (file, "  equal to %p %s %p in type ",
-	       (void *) chain->ch1, op_symbol_code (chain->op),
-	       (void *) chain->ch2);
-      print_generic_expr (file, chain->rslt_type, TDF_SLIM);
-      fprintf (file, "\n");
-    }
-
-  if (chain->vars.exists ())
-    {
-      fprintf (file, "  vars");
-      FOR_EACH_VEC_ELT (chain->vars, i, var)
-	{
-	  fprintf (file, " ");
-	  print_generic_expr (file, var, TDF_SLIM);
-	}
-      fprintf (file, "\n");
-    }
-
-  if (chain->inits.exists ())
-    {
-      fprintf (file, "  inits");
-      FOR_EACH_VEC_ELT (chain->inits, i, var)
-	{
-	  fprintf (file, " ");
-	  print_generic_expr (file, var, TDF_SLIM);
-	}
-      fprintf (file, "\n");
-    }
-
-  fprintf (file, "  references:\n");
-  FOR_EACH_VEC_ELT (chain->refs, i, a)
-    dump_dref (file, a);
-
-  fprintf (file, "\n");
-}
-
-/* Dumps CHAINS to FILE.  */
-
-void
-dump_chains (FILE *file, const vec<chain_p> &chains)
-{
-  chain_p chain;
-  unsigned i;
-
-  FOR_EACH_VEC_ELT (chains, i, chain)
-    dump_chain (file, chain);
-}
-
-/* Dumps COMP to FILE.  */
-
-extern void dump_component (FILE *, struct component *);
-void
-dump_component (FILE *file, struct component *comp)
-{
-  dref a;
-  unsigned i;
-
-  fprintf (file, "Component%s:\n",
-	   comp->comp_step == RS_INVARIANT ? " (invariant)" : "");
-  FOR_EACH_VEC_ELT (comp->refs, i, a)
-    dump_dref (file, a);
-  fprintf (file, "\n");
-}
-
-/* Dumps COMPS to FILE.  */
-
-extern void dump_components (FILE *, struct component *);
-void
-dump_components (FILE *file, struct component *comps)
-{
-  struct component *comp;
-
-  for (comp = comps; comp; comp = comp->next)
-    dump_component (file, comp);
-}
-
-/* Frees a chain CHAIN.  */
-
-void
-pcom_worker::release_chain (chain_p chain)
-{
-  dref ref;
-  unsigned i;
-
-  if (chain == NULL)
-    return;
-
-  FOR_EACH_VEC_ELT (chain->refs, i, ref)
-    free (ref);
-
-  if (chain->init_seq)
-    gimple_seq_discard (chain->init_seq);
-
-  if (chain->fini_seq)
-    gimple_seq_discard (chain->fini_seq);
-
-  free (chain);
-}
-
-/* Frees CHAINS.  */
-
-void
-pcom_worker::release_chains ()
-{
-  unsigned i;
-  chain_p chain;
-
-  FOR_EACH_VEC_ELT (m_chains, i, chain)
-    release_chain (chain);
-}
-
-/* Frees list of components COMPS.  */
-
-static void
-release_components (struct component *comps)
-{
-  struct component *act, *next;
-
-  for (act = comps; act; act = next)
-    {
-      next = act->next;
-      XDELETE (act);
-    }
-}
-
-/* Finds a root of tree given by FATHERS containing A, and performs path
-   shortening.  */
-
-static unsigned
-component_of (vec<unsigned> &fathers, unsigned a)
-{
-  unsigned root, n;
-
-  for (root = a; root != fathers[root]; root = fathers[root])
-    continue;
-
-  for (; a != root; a = n)
-    {
-      n = fathers[a];
-      fathers[a] = root;
-    }
-
-  return root;
-}
-
-/* Join operation for DFU.  FATHERS gives the tree, SIZES are sizes of the
-   components, A and B are components to merge.  */
-
-static void
-merge_comps (vec<unsigned> &fathers, vec<unsigned> &sizes,
-	     unsigned a, unsigned b)
-{
-  unsigned ca = component_of (fathers, a);
-  unsigned cb = component_of (fathers, b);
-
-  if (ca == cb)
-    return;
-
-  if (sizes[ca] < sizes[cb])
-    {
-      sizes[cb] += sizes[ca];
-      fathers[ca] = cb;
-    }
-  else
-    {
-      sizes[ca] += sizes[cb];
-      fathers[cb] = ca;
-    }
-}
-
-/* Returns true if A is a reference that is suitable for predictive commoning
-   in the innermost loop that contains it.  REF_STEP is set according to the
-   step of the reference A.  */
-
-static bool
-suitable_reference_p (struct data_reference *a, enum ref_step_type *ref_step)
-{
-  tree ref = DR_REF (a), step = DR_STEP (a);
-
-  if (!step
-      || TREE_THIS_VOLATILE (ref)
-      || !is_gimple_reg_type (TREE_TYPE (ref))
-      || tree_could_throw_p (ref))
-    return false;
-
-  if (integer_zerop (step))
-    *ref_step = RS_INVARIANT;
-  else if (integer_nonzerop (step))
-    *ref_step = RS_NONZERO;
-  else
-    *ref_step = RS_ANY;
-
-  return true;
-}
-
-/* Stores DR_OFFSET (DR) + DR_INIT (DR) to OFFSET.  */
-
-void
-pcom_worker::aff_combination_dr_offset (struct data_reference *dr,
-					aff_tree *offset)
-{
-  tree type = TREE_TYPE (DR_OFFSET (dr));
-  aff_tree delta;
-
-  tree_to_aff_combination_expand (DR_OFFSET (dr), type, offset, &m_cache);
-  aff_combination_const (&delta, type, wi::to_poly_widest (DR_INIT (dr)));
-  aff_combination_add (offset, &delta);
-}
-
-/* Determines number of iterations of the innermost enclosing loop before B
-   refers to exactly the same location as A and stores it to OFF.  If A and
-   B do not have the same step, they never meet, or anything else fails,
-   returns false, otherwise returns true.  Both A and B are assumed to
-   satisfy suitable_reference_p.  */
-
-bool
-pcom_worker::determine_offset (struct data_reference *a,
-			       struct data_reference *b, poly_widest_int *off)
-{
-  aff_tree diff, baseb, step;
-  tree typea, typeb;
-
-  /* Check that both the references access the location in the same type.  */
-  typea = TREE_TYPE (DR_REF (a));
-  typeb = TREE_TYPE (DR_REF (b));
-  if (!useless_type_conversion_p (typeb, typea))
-    return false;
-
-  /* Check whether the base address and the step of both references is the
-     same.  */
-  if (!operand_equal_p (DR_STEP (a), DR_STEP (b), 0)
-      || !operand_equal_p (DR_BASE_ADDRESS (a), DR_BASE_ADDRESS (b), 0))
-    return false;
-
-  if (integer_zerop (DR_STEP (a)))
-    {
-      /* If the references have loop invariant address, check that they access
-	 exactly the same location.  */
-      *off = 0;
-      return (operand_equal_p (DR_OFFSET (a), DR_OFFSET (b), 0)
-	      && operand_equal_p (DR_INIT (a), DR_INIT (b), 0));
-    }
-
-  /* Compare the offsets of the addresses, and check whether the difference
-     is a multiple of step.  */
-  aff_combination_dr_offset (a, &diff);
-  aff_combination_dr_offset (b, &baseb);
-  aff_combination_scale (&baseb, -1);
-  aff_combination_add (&diff, &baseb);
-
-  tree_to_aff_combination_expand (DR_STEP (a), TREE_TYPE (DR_STEP (a)),
-				  &step, &m_cache);
-  return aff_combination_constant_multiple_p (&diff, &step, off);
-}
-
-/* Returns the last basic block in LOOP for that we are sure that
-   it is executed whenever the loop is entered.  */
-
-static basic_block
-last_always_executed_block (class loop *loop)
-{
-  unsigned i;
-  auto_vec<edge> exits = get_loop_exit_edges (loop);
-  edge ex;
-  basic_block last = loop->latch;
-
-  FOR_EACH_VEC_ELT (exits, i, ex)
-    last = nearest_common_dominator (CDI_DOMINATORS, last, ex->src);
-
-  return last;
-}
-
-/* Splits dependence graph on DATAREFS described by DEPENDENCES to
-   components.  */
-
-struct component *
-pcom_worker::split_data_refs_to_components ()
-{
-  unsigned i, n = m_datarefs.length ();
-  unsigned ca, ia, ib, bad;
-  struct data_reference *dr, *dra, *drb;
-  struct data_dependence_relation *ddr;
-  struct component *comp_list = NULL, *comp;
-  dref dataref;
-  /* Don't do store elimination if loop has multiple exit edges.  */
-  bool eliminate_store_p = single_exit (m_loop) != NULL;
-  basic_block last_always_executed = last_always_executed_block (m_loop);
-  auto_bitmap no_store_store_comps;
-  auto_vec<unsigned> comp_father (n + 1);
-  auto_vec<unsigned> comp_size (n + 1);
-  comp_father.quick_grow (n + 1);
-  comp_size.quick_grow (n + 1);
-
-  FOR_EACH_VEC_ELT (m_datarefs, i, dr)
-    {
-      if (!DR_REF (dr))
-	  /* A fake reference for call or asm_expr that may clobber memory;
-	     just fail.  */
-	  return NULL;
-      /* predcom pass isn't prepared to handle calls with data references.  */
-      if (is_gimple_call (DR_STMT (dr)))
-	return NULL;
-      dr->aux = (void *) (size_t) i;
-      comp_father[i] = i;
-      comp_size[i] = 1;
-    }
-
-  /* A component reserved for the "bad" data references.  */
-  comp_father[n] = n;
-  comp_size[n] = 1;
-
-  FOR_EACH_VEC_ELT (m_datarefs, i, dr)
-    {
-      enum ref_step_type dummy;
-
-      if (!suitable_reference_p (dr, &dummy))
-	{
-	  ia = (unsigned) (size_t) dr->aux;
-	  merge_comps (comp_father, comp_size, n, ia);
-	}
-    }
-
-  FOR_EACH_VEC_ELT (m_dependences, i, ddr)
-    {
-      poly_widest_int dummy_off;
-
-      if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
-	continue;
-
-      dra = DDR_A (ddr);
-      drb = DDR_B (ddr);
-
-      /* Don't do store elimination if there is any unknown dependence for
-	 any store data reference.  */
-      if ((DR_IS_WRITE (dra) || DR_IS_WRITE (drb))
-	  && (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know
-	      || DDR_NUM_DIST_VECTS (ddr) == 0))
-	eliminate_store_p = false;
-
-      ia = component_of (comp_father, (unsigned) (size_t) dra->aux);
-      ib = component_of (comp_father, (unsigned) (size_t) drb->aux);
-      if (ia == ib)
-	continue;
-
-      bad = component_of (comp_father, n);
-
-      /* If both A and B are reads, we may ignore unsuitable dependences.  */
-      if (DR_IS_READ (dra) && DR_IS_READ (drb))
-	{
-	  if (ia == bad || ib == bad
-	      || !determine_offset (dra, drb, &dummy_off))
-	    continue;
-	}
-      /* If A is read and B write or vice versa and there is unsuitable
-	 dependence, instead of merging both components into a component
-	 that will certainly not pass suitable_component_p, just put the
-	 read into bad component, perhaps at least the write together with
-	 all the other data refs in it's component will be optimizable.  */
-      else if (DR_IS_READ (dra) && ib != bad)
-	{
-	  if (ia == bad)
-	    {
-	      bitmap_set_bit (no_store_store_comps, ib);
-	      continue;
-	    }
-	  else if (!determine_offset (dra, drb, &dummy_off))
-	    {
-	      bitmap_set_bit (no_store_store_comps, ib);
-	      merge_comps (comp_father, comp_size, bad, ia);
-	      continue;
-	    }
-	}
-      else if (DR_IS_READ (drb) && ia != bad)
-	{
-	  if (ib == bad)
-	    {
-	      bitmap_set_bit (no_store_store_comps, ia);
-	      continue;
-	    }
-	  else if (!determine_offset (dra, drb, &dummy_off))
-	    {
-	      bitmap_set_bit (no_store_store_comps, ia);
-	      merge_comps (comp_father, comp_size, bad, ib);
-	      continue;
-	    }
-	}
-      else if (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)
-	       && ia != bad && ib != bad
-	       && !determine_offset (dra, drb, &dummy_off))
-	{
-	  merge_comps (comp_father, comp_size, bad, ia);
-	  merge_comps (comp_father, comp_size, bad, ib);
-	  continue;
-	}
-
-      merge_comps (comp_father, comp_size, ia, ib);
-    }
-
-  if (eliminate_store_p)
-    {
-      tree niters = number_of_latch_executions (m_loop);
-
-      /* Don't do store elimination if niters info is unknown because stores
-	 in the last iteration can't be eliminated and we need to recover it
-	 after loop.  */
-      eliminate_store_p = (niters != NULL_TREE && niters != chrec_dont_know);
-    }
-
-  auto_vec<struct component *> comps;
-  comps.safe_grow_cleared (n, true);
-  bad = component_of (comp_father, n);
-  FOR_EACH_VEC_ELT (m_datarefs, i, dr)
-    {
-      ia = (unsigned) (size_t) dr->aux;
-      ca = component_of (comp_father, ia);
-      if (ca == bad)
-	continue;
-
-      comp = comps[ca];
-      if (!comp)
-	{
-	  comp = XCNEW (struct component);
-	  comp->refs.create (comp_size[ca]);
-	  comp->eliminate_store_p = eliminate_store_p;
-	  comps[ca] = comp;
-	}
-
-      dataref = XCNEW (class dref_d);
-      dataref->ref = dr;
-      dataref->stmt = DR_STMT (dr);
-      dataref->offset = 0;
-      dataref->distance = 0;
-
-      dataref->always_accessed
-	      = dominated_by_p (CDI_DOMINATORS, last_always_executed,
-				gimple_bb (dataref->stmt));
-      dataref->pos = comp->refs.length ();
-      comp->refs.quick_push (dataref);
-    }
-
-  if (eliminate_store_p)
-    {
-      bitmap_iterator bi;
-      EXECUTE_IF_SET_IN_BITMAP (no_store_store_comps, 0, ia, bi)
-	{
-	  ca = component_of (comp_father, ia);
-	  if (ca != bad)
-	    comps[ca]->eliminate_store_p = false;
-	}
-    }
-
-  for (i = 0; i < n; i++)
-    {
-      comp = comps[i];
-      if (comp)
-	{
-	  comp->next = comp_list;
-	  comp_list = comp;
-	}
-    }
-  return comp_list;
-}
-
-/* Returns true if the component COMP satisfies the conditions
-   described in 2) at the beginning of this file.  */
-
-bool
-pcom_worker::suitable_component_p (struct component *comp)
-{
-  unsigned i;
-  dref a, first;
-  basic_block ba, bp = m_loop->header;
-  bool ok, has_write = false;
-
-  FOR_EACH_VEC_ELT (comp->refs, i, a)
-    {
-      ba = gimple_bb (a->stmt);
-
-      if (!just_once_each_iteration_p (m_loop, ba))
-	return false;
-
-      gcc_assert (dominated_by_p (CDI_DOMINATORS, ba, bp));
-      bp = ba;
-
-      if (DR_IS_WRITE (a->ref))
-	has_write = true;
-    }
-
-  first = comp->refs[0];
-  ok = suitable_reference_p (first->ref, &comp->comp_step);
-  gcc_assert (ok);
-  first->offset = 0;
-
-  for (i = 1; comp->refs.iterate (i, &a); i++)
-    {
-      /* Polynomial offsets are no use, since we need to know the
-	 gap between iteration numbers at compile time.  */
-      poly_widest_int offset;
-      if (!determine_offset (first->ref, a->ref, &offset)
-	  || !offset.is_constant (&a->offset))
-	return false;
-
-      enum ref_step_type a_step;
-      gcc_checking_assert (suitable_reference_p (a->ref, &a_step)
-			   && a_step == comp->comp_step);
-    }
-
-  /* If there is a write inside the component, we must know whether the
-     step is nonzero or not -- we would not otherwise be able to recognize
-     whether the value accessed by reads comes from the OFFSET-th iteration
-     or the previous one.  */
-  if (has_write && comp->comp_step == RS_ANY)
-    return false;
-
-  return true;
-}
-
-/* Check the conditions on references inside each of components COMPS,
-   and remove the unsuitable components from the list.  The new list
-   of components is returned.  The conditions are described in 2) at
-   the beginning of this file.  */
-
-struct component *
-pcom_worker::filter_suitable_components (struct component *comps)
-{
-  struct component **comp, *act;
-
-  for (comp = &comps; *comp; )
-    {
-      act = *comp;
-      if (suitable_component_p (act))
-	comp = &act->next;
-      else
-	{
-	  dref ref;
-	  unsigned i;
-
-	  *comp = act->next;
-	  FOR_EACH_VEC_ELT (act->refs, i, ref)
-	    free (ref);
-	  XDELETE (act);
-	}
-    }
-
-  return comps;
-}
-
-/* Compares two drefs A and B by their offset and position.  Callback for
-   qsort.  */
-
-static int
-order_drefs (const void *a, const void *b)
-{
-  const dref *const da = (const dref *) a;
-  const dref *const db = (const dref *) b;
-  int offcmp = wi::cmps ((*da)->offset, (*db)->offset);
-
-  if (offcmp != 0)
-    return offcmp;
-
-  return (*da)->pos - (*db)->pos;
-}
-
-/* Compares two drefs A and B by their position.  Callback for qsort.  */
-
-static int
-order_drefs_by_pos (const void *a, const void *b)
-{
-  const dref *const da = (const dref *) a;
-  const dref *const db = (const dref *) b;
-
-  return (*da)->pos - (*db)->pos;
-}
-
-/* Returns root of the CHAIN.  */
-
-static inline dref
-get_chain_root (chain_p chain)
-{
-  return chain->refs[0];
-}
-
-/* Given CHAIN, returns the last write ref at DISTANCE, or NULL if it doesn't
-   exist.  */
-
-static inline dref
-get_chain_last_write_at (chain_p chain, unsigned distance)
-{
-  for (unsigned i = chain->refs.length (); i > 0; i--)
-    if (DR_IS_WRITE (chain->refs[i - 1]->ref)
-	&& distance == chain->refs[i - 1]->distance)
-      return chain->refs[i - 1];
-
-  return NULL;
-}
-
-/* Given CHAIN, returns the last write ref with the same distance before load
-   at index LOAD_IDX, or NULL if it doesn't exist.  */
-
-static inline dref
-get_chain_last_write_before_load (chain_p chain, unsigned load_idx)
-{
-  gcc_assert (load_idx < chain->refs.length ());
-
-  unsigned distance = chain->refs[load_idx]->distance;
-
-  for (unsigned i = load_idx; i > 0; i--)
-    if (DR_IS_WRITE (chain->refs[i - 1]->ref)
-	&& distance == chain->refs[i - 1]->distance)
-      return chain->refs[i - 1];
-
-  return NULL;
-}
-
-/* Adds REF to the chain CHAIN.  */
-
-static void
-add_ref_to_chain (chain_p chain, dref ref)
-{
-  dref root = get_chain_root (chain);
-
-  gcc_assert (wi::les_p (root->offset, ref->offset));
-  widest_int dist = ref->offset - root->offset;
-  gcc_assert (wi::fits_uhwi_p (dist));
-
-  chain->refs.safe_push (ref);
-
-  ref->distance = dist.to_uhwi ();
-
-  if (ref->distance >= chain->length)
-    {
-      chain->length = ref->distance;
-      chain->has_max_use_after = false;
-    }
-
-  /* Promote this chain to CT_STORE_STORE if it has multiple stores.  */
-  if (DR_IS_WRITE (ref->ref))
-    chain->type = CT_STORE_STORE;
-
-  /* Don't set the flag for store-store chain since there is no use.  */
-  if (chain->type != CT_STORE_STORE
-      && ref->distance == chain->length
-      && ref->pos > root->pos)
-    chain->has_max_use_after = true;
-
-  chain->all_always_accessed &= ref->always_accessed;
-}
-
-/* Returns the chain for invariant component COMP.  */
-
-static chain_p
-make_invariant_chain (struct component *comp)
-{
-  chain_p chain = XCNEW (struct chain);
-  unsigned i;
-  dref ref;
-
-  chain->type = CT_INVARIANT;
-
-  chain->all_always_accessed = true;
-
-  FOR_EACH_VEC_ELT (comp->refs, i, ref)
-    {
-      chain->refs.safe_push (ref);
-      chain->all_always_accessed &= ref->always_accessed;
-    }
-
-  chain->inits = vNULL;
-  chain->finis = vNULL;
-
-  return chain;
-}
-
-/* Make a new chain of type TYPE rooted at REF.  */
-
-static chain_p
-make_rooted_chain (dref ref, enum chain_type type)
-{
-  chain_p chain = XCNEW (struct chain);
-
-  chain->type = type;
-  chain->refs.safe_push (ref);
-  chain->all_always_accessed = ref->always_accessed;
-  ref->distance = 0;
-
-  chain->inits = vNULL;
-  chain->finis = vNULL;
-
-  return chain;
-}
-
-/* Returns true if CHAIN is not trivial.  */
-
-static bool
-nontrivial_chain_p (chain_p chain)
-{
-  return chain != NULL && chain->refs.length () > 1;
-}
-
-/* Returns the ssa name that contains the value of REF, or NULL_TREE if there
-   is no such name.  */
-
-static tree
-name_for_ref (dref ref)
-{
-  tree name;
-
-  if (is_gimple_assign (ref->stmt))
-    {
-      if (!ref->ref || DR_IS_READ (ref->ref))
-	name = gimple_assign_lhs (ref->stmt);
-      else
-	name = gimple_assign_rhs1 (ref->stmt);
-    }
-  else
-    name = PHI_RESULT (ref->stmt);
-
-  return (TREE_CODE (name) == SSA_NAME ? name : NULL_TREE);
-}
-
-/* Returns true if REF is a valid initializer for ROOT with given DISTANCE (in
-   iterations of the innermost enclosing loop).  */
-
-bool
-pcom_worker::valid_initializer_p (struct data_reference *ref, unsigned distance,
-				  struct data_reference *root)
-{
-  aff_tree diff, base, step;
-  poly_widest_int off;
-
-  /* Both REF and ROOT must be accessing the same object.  */
-  if (!operand_equal_p (DR_BASE_ADDRESS (ref), DR_BASE_ADDRESS (root), 0))
-    return false;
-
-  /* The initializer is defined outside of loop, hence its address must be
-     invariant inside the loop.  */
-  gcc_assert (integer_zerop (DR_STEP (ref)));
-
-  /* If the address of the reference is invariant, initializer must access
-     exactly the same location.  */
-  if (integer_zerop (DR_STEP (root)))
-    return (operand_equal_p (DR_OFFSET (ref), DR_OFFSET (root), 0)
-	    && operand_equal_p (DR_INIT (ref), DR_INIT (root), 0));
-
-  /* Verify that this index of REF is equal to the root's index at
-     -DISTANCE-th iteration.  */
-  aff_combination_dr_offset (root, &diff);
-  aff_combination_dr_offset (ref, &base);
-  aff_combination_scale (&base, -1);
-  aff_combination_add (&diff, &base);
-
-  tree_to_aff_combination_expand (DR_STEP (root), TREE_TYPE (DR_STEP (root)),
-				  &step, &m_cache);
-  if (!aff_combination_constant_multiple_p (&diff, &step, &off))
-    return false;
-
-  if (maybe_ne (off, distance))
-    return false;
-
-  return true;
-}
-
-/* Finds looparound phi node of loop that copies the value of REF, and if its
-   initial value is correct (equal to initial value of REF shifted by one
-   iteration), returns the phi node.  Otherwise, NULL_TREE is returned.  ROOT
-   is the root of the current chain.  */
-
-gphi *
-pcom_worker::find_looparound_phi (dref ref, dref root)
-{
-  tree name, init, init_ref;
-  gphi *phi = NULL;
-  gimple *init_stmt;
-  edge latch = loop_latch_edge (m_loop);
-  struct data_reference init_dr;
-  gphi_iterator psi;
-
-  if (is_gimple_assign (ref->stmt))
-    {
-      if (DR_IS_READ (ref->ref))
-	name = gimple_assign_lhs (ref->stmt);
-      else
-	name = gimple_assign_rhs1 (ref->stmt);
-    }
-  else
-    name = PHI_RESULT (ref->stmt);
-  if (!name)
-    return NULL;
-
-  for (psi = gsi_start_phis (m_loop->header); !gsi_end_p (psi); gsi_next (&psi))
-    {
-      phi = psi.phi ();
-      if (PHI_ARG_DEF_FROM_EDGE (phi, latch) == name)
-	break;
-    }
-
-  if (gsi_end_p (psi))
-    return NULL;
-
-  init = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (m_loop));
-  if (TREE_CODE (init) != SSA_NAME)
-    return NULL;
-  init_stmt = SSA_NAME_DEF_STMT (init);
-  if (gimple_code (init_stmt) != GIMPLE_ASSIGN)
-    return NULL;
-  gcc_assert (gimple_assign_lhs (init_stmt) == init);
-
-  init_ref = gimple_assign_rhs1 (init_stmt);
-  if (!REFERENCE_CLASS_P (init_ref)
-      && !DECL_P (init_ref))
-    return NULL;
-
-  /* Analyze the behavior of INIT_REF with respect to LOOP (innermost
-     loop enclosing PHI).  */
-  memset (&init_dr, 0, sizeof (struct data_reference));
-  DR_REF (&init_dr) = init_ref;
-  DR_STMT (&init_dr) = phi;
-  if (!dr_analyze_innermost (&DR_INNERMOST (&init_dr), init_ref, m_loop,
-			     init_stmt))
-    return NULL;
-
-  if (!valid_initializer_p (&init_dr, ref->distance + 1, root->ref))
-    return NULL;
-
-  return phi;
-}
-
-/* Adds a reference for the looparound copy of REF in PHI to CHAIN.  */
-
-static void
-insert_looparound_copy (chain_p chain, dref ref, gphi *phi)
-{
-  dref nw = XCNEW (class dref_d), aref;
-  unsigned i;
-
-  nw->stmt = phi;
-  nw->distance = ref->distance + 1;
-  nw->always_accessed = 1;
-
-  FOR_EACH_VEC_ELT (chain->refs, i, aref)
-    if (aref->distance >= nw->distance)
-      break;
-  chain->refs.safe_insert (i, nw);
-
-  if (nw->distance > chain->length)
-    {
-      chain->length = nw->distance;
-      chain->has_max_use_after = false;
-    }
-}
-
-/* For references in CHAIN that are copied around the loop (created previously
-   by PRE, or by user), add the results of such copies to the chain.  This
-   enables us to remove the copies by unrolling, and may need less registers
-   (also, it may allow us to combine chains together).  */
-
-void
-pcom_worker::add_looparound_copies (chain_p chain)
-{
-  unsigned i;
-  dref ref, root = get_chain_root (chain);
-  gphi *phi;
-
-  if (chain->type == CT_STORE_STORE)
-    return;
-
-  FOR_EACH_VEC_ELT (chain->refs, i, ref)
-    {
-      phi = find_looparound_phi (ref, root);
-      if (!phi)
-	continue;
-
-      bitmap_set_bit (m_looparound_phis, SSA_NAME_VERSION (PHI_RESULT (phi)));
-      insert_looparound_copy (chain, ref, phi);
-    }
-}
-
-/* Find roots of the values and determine distances in the component COMP.
-   The references are redistributed into chains.  */
-
-void
-pcom_worker::determine_roots_comp (struct component *comp)
-{
-  unsigned i;
-  dref a;
-  chain_p chain = NULL;
-  widest_int last_ofs = 0;
-  enum chain_type type;
-
-  /* Invariants are handled specially.  */
-  if (comp->comp_step == RS_INVARIANT)
-    {
-      chain = make_invariant_chain (comp);
-      m_chains.safe_push (chain);
-      return;
-    }
-
-  /* Trivial component.  */
-  if (comp->refs.length () <= 1)
-    {
-      if (comp->refs.length () == 1)
-	{
-	  free (comp->refs[0]);
-	  comp->refs.truncate (0);
-	}
-      return;
-    }
-
-  comp->refs.qsort (order_drefs);
-
-  /* For Store-Store chain, we only support load if it is dominated by a
-     store statement in the same iteration of loop.  */
-  if (comp->eliminate_store_p)
-    for (a = NULL, i = 0; i < comp->refs.length (); i++)
-      {
-	if (DR_IS_WRITE (comp->refs[i]->ref))
-	  a = comp->refs[i];
-	else if (a == NULL || a->offset != comp->refs[i]->offset)
-	  {
-	    /* If there is load that is not dominated by a store in the
-	       same iteration of loop, clear the flag so no Store-Store
-	       chain is generated for this component.  */
-	    comp->eliminate_store_p = false;
-	    break;
-	  }
-      }
-
-  /* Determine roots and create chains for components.  */
-  FOR_EACH_VEC_ELT (comp->refs, i, a)
-    {
-      if (!chain
-	  || (chain->type == CT_LOAD && DR_IS_WRITE (a->ref))
-	  || (!comp->eliminate_store_p && DR_IS_WRITE (a->ref))
-	  || wi::leu_p (MAX_DISTANCE, a->offset - last_ofs))
-	{
-	  if (nontrivial_chain_p (chain))
-	    {
-	      add_looparound_copies (chain);
-	      m_chains.safe_push (chain);
-	    }
-	  else
-	    release_chain (chain);
-
-	  /* Determine type of the chain.  If the root reference is a load,
-	     this can only be a CT_LOAD chain; other chains are intialized
-	     to CT_STORE_LOAD and might be promoted to CT_STORE_STORE when
-	     new reference is added.  */
-	  type = DR_IS_READ (a->ref) ? CT_LOAD : CT_STORE_LOAD;
-	  chain = make_rooted_chain (a, type);
-	  last_ofs = a->offset;
-	  continue;
-	}
-
-      add_ref_to_chain (chain, a);
-    }
-
-  if (nontrivial_chain_p (chain))
-    {
-      add_looparound_copies (chain);
-      m_chains.safe_push (chain);
-    }
-  else
-    release_chain (chain);
-}
-
-/* Find roots of the values and determine distances in components COMPS, and
-   separates the references to chains.  */
-
-void
-pcom_worker::determine_roots (struct component *comps)
-{
-  struct component *comp;
-
-  for (comp = comps; comp; comp = comp->next)
-    determine_roots_comp (comp);
-}
-
-/* Replace the reference in statement STMT with temporary variable
-   NEW_TREE.  If SET is true, NEW_TREE is instead initialized to the value of
-   the reference in the statement.  IN_LHS is true if the reference
-   is in the lhs of STMT, false if it is in rhs.  */
-
-static void
-replace_ref_with (gimple *stmt, tree new_tree, bool set, bool in_lhs)
-{
-  tree val;
-  gassign *new_stmt;
-  gimple_stmt_iterator bsi, psi;
-
-  if (gimple_code (stmt) == GIMPLE_PHI)
-    {
-      gcc_assert (!in_lhs && !set);
-
-      val = PHI_RESULT (stmt);
-      bsi = gsi_after_labels (gimple_bb (stmt));
-      psi = gsi_for_stmt (stmt);
-      remove_phi_node (&psi, false);
-
-      /* Turn the phi node into GIMPLE_ASSIGN.  */
-      new_stmt = gimple_build_assign (val, new_tree);
-      gsi_insert_before (&bsi, new_stmt, GSI_NEW_STMT);
-      return;
-    }
-
-  /* Since the reference is of gimple_reg type, it should only
-     appear as lhs or rhs of modify statement.  */
-  gcc_assert (is_gimple_assign (stmt));
-
-  bsi = gsi_for_stmt (stmt);
-
-  /* If we do not need to initialize NEW_TREE, just replace the use of OLD.  */
-  if (!set)
-    {
-      gcc_assert (!in_lhs);
-      gimple_assign_set_rhs_from_tree (&bsi, new_tree);
-      stmt = gsi_stmt (bsi);
-      update_stmt (stmt);
-      return;
-    }
-
-  if (in_lhs)
-    {
-      /* We have statement
-
-	 OLD = VAL
-
-	 If OLD is a memory reference, then VAL is gimple_val, and we transform
-	 this to
-
-	 OLD = VAL
-	 NEW = VAL
-
-	 Otherwise, we are replacing a combination chain,
-	 VAL is the expression that performs the combination, and OLD is an
-	 SSA name.  In this case, we transform the assignment to
-
-	 OLD = VAL
-	 NEW = OLD
-
-	 */
-
-      val = gimple_assign_lhs (stmt);
-      if (TREE_CODE (val) != SSA_NAME)
-	{
-	  val = gimple_assign_rhs1 (stmt);
-	  gcc_assert (gimple_assign_single_p (stmt));
-	  if (TREE_CLOBBER_P (val))
-	    val = get_or_create_ssa_default_def (cfun, SSA_NAME_VAR (new_tree));
-	  else
-	    gcc_assert (gimple_assign_copy_p (stmt));
-	}
-    }
-  else
-    {
-      /* VAL = OLD
-
-	 is transformed to
-
-	 VAL = OLD
-	 NEW = VAL  */
-
-      val = gimple_assign_lhs (stmt);
-    }
-
-  new_stmt = gimple_build_assign (new_tree, unshare_expr (val));
-  gsi_insert_after (&bsi, new_stmt, GSI_NEW_STMT);
-}
-
-/* Returns a memory reference to DR in the (NITERS + ITER)-th iteration
-   of the loop it was analyzed in.  Append init stmts to STMTS.  */
-
-static tree
-ref_at_iteration (data_reference_p dr, int iter,
-		  gimple_seq *stmts, tree niters = NULL_TREE)
-{
-  tree off = DR_OFFSET (dr);
-  tree coff = DR_INIT (dr);
-  tree ref = DR_REF (dr);
-  enum tree_code ref_code = ERROR_MARK;
-  tree ref_type = NULL_TREE;
-  tree ref_op1 = NULL_TREE;
-  tree ref_op2 = NULL_TREE;
-  tree new_offset;
-
-  if (iter != 0)
-    {
-      new_offset = size_binop (MULT_EXPR, DR_STEP (dr), ssize_int (iter));
-      if (TREE_CODE (new_offset) == INTEGER_CST)
-	coff = size_binop (PLUS_EXPR, coff, new_offset);
-      else
-	off = size_binop (PLUS_EXPR, off, new_offset);
-    }
-
-  if (niters != NULL_TREE)
-    {
-      niters = fold_convert (ssizetype, niters);
-      new_offset = size_binop (MULT_EXPR, DR_STEP (dr), niters);
-      if (TREE_CODE (niters) == INTEGER_CST)
-	coff = size_binop (PLUS_EXPR, coff, new_offset);
-      else
-	off = size_binop (PLUS_EXPR, off, new_offset);
-    }
-
-  /* While data-ref analysis punts on bit offsets it still handles
-     bitfield accesses at byte boundaries.  Cope with that.  Note that
-     if the bitfield object also starts at a byte-boundary we can simply
-     replicate the COMPONENT_REF, but we have to subtract the component's
-     byte-offset from the MEM_REF address first.
-     Otherwise we simply build a BIT_FIELD_REF knowing that the bits
-     start at offset zero.  */
-  if (TREE_CODE (ref) == COMPONENT_REF
-      && DECL_BIT_FIELD (TREE_OPERAND (ref, 1)))
-    {
-      unsigned HOST_WIDE_INT boff;
-      tree field = TREE_OPERAND (ref, 1);
-      tree offset = component_ref_field_offset (ref);
-      ref_type = TREE_TYPE (ref);
-      boff = tree_to_uhwi (DECL_FIELD_BIT_OFFSET (field));
-      /* This can occur in Ada.  See the comment in get_bit_range.  */
-      if (boff % BITS_PER_UNIT != 0
-	  || !tree_fits_uhwi_p (offset))
-	{
-	  ref_code = BIT_FIELD_REF;
-	  ref_op1 = DECL_SIZE (field);
-	  ref_op2 = bitsize_zero_node;
-	}
-      else
-	{
-	  boff >>= LOG2_BITS_PER_UNIT;
-	  boff += tree_to_uhwi (offset);
-	  coff = size_binop (MINUS_EXPR, coff, ssize_int (boff));
-	  ref_code = COMPONENT_REF;
-	  ref_op1 = field;
-	  ref_op2 = TREE_OPERAND (ref, 2);
-	  ref = TREE_OPERAND (ref, 0);
-	}
-    }
-  tree addr = fold_build_pointer_plus (DR_BASE_ADDRESS (dr), off);
-  addr = force_gimple_operand_1 (unshare_expr (addr), stmts,
-				 is_gimple_mem_ref_addr, NULL_TREE);
-  tree alias_ptr = fold_convert (reference_alias_ptr_type (ref), coff);
-  tree type = build_aligned_type (TREE_TYPE (ref),
-				  get_object_alignment (ref));
-  ref = build2 (MEM_REF, type, addr, alias_ptr);
-  if (ref_type)
-    ref = build3 (ref_code, ref_type, ref, ref_op1, ref_op2);
-  return ref;
-}
-
-/* Get the initialization expression for the INDEX-th temporary variable
-   of CHAIN.  */
-
-static tree
-get_init_expr (chain_p chain, unsigned index)
-{
-  if (chain->type == CT_COMBINATION)
-    {
-      tree e1 = get_init_expr (chain->ch1, index);
-      tree e2 = get_init_expr (chain->ch2, index);
-
-      return fold_build2 (chain->op, chain->rslt_type, e1, e2);
-    }
-  else
-    return chain->inits[index];
-}
-
-/* Returns a new temporary variable used for the I-th variable carrying
-   value of REF.  The variable's uid is marked in TMP_VARS.  */
-
-static tree
-predcom_tmp_var (tree ref, unsigned i, bitmap tmp_vars)
-{
-  tree type = TREE_TYPE (ref);
-  /* We never access the components of the temporary variable in predictive
-     commoning.  */
-  tree var = create_tmp_reg (type, get_lsm_tmp_name (ref, i));
-  bitmap_set_bit (tmp_vars, DECL_UID (var));
-  return var;
-}
-
-/* Creates the variables for CHAIN, as well as phi nodes for them and
-   initialization on entry to LOOP.  Uids of the newly created
-   temporary variables are marked in TMP_VARS.  */
-
-static void
-initialize_root_vars (class loop *loop, chain_p chain, bitmap tmp_vars)
-{
-  unsigned i;
-  unsigned n = chain->length;
-  dref root = get_chain_root (chain);
-  bool reuse_first = !chain->has_max_use_after;
-  tree ref, init, var, next;
-  gphi *phi;
-  gimple_seq stmts;
-  edge entry = loop_preheader_edge (loop), latch = loop_latch_edge (loop);
-
-  /* If N == 0, then all the references are within the single iteration.  And
-     since this is an nonempty chain, reuse_first cannot be true.  */
-  gcc_assert (n > 0 || !reuse_first);
-
-  chain->vars.create (n + 1);
-
-  if (chain->type == CT_COMBINATION)
-    ref = gimple_assign_lhs (root->stmt);
-  else
-    ref = DR_REF (root->ref);
-
-  for (i = 0; i < n + (reuse_first ? 0 : 1); i++)
-    {
-      var = predcom_tmp_var (ref, i, tmp_vars);
-      chain->vars.quick_push (var);
-    }
-  if (reuse_first)
-    chain->vars.quick_push (chain->vars[0]);
-
-  FOR_EACH_VEC_ELT (chain->vars, i, var)
-    chain->vars[i] = make_ssa_name (var);
-
-  for (i = 0; i < n; i++)
-    {
-      var = chain->vars[i];
-      next = chain->vars[i + 1];
-      init = get_init_expr (chain, i);
-
-      init = force_gimple_operand (init, &stmts, true, NULL_TREE);
-      if (stmts)
-	gsi_insert_seq_on_edge_immediate (entry, stmts);
-
-      phi = create_phi_node (var, loop->header);
-      add_phi_arg (phi, init, entry, UNKNOWN_LOCATION);
-      add_phi_arg (phi, next, latch, UNKNOWN_LOCATION);
-    }
-}
-
-/* For inter-iteration store elimination CHAIN in LOOP, returns true if
-   all stores to be eliminated store loop invariant values into memory.
-   In this case, we can use these invariant values directly after LOOP.  */
-
-static bool
-is_inv_store_elimination_chain (class loop *loop, chain_p chain)
-{
-  if (chain->length == 0 || chain->type != CT_STORE_STORE)
-    return false;
-
-  gcc_assert (!chain->has_max_use_after);
-
-  /* If loop iterates for unknown times or fewer times than chain->length,
-     we still need to setup root variable and propagate it with PHI node.  */
-  tree niters = number_of_latch_executions (loop);
-  if (TREE_CODE (niters) != INTEGER_CST
-      || wi::leu_p (wi::to_wide (niters), chain->length))
-    return false;
-
-  /* Check stores in chain for elimination if they only store loop invariant
-     values.  */
-  for (unsigned i = 0; i < chain->length; i++)
-    {
-      dref a = get_chain_last_write_at (chain, i);
-      if (a == NULL)
-	continue;
-
-      gimple *def_stmt, *stmt = a->stmt;
-      if (!gimple_assign_single_p (stmt))
-	return false;
-
-      tree val = gimple_assign_rhs1 (stmt);
-      if (TREE_CLOBBER_P (val))
-	return false;
-
-      if (CONSTANT_CLASS_P (val))
-	continue;
-
-      if (TREE_CODE (val) != SSA_NAME)
-	return false;
-
-      def_stmt = SSA_NAME_DEF_STMT (val);
-      if (gimple_nop_p (def_stmt))
-	continue;
-
-      if (flow_bb_inside_loop_p (loop, gimple_bb (def_stmt)))
-	return false;
-    }
-  return true;
-}
-
-/* Creates root variables for store elimination CHAIN in which stores for
-   elimination only store loop invariant values.  In this case, we neither
-   need to load root variables before loop nor propagate it with PHI nodes.  */
-
-static void
-initialize_root_vars_store_elim_1 (chain_p chain)
-{
-  tree var;
-  unsigned i, n = chain->length;
-
-  chain->vars.create (n);
-  chain->vars.safe_grow_cleared (n, true);
-
-  /* Initialize root value for eliminated stores at each distance.  */
-  for (i = 0; i < n; i++)
-    {
-      dref a = get_chain_last_write_at (chain, i);
-      if (a == NULL)
-	continue;
-
-      var = gimple_assign_rhs1 (a->stmt);
-      chain->vars[a->distance] = var;
-    }
-
-  /* We don't propagate values with PHI nodes, so manually propagate value
-     to bubble positions.  */
-  var = chain->vars[0];
-  for (i = 1; i < n; i++)
-    {
-      if (chain->vars[i] != NULL_TREE)
-	{
-	  var = chain->vars[i];
-	  continue;
-	}
-      chain->vars[i] = var;
-    }
-
-  /* Revert the vector.  */
-  for (i = 0; i < n / 2; i++)
-    std::swap (chain->vars[i], chain->vars[n - i - 1]);
-}
-
-/* Creates root variables for store elimination CHAIN in which stores for
-   elimination store loop variant values.  In this case, we may need to
-   load root variables before LOOP and propagate it with PHI nodes.  Uids
-   of the newly created root variables are marked in TMP_VARS.  */
-
-static void
-initialize_root_vars_store_elim_2 (class loop *loop,
-				   chain_p chain, bitmap tmp_vars)
-{
-  unsigned i, n = chain->length;
-  tree ref, init, var, next, val, phi_result;
-  gimple *stmt;
-  gimple_seq stmts;
-
-  chain->vars.create (n);
-
-  ref = DR_REF (get_chain_root (chain)->ref);
-  for (i = 0; i < n; i++)
-    {
-      var = predcom_tmp_var (ref, i, tmp_vars);
-      chain->vars.quick_push (var);
-    }
-
-  FOR_EACH_VEC_ELT (chain->vars, i, var)
-    chain->vars[i] = make_ssa_name (var);
-
-  /* Root values are either rhs operand of stores to be eliminated, or
-     loaded from memory before loop.  */
-  auto_vec<tree> vtemps;
-  vtemps.safe_grow_cleared (n, true);
-  for (i = 0; i < n; i++)
-    {
-      init = get_init_expr (chain, i);
-      if (init == NULL_TREE)
-	{
-	  /* Root value is rhs operand of the store to be eliminated if
-	     it isn't loaded from memory before loop.  */
-	  dref a = get_chain_last_write_at (chain, i);
-	  val = gimple_assign_rhs1 (a->stmt);
-	  if (TREE_CLOBBER_P (val))
-	    {
-	      val = get_or_create_ssa_default_def (cfun, SSA_NAME_VAR (var));
-	      gimple_assign_set_rhs1 (a->stmt, val);
-	    }
-
-	  vtemps[n - i - 1] = val;
-	}
-      else
-	{
-	  edge latch = loop_latch_edge (loop);
-	  edge entry = loop_preheader_edge (loop);
-
-	  /* Root value is loaded from memory before loop, we also need
-	     to add PHI nodes to propagate the value across iterations.  */
-	  init = force_gimple_operand (init, &stmts, true, NULL_TREE);
-	  if (stmts)
-	    gsi_insert_seq_on_edge_immediate (entry, stmts);
-
-	  next = chain->vars[n - i];
-	  phi_result = copy_ssa_name (next);
-	  gphi *phi = create_phi_node (phi_result, loop->header);
-	  add_phi_arg (phi, init, entry, UNKNOWN_LOCATION);
-	  add_phi_arg (phi, next, latch, UNKNOWN_LOCATION);
-	  vtemps[n - i - 1] = phi_result;
-	}
-    }
-
-  /* Find the insertion position.  */
-  dref last = get_chain_root (chain);
-  for (i = 0; i < chain->refs.length (); i++)
-    {
-      if (chain->refs[i]->pos > last->pos)
-	last = chain->refs[i];
-    }
-
-  gimple_stmt_iterator gsi = gsi_for_stmt (last->stmt);
-
-  /* Insert statements copying root value to root variable.  */
-  for (i = 0; i < n; i++)
-    {
-      var = chain->vars[i];
-      val = vtemps[i];
-      stmt = gimple_build_assign (var, val);
-      gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
-    }
-}
-
-/* Generates stores for CHAIN's eliminated stores in LOOP's last
-   (CHAIN->length - 1) iterations.  */
-
-static void
-finalize_eliminated_stores (class loop *loop, chain_p chain)
-{
-  unsigned i, n = chain->length;
-
-  for (i = 0; i < n; i++)
-    {
-      tree var = chain->vars[i];
-      tree fini = chain->finis[n - i - 1];
-      gimple *stmt = gimple_build_assign (fini, var);
-
-      gimple_seq_add_stmt_without_update (&chain->fini_seq, stmt);
-    }
-
-  if (chain->fini_seq)
-    {
-      gsi_insert_seq_on_edge_immediate (single_exit (loop), chain->fini_seq);
-      chain->fini_seq = NULL;
-    }
-}
-
-/* Initializes a variable for load motion for ROOT and prepares phi nodes and
-   initialization on entry to LOOP if necessary.  The ssa name for the variable
-   is stored in VARS.  If WRITTEN is true, also a phi node to copy its value
-   around the loop is created.  Uid of the newly created temporary variable
-   is marked in TMP_VARS.  INITS is the list containing the (single)
-   initializer.  */
-
-static void
-initialize_root_vars_lm (class loop *loop, dref root, bool written,
-			 vec<tree> *vars, const vec<tree> &inits,
-			 bitmap tmp_vars)
-{
-  unsigned i;
-  tree ref = DR_REF (root->ref), init, var, next;
-  gimple_seq stmts;
-  gphi *phi;
-  edge entry = loop_preheader_edge (loop), latch = loop_latch_edge (loop);
-
-  /* Find the initializer for the variable, and check that it cannot
-     trap.  */
-  init = inits[0];
-
-  vars->create (written ? 2 : 1);
-  var = predcom_tmp_var (ref, 0, tmp_vars);
-  vars->quick_push (var);
-  if (written)
-    vars->quick_push ((*vars)[0]);
-
-  FOR_EACH_VEC_ELT (*vars, i, var)
-    (*vars)[i] = make_ssa_name (var);
-
-  var = (*vars)[0];
-
-  init = force_gimple_operand (init, &stmts, written, NULL_TREE);
-  if (stmts)
-    gsi_insert_seq_on_edge_immediate (entry, stmts);
-
-  if (written)
-    {
-      next = (*vars)[1];
-      phi = create_phi_node (var, loop->header);
-      add_phi_arg (phi, init, entry, UNKNOWN_LOCATION);
-      add_phi_arg (phi, next, latch, UNKNOWN_LOCATION);
-    }
-  else
-    {
-      gassign *init_stmt = gimple_build_assign (var, init);
-      gsi_insert_on_edge_immediate (entry, init_stmt);
-    }
-}
-
-
-/* Execute load motion for references in chain CHAIN.  Uids of the newly
-   created temporary variables are marked in TMP_VARS.  */
-
-static void
-execute_load_motion (class loop *loop, chain_p chain, bitmap tmp_vars)
-{
-  auto_vec<tree> vars;
-  dref a;
-  unsigned n_writes = 0, ridx, i;
-  tree var;
-
-  gcc_assert (chain->type == CT_INVARIANT);
-  gcc_assert (!chain->combined);
-  FOR_EACH_VEC_ELT (chain->refs, i, a)
-    if (DR_IS_WRITE (a->ref))
-      n_writes++;
-
-  /* If there are no reads in the loop, there is nothing to do.  */
-  if (n_writes == chain->refs.length ())
-    return;
-
-  initialize_root_vars_lm (loop, get_chain_root (chain), n_writes > 0,
-			   &vars, chain->inits, tmp_vars);
-
-  ridx = 0;
-  FOR_EACH_VEC_ELT (chain->refs, i, a)
-    {
-      bool is_read = DR_IS_READ (a->ref);
-
-      if (DR_IS_WRITE (a->ref))
-	{
-	  n_writes--;
-	  if (n_writes)
-	    {
-	      var = vars[0];
-	      var = make_ssa_name (SSA_NAME_VAR (var));
-	      vars[0] = var;
-	    }
-	  else
-	    ridx = 1;
-	}
-
-      replace_ref_with (a->stmt, vars[ridx],
-			!is_read, !is_read);
-    }
-}
-
-/* Returns the single statement in that NAME is used, excepting
-   the looparound phi nodes contained in one of the chains.  If there is no
-   such statement, or more statements, NULL is returned.  */
-
-gimple *
-pcom_worker::single_nonlooparound_use (tree name)
-{
-  use_operand_p use;
-  imm_use_iterator it;
-  gimple *stmt, *ret = NULL;
-
-  FOR_EACH_IMM_USE_FAST (use, it, name)
-    {
-      stmt = USE_STMT (use);
-
-      if (gimple_code (stmt) == GIMPLE_PHI)
-	{
-	  /* Ignore uses in looparound phi nodes.  Uses in other phi nodes
-	     could not be processed anyway, so just fail for them.  */
-	  if (bitmap_bit_p (m_looparound_phis,
-			    SSA_NAME_VERSION (PHI_RESULT (stmt))))
-	    continue;
-
-	  return NULL;
-	}
-      else if (is_gimple_debug (stmt))
-	continue;
-      else if (ret != NULL)
-	return NULL;
-      else
-	ret = stmt;
-    }
-
-  return ret;
-}
-
-/* Remove statement STMT, as well as the chain of assignments in that it is
-   used.  */
-
-void
-pcom_worker::remove_stmt (gimple *stmt)
-{
-  tree name;
-  gimple *next;
-  gimple_stmt_iterator psi;
-
-  if (gimple_code (stmt) == GIMPLE_PHI)
-    {
-      name = PHI_RESULT (stmt);
-      next = single_nonlooparound_use (name);
-      reset_debug_uses (stmt);
-      psi = gsi_for_stmt (stmt);
-      remove_phi_node (&psi, true);
-
-      if (!next
-	  || !gimple_assign_ssa_name_copy_p (next)
-	  || gimple_assign_rhs1 (next) != name)
-	return;
-
-      stmt = next;
-    }
-
-  while (1)
-    {
-      gimple_stmt_iterator bsi;
-
-      bsi = gsi_for_stmt (stmt);
-
-      name = gimple_assign_lhs (stmt);
-      if (TREE_CODE (name) == SSA_NAME)
-	{
-	  next = single_nonlooparound_use (name);
-	  reset_debug_uses (stmt);
-	}
-      else
-	{
-	  /* This is a store to be eliminated.  */
-	  gcc_assert (gimple_vdef (stmt) != NULL);
-	  next = NULL;
-	}
-
-      unlink_stmt_vdef (stmt);
-      gsi_remove (&bsi, true);
-      release_defs (stmt);
-
-      if (!next
-	  || !gimple_assign_ssa_name_copy_p (next)
-	  || gimple_assign_rhs1 (next) != name)
-	return;
-
-      stmt = next;
-    }
-}
-
-/* Perform the predictive commoning optimization for a chain CHAIN.
-   Uids of the newly created temporary variables are marked in TMP_VARS.*/
-
-void
-pcom_worker::execute_pred_commoning_chain (chain_p chain,
-			      bitmap tmp_vars)
-{
-  unsigned i;
-  dref a;
-  tree var;
-  bool in_lhs;
-
-  if (chain->combined)
-    {
-      /* For combined chains, just remove the statements that are used to
-	 compute the values of the expression (except for the root one).
-	 We delay this until after all chains are processed.  */
-    }
-  else if (chain->type == CT_STORE_STORE)
-    {
-      if (chain->length > 0)
-	{
-	  if (chain->inv_store_elimination)
-	    {
-	      /* If dead stores in this chain only store loop invariant
-		 values, we can simply record the invariant value and use
-		 it directly after loop.  */
-	      initialize_root_vars_store_elim_1 (chain);
-	    }
-	  else
-	    {
-	      /* If dead stores in this chain store loop variant values,
-		 we need to set up the variables by loading from memory
-		 before loop and propagating it with PHI nodes.  */
-	      initialize_root_vars_store_elim_2 (m_loop, chain, tmp_vars);
-	    }
-
-	  /* For inter-iteration store elimination chain, stores at each
-	     distance in loop's last (chain->length - 1) iterations can't
-	     be eliminated, because there is no following killing store.
-	     We need to generate these stores after loop.  */
-	  finalize_eliminated_stores (m_loop, chain);
-	}
-
-      bool last_store_p = true;
-      for (i = chain->refs.length (); i > 0; i--)
-	{
-	  a = chain->refs[i - 1];
-	  /* Preserve the last store of the chain.  Eliminate other stores
-	     which are killed by the last one.  */
-	  if (DR_IS_WRITE (a->ref))
-	    {
-	      if (last_store_p)
-		last_store_p = false;
-	      else
-		remove_stmt (a->stmt);
-
-	      continue;
-	    }
-
-	  /* Any load in Store-Store chain must be dominated by a previous
-	     store, we replace the load reference with rhs of the store.  */
-	  dref b = get_chain_last_write_before_load (chain, i - 1);
-	  gcc_assert (b != NULL);
-	  var = gimple_assign_rhs1 (b->stmt);
-	  replace_ref_with (a->stmt, var, false, false);
-	}
-    }
-  else
-    {
-      /* For non-combined chains, set up the variables that hold its value.  */
-      initialize_root_vars (m_loop, chain, tmp_vars);
-      a = get_chain_root (chain);
-      in_lhs = (chain->type == CT_STORE_LOAD
-		|| chain->type == CT_COMBINATION);
-      replace_ref_with (a->stmt, chain->vars[chain->length], true, in_lhs);
-
-      /* Replace the uses of the original references by these variables.  */
-      for (i = 1; chain->refs.iterate (i, &a); i++)
-	{
-	  var = chain->vars[chain->length - a->distance];
-	  replace_ref_with (a->stmt, var, false, false);
-	}
-    }
-}
-
-/* Determines the unroll factor necessary to remove as many temporary variable
-   copies as possible.  CHAINS is the list of chains that will be
-   optimized.  */
-
-static unsigned
-determine_unroll_factor (const vec<chain_p> &chains)
-{
-  chain_p chain;
-  unsigned factor = 1, af, nfactor, i;
-  unsigned max = param_max_unroll_times;
-
-  FOR_EACH_VEC_ELT (chains, i, chain)
-    {
-      if (chain->type == CT_INVARIANT)
-	continue;
-      /* For now we can't handle unrolling when eliminating stores.  */
-      else if (chain->type == CT_STORE_STORE)
-	return 1;
-
-      if (chain->combined)
-	{
-	  /* For combined chains, we can't handle unrolling if we replace
-	     looparound PHIs.  */
-	  dref a;
-	  unsigned j;
-	  for (j = 1; chain->refs.iterate (j, &a); j++)
-	    if (gimple_code (a->stmt) == GIMPLE_PHI)
-	      return 1;
-	  continue;
-	}
-
-      /* The best unroll factor for this chain is equal to the number of
-	 temporary variables that we create for it.  */
-      af = chain->length;
-      if (chain->has_max_use_after)
-	af++;
-
-      nfactor = factor * af / gcd (factor, af);
-      if (nfactor <= max)
-	factor = nfactor;
-    }
-
-  return factor;
-}
-
-/* Perform the predictive commoning optimization for chains.
-   Uids of the newly created temporary variables are marked in TMP_VARS.  */
-
-void
-pcom_worker::execute_pred_commoning (bitmap tmp_vars)
-{
-  chain_p chain;
-  unsigned i;
-
-  FOR_EACH_VEC_ELT (m_chains, i, chain)
-    {
-      if (chain->type == CT_INVARIANT)
-	execute_load_motion (m_loop, chain, tmp_vars);
-      else
-	execute_pred_commoning_chain (chain, tmp_vars);
-    }
-
-  FOR_EACH_VEC_ELT (m_chains, i, chain)
-    {
-      if (chain->type == CT_INVARIANT)
-	;
-      else if (chain->combined)
-	{
-	  /* For combined chains, just remove the statements that are used to
-	     compute the values of the expression (except for the root one).  */
-	  dref a;
-	  unsigned j;
-	  for (j = 1; chain->refs.iterate (j, &a); j++)
-	    remove_stmt (a->stmt);
-	}
-    }
-}
-
-/* For each reference in CHAINS, if its defining statement is
-   phi node, record the ssa name that is defined by it.  */
-
-static void
-replace_phis_by_defined_names (vec<chain_p> &chains)
-{
-  chain_p chain;
-  dref a;
-  unsigned i, j;
-
-  FOR_EACH_VEC_ELT (chains, i, chain)
-    FOR_EACH_VEC_ELT (chain->refs, j, a)
-      {
-	if (gimple_code (a->stmt) == GIMPLE_PHI)
-	  {
-	    a->name_defined_by_phi = PHI_RESULT (a->stmt);
-	    a->stmt = NULL;
-	  }
-      }
-}
-
-/* For each reference in CHAINS, if name_defined_by_phi is not
-   NULL, use it to set the stmt field.  */
-
-static void
-replace_names_by_phis (vec<chain_p> chains)
-{
-  chain_p chain;
-  dref a;
-  unsigned i, j;
-
-  FOR_EACH_VEC_ELT (chains, i, chain)
-    FOR_EACH_VEC_ELT (chain->refs, j, a)
-      if (a->stmt == NULL)
-	{
-	  a->stmt = SSA_NAME_DEF_STMT (a->name_defined_by_phi);
-	  gcc_assert (gimple_code (a->stmt) == GIMPLE_PHI);
-	  a->name_defined_by_phi = NULL_TREE;
-	}
-}
-
-/* Wrapper over execute_pred_commoning, to pass it as a callback
-   to tree_transform_and_unroll_loop.  */
-
-struct epcc_data
-{
-  vec<chain_p> chains;
-  bitmap tmp_vars;
-  pcom_worker *worker;
-};
-
-static void
-execute_pred_commoning_cbck (class loop *loop ATTRIBUTE_UNUSED, void *data)
-{
-  struct epcc_data *const dta = (struct epcc_data *) data;
-  pcom_worker *worker = dta->worker;
-
-  /* Restore phi nodes that were replaced by ssa names before
-     tree_transform_and_unroll_loop (see detailed description in
-     tree_predictive_commoning_loop).  */
-  replace_names_by_phis (dta->chains);
-  worker->execute_pred_commoning (dta->tmp_vars);
-}
-
-/* Base NAME and all the names in the chain of phi nodes that use it
-   on variable VAR.  The phi nodes are recognized by being in the copies of
-   the header of the LOOP.  */
-
-static void
-base_names_in_chain_on (class loop *loop, tree name, tree var)
-{
-  gimple *stmt, *phi;
-  imm_use_iterator iter;
-
-  replace_ssa_name_symbol (name, var);
-
-  while (1)
-    {
-      phi = NULL;
-      FOR_EACH_IMM_USE_STMT (stmt, iter, name)
-	{
-	  if (gimple_code (stmt) == GIMPLE_PHI
-	      && flow_bb_inside_loop_p (loop, gimple_bb (stmt)))
-	    {
-	      phi = stmt;
-	      break;
-	    }
-	}
-      if (!phi)
-	return;
-
-      name = PHI_RESULT (phi);
-      replace_ssa_name_symbol (name, var);
-    }
-}
-
-/* Given an unrolled LOOP after predictive commoning, remove the
-   register copies arising from phi nodes by changing the base
-   variables of SSA names.  TMP_VARS is the set of the temporary variables
-   for those we want to perform this.  */
-
-static void
-eliminate_temp_copies (class loop *loop, bitmap tmp_vars)
-{
-  edge e;
-  gphi *phi;
-  gimple *stmt;
-  tree name, use, var;
-  gphi_iterator psi;
-
-  e = loop_latch_edge (loop);
-  for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi))
-    {
-      phi = psi.phi ();
-      name = PHI_RESULT (phi);
-      var = SSA_NAME_VAR (name);
-      if (!var || !bitmap_bit_p (tmp_vars, DECL_UID (var)))
-	continue;
-      use = PHI_ARG_DEF_FROM_EDGE (phi, e);
-      gcc_assert (TREE_CODE (use) == SSA_NAME);
-
-      /* Base all the ssa names in the ud and du chain of NAME on VAR.  */
-      stmt = SSA_NAME_DEF_STMT (use);
-      while (gimple_code (stmt) == GIMPLE_PHI
-	     /* In case we could not unroll the loop enough to eliminate
-		all copies, we may reach the loop header before the defining
-		statement (in that case, some register copies will be present
-		in loop latch in the final code, corresponding to the newly
-		created looparound phi nodes).  */
-	     && gimple_bb (stmt) != loop->header)
-	{
-	  gcc_assert (single_pred_p (gimple_bb (stmt)));
-	  use = PHI_ARG_DEF (stmt, 0);
-	  stmt = SSA_NAME_DEF_STMT (use);
-	}
-
-      base_names_in_chain_on (loop, use, var);
-    }
-}
-
-/* Returns true if CHAIN is suitable to be combined.  */
-
-static bool
-chain_can_be_combined_p (chain_p chain)
-{
-  return (!chain->combined
-	  && (chain->type == CT_LOAD || chain->type == CT_COMBINATION));
-}
-
-/* Returns the modify statement that uses NAME.  Skips over assignment
-   statements, NAME is replaced with the actual name used in the returned
-   statement.  */
-
-gimple *
-pcom_worker::find_use_stmt (tree *name)
-{
-  gimple *stmt;
-  tree rhs, lhs;
-
-  /* Skip over assignments.  */
-  while (1)
-    {
-      stmt = single_nonlooparound_use (*name);
-      if (!stmt)
-	return NULL;
-
-      if (gimple_code (stmt) != GIMPLE_ASSIGN)
-	return NULL;
-
-      lhs = gimple_assign_lhs (stmt);
-      if (TREE_CODE (lhs) != SSA_NAME)
-	return NULL;
-
-      if (gimple_assign_copy_p (stmt))
-	{
-	  rhs = gimple_assign_rhs1 (stmt);
-	  if (rhs != *name)
-	    return NULL;
-
-	  *name = lhs;
-	}
-      else if (get_gimple_rhs_class (gimple_assign_rhs_code (stmt))
-	       == GIMPLE_BINARY_RHS)
-	return stmt;
-      else
-	return NULL;
-    }
-}
-
-/* Returns true if we may perform reassociation for operation CODE in TYPE.  */
-
-static bool
-may_reassociate_p (tree type, enum tree_code code)
-{
-  if (FLOAT_TYPE_P (type)
-      && !flag_unsafe_math_optimizations)
-    return false;
-
-  return (commutative_tree_code (code)
-	  && associative_tree_code (code));
-}
-
-/* If the operation used in STMT is associative and commutative, go through the
-   tree of the same operations and returns its root.  Distance to the root
-   is stored in DISTANCE.  */
-
-gimple *
-pcom_worker::find_associative_operation_root (gimple *stmt, unsigned *distance)
-{
-  tree lhs;
-  gimple *next;
-  enum tree_code code = gimple_assign_rhs_code (stmt);
-  tree type = TREE_TYPE (gimple_assign_lhs (stmt));
-  unsigned dist = 0;
-
-  if (!may_reassociate_p (type, code))
-    return NULL;
-
-  while (1)
-    {
-      lhs = gimple_assign_lhs (stmt);
-      gcc_assert (TREE_CODE (lhs) == SSA_NAME);
-
-      next = find_use_stmt (&lhs);
-      if (!next
-	  || gimple_assign_rhs_code (next) != code)
-	break;
-
-      stmt = next;
-      dist++;
-    }
-
-  if (distance)
-    *distance = dist;
-  return stmt;
-}
-
-/* Returns the common statement in that NAME1 and NAME2 have a use.  If there
-   is no such statement, returns NULL_TREE.  In case the operation used on
-   NAME1 and NAME2 is associative and commutative, returns the root of the
-   tree formed by this operation instead of the statement that uses NAME1 or
-   NAME2.  */
-
-gimple *
-pcom_worker::find_common_use_stmt (tree *name1, tree *name2)
-{
-  gimple *stmt1, *stmt2;
-
-  stmt1 = find_use_stmt (name1);
-  if (!stmt1)
-    return NULL;
-
-  stmt2 = find_use_stmt (name2);
-  if (!stmt2)
-    return NULL;
-
-  if (stmt1 == stmt2)
-    return stmt1;
-
-  stmt1 = find_associative_operation_root (stmt1, NULL);
-  if (!stmt1)
-    return NULL;
-  stmt2 = find_associative_operation_root (stmt2, NULL);
-  if (!stmt2)
-    return NULL;
-
-  return (stmt1 == stmt2 ? stmt1 : NULL);
-}
-
-/* Checks whether R1 and R2 are combined together using CODE, with the result
-   in RSLT_TYPE, in order R1 CODE R2 if SWAP is false and in order R2 CODE R1
-   if it is true.  If CODE is ERROR_MARK, set these values instead.  */
-
-bool
-pcom_worker::combinable_refs_p (dref r1, dref r2,
-		   enum tree_code *code, bool *swap, tree *rslt_type)
-{
-  enum tree_code acode;
-  bool aswap;
-  tree atype;
-  tree name1, name2;
-  gimple *stmt;
-
-  name1 = name_for_ref (r1);
-  name2 = name_for_ref (r2);
-  gcc_assert (name1 != NULL_TREE && name2 != NULL_TREE);
-
-  stmt = find_common_use_stmt (&name1, &name2);
-
-  if (!stmt
-      /* A simple post-dominance check - make sure the combination
-         is executed under the same condition as the references.  */
-      || (gimple_bb (stmt) != gimple_bb (r1->stmt)
-	  && gimple_bb (stmt) != gimple_bb (r2->stmt)))
-    return false;
-
-  acode = gimple_assign_rhs_code (stmt);
-  aswap = (!commutative_tree_code (acode)
-	   && gimple_assign_rhs1 (stmt) != name1);
-  atype = TREE_TYPE (gimple_assign_lhs (stmt));
-
-  if (*code == ERROR_MARK)
-    {
-      *code = acode;
-      *swap = aswap;
-      *rslt_type = atype;
-      return true;
-    }
-
-  return (*code == acode
-	  && *swap == aswap
-	  && *rslt_type == atype);
-}
-
-/* Remove OP from the operation on rhs of STMT, and replace STMT with
-   an assignment of the remaining operand.  */
-
-static void
-remove_name_from_operation (gimple *stmt, tree op)
-{
-  tree other_op;
-  gimple_stmt_iterator si;
-
-  gcc_assert (is_gimple_assign (stmt));
-
-  if (gimple_assign_rhs1 (stmt) == op)
-    other_op = gimple_assign_rhs2 (stmt);
-  else
-    other_op = gimple_assign_rhs1 (stmt);
-
-  si = gsi_for_stmt (stmt);
-  gimple_assign_set_rhs_from_tree (&si, other_op);
-
-  /* We should not have reallocated STMT.  */
-  gcc_assert (gsi_stmt (si) == stmt);
-
-  update_stmt (stmt);
-}
-
-/* Reassociates the expression in that NAME1 and NAME2 are used so that they
-   are combined in a single statement, and returns this statement.  */
-
-gimple *
-pcom_worker::reassociate_to_the_same_stmt (tree name1, tree name2)
-{
-  gimple *stmt1, *stmt2, *root1, *root2, *s1, *s2;
-  gassign *new_stmt, *tmp_stmt;
-  tree new_name, tmp_name, var, r1, r2;
-  unsigned dist1, dist2;
-  enum tree_code code;
-  tree type = TREE_TYPE (name1);
-  gimple_stmt_iterator bsi;
-
-  stmt1 = find_use_stmt (&name1);
-  stmt2 = find_use_stmt (&name2);
-  root1 = find_associative_operation_root (stmt1, &dist1);
-  root2 = find_associative_operation_root (stmt2, &dist2);
-  code = gimple_assign_rhs_code (stmt1);
-
-  gcc_assert (root1 && root2 && root1 == root2
-	      && code == gimple_assign_rhs_code (stmt2));
-
-  /* Find the root of the nearest expression in that both NAME1 and NAME2
-     are used.  */
-  r1 = name1;
-  s1 = stmt1;
-  r2 = name2;
-  s2 = stmt2;
-
-  while (dist1 > dist2)
-    {
-      s1 = find_use_stmt (&r1);
-      r1 = gimple_assign_lhs (s1);
-      dist1--;
-    }
-  while (dist2 > dist1)
-    {
-      s2 = find_use_stmt (&r2);
-      r2 = gimple_assign_lhs (s2);
-      dist2--;
-    }
-
-  while (s1 != s2)
-    {
-      s1 = find_use_stmt (&r1);
-      r1 = gimple_assign_lhs (s1);
-      s2 = find_use_stmt (&r2);
-      r2 = gimple_assign_lhs (s2);
-    }
-
-  /* Remove NAME1 and NAME2 from the statements in that they are used
-     currently.  */
-  remove_name_from_operation (stmt1, name1);
-  remove_name_from_operation (stmt2, name2);
-
-  /* Insert the new statement combining NAME1 and NAME2 before S1, and
-     combine it with the rhs of S1.  */
-  var = create_tmp_reg (type, "predreastmp");
-  new_name = make_ssa_name (var);
-  new_stmt = gimple_build_assign (new_name, code, name1, name2);
-
-  var = create_tmp_reg (type, "predreastmp");
-  tmp_name = make_ssa_name (var);
-
-  /* Rhs of S1 may now be either a binary expression with operation
-     CODE, or gimple_val (in case that stmt1 == s1 or stmt2 == s1,
-     so that name1 or name2 was removed from it).  */
-  tmp_stmt = gimple_build_assign (tmp_name, gimple_assign_rhs_code (s1),
-				  gimple_assign_rhs1 (s1),
-				  gimple_assign_rhs2 (s1));
-
-  bsi = gsi_for_stmt (s1);
-  gimple_assign_set_rhs_with_ops (&bsi, code, new_name, tmp_name);
-  s1 = gsi_stmt (bsi);
-  update_stmt (s1);
-
-  gsi_insert_before (&bsi, new_stmt, GSI_SAME_STMT);
-  gsi_insert_before (&bsi, tmp_stmt, GSI_SAME_STMT);
-
-  return new_stmt;
-}
-
-/* Returns the statement that combines references R1 and R2.  In case R1
-   and R2 are not used in the same statement, but they are used with an
-   associative and commutative operation in the same expression, reassociate
-   the expression so that they are used in the same statement.  */
-
-gimple *
-pcom_worker::stmt_combining_refs (dref r1, dref r2)
-{
-  gimple *stmt1, *stmt2;
-  tree name1 = name_for_ref (r1);
-  tree name2 = name_for_ref (r2);
-
-  stmt1 = find_use_stmt (&name1);
-  stmt2 = find_use_stmt (&name2);
-  if (stmt1 == stmt2)
-    return stmt1;
-
-  return reassociate_to_the_same_stmt (name1, name2);
-}
-
-/* Tries to combine chains CH1 and CH2 together.  If this succeeds, the
-   description of the new chain is returned, otherwise we return NULL.  */
-
-chain_p
-pcom_worker::combine_chains (chain_p ch1, chain_p ch2)
-{
-  dref r1, r2, nw;
-  enum tree_code op = ERROR_MARK;
-  bool swap = false;
-  chain_p new_chain;
-  unsigned i;
-  tree rslt_type = NULL_TREE;
-
-  if (ch1 == ch2)
-    return NULL;
-  if (ch1->length != ch2->length)
-    return NULL;
-
-  if (ch1->refs.length () != ch2->refs.length ())
-    return NULL;
-
-  for (i = 0; (ch1->refs.iterate (i, &r1)
-	       && ch2->refs.iterate (i, &r2)); i++)
-    {
-      if (r1->distance != r2->distance)
-	return NULL;
-
-      if (!combinable_refs_p (r1, r2, &op, &swap, &rslt_type))
-	return NULL;
-    }
-
-  if (swap)
-    std::swap (ch1, ch2);
-
-  new_chain = XCNEW (struct chain);
-  new_chain->type = CT_COMBINATION;
-  new_chain->op = op;
-  new_chain->ch1 = ch1;
-  new_chain->ch2 = ch2;
-  new_chain->rslt_type = rslt_type;
-  new_chain->length = ch1->length;
-
-  for (i = 0; (ch1->refs.iterate (i, &r1)
-	       && ch2->refs.iterate (i, &r2)); i++)
-    {
-      nw = XCNEW (class dref_d);
-      nw->stmt = stmt_combining_refs (r1, r2);
-      nw->distance = r1->distance;
-
-      new_chain->refs.safe_push (nw);
-    }
-
-  ch1->combined = true;
-  ch2->combined = true;
-  return new_chain;
-}
-
-/* Recursively update position information of all offspring chains to ROOT
-   chain's position information.  */
-
-static void
-update_pos_for_combined_chains (chain_p root)
-{
-  chain_p ch1 = root->ch1, ch2 = root->ch2;
-  dref ref, ref1, ref2;
-  for (unsigned j = 0; (root->refs.iterate (j, &ref)
-			&& ch1->refs.iterate (j, &ref1)
-			&& ch2->refs.iterate (j, &ref2)); ++j)
-    ref1->pos = ref2->pos = ref->pos;
-
-  if (ch1->type == CT_COMBINATION)
-    update_pos_for_combined_chains (ch1);
-  if (ch2->type == CT_COMBINATION)
-    update_pos_for_combined_chains (ch2);
-}
-
-/* Returns true if statement S1 dominates statement S2.  */
-
-static bool
-pcom_stmt_dominates_stmt_p (gimple *s1, gimple *s2)
-{
-  basic_block bb1 = gimple_bb (s1), bb2 = gimple_bb (s2);
-
-  if (!bb1 || s1 == s2)
-    return true;
-
-  if (bb1 == bb2)
-    return gimple_uid (s1) < gimple_uid (s2);
-
-  return dominated_by_p (CDI_DOMINATORS, bb2, bb1);
-}
-
-/* Try to combine the chains.  */
-
-void
-pcom_worker::try_combine_chains ()
-{
-  unsigned i, j;
-  chain_p ch1, ch2, cch;
-  auto_vec<chain_p> worklist;
-  bool combined_p = false;
-
-  FOR_EACH_VEC_ELT (m_chains, i, ch1)
-    if (chain_can_be_combined_p (ch1))
-      worklist.safe_push (ch1);
-
-  while (!worklist.is_empty ())
-    {
-      ch1 = worklist.pop ();
-      if (!chain_can_be_combined_p (ch1))
-	continue;
-
-      FOR_EACH_VEC_ELT (m_chains, j, ch2)
-	{
-	  if (!chain_can_be_combined_p (ch2))
-	    continue;
-
-	  cch = combine_chains (ch1, ch2);
-	  if (cch)
-	    {
-	      worklist.safe_push (cch);
-	      m_chains.safe_push (cch);
-	      combined_p = true;
-	      break;
-	    }
-	}
-    }
-  if (!combined_p)
-    return;
-
-  /* Setup UID for all statements in dominance order.  */
-  basic_block *bbs = get_loop_body_in_dom_order (m_loop);
-  renumber_gimple_stmt_uids_in_blocks (bbs, m_loop->num_nodes);
-  free (bbs);
-
-  /* Re-association in combined chains may generate statements different to
-     order of references of the original chain.  We need to keep references
-     of combined chain in dominance order so that all uses will be inserted
-     after definitions.  Note:
-       A) This is necessary for all combined chains.
-       B) This is only necessary for ZERO distance references because other
-	  references inherit value from loop carried PHIs.
-
-     We first update position information for all combined chains.  */
-  dref ref;
-  for (i = 0; m_chains.iterate (i, &ch1); ++i)
-    {
-      if (ch1->type != CT_COMBINATION || ch1->combined)
-	continue;
-
-      for (j = 0; ch1->refs.iterate (j, &ref); ++j)
-	ref->pos = gimple_uid (ref->stmt);
-
-      update_pos_for_combined_chains (ch1);
-    }
-  /* Then sort references according to newly updated position information.  */
-  for (i = 0; m_chains.iterate (i, &ch1); ++i)
-    {
-      if (ch1->type != CT_COMBINATION && !ch1->combined)
-	continue;
-
-      /* Find the first reference with non-ZERO distance.  */
-      if (ch1->length == 0)
-	j = ch1->refs.length();
-      else
-	{
-	  for (j = 0; ch1->refs.iterate (j, &ref); ++j)
-	    if (ref->distance != 0)
-	      break;
-	}
-
-      /* Sort all ZERO distance references by position.  */
-      qsort (&ch1->refs[0], j, sizeof (ch1->refs[0]), order_drefs_by_pos);
-
-      if (ch1->combined)
-	continue;
-
-      /* For ZERO length chain, has_max_use_after must be true since root
-	 combined stmt must dominates others.  */
-      if (ch1->length == 0)
-	{
-	  ch1->has_max_use_after = true;
-	  continue;
-	}
-      /* Check if there is use at max distance after root for combined chains
-	 and set flag accordingly.  */
-      ch1->has_max_use_after = false;
-      gimple *root_stmt = get_chain_root (ch1)->stmt;
-      for (j = 1; ch1->refs.iterate (j, &ref); ++j)
-	{
-	  if (ref->distance == ch1->length
-	      && !pcom_stmt_dominates_stmt_p (ref->stmt, root_stmt))
-	    {
-	      ch1->has_max_use_after = true;
-	      break;
-	    }
-	}
-    }
-}
-
-/* Prepare initializers for store elimination CHAIN in LOOP.  Returns false
-   if this is impossible because one of these initializers may trap, true
-   otherwise.  */
-
-static bool
-prepare_initializers_chain_store_elim (class loop *loop, chain_p chain)
-{
-  unsigned i, n = chain->length;
-
-  /* For now we can't eliminate stores if some of them are conditional
-     executed.  */
-  if (!chain->all_always_accessed)
-    return false;
-
-  /* Nothing to intialize for intra-iteration store elimination.  */
-  if (n == 0 && chain->type == CT_STORE_STORE)
-    return true;
-
-  /* For store elimination chain, there is nothing to initialize if stores
-     to be eliminated only store loop invariant values into memory.  */
-  if (chain->type == CT_STORE_STORE
-      && is_inv_store_elimination_chain (loop, chain))
-    {
-      chain->inv_store_elimination = true;
-      return true;
-    }
-
-  chain->inits.create (n);
-  chain->inits.safe_grow_cleared (n, true);
-
-  /* For store eliminatin chain like below:
-
-     for (i = 0; i < len; i++)
-       {
-	 a[i] = 1;
-	 // a[i + 1] = ...
-	 a[i + 2] = 3;
-       }
-
-     store to a[i + 1] is missed in loop body, it acts like bubbles.  The
-     content of a[i + 1] remain the same if the loop iterates fewer times
-     than chain->length.  We need to set up root variables for such stores
-     by loading from memory before loop.  Note we only need to load bubble
-     elements because loop body is guaranteed to be executed at least once
-     after loop's preheader edge.  */
-  auto_vec<bool> bubbles;
-  bubbles.safe_grow_cleared (n + 1, true);
-  for (i = 0; i < chain->refs.length (); i++)
-    bubbles[chain->refs[i]->distance] = true;
-
-  struct data_reference *dr = get_chain_root (chain)->ref;
-  for (i = 0; i < n; i++)
-    {
-      if (bubbles[i])
-	continue;
-
-      gimple_seq stmts = NULL;
-
-      tree init = ref_at_iteration (dr, (int) 0 - i, &stmts);
-      if (stmts)
-	gimple_seq_add_seq_without_update (&chain->init_seq, stmts);
-
-      chain->inits[i] = init;
-    }
-
-  return true;
-}
-
-/* Prepare initializers for CHAIN.  Returns false if this is impossible
-   because one of these initializers may trap, true otherwise.  */
-
-bool
-pcom_worker::prepare_initializers_chain (chain_p chain)
-{
-  unsigned i, n = (chain->type == CT_INVARIANT) ? 1 : chain->length;
-  struct data_reference *dr = get_chain_root (chain)->ref;
-  tree init;
-  dref laref;
-  edge entry = loop_preheader_edge (m_loop);
-
-  if (chain->type == CT_STORE_STORE)
-    return prepare_initializers_chain_store_elim (m_loop, chain);
-
-  /* Find the initializers for the variables, and check that they cannot
-     trap.  */
-  chain->inits.create (n);
-  for (i = 0; i < n; i++)
-    chain->inits.quick_push (NULL_TREE);
-
-  /* If we have replaced some looparound phi nodes, use their initializers
-     instead of creating our own.  */
-  FOR_EACH_VEC_ELT (chain->refs, i, laref)
-    {
-      if (gimple_code (laref->stmt) != GIMPLE_PHI)
-	continue;
-
-      gcc_assert (laref->distance > 0);
-      chain->inits[n - laref->distance] 
-	= PHI_ARG_DEF_FROM_EDGE (laref->stmt, entry);
-    }
-
-  for (i = 0; i < n; i++)
-    {
-      gimple_seq stmts = NULL;
-
-      if (chain->inits[i] != NULL_TREE)
-	continue;
-
-      init = ref_at_iteration (dr, (int) i - n, &stmts);
-      if (!chain->all_always_accessed && tree_could_trap_p (init))
-	{
-	  gimple_seq_discard (stmts);
-	  return false;
-	}
-
-      if (stmts)
-	gimple_seq_add_seq_without_update (&chain->init_seq, stmts);
-
-      chain->inits[i] = init;
-    }
-
-  return true;
-}
-
-/* Prepare initializers for chains, and free chains that cannot
-   be used because the initializers might trap.  */
-
-void
-pcom_worker::prepare_initializers ()
-{
-  chain_p chain;
-  unsigned i;
-
-  for (i = 0; i < m_chains.length (); )
-    {
-      chain = m_chains[i];
-      if (prepare_initializers_chain (chain))
-	i++;
-      else
-	{
-	  release_chain (chain);
-	  m_chains.unordered_remove (i);
-	}
-    }
-}
-
-/* Generates finalizer memory references for CHAIN.  Returns true
-   if finalizer code for CHAIN can be generated, otherwise false.  */
-
-bool
-pcom_worker::prepare_finalizers_chain (chain_p chain)
-{
-  unsigned i, n = chain->length;
-  struct data_reference *dr = get_chain_root (chain)->ref;
-  tree fini, niters = number_of_latch_executions (m_loop);
-
-  /* For now we can't eliminate stores if some of them are conditional
-     executed.  */
-  if (!chain->all_always_accessed)
-    return false;
-
-  chain->finis.create (n);
-  for (i = 0; i < n; i++)
-    chain->finis.quick_push (NULL_TREE);
-
-  /* We never use looparound phi node for store elimination chains.  */
-
-  /* Find the finalizers for the variables, and check that they cannot
-     trap.  */
-  for (i = 0; i < n; i++)
-    {
-      gimple_seq stmts = NULL;
-      gcc_assert (chain->finis[i] == NULL_TREE);
-
-      if (TREE_CODE (niters) != INTEGER_CST && TREE_CODE (niters) != SSA_NAME)
-	{
-	  niters = unshare_expr (niters);
-	  niters = force_gimple_operand (niters, &stmts, true, NULL);
-	  if (stmts)
-	    {
-	      gimple_seq_add_seq_without_update (&chain->fini_seq, stmts);
-	      stmts = NULL;
-	    }
-	}
-      fini = ref_at_iteration (dr, (int) 0 - i, &stmts, niters);
-      if (stmts)
-	gimple_seq_add_seq_without_update (&chain->fini_seq, stmts);
-
-      chain->finis[i] = fini;
-    }
-
-  return true;
-}
-
-/* Generates finalizer memory reference for chains.  Returns true if
-   finalizer code generation for chains breaks loop closed ssa form.  */
-
-bool
-pcom_worker::prepare_finalizers ()
-{
-  chain_p chain;
-  unsigned i;
-  bool loop_closed_ssa = false;
-
-  for (i = 0; i < m_chains.length ();)
-    {
-      chain = m_chains[i];
-
-      /* Finalizer is only necessary for inter-iteration store elimination
-	 chains.  */
-      if (chain->length == 0 || chain->type != CT_STORE_STORE)
-	{
-	  i++;
-	  continue;
-	}
-
-      if (prepare_finalizers_chain (chain))
-	{
-	  i++;
-	  /* Be conservative, assume loop closed ssa form is corrupted
-	     by store-store chain.  Though it's not always the case if
-	     eliminated stores only store loop invariant values into
-	     memory.  */
-	  loop_closed_ssa = true;
-	}
-      else
-	{
-	  release_chain (chain);
-	  m_chains.unordered_remove (i);
-	}
-    }
-  return loop_closed_ssa;
-}
-
-/* Insert all initializing gimple stmts into LOOP's entry edge.  */
-
-static void
-insert_init_seqs (class loop *loop, vec<chain_p> &chains)
-{
-  unsigned i;
-  edge entry = loop_preheader_edge (loop);
-
-  for (i = 0; i < chains.length (); ++i)
-    if (chains[i]->init_seq)
-      {
-	gsi_insert_seq_on_edge_immediate (entry, chains[i]->init_seq);
-	chains[i]->init_seq = NULL;
-      }
-}
-
-/* Performs predictive commoning for LOOP.  Sets bit 1<<1 of return value
-   if LOOP was unrolled; Sets bit 1<<2 of return value if loop closed ssa
-   form was corrupted.  Non-zero return value indicates some changes were
-   applied to this loop.  */
-
-unsigned
-pcom_worker::tree_predictive_commoning_loop (bool allow_unroll_p)
-{
-  struct component *components;
-  unsigned unroll_factor = 0;
-  class tree_niter_desc desc;
-  bool unroll = false, loop_closed_ssa = false;
-
-  if (dump_file && (dump_flags & TDF_DETAILS))
-    fprintf (dump_file, "Processing loop %d\n", m_loop->num);
-
-  /* Nothing for predicitive commoning if loop only iterates 1 time.  */
-  if (get_max_loop_iterations_int (m_loop) == 0)
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file, "Loop iterates only 1 time, nothing to do.\n");
-
-      return 0;
-    }
-
-  /* Find the data references and split them into components according to their
-     dependence relations.  */
-  auto_vec<loop_p, 3> loop_nest;
-  if (!compute_data_dependences_for_loop (m_loop, true, &loop_nest, &m_datarefs,
-					  &m_dependences))
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file, "Cannot analyze data dependencies\n");
-      return 0;
-    }
-
-  if (dump_file && (dump_flags & TDF_DETAILS))
-    dump_data_dependence_relations (dump_file, m_dependences);
-
-  components = split_data_refs_to_components ();
-
-  loop_nest.release ();
-  if (!components)
-    return 0;
-
-  if (dump_file && (dump_flags & TDF_DETAILS))
-    {
-      fprintf (dump_file, "Initial state:\n\n");
-      dump_components (dump_file, components);
-    }
-
-  /* Find the suitable components and split them into chains.  */
-  components = filter_suitable_components (components);
-
-  auto_bitmap tmp_vars;
-  determine_roots (components);
-  release_components (components);
-
-  if (!m_chains.exists ())
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file,
-		 "Predictive commoning failed: no suitable chains\n");
-      return 0;
-    }
-
-  prepare_initializers ();
-  loop_closed_ssa = prepare_finalizers ();
-
-  /* Try to combine the chains that are always worked with together.  */
-  try_combine_chains ();
-
-  insert_init_seqs (m_loop, m_chains);
-
-  if (dump_file && (dump_flags & TDF_DETAILS))
-    {
-      fprintf (dump_file, "Before commoning:\n\n");
-      dump_chains (dump_file, m_chains);
-    }
-
-  if (allow_unroll_p)
-    /* Determine the unroll factor, and if the loop should be unrolled, ensure
-       that its number of iterations is divisible by the factor.  */
-    unroll_factor = determine_unroll_factor (m_chains);
-
-  if (unroll_factor > 1)
-    unroll = can_unroll_loop_p (m_loop, unroll_factor, &desc);
-
-  /* Execute the predictive commoning transformations, and possibly unroll the
-     loop.  */
-  if (unroll)
-    {
-      struct epcc_data dta;
-
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file, "Unrolling %u times.\n", unroll_factor);
-
-      dta.tmp_vars = tmp_vars;
-      dta.chains = m_chains.to_vec_legacy ();
-      dta.worker = this;
-
-      /* Cfg manipulations performed in tree_transform_and_unroll_loop before
-	 execute_pred_commoning_cbck is called may cause phi nodes to be
-	 reallocated, which is a problem since CHAINS may point to these
-	 statements.  To fix this, we store the ssa names defined by the
-	 phi nodes here instead of the phi nodes themselves, and restore
-	 the phi nodes in execute_pred_commoning_cbck.  A bit hacky.  */
-      replace_phis_by_defined_names (m_chains);
-
-      tree_transform_and_unroll_loop (m_loop, unroll_factor, &desc,
-				      execute_pred_commoning_cbck, &dta);
-      eliminate_temp_copies (m_loop, tmp_vars);
-    }
-  else
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file,
-		 "Executing predictive commoning without unrolling.\n");
-      execute_pred_commoning (tmp_vars);
-    }
-
-  return (unroll ? 2 : 1) | (loop_closed_ssa ? 4 : 1);
-}
-
-/* Runs predictive commoning.  */
-
-unsigned
-tree_predictive_commoning (bool allow_unroll_p)
-{
-  unsigned ret = 0, changed = 0;
-
-  initialize_original_copy_tables ();
-  for (auto loop : loops_list (cfun, LI_ONLY_INNERMOST))
-    if (optimize_loop_for_speed_p (loop))
-      {
-	pcom_worker w(loop);
-	changed |= w.tree_predictive_commoning_loop (allow_unroll_p);
-      }
-  free_original_copy_tables ();
-
-  if (changed > 0)
-    {
-      ret = TODO_update_ssa_only_virtuals;
-
-      /* Some loop(s) got unrolled.  */
-      if (changed > 1)
-	{
-	  scev_reset ();
-
-	  /* Need to fix up loop closed SSA.  */
-	  if (changed >= 4)
-	    rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
-
-	  ret |= TODO_cleanup_cfg;
-	}
-    }
-
-  return ret;
-}
-
-/* Predictive commoning Pass.  */
-
-static unsigned
-run_tree_predictive_commoning (struct function *fun, bool allow_unroll_p)
-{
-  if (number_of_loops (fun) <= 1)
-    return 0;
-
-  return tree_predictive_commoning (allow_unroll_p);
-}
-
-namespace {
-
-const pass_data pass_data_predcom =
-{
-  GIMPLE_PASS, /* type */
-  "pcom", /* name */
-  OPTGROUP_LOOP, /* optinfo_flags */
-  TV_PREDCOM, /* tv_id */
-  PROP_cfg, /* properties_required */
-  0, /* properties_provided */
-  0, /* properties_destroyed */
-  0, /* todo_flags_start */
-  0, /* todo_flags_finish */
-};
-
-class pass_predcom : public gimple_opt_pass
-{
-public:
-  pass_predcom (gcc::context *ctxt)
-    : gimple_opt_pass (pass_data_predcom, ctxt)
-  {}
-
-  /* opt_pass methods: */
-  virtual bool
-  gate (function *)
-  {
-    if (flag_predictive_commoning != 0)
-      return true;
-    /* Loop vectorization enables predictive commoning implicitly
-       only if predictive commoning isn't set explicitly, and it
-       doesn't allow unrolling.  */
-    if (flag_tree_loop_vectorize
-	&& !OPTION_SET_P (flag_predictive_commoning))
-      return true;
-
-    return false;
-  }
-
-  virtual unsigned int
-  execute (function *fun)
-  {
-    bool allow_unroll_p = flag_predictive_commoning != 0;
-    return run_tree_predictive_commoning (fun, allow_unroll_p);
-  }
-
-}; // class pass_predcom
-
-} // anon namespace
-
-gimple_opt_pass *
-make_pass_predcom (gcc::context *ctxt)
-{
-  return new pass_predcom (ctxt);
-}