Merge commit 'ff7aeceb6b3a476c3bac66a7f39a5ef4240206fc' [#247, #906]

1 files changed, 3632 insertions, 0 deletions

diff --git a/gcc/tree-ssa-loop-im.cc b/gcc/tree-ssa-loop-im.cc
new file mode 100644
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+++ b/gcc/tree-ssa-loop-im.cc
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+/* Loop invariant motion.
+   Copyright (C) 2003-2022 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/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "backend.h"
+#include "tree.h"
+#include "gimple.h"
+#include "cfghooks.h"
+#include "tree-pass.h"
+#include "ssa.h"
+#include "gimple-pretty-print.h"
+#include "fold-const.h"
+#include "cfganal.h"
+#include "tree-eh.h"
+#include "gimplify.h"
+#include "gimple-iterator.h"
+#include "tree-cfg.h"
+#include "tree-ssa-loop-manip.h"
+#include "tree-ssa-loop.h"
+#include "tree-into-ssa.h"
+#include "cfgloop.h"
+#include "tree-affine.h"
+#include "tree-ssa-propagate.h"
+#include "trans-mem.h"
+#include "gimple-fold.h"
+#include "tree-scalar-evolution.h"
+#include "tree-ssa-loop-niter.h"
+#include "alias.h"
+#include "builtins.h"
+#include "tree-dfa.h"
+#include "dbgcnt.h"
+
+/* TODO:  Support for predicated code motion.  I.e.
+
+   while (1)
+     {
+       if (cond)
+	 {
+	   a = inv;
+	   something;
+	 }
+     }
+
+   Where COND and INV are invariants, but evaluating INV may trap or be
+   invalid from some other reason if !COND.  This may be transformed to
+
+   if (cond)
+     a = inv;
+   while (1)
+     {
+       if (cond)
+	 something;
+     }  */
+
+/* The auxiliary data kept for each statement.  */
+
+struct lim_aux_data
+{
+  class loop *max_loop;	/* The outermost loop in that the statement
+				   is invariant.  */
+
+  class loop *tgt_loop;	/* The loop out of that we want to move the
+				   invariant.  */
+
+  class loop *always_executed_in;
+				/* The outermost loop for that we are sure
+				   the statement is executed if the loop
+				   is entered.  */
+
+  unsigned cost;		/* Cost of the computation performed by the
+				   statement.  */
+
+  unsigned ref;			/* The simple_mem_ref in this stmt or 0.  */
+
+  vec<gimple *> depends;	/* Vector of statements that must be also
+				   hoisted out of the loop when this statement
+				   is hoisted; i.e. those that define the
+				   operands of the statement and are inside of
+				   the MAX_LOOP loop.  */
+};
+
+/* Maps statements to their lim_aux_data.  */
+
+static hash_map<gimple *, lim_aux_data *> *lim_aux_data_map;
+
+/* Description of a memory reference location.  */
+
+struct mem_ref_loc
+{
+  tree *ref;			/* The reference itself.  */
+  gimple *stmt;			/* The statement in that it occurs.  */
+};
+
+
+/* Description of a memory reference.  */
+
+class im_mem_ref
+{
+public:
+  unsigned id : 30;		/* ID assigned to the memory reference
+				   (its index in memory_accesses.refs_list)  */
+  unsigned ref_canonical : 1;   /* Whether mem.ref was canonicalized.  */
+  unsigned ref_decomposed : 1;  /* Whether the ref was hashed from mem.  */
+  hashval_t hash;		/* Its hash value.  */
+
+  /* The memory access itself and associated caching of alias-oracle
+     query meta-data.  We are using mem.ref == error_mark_node for the
+     case the reference is represented by its single access stmt
+     in accesses_in_loop[0].  */
+  ao_ref mem;
+
+  bitmap stored;		/* The set of loops in that this memory location
+				   is stored to.  */
+  bitmap loaded;		/* The set of loops in that this memory location
+				   is loaded from.  */
+  vec<mem_ref_loc>		accesses_in_loop;
+				/* The locations of the accesses.  */
+
+  /* The following set is computed on demand.  */
+  bitmap_head dep_loop;		/* The set of loops in that the memory
+				   reference is {in,}dependent in
+				   different modes.  */
+};
+
+/* We use six bits per loop in the ref->dep_loop bitmap to record
+   the dep_kind x dep_state combinations.  */
+
+enum dep_kind { lim_raw, sm_war, sm_waw };
+enum dep_state { dep_unknown, dep_independent, dep_dependent };
+
+/* coldest outermost loop for given loop.  */
+vec<class loop *> coldest_outermost_loop;
+/* hotter outer loop nearest to given loop.  */
+vec<class loop *> hotter_than_inner_loop;
+
+/* Populate the loop dependence cache of REF for LOOP, KIND with STATE.  */
+
+static void
+record_loop_dependence (class loop *loop, im_mem_ref *ref,
+			dep_kind kind, dep_state state)
+{
+  gcc_assert (state != dep_unknown);
+  unsigned bit = 6 * loop->num + kind * 2 + state == dep_dependent ? 1 : 0;
+  bitmap_set_bit (&ref->dep_loop, bit);
+}
+
+/* Query the loop dependence cache of REF for LOOP, KIND.  */
+
+static dep_state
+query_loop_dependence (class loop *loop, im_mem_ref *ref, dep_kind kind)
+{
+  unsigned first_bit = 6 * loop->num + kind * 2;
+  if (bitmap_bit_p (&ref->dep_loop, first_bit))
+    return dep_independent;
+  else if (bitmap_bit_p (&ref->dep_loop, first_bit + 1))
+    return dep_dependent;
+  return dep_unknown;
+}
+
+/* Mem_ref hashtable helpers.  */
+
+struct mem_ref_hasher : nofree_ptr_hash <im_mem_ref>
+{
+  typedef ao_ref *compare_type;
+  static inline hashval_t hash (const im_mem_ref *);
+  static inline bool equal (const im_mem_ref *, const ao_ref *);
+};
+
+/* A hash function for class im_mem_ref object OBJ.  */
+
+inline hashval_t
+mem_ref_hasher::hash (const im_mem_ref *mem)
+{
+  return mem->hash;
+}
+
+/* An equality function for class im_mem_ref object MEM1 with
+   memory reference OBJ2.  */
+
+inline bool
+mem_ref_hasher::equal (const im_mem_ref *mem1, const ao_ref *obj2)
+{
+  if (obj2->max_size_known_p ())
+    return (mem1->ref_decomposed
+	    && ((TREE_CODE (mem1->mem.base) == MEM_REF
+		 && TREE_CODE (obj2->base) == MEM_REF
+		 && operand_equal_p (TREE_OPERAND (mem1->mem.base, 0),
+				     TREE_OPERAND (obj2->base, 0), 0)
+		 && known_eq (mem_ref_offset (mem1->mem.base) * BITS_PER_UNIT + mem1->mem.offset,
+			      mem_ref_offset (obj2->base) * BITS_PER_UNIT + obj2->offset))
+		|| (operand_equal_p (mem1->mem.base, obj2->base, 0)
+		    && known_eq (mem1->mem.offset, obj2->offset)))
+	    && known_eq (mem1->mem.size, obj2->size)
+	    && known_eq (mem1->mem.max_size, obj2->max_size)
+	    && mem1->mem.volatile_p == obj2->volatile_p
+	    && (mem1->mem.ref_alias_set == obj2->ref_alias_set
+		/* We are not canonicalizing alias-sets but for the
+		   special-case we didn't canonicalize yet and the
+		   incoming ref is a alias-set zero MEM we pick
+		   the correct one already.  */
+		|| (!mem1->ref_canonical
+		    && (TREE_CODE (obj2->ref) == MEM_REF
+			|| TREE_CODE (obj2->ref) == TARGET_MEM_REF)
+		    && obj2->ref_alias_set == 0)
+		/* Likewise if there's a canonical ref with alias-set zero.  */
+		|| (mem1->ref_canonical && mem1->mem.ref_alias_set == 0))
+	    && types_compatible_p (TREE_TYPE (mem1->mem.ref),
+				   TREE_TYPE (obj2->ref)));
+  else
+    return operand_equal_p (mem1->mem.ref, obj2->ref, 0);
+}
+
+
+/* Description of memory accesses in loops.  */
+
+static struct
+{
+  /* The hash table of memory references accessed in loops.  */
+  hash_table<mem_ref_hasher> *refs;
+
+  /* The list of memory references.  */
+  vec<im_mem_ref *> refs_list;
+
+  /* The set of memory references accessed in each loop.  */
+  vec<bitmap_head> refs_loaded_in_loop;
+
+  /* The set of memory references stored in each loop.  */
+  vec<bitmap_head> refs_stored_in_loop;
+
+  /* The set of memory references stored in each loop, including subloops .  */
+  vec<bitmap_head> all_refs_stored_in_loop;
+
+  /* Cache for expanding memory addresses.  */
+  hash_map<tree, name_expansion *> *ttae_cache;
+} memory_accesses;
+
+/* Obstack for the bitmaps in the above data structures.  */
+static bitmap_obstack lim_bitmap_obstack;
+static obstack mem_ref_obstack;
+
+static bool ref_indep_loop_p (class loop *, im_mem_ref *, dep_kind);
+static bool ref_always_accessed_p (class loop *, im_mem_ref *, bool);
+static bool refs_independent_p (im_mem_ref *, im_mem_ref *, bool = true);
+
+/* Minimum cost of an expensive expression.  */
+#define LIM_EXPENSIVE ((unsigned) param_lim_expensive)
+
+/* The outermost loop for which execution of the header guarantees that the
+   block will be executed.  */
+#define ALWAYS_EXECUTED_IN(BB) ((class loop *) (BB)->aux)
+#define SET_ALWAYS_EXECUTED_IN(BB, VAL) ((BB)->aux = (void *) (VAL))
+
+/* ID of the shared unanalyzable mem.  */
+#define UNANALYZABLE_MEM_ID 0
+
+/* Whether the reference was analyzable.  */
+#define MEM_ANALYZABLE(REF) ((REF)->id != UNANALYZABLE_MEM_ID)
+
+static struct lim_aux_data *
+init_lim_data (gimple *stmt)
+{
+  lim_aux_data *p = XCNEW (struct lim_aux_data);
+  lim_aux_data_map->put (stmt, p);
+
+  return p;
+}
+
+static struct lim_aux_data *
+get_lim_data (gimple *stmt)
+{
+  lim_aux_data **p = lim_aux_data_map->get (stmt);
+  if (!p)
+    return NULL;
+
+  return *p;
+}
+
+/* Releases the memory occupied by DATA.  */
+
+static void
+free_lim_aux_data (struct lim_aux_data *data)
+{
+  data->depends.release ();
+  free (data);
+}
+
+static void
+clear_lim_data (gimple *stmt)
+{
+  lim_aux_data **p = lim_aux_data_map->get (stmt);
+  if (!p)
+    return;
+
+  free_lim_aux_data (*p);
+  *p = NULL;
+}
+
+
+/* The possibilities of statement movement.  */
+enum move_pos
+  {
+    MOVE_IMPOSSIBLE,		/* No movement -- side effect expression.  */
+    MOVE_PRESERVE_EXECUTION,	/* Must not cause the non-executed statement
+				   become executed -- memory accesses, ... */
+    MOVE_POSSIBLE		/* Unlimited movement.  */
+  };
+
+
+/* If it is possible to hoist the statement STMT unconditionally,
+   returns MOVE_POSSIBLE.
+   If it is possible to hoist the statement STMT, but we must avoid making
+   it executed if it would not be executed in the original program (e.g.
+   because it may trap), return MOVE_PRESERVE_EXECUTION.
+   Otherwise return MOVE_IMPOSSIBLE.  */
+
+enum move_pos
+movement_possibility (gimple *stmt)
+{
+  tree lhs;
+  enum move_pos ret = MOVE_POSSIBLE;
+
+  if (flag_unswitch_loops
+      && gimple_code (stmt) == GIMPLE_COND)
+    {
+      /* If we perform unswitching, force the operands of the invariant
+	 condition to be moved out of the loop.  */
+      return MOVE_POSSIBLE;
+    }
+
+  if (gimple_code (stmt) == GIMPLE_PHI
+      && gimple_phi_num_args (stmt) <= 2
+      && !virtual_operand_p (gimple_phi_result (stmt))
+      && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_phi_result (stmt)))
+    return MOVE_POSSIBLE;
+
+  if (gimple_get_lhs (stmt) == NULL_TREE)
+    return MOVE_IMPOSSIBLE;
+
+  if (gimple_vdef (stmt))
+    return MOVE_IMPOSSIBLE;
+
+  if (stmt_ends_bb_p (stmt)
+      || gimple_has_volatile_ops (stmt)
+      || gimple_has_side_effects (stmt)
+      || stmt_could_throw_p (cfun, stmt))
+    return MOVE_IMPOSSIBLE;
+
+  if (is_gimple_call (stmt))
+    {
+      /* While pure or const call is guaranteed to have no side effects, we
+	 cannot move it arbitrarily.  Consider code like
+
+	 char *s = something ();
+
+	 while (1)
+	   {
+	     if (s)
+	       t = strlen (s);
+	     else
+	       t = 0;
+	   }
+
+	 Here the strlen call cannot be moved out of the loop, even though
+	 s is invariant.  In addition to possibly creating a call with
+	 invalid arguments, moving out a function call that is not executed
+	 may cause performance regressions in case the call is costly and
+	 not executed at all.  */
+      ret = MOVE_PRESERVE_EXECUTION;
+      lhs = gimple_call_lhs (stmt);
+    }
+  else if (is_gimple_assign (stmt))
+    lhs = gimple_assign_lhs (stmt);
+  else
+    return MOVE_IMPOSSIBLE;
+
+  if (TREE_CODE (lhs) == SSA_NAME
+      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
+    return MOVE_IMPOSSIBLE;
+
+  if (TREE_CODE (lhs) != SSA_NAME
+      || gimple_could_trap_p (stmt))
+    return MOVE_PRESERVE_EXECUTION;
+
+  /* Non local loads in a transaction cannot be hoisted out.  Well,
+     unless the load happens on every path out of the loop, but we
+     don't take this into account yet.  */
+  if (flag_tm
+      && gimple_in_transaction (stmt)
+      && gimple_assign_single_p (stmt))
+    {
+      tree rhs = gimple_assign_rhs1 (stmt);
+      if (DECL_P (rhs) && is_global_var (rhs))
+	{
+	  if (dump_file)
+	    {
+	      fprintf (dump_file, "Cannot hoist conditional load of ");
+	      print_generic_expr (dump_file, rhs, TDF_SLIM);
+	      fprintf (dump_file, " because it is in a transaction.\n");
+	    }
+	  return MOVE_IMPOSSIBLE;
+	}
+    }
+
+  return ret;
+}
+
+/* Compare the profile count inequality of bb and loop's preheader, it is
+   three-state as stated in profile-count.h, FALSE is returned if inequality
+   cannot be decided.  */
+bool
+bb_colder_than_loop_preheader (basic_block bb, class loop *loop)
+{
+  gcc_assert (bb && loop);
+  return bb->count < loop_preheader_edge (loop)->src->count;
+}
+
+/* Check coldest loop between OUTERMOST_LOOP and LOOP by comparing profile
+   count.
+  It does three steps check:
+  1) Check whether CURR_BB is cold in it's own loop_father, if it is cold, just
+  return NULL which means it should not be moved out at all;
+  2) CURR_BB is NOT cold, check if pre-computed COLDEST_LOOP is outside of
+  OUTERMOST_LOOP, if it is inside of OUTERMOST_LOOP, return the COLDEST_LOOP;
+  3) If COLDEST_LOOP is outside of OUTERMOST_LOOP, check whether there is a
+  hotter loop between OUTERMOST_LOOP and loop in pre-computed
+  HOTTER_THAN_INNER_LOOP, return it's nested inner loop, otherwise return
+  OUTERMOST_LOOP.
+  At last, the coldest_loop is inside of OUTERMOST_LOOP, just return it as
+  the hoist target.  */
+
+static class loop *
+get_coldest_out_loop (class loop *outermost_loop, class loop *loop,
+		      basic_block curr_bb)
+{
+  gcc_assert (outermost_loop == loop
+	      || flow_loop_nested_p (outermost_loop, loop));
+
+  /* If bb_colder_than_loop_preheader returns false due to three-state
+    comparision, OUTERMOST_LOOP is returned finally to preserve the behavior.
+    Otherwise, return the coldest loop between OUTERMOST_LOOP and LOOP.  */
+  if (curr_bb && bb_colder_than_loop_preheader (curr_bb, loop))
+    return NULL;
+
+  class loop *coldest_loop = coldest_outermost_loop[loop->num];
+  if (loop_depth (coldest_loop) < loop_depth (outermost_loop))
+    {
+      class loop *hotter_loop = hotter_than_inner_loop[loop->num];
+      if (!hotter_loop
+	  || loop_depth (hotter_loop) < loop_depth (outermost_loop))
+	return outermost_loop;
+
+      /*  hotter_loop is between OUTERMOST_LOOP and LOOP like:
+	[loop tree root, ..., coldest_loop, ..., outermost_loop, ...,
+	hotter_loop, second_coldest_loop, ..., loop]
+	return second_coldest_loop to be the hoist target.  */
+      class loop *aloop;
+      for (aloop = hotter_loop->inner; aloop; aloop = aloop->next)
+	if (aloop == loop || flow_loop_nested_p (aloop, loop))
+	  return aloop;
+    }
+  return coldest_loop;
+}
+
+/* Suppose that operand DEF is used inside the LOOP.  Returns the outermost
+   loop to that we could move the expression using DEF if it did not have
+   other operands, i.e. the outermost loop enclosing LOOP in that the value
+   of DEF is invariant.  */
+
+static class loop *
+outermost_invariant_loop (tree def, class loop *loop)
+{
+  gimple *def_stmt;
+  basic_block def_bb;
+  class loop *max_loop;
+  struct lim_aux_data *lim_data;
+
+  if (!def)
+    return superloop_at_depth (loop, 1);
+
+  if (TREE_CODE (def) != SSA_NAME)
+    {
+      gcc_assert (is_gimple_min_invariant (def));
+      return superloop_at_depth (loop, 1);
+    }
+
+  def_stmt = SSA_NAME_DEF_STMT (def);
+  def_bb = gimple_bb (def_stmt);
+  if (!def_bb)
+    return superloop_at_depth (loop, 1);
+
+  max_loop = find_common_loop (loop, def_bb->loop_father);
+
+  lim_data = get_lim_data (def_stmt);
+  if (lim_data != NULL && lim_data->max_loop != NULL)
+    max_loop = find_common_loop (max_loop,
+				 loop_outer (lim_data->max_loop));
+  if (max_loop == loop)
+    return NULL;
+  max_loop = superloop_at_depth (loop, loop_depth (max_loop) + 1);
+
+  return max_loop;
+}
+
+/* DATA is a structure containing information associated with a statement
+   inside LOOP.  DEF is one of the operands of this statement.
+
+   Find the outermost loop enclosing LOOP in that value of DEF is invariant
+   and record this in DATA->max_loop field.  If DEF itself is defined inside
+   this loop as well (i.e. we need to hoist it out of the loop if we want
+   to hoist the statement represented by DATA), record the statement in that
+   DEF is defined to the DATA->depends list.  Additionally if ADD_COST is true,
+   add the cost of the computation of DEF to the DATA->cost.
+
+   If DEF is not invariant in LOOP, return false.  Otherwise return TRUE.  */
+
+static bool
+add_dependency (tree def, struct lim_aux_data *data, class loop *loop,
+		bool add_cost)
+{
+  gimple *def_stmt = SSA_NAME_DEF_STMT (def);
+  basic_block def_bb = gimple_bb (def_stmt);
+  class loop *max_loop;
+  struct lim_aux_data *def_data;
+
+  if (!def_bb)
+    return true;
+
+  max_loop = outermost_invariant_loop (def, loop);
+  if (!max_loop)
+    return false;
+
+  if (flow_loop_nested_p (data->max_loop, max_loop))
+    data->max_loop = max_loop;
+
+  def_data = get_lim_data (def_stmt);
+  if (!def_data)
+    return true;
+
+  if (add_cost
+      /* Only add the cost if the statement defining DEF is inside LOOP,
+	 i.e. if it is likely that by moving the invariants dependent
+	 on it, we will be able to avoid creating a new register for
+	 it (since it will be only used in these dependent invariants).  */
+      && def_bb->loop_father == loop)
+    data->cost += def_data->cost;
+
+  data->depends.safe_push (def_stmt);
+
+  return true;
+}
+
+/* Returns an estimate for a cost of statement STMT.  The values here
+   are just ad-hoc constants, similar to costs for inlining.  */
+
+static unsigned
+stmt_cost (gimple *stmt)
+{
+  /* Always try to create possibilities for unswitching.  */
+  if (gimple_code (stmt) == GIMPLE_COND
+      || gimple_code (stmt) == GIMPLE_PHI)
+    return LIM_EXPENSIVE;
+
+  /* We should be hoisting calls if possible.  */
+  if (is_gimple_call (stmt))
+    {
+      tree fndecl;
+
+      /* Unless the call is a builtin_constant_p; this always folds to a
+	 constant, so moving it is useless.  */
+      fndecl = gimple_call_fndecl (stmt);
+      if (fndecl && fndecl_built_in_p (fndecl, BUILT_IN_CONSTANT_P))
+	return 0;
+
+      return LIM_EXPENSIVE;
+    }
+
+  /* Hoisting memory references out should almost surely be a win.  */
+  if (gimple_references_memory_p (stmt))
+    return LIM_EXPENSIVE;
+
+  if (gimple_code (stmt) != GIMPLE_ASSIGN)
+    return 1;
+
+  switch (gimple_assign_rhs_code (stmt))
+    {
+    case MULT_EXPR:
+    case WIDEN_MULT_EXPR:
+    case WIDEN_MULT_PLUS_EXPR:
+    case WIDEN_MULT_MINUS_EXPR:
+    case DOT_PROD_EXPR:
+    case TRUNC_DIV_EXPR:
+    case CEIL_DIV_EXPR:
+    case FLOOR_DIV_EXPR:
+    case ROUND_DIV_EXPR:
+    case EXACT_DIV_EXPR:
+    case CEIL_MOD_EXPR:
+    case FLOOR_MOD_EXPR:
+    case ROUND_MOD_EXPR:
+    case TRUNC_MOD_EXPR:
+    case RDIV_EXPR:
+      /* Division and multiplication are usually expensive.  */
+      return LIM_EXPENSIVE;
+
+    case LSHIFT_EXPR:
+    case RSHIFT_EXPR:
+    case WIDEN_LSHIFT_EXPR:
+    case LROTATE_EXPR:
+    case RROTATE_EXPR:
+      /* Shifts and rotates are usually expensive.  */
+      return LIM_EXPENSIVE;
+
+    case CONSTRUCTOR:
+      /* Make vector construction cost proportional to the number
+         of elements.  */
+      return CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt));
+
+    case SSA_NAME:
+    case PAREN_EXPR:
+      /* Whether or not something is wrapped inside a PAREN_EXPR
+         should not change move cost.  Nor should an intermediate
+	 unpropagated SSA name copy.  */
+      return 0;
+
+    default:
+      return 1;
+    }
+}
+
+/* Finds the outermost loop between OUTER and LOOP in that the memory reference
+   REF is independent.  If REF is not independent in LOOP, NULL is returned
+   instead.  */
+
+static class loop *
+outermost_indep_loop (class loop *outer, class loop *loop, im_mem_ref *ref)
+{
+  class loop *aloop;
+
+  if (ref->stored && bitmap_bit_p (ref->stored, loop->num))
+    return NULL;
+
+  for (aloop = outer;
+       aloop != loop;
+       aloop = superloop_at_depth (loop, loop_depth (aloop) + 1))
+    if ((!ref->stored || !bitmap_bit_p (ref->stored, aloop->num))
+	&& ref_indep_loop_p (aloop, ref, lim_raw))
+      return aloop;
+
+  if (ref_indep_loop_p (loop, ref, lim_raw))
+    return loop;
+  else
+    return NULL;
+}
+
+/* If there is a simple load or store to a memory reference in STMT, returns
+   the location of the memory reference, and sets IS_STORE according to whether
+   it is a store or load.  Otherwise, returns NULL.  */
+
+static tree *
+simple_mem_ref_in_stmt (gimple *stmt, bool *is_store)
+{
+  tree *lhs, *rhs;
+
+  /* Recognize SSA_NAME = MEM and MEM = (SSA_NAME | invariant) patterns.  */
+  if (!gimple_assign_single_p (stmt))
+    return NULL;
+
+  lhs = gimple_assign_lhs_ptr (stmt);
+  rhs = gimple_assign_rhs1_ptr (stmt);
+
+  if (TREE_CODE (*lhs) == SSA_NAME && gimple_vuse (stmt))
+    {
+      *is_store = false;
+      return rhs;
+    }
+  else if (gimple_vdef (stmt)
+	   && (TREE_CODE (*rhs) == SSA_NAME || is_gimple_min_invariant (*rhs)))
+    {
+      *is_store = true;
+      return lhs;
+    }
+  else
+    return NULL;
+}
+
+/* From a controlling predicate in DOM determine the arguments from
+   the PHI node PHI that are chosen if the predicate evaluates to
+   true and false and store them to *TRUE_ARG_P and *FALSE_ARG_P if
+   they are non-NULL.  Returns true if the arguments can be determined,
+   else return false.  */
+
+static bool
+extract_true_false_args_from_phi (basic_block dom, gphi *phi,
+				  tree *true_arg_p, tree *false_arg_p)
+{
+  edge te, fe;
+  if (! extract_true_false_controlled_edges (dom, gimple_bb (phi),
+					     &te, &fe))
+    return false;
+
+  if (true_arg_p)
+    *true_arg_p = PHI_ARG_DEF (phi, te->dest_idx);
+  if (false_arg_p)
+    *false_arg_p = PHI_ARG_DEF (phi, fe->dest_idx);
+
+  return true;
+}
+
+/* Determine the outermost loop to that it is possible to hoist a statement
+   STMT and store it to LIM_DATA (STMT)->max_loop.  To do this we determine
+   the outermost loop in that the value computed by STMT is invariant.
+   If MUST_PRESERVE_EXEC is true, additionally choose such a loop that
+   we preserve the fact whether STMT is executed.  It also fills other related
+   information to LIM_DATA (STMT).
+
+   The function returns false if STMT cannot be hoisted outside of the loop it
+   is defined in, and true otherwise.  */
+
+static bool
+determine_max_movement (gimple *stmt, bool must_preserve_exec)
+{
+  basic_block bb = gimple_bb (stmt);
+  class loop *loop = bb->loop_father;
+  class loop *level;
+  struct lim_aux_data *lim_data = get_lim_data (stmt);
+  tree val;
+  ssa_op_iter iter;
+
+  if (must_preserve_exec)
+    level = ALWAYS_EXECUTED_IN (bb);
+  else
+    level = superloop_at_depth (loop, 1);
+  lim_data->max_loop = get_coldest_out_loop (level, loop, bb);
+  if (!lim_data->max_loop)
+    return false;
+
+  if (gphi *phi = dyn_cast <gphi *> (stmt))
+    {
+      use_operand_p use_p;
+      unsigned min_cost = UINT_MAX;
+      unsigned total_cost = 0;
+      struct lim_aux_data *def_data;
+
+      /* We will end up promoting dependencies to be unconditionally
+	 evaluated.  For this reason the PHI cost (and thus the
+	 cost we remove from the loop by doing the invariant motion)
+	 is that of the cheapest PHI argument dependency chain.  */
+      FOR_EACH_PHI_ARG (use_p, phi, iter, SSA_OP_USE)
+	{
+	  val = USE_FROM_PTR (use_p);
+
+	  if (TREE_CODE (val) != SSA_NAME)
+	    {
+	      /* Assign const 1 to constants.  */
+	      min_cost = MIN (min_cost, 1);
+	      total_cost += 1;
+	      continue;
+	    }
+	  if (!add_dependency (val, lim_data, loop, false))
+	    return false;
+
+	  gimple *def_stmt = SSA_NAME_DEF_STMT (val);
+	  if (gimple_bb (def_stmt)
+	      && gimple_bb (def_stmt)->loop_father == loop)
+	    {
+	      def_data = get_lim_data (def_stmt);
+	      if (def_data)
+		{
+		  min_cost = MIN (min_cost, def_data->cost);
+		  total_cost += def_data->cost;
+		}
+	    }
+	}
+
+      min_cost = MIN (min_cost, total_cost);
+      lim_data->cost += min_cost;
+
+      if (gimple_phi_num_args (phi) > 1)
+	{
+	  basic_block dom = get_immediate_dominator (CDI_DOMINATORS, bb);
+	  gimple *cond;
+	  if (gsi_end_p (gsi_last_bb (dom)))
+	    return false;
+	  cond = gsi_stmt (gsi_last_bb (dom));
+	  if (gimple_code (cond) != GIMPLE_COND)
+	    return false;
+	  /* Verify that this is an extended form of a diamond and
+	     the PHI arguments are completely controlled by the
+	     predicate in DOM.  */
+	  if (!extract_true_false_args_from_phi (dom, phi, NULL, NULL))
+	    return false;
+
+	  /* Fold in dependencies and cost of the condition.  */
+	  FOR_EACH_SSA_TREE_OPERAND (val, cond, iter, SSA_OP_USE)
+	    {
+	      if (!add_dependency (val, lim_data, loop, false))
+		return false;
+	      def_data = get_lim_data (SSA_NAME_DEF_STMT (val));
+	      if (def_data)
+		lim_data->cost += def_data->cost;
+	    }
+
+	  /* We want to avoid unconditionally executing very expensive
+	     operations.  As costs for our dependencies cannot be
+	     negative just claim we are not invariand for this case.
+	     We also are not sure whether the control-flow inside the
+	     loop will vanish.  */
+	  if (total_cost - min_cost >= 2 * LIM_EXPENSIVE
+	      && !(min_cost != 0
+		   && total_cost / min_cost <= 2))
+	    return false;
+
+	  /* Assume that the control-flow in the loop will vanish.
+	     ???  We should verify this and not artificially increase
+	     the cost if that is not the case.  */
+	  lim_data->cost += stmt_cost (stmt);
+	}
+
+      return true;
+    }
+  else
+    FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_USE)
+      if (!add_dependency (val, lim_data, loop, true))
+	return false;
+
+  if (gimple_vuse (stmt))
+    {
+      im_mem_ref *ref
+	= lim_data ? memory_accesses.refs_list[lim_data->ref] : NULL;
+      if (ref
+	  && MEM_ANALYZABLE (ref))
+	{
+	  lim_data->max_loop = outermost_indep_loop (lim_data->max_loop,
+						     loop, ref);
+	  if (!lim_data->max_loop)
+	    return false;
+	}
+      else if (! add_dependency (gimple_vuse (stmt), lim_data, loop, false))
+	return false;
+    }
+
+  lim_data->cost += stmt_cost (stmt);
+
+  return true;
+}
+
+/* Suppose that some statement in ORIG_LOOP is hoisted to the loop LEVEL,
+   and that one of the operands of this statement is computed by STMT.
+   Ensure that STMT (together with all the statements that define its
+   operands) is hoisted at least out of the loop LEVEL.  */
+
+static void
+set_level (gimple *stmt, class loop *orig_loop, class loop *level)
+{
+  class loop *stmt_loop = gimple_bb (stmt)->loop_father;
+  struct lim_aux_data *lim_data;
+  gimple *dep_stmt;
+  unsigned i;
+
+  stmt_loop = find_common_loop (orig_loop, stmt_loop);
+  lim_data = get_lim_data (stmt);
+  if (lim_data != NULL && lim_data->tgt_loop != NULL)
+    stmt_loop = find_common_loop (stmt_loop,
+				  loop_outer (lim_data->tgt_loop));
+  if (flow_loop_nested_p (stmt_loop, level))
+    return;
+
+  gcc_assert (level == lim_data->max_loop
+	      || flow_loop_nested_p (lim_data->max_loop, level));
+
+  lim_data->tgt_loop = level;
+  FOR_EACH_VEC_ELT (lim_data->depends, i, dep_stmt)
+    set_level (dep_stmt, orig_loop, level);
+}
+
+/* Determines an outermost loop from that we want to hoist the statement STMT.
+   For now we chose the outermost possible loop.  TODO -- use profiling
+   information to set it more sanely.  */
+
+static void
+set_profitable_level (gimple *stmt)
+{
+  set_level (stmt, gimple_bb (stmt)->loop_father, get_lim_data (stmt)->max_loop);
+}
+
+/* Returns true if STMT is a call that has side effects.  */
+
+static bool
+nonpure_call_p (gimple *stmt)
+{
+  if (gimple_code (stmt) != GIMPLE_CALL)
+    return false;
+
+  return gimple_has_side_effects (stmt);
+}
+
+/* Rewrite a/b to a*(1/b).  Return the invariant stmt to process.  */
+
+static gimple *
+rewrite_reciprocal (gimple_stmt_iterator *bsi)
+{
+  gassign *stmt, *stmt1, *stmt2;
+  tree name, lhs, type;
+  tree real_one;
+  gimple_stmt_iterator gsi;
+
+  stmt = as_a <gassign *> (gsi_stmt (*bsi));
+  lhs = gimple_assign_lhs (stmt);
+  type = TREE_TYPE (lhs);
+
+  real_one = build_one_cst (type);
+
+  name = make_temp_ssa_name (type, NULL, "reciptmp");
+  stmt1 = gimple_build_assign (name, RDIV_EXPR, real_one,
+			       gimple_assign_rhs2 (stmt));
+  stmt2 = gimple_build_assign (lhs, MULT_EXPR, name,
+			       gimple_assign_rhs1 (stmt));
+
+  /* Replace division stmt with reciprocal and multiply stmts.
+     The multiply stmt is not invariant, so update iterator
+     and avoid rescanning.  */
+  gsi = *bsi;
+  gsi_insert_before (bsi, stmt1, GSI_NEW_STMT);
+  gsi_replace (&gsi, stmt2, true);
+
+  /* Continue processing with invariant reciprocal statement.  */
+  return stmt1;
+}
+
+/* Check if the pattern at *BSI is a bittest of the form
+   (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0.  */
+
+static gimple *
+rewrite_bittest (gimple_stmt_iterator *bsi)
+{
+  gassign *stmt;
+  gimple *stmt1;
+  gassign *stmt2;
+  gimple *use_stmt;
+  gcond *cond_stmt;
+  tree lhs, name, t, a, b;
+  use_operand_p use;
+
+  stmt = as_a <gassign *> (gsi_stmt (*bsi));
+  lhs = gimple_assign_lhs (stmt);
+
+  /* Verify that the single use of lhs is a comparison against zero.  */
+  if (TREE_CODE (lhs) != SSA_NAME
+      || !single_imm_use (lhs, &use, &use_stmt))
+    return stmt;
+  cond_stmt = dyn_cast <gcond *> (use_stmt);
+  if (!cond_stmt)
+    return stmt;
+  if (gimple_cond_lhs (cond_stmt) != lhs
+      || (gimple_cond_code (cond_stmt) != NE_EXPR
+	  && gimple_cond_code (cond_stmt) != EQ_EXPR)
+      || !integer_zerop (gimple_cond_rhs (cond_stmt)))
+    return stmt;
+
+  /* Get at the operands of the shift.  The rhs is TMP1 & 1.  */
+  stmt1 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt));
+  if (gimple_code (stmt1) != GIMPLE_ASSIGN)
+    return stmt;
+
+  /* There is a conversion in between possibly inserted by fold.  */
+  if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt1)))
+    {
+      t = gimple_assign_rhs1 (stmt1);
+      if (TREE_CODE (t) != SSA_NAME
+	  || !has_single_use (t))
+	return stmt;
+      stmt1 = SSA_NAME_DEF_STMT (t);
+      if (gimple_code (stmt1) != GIMPLE_ASSIGN)
+	return stmt;
+    }
+
+  /* Verify that B is loop invariant but A is not.  Verify that with
+     all the stmt walking we are still in the same loop.  */
+  if (gimple_assign_rhs_code (stmt1) != RSHIFT_EXPR
+      || loop_containing_stmt (stmt1) != loop_containing_stmt (stmt))
+    return stmt;
+
+  a = gimple_assign_rhs1 (stmt1);
+  b = gimple_assign_rhs2 (stmt1);
+
+  if (outermost_invariant_loop (b, loop_containing_stmt (stmt1)) != NULL
+      && outermost_invariant_loop (a, loop_containing_stmt (stmt1)) == NULL)
+    {
+      gimple_stmt_iterator rsi;
+
+      /* 1 << B */
+      t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (a),
+		       build_int_cst (TREE_TYPE (a), 1), b);
+      name = make_temp_ssa_name (TREE_TYPE (a), NULL, "shifttmp");
+      stmt1 = gimple_build_assign (name, t);
+
+      /* A & (1 << B) */
+      t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (a), a, name);
+      name = make_temp_ssa_name (TREE_TYPE (a), NULL, "shifttmp");
+      stmt2 = gimple_build_assign (name, t);
+
+      /* Replace the SSA_NAME we compare against zero.  Adjust
+	 the type of zero accordingly.  */
+      SET_USE (use, name);
+      gimple_cond_set_rhs (cond_stmt,
+			   build_int_cst_type (TREE_TYPE (name),
+					       0));
+
+      /* Don't use gsi_replace here, none of the new assignments sets
+	 the variable originally set in stmt.  Move bsi to stmt1, and
+	 then remove the original stmt, so that we get a chance to
+	 retain debug info for it.  */
+      rsi = *bsi;
+      gsi_insert_before (bsi, stmt1, GSI_NEW_STMT);
+      gsi_insert_before (&rsi, stmt2, GSI_SAME_STMT);
+      gimple *to_release = gsi_stmt (rsi);
+      gsi_remove (&rsi, true);
+      release_defs (to_release);
+
+      return stmt1;
+    }
+
+  return stmt;
+}
+
+/* Determine the outermost loops in that statements in basic block BB are
+   invariant, and record them to the LIM_DATA associated with the
+   statements.  */
+
+static void
+compute_invariantness (basic_block bb)
+{
+  enum move_pos pos;
+  gimple_stmt_iterator bsi;
+  gimple *stmt;
+  bool maybe_never = ALWAYS_EXECUTED_IN (bb) == NULL;
+  class loop *outermost = ALWAYS_EXECUTED_IN (bb);
+  struct lim_aux_data *lim_data;
+
+  if (!loop_outer (bb->loop_father))
+    return;
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    fprintf (dump_file, "Basic block %d (loop %d -- depth %d):\n\n",
+	     bb->index, bb->loop_father->num, loop_depth (bb->loop_father));
+
+  /* Look at PHI nodes, but only if there is at most two.
+     ???  We could relax this further by post-processing the inserted
+     code and transforming adjacent cond-exprs with the same predicate
+     to control flow again.  */
+  bsi = gsi_start_phis (bb);
+  if (!gsi_end_p (bsi)
+      && ((gsi_next (&bsi), gsi_end_p (bsi))
+	  || (gsi_next (&bsi), gsi_end_p (bsi))))
+    for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+      {
+	stmt = gsi_stmt (bsi);
+
+	pos = movement_possibility (stmt);
+	if (pos == MOVE_IMPOSSIBLE)
+	  continue;
+
+	lim_data = get_lim_data (stmt);
+	if (! lim_data)
+	  lim_data = init_lim_data (stmt);
+	lim_data->always_executed_in = outermost;
+
+	if (!determine_max_movement (stmt, false))
+	  {
+	    lim_data->max_loop = NULL;
+	    continue;
+	  }
+
+	if (dump_file && (dump_flags & TDF_DETAILS))
+	  {
+	    print_gimple_stmt (dump_file, stmt, 2);
+	    fprintf (dump_file, "  invariant up to level %d, cost %d.\n\n",
+		     loop_depth (lim_data->max_loop),
+		     lim_data->cost);
+	  }
+
+	if (lim_data->cost >= LIM_EXPENSIVE)
+	  set_profitable_level (stmt);
+      }
+
+  for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+    {
+      stmt = gsi_stmt (bsi);
+
+      pos = movement_possibility (stmt);
+      if (pos == MOVE_IMPOSSIBLE)
+	{
+	  if (nonpure_call_p (stmt))
+	    {
+	      maybe_never = true;
+	      outermost = NULL;
+	    }
+	  /* Make sure to note always_executed_in for stores to make
+	     store-motion work.  */
+	  else if (stmt_makes_single_store (stmt))
+	    {
+	      struct lim_aux_data *lim_data = get_lim_data (stmt);
+	      if (! lim_data)
+		lim_data = init_lim_data (stmt);
+	      lim_data->always_executed_in = outermost;
+	    }
+	  continue;
+	}
+
+      if (is_gimple_assign (stmt)
+	  && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt))
+	      == GIMPLE_BINARY_RHS))
+	{
+	  tree op0 = gimple_assign_rhs1 (stmt);
+	  tree op1 = gimple_assign_rhs2 (stmt);
+	  class loop *ol1 = outermost_invariant_loop (op1,
+					loop_containing_stmt (stmt));
+
+	  /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal
+	     to be hoisted out of loop, saving expensive divide.  */
+	  if (pos == MOVE_POSSIBLE
+	      && gimple_assign_rhs_code (stmt) == RDIV_EXPR
+	      && flag_unsafe_math_optimizations
+	      && !flag_trapping_math
+	      && ol1 != NULL
+	      && outermost_invariant_loop (op0, ol1) == NULL)
+	    stmt = rewrite_reciprocal (&bsi);
+
+	  /* If the shift count is invariant, convert (A >> B) & 1 to
+	     A & (1 << B) allowing the bit mask to be hoisted out of the loop
+	     saving an expensive shift.  */
+	  if (pos == MOVE_POSSIBLE
+	      && gimple_assign_rhs_code (stmt) == BIT_AND_EXPR
+	      && integer_onep (op1)
+	      && TREE_CODE (op0) == SSA_NAME
+	      && has_single_use (op0))
+	    stmt = rewrite_bittest (&bsi);
+	}
+
+      lim_data = get_lim_data (stmt);
+      if (! lim_data)
+	lim_data = init_lim_data (stmt);
+      lim_data->always_executed_in = outermost;
+
+      if (maybe_never && pos == MOVE_PRESERVE_EXECUTION)
+	continue;
+
+      if (!determine_max_movement (stmt, pos == MOVE_PRESERVE_EXECUTION))
+	{
+	  lim_data->max_loop = NULL;
+	  continue;
+	}
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  print_gimple_stmt (dump_file, stmt, 2);
+	  fprintf (dump_file, "  invariant up to level %d, cost %d.\n\n",
+		   loop_depth (lim_data->max_loop),
+		   lim_data->cost);
+	}
+
+      if (lim_data->cost >= LIM_EXPENSIVE)
+	set_profitable_level (stmt);
+    }
+}
+
+/* Hoist the statements in basic block BB out of the loops prescribed by
+   data stored in LIM_DATA structures associated with each statement.  Callback
+   for walk_dominator_tree.  */
+
+unsigned int
+move_computations_worker (basic_block bb)
+{
+  class loop *level;
+  unsigned cost = 0;
+  struct lim_aux_data *lim_data;
+  unsigned int todo = 0;
+
+  if (!loop_outer (bb->loop_father))
+    return todo;
+
+  for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi); )
+    {
+      gassign *new_stmt;
+      gphi *stmt = bsi.phi ();
+
+      lim_data = get_lim_data (stmt);
+      if (lim_data == NULL)
+	{
+	  gsi_next (&bsi);
+	  continue;
+	}
+
+      cost = lim_data->cost;
+      level = lim_data->tgt_loop;
+      clear_lim_data (stmt);
+
+      if (!level)
+	{
+	  gsi_next (&bsi);
+	  continue;
+	}
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "Moving PHI node\n");
+	  print_gimple_stmt (dump_file, stmt, 0);
+	  fprintf (dump_file, "(cost %u) out of loop %d.\n\n",
+		   cost, level->num);
+	}
+
+      if (gimple_phi_num_args (stmt) == 1)
+	{
+	  tree arg = PHI_ARG_DEF (stmt, 0);
+	  new_stmt = gimple_build_assign (gimple_phi_result (stmt),
+					  TREE_CODE (arg), arg);
+	}
+      else
+	{
+	  basic_block dom = get_immediate_dominator (CDI_DOMINATORS, bb);
+	  gimple *cond = gsi_stmt (gsi_last_bb (dom));
+	  tree arg0 = NULL_TREE, arg1 = NULL_TREE, t;
+	  /* Get the PHI arguments corresponding to the true and false
+	     edges of COND.  */
+	  extract_true_false_args_from_phi (dom, stmt, &arg0, &arg1);
+	  gcc_assert (arg0 && arg1);
+	  t = build2 (gimple_cond_code (cond), boolean_type_node,
+		      gimple_cond_lhs (cond), gimple_cond_rhs (cond));
+	  new_stmt = gimple_build_assign (gimple_phi_result (stmt),
+					  COND_EXPR, t, arg0, arg1);
+	  todo |= TODO_cleanup_cfg;
+	}
+      if (!ALWAYS_EXECUTED_IN (bb)
+	  || (ALWAYS_EXECUTED_IN (bb) != level
+	      && !flow_loop_nested_p (ALWAYS_EXECUTED_IN (bb), level)))
+	reset_flow_sensitive_info (gimple_assign_lhs (new_stmt));
+      gsi_insert_on_edge (loop_preheader_edge (level), new_stmt);
+      remove_phi_node (&bsi, false);
+    }
+
+  for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi); )
+    {
+      edge e;
+
+      gimple *stmt = gsi_stmt (bsi);
+
+      lim_data = get_lim_data (stmt);
+      if (lim_data == NULL)
+	{
+	  gsi_next (&bsi);
+	  continue;
+	}
+
+      cost = lim_data->cost;
+      level = lim_data->tgt_loop;
+      clear_lim_data (stmt);
+
+      if (!level)
+	{
+	  gsi_next (&bsi);
+	  continue;
+	}
+
+      /* We do not really want to move conditionals out of the loop; we just
+	 placed it here to force its operands to be moved if necessary.  */
+      if (gimple_code (stmt) == GIMPLE_COND)
+	{
+	  gsi_next (&bsi);
+	  continue;
+	}
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "Moving statement\n");
+	  print_gimple_stmt (dump_file, stmt, 0);
+	  fprintf (dump_file, "(cost %u) out of loop %d.\n\n",
+		   cost, level->num);
+	}
+
+      e = loop_preheader_edge (level);
+      gcc_assert (!gimple_vdef (stmt));
+      if (gimple_vuse (stmt))
+	{
+	  /* The new VUSE is the one from the virtual PHI in the loop
+	     header or the one already present.  */
+	  gphi_iterator gsi2;
+	  for (gsi2 = gsi_start_phis (e->dest);
+	       !gsi_end_p (gsi2); gsi_next (&gsi2))
+	    {
+	      gphi *phi = gsi2.phi ();
+	      if (virtual_operand_p (gimple_phi_result (phi)))
+		{
+		  SET_USE (gimple_vuse_op (stmt),
+			   PHI_ARG_DEF_FROM_EDGE (phi, e));
+		  break;
+		}
+	    }
+	}
+      gsi_remove (&bsi, false);
+      if (gimple_has_lhs (stmt)
+	  && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME
+	  && (!ALWAYS_EXECUTED_IN (bb)
+	      || !(ALWAYS_EXECUTED_IN (bb) == level
+		   || flow_loop_nested_p (ALWAYS_EXECUTED_IN (bb), level))))
+	reset_flow_sensitive_info (gimple_get_lhs (stmt));
+      /* In case this is a stmt that is not unconditionally executed
+         when the target loop header is executed and the stmt may
+	 invoke undefined integer or pointer overflow rewrite it to
+	 unsigned arithmetic.  */
+      if (is_gimple_assign (stmt)
+	  && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_lhs (stmt)))
+	  && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (gimple_assign_lhs (stmt)))
+	  && arith_code_with_undefined_signed_overflow
+	       (gimple_assign_rhs_code (stmt))
+	  && (!ALWAYS_EXECUTED_IN (bb)
+	      || !(ALWAYS_EXECUTED_IN (bb) == level
+		   || flow_loop_nested_p (ALWAYS_EXECUTED_IN (bb), level))))
+	gsi_insert_seq_on_edge (e, rewrite_to_defined_overflow (stmt));
+      else
+	gsi_insert_on_edge (e, stmt);
+    }
+
+  return todo;
+}
+
+/* Checks whether the statement defining variable *INDEX can be hoisted
+   out of the loop passed in DATA.  Callback for for_each_index.  */
+
+static bool
+may_move_till (tree ref, tree *index, void *data)
+{
+  class loop *loop = (class loop *) data, *max_loop;
+
+  /* If REF is an array reference, check also that the step and the lower
+     bound is invariant in LOOP.  */
+  if (TREE_CODE (ref) == ARRAY_REF)
+    {
+      tree step = TREE_OPERAND (ref, 3);
+      tree lbound = TREE_OPERAND (ref, 2);
+
+      max_loop = outermost_invariant_loop (step, loop);
+      if (!max_loop)
+	return false;
+
+      max_loop = outermost_invariant_loop (lbound, loop);
+      if (!max_loop)
+	return false;
+    }
+
+  max_loop = outermost_invariant_loop (*index, loop);
+  if (!max_loop)
+    return false;
+
+  return true;
+}
+
+/* If OP is SSA NAME, force the statement that defines it to be
+   moved out of the LOOP.  ORIG_LOOP is the loop in that EXPR is used.  */
+
+static void
+force_move_till_op (tree op, class loop *orig_loop, class loop *loop)
+{
+  gimple *stmt;
+
+  if (!op
+      || is_gimple_min_invariant (op))
+    return;
+
+  gcc_assert (TREE_CODE (op) == SSA_NAME);
+
+  stmt = SSA_NAME_DEF_STMT (op);
+  if (gimple_nop_p (stmt))
+    return;
+
+  set_level (stmt, orig_loop, loop);
+}
+
+/* Forces statement defining invariants in REF (and *INDEX) to be moved out of
+   the LOOP.  The reference REF is used in the loop ORIG_LOOP.  Callback for
+   for_each_index.  */
+
+struct fmt_data
+{
+  class loop *loop;
+  class loop *orig_loop;
+};
+
+static bool
+force_move_till (tree ref, tree *index, void *data)
+{
+  struct fmt_data *fmt_data = (struct fmt_data *) data;
+
+  if (TREE_CODE (ref) == ARRAY_REF)
+    {
+      tree step = TREE_OPERAND (ref, 3);
+      tree lbound = TREE_OPERAND (ref, 2);
+
+      force_move_till_op (step, fmt_data->orig_loop, fmt_data->loop);
+      force_move_till_op (lbound, fmt_data->orig_loop, fmt_data->loop);
+    }
+
+  force_move_till_op (*index, fmt_data->orig_loop, fmt_data->loop);
+
+  return true;
+}
+
+/* A function to free the mem_ref object OBJ.  */
+
+static void
+memref_free (class im_mem_ref *mem)
+{
+  mem->accesses_in_loop.release ();
+}
+
+/* Allocates and returns a memory reference description for MEM whose hash
+   value is HASH and id is ID.  */
+
+static im_mem_ref *
+mem_ref_alloc (ao_ref *mem, unsigned hash, unsigned id)
+{
+  im_mem_ref *ref = XOBNEW (&mem_ref_obstack, class im_mem_ref);
+  if (mem)
+    ref->mem = *mem;
+  else
+    ao_ref_init (&ref->mem, error_mark_node);
+  ref->id = id;
+  ref->ref_canonical = false;
+  ref->ref_decomposed = false;
+  ref->hash = hash;
+  ref->stored = NULL;
+  ref->loaded = NULL;
+  bitmap_initialize (&ref->dep_loop, &lim_bitmap_obstack);
+  ref->accesses_in_loop.create (1);
+
+  return ref;
+}
+
+/* Records memory reference location *LOC in LOOP to the memory reference
+   description REF.  The reference occurs in statement STMT.  */
+
+static void
+record_mem_ref_loc (im_mem_ref *ref, gimple *stmt, tree *loc)
+{
+  mem_ref_loc aref;
+  aref.stmt = stmt;
+  aref.ref = loc;
+  ref->accesses_in_loop.safe_push (aref);
+}
+
+/* Set the LOOP bit in REF stored bitmap and allocate that if
+   necessary.  Return whether a bit was changed.  */
+
+static bool
+set_ref_stored_in_loop (im_mem_ref *ref, class loop *loop)
+{
+  if (!ref->stored)
+    ref->stored = BITMAP_ALLOC (&lim_bitmap_obstack);
+  return bitmap_set_bit (ref->stored, loop->num);
+}
+
+/* Marks reference REF as stored in LOOP.  */
+
+static void
+mark_ref_stored (im_mem_ref *ref, class loop *loop)
+{
+  while (loop != current_loops->tree_root
+	 && set_ref_stored_in_loop (ref, loop))
+    loop = loop_outer (loop);
+}
+
+/* Set the LOOP bit in REF loaded bitmap and allocate that if
+   necessary.  Return whether a bit was changed.  */
+
+static bool
+set_ref_loaded_in_loop (im_mem_ref *ref, class loop *loop)
+{
+  if (!ref->loaded)
+    ref->loaded = BITMAP_ALLOC (&lim_bitmap_obstack);
+  return bitmap_set_bit (ref->loaded, loop->num);
+}
+
+/* Marks reference REF as loaded in LOOP.  */
+
+static void
+mark_ref_loaded (im_mem_ref *ref, class loop *loop)
+{
+  while (loop != current_loops->tree_root
+	 && set_ref_loaded_in_loop (ref, loop))
+    loop = loop_outer (loop);
+}
+
+/* Gathers memory references in statement STMT in LOOP, storing the
+   information about them in the memory_accesses structure.  Marks
+   the vops accessed through unrecognized statements there as
+   well.  */
+
+static void
+gather_mem_refs_stmt (class loop *loop, gimple *stmt)
+{
+  tree *mem = NULL;
+  hashval_t hash;
+  im_mem_ref **slot;
+  im_mem_ref *ref;
+  bool is_stored;
+  unsigned id;
+
+  if (!gimple_vuse (stmt))
+    return;
+
+  mem = simple_mem_ref_in_stmt (stmt, &is_stored);
+  if (!mem && is_gimple_assign (stmt))
+    {
+      /* For aggregate copies record distinct references but use them
+	 only for disambiguation purposes.  */
+      id = memory_accesses.refs_list.length ();
+      ref = mem_ref_alloc (NULL, 0, id);
+      memory_accesses.refs_list.safe_push (ref);
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "Unhandled memory reference %u: ", id);
+	  print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+	}
+      record_mem_ref_loc (ref, stmt, mem);
+      is_stored = gimple_vdef (stmt);
+    }
+  else if (!mem)
+    {
+      /* We use the shared mem_ref for all unanalyzable refs.  */
+      id = UNANALYZABLE_MEM_ID;
+      ref = memory_accesses.refs_list[id];
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "Unanalyzed memory reference %u: ", id);
+	  print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+	}
+      is_stored = gimple_vdef (stmt);
+    }
+  else
+    {
+      /* We are looking for equal refs that might differ in structure
+         such as a.b vs. MEM[&a + 4].  So we key off the ao_ref but
+	 make sure we can canonicalize the ref in the hashtable if
+	 non-operand_equal_p refs are found.  For the lookup we mark
+	 the case we want strict equality with aor.max_size == -1.  */
+      ao_ref aor;
+      ao_ref_init (&aor, *mem);
+      ao_ref_base (&aor);
+      ao_ref_alias_set (&aor);
+      HOST_WIDE_INT offset, size, max_size;
+      poly_int64 saved_maxsize = aor.max_size, mem_off;
+      tree mem_base;
+      bool ref_decomposed;
+      if (aor.max_size_known_p ()
+	  && aor.offset.is_constant (&offset)
+	  && aor.size.is_constant (&size)
+	  && aor.max_size.is_constant (&max_size)
+	  && size == max_size
+	  && (size % BITS_PER_UNIT) == 0
+	  /* We're canonicalizing to a MEM where TYPE_SIZE specifies the
+	     size.  Make sure this is consistent with the extraction.  */
+	  && poly_int_tree_p (TYPE_SIZE (TREE_TYPE (*mem)))
+	  && known_eq (wi::to_poly_offset (TYPE_SIZE (TREE_TYPE (*mem))),
+		       aor.size)
+	  && (mem_base = get_addr_base_and_unit_offset (aor.ref, &mem_off)))
+	{
+	  ref_decomposed = true;
+	  tree base = ao_ref_base (&aor);
+	  poly_int64 moffset;
+	  HOST_WIDE_INT mcoffset;
+	  if (TREE_CODE (base) == MEM_REF
+	      && (mem_ref_offset (base) * BITS_PER_UNIT + offset).to_shwi (&moffset)
+	      && moffset.is_constant (&mcoffset))
+	    {
+	      hash = iterative_hash_expr (TREE_OPERAND (base, 0), 0);
+	      hash = iterative_hash_host_wide_int (mcoffset, hash);
+	    }
+	  else
+	    {
+	      hash = iterative_hash_expr (base, 0);
+	      hash = iterative_hash_host_wide_int (offset, hash);
+	    }
+	  hash = iterative_hash_host_wide_int (size, hash);
+	}
+      else
+	{
+	  ref_decomposed = false;
+	  hash = iterative_hash_expr (aor.ref, 0);
+	  aor.max_size = -1;
+	}
+      slot = memory_accesses.refs->find_slot_with_hash (&aor, hash, INSERT);
+      aor.max_size = saved_maxsize;
+      if (*slot)
+	{
+	  if (!(*slot)->ref_canonical 
+	      && !operand_equal_p (*mem, (*slot)->mem.ref, 0))
+	    {
+	      /* If we didn't yet canonicalize the hashtable ref (which
+	         we'll end up using for code insertion) and hit a second
+		 equal ref that is not structurally equivalent create
+		 a canonical ref which is a bare MEM_REF.  */
+	      if (TREE_CODE (*mem) == MEM_REF
+		  || TREE_CODE (*mem) == TARGET_MEM_REF)
+		{
+		  (*slot)->mem.ref = *mem;
+		  (*slot)->mem.base_alias_set = ao_ref_base_alias_set (&aor);
+		}
+	      else
+		{
+		  tree ref_alias_type = reference_alias_ptr_type (*mem);
+		  unsigned int ref_align = get_object_alignment (*mem);
+		  tree ref_type = TREE_TYPE (*mem);
+		  tree tmp = build1 (ADDR_EXPR, ptr_type_node,
+				     unshare_expr (mem_base));
+		  if (TYPE_ALIGN (ref_type) != ref_align)
+		    ref_type = build_aligned_type (ref_type, ref_align);
+		  (*slot)->mem.ref
+		    = fold_build2 (MEM_REF, ref_type, tmp,
+				   build_int_cst (ref_alias_type, mem_off));
+		  if ((*slot)->mem.volatile_p)
+		    TREE_THIS_VOLATILE ((*slot)->mem.ref) = 1;
+		  gcc_checking_assert (TREE_CODE ((*slot)->mem.ref) == MEM_REF
+				       && is_gimple_mem_ref_addr
+				            (TREE_OPERAND ((*slot)->mem.ref,
+							   0)));
+		  (*slot)->mem.base_alias_set = (*slot)->mem.ref_alias_set;
+		}
+	      (*slot)->ref_canonical = true;
+	    }
+	  ref = *slot;
+	  id = ref->id;
+	}
+      else
+	{
+	  id = memory_accesses.refs_list.length ();
+	  ref = mem_ref_alloc (&aor, hash, id);
+	  ref->ref_decomposed = ref_decomposed;
+	  memory_accesses.refs_list.safe_push (ref);
+	  *slot = ref;
+
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "Memory reference %u: ", id);
+	      print_generic_expr (dump_file, ref->mem.ref, TDF_SLIM);
+	      fprintf (dump_file, "\n");
+	    }
+	}
+
+      record_mem_ref_loc (ref, stmt, mem);
+    }
+  if (is_stored)
+    {
+      bitmap_set_bit (&memory_accesses.refs_stored_in_loop[loop->num], ref->id);
+      mark_ref_stored (ref, loop);
+    }
+  /* A not simple memory op is also a read when it is a write.  */
+  if (!is_stored || id == UNANALYZABLE_MEM_ID
+      || ref->mem.ref == error_mark_node)
+    {
+      bitmap_set_bit (&memory_accesses.refs_loaded_in_loop[loop->num], ref->id);
+      mark_ref_loaded (ref, loop);
+    }
+  init_lim_data (stmt)->ref = ref->id;
+  return;
+}
+
+static unsigned *bb_loop_postorder;
+
+/* qsort sort function to sort blocks after their loop fathers postorder.  */
+
+static int
+sort_bbs_in_loop_postorder_cmp (const void *bb1_, const void *bb2_,
+				void *bb_loop_postorder_)
+{
+  unsigned *bb_loop_postorder = (unsigned *)bb_loop_postorder_;
+  basic_block bb1 = *(const basic_block *)bb1_;
+  basic_block bb2 = *(const basic_block *)bb2_;
+  class loop *loop1 = bb1->loop_father;
+  class loop *loop2 = bb2->loop_father;
+  if (loop1->num == loop2->num)
+    return bb1->index - bb2->index;
+  return bb_loop_postorder[loop1->num] < bb_loop_postorder[loop2->num] ? -1 : 1;
+}
+
+/* qsort sort function to sort ref locs after their loop fathers postorder.  */
+
+static int
+sort_locs_in_loop_postorder_cmp (const void *loc1_, const void *loc2_,
+				 void *bb_loop_postorder_)
+{
+  unsigned *bb_loop_postorder = (unsigned *)bb_loop_postorder_;
+  const mem_ref_loc *loc1 = (const mem_ref_loc *)loc1_;
+  const mem_ref_loc *loc2 = (const mem_ref_loc *)loc2_;
+  class loop *loop1 = gimple_bb (loc1->stmt)->loop_father;
+  class loop *loop2 = gimple_bb (loc2->stmt)->loop_father;
+  if (loop1->num == loop2->num)
+    return 0;
+  return bb_loop_postorder[loop1->num] < bb_loop_postorder[loop2->num] ? -1 : 1;
+}
+
+/* Gathers memory references in loops.  */
+
+static void
+analyze_memory_references (bool store_motion)
+{
+  gimple_stmt_iterator bsi;
+  basic_block bb, *bbs;
+  class loop *outer;
+  unsigned i, n;
+
+  /* Collect all basic-blocks in loops and sort them after their
+     loops postorder.  */
+  i = 0;
+  bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS);
+  FOR_EACH_BB_FN (bb, cfun)
+    if (bb->loop_father != current_loops->tree_root)
+      bbs[i++] = bb;
+  n = i;
+  gcc_sort_r (bbs, n, sizeof (basic_block), sort_bbs_in_loop_postorder_cmp,
+	      bb_loop_postorder);
+
+  /* Visit blocks in loop postorder and assign mem-ref IDs in that order.
+     That results in better locality for all the bitmaps.  It also
+     automatically sorts the location list of gathered memory references
+     after their loop postorder number allowing to binary-search it.  */
+  for (i = 0; i < n; ++i)
+    {
+      basic_block bb = bbs[i];
+      for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
+        gather_mem_refs_stmt (bb->loop_father, gsi_stmt (bsi));
+    }
+
+  /* Verify the list of gathered memory references is sorted after their
+     loop postorder number.  */
+  if (flag_checking)
+    {
+      im_mem_ref *ref;
+      FOR_EACH_VEC_ELT (memory_accesses.refs_list, i, ref)
+	for (unsigned j = 1; j < ref->accesses_in_loop.length (); ++j)
+	  gcc_assert (sort_locs_in_loop_postorder_cmp
+			(&ref->accesses_in_loop[j-1], &ref->accesses_in_loop[j],
+			 bb_loop_postorder) <= 0);
+    }
+
+  free (bbs);
+
+  if (!store_motion)
+    return;
+
+  /* Propagate the information about accessed memory references up
+     the loop hierarchy.  */
+  for (auto loop : loops_list (cfun, LI_FROM_INNERMOST))
+    {
+      /* Finalize the overall touched references (including subloops).  */
+      bitmap_ior_into (&memory_accesses.all_refs_stored_in_loop[loop->num],
+		       &memory_accesses.refs_stored_in_loop[loop->num]);
+
+      /* Propagate the information about accessed memory references up
+	 the loop hierarchy.  */
+      outer = loop_outer (loop);
+      if (outer == current_loops->tree_root)
+	continue;
+
+      bitmap_ior_into (&memory_accesses.all_refs_stored_in_loop[outer->num],
+		       &memory_accesses.all_refs_stored_in_loop[loop->num]);
+    }
+}
+
+/* Returns true if MEM1 and MEM2 may alias.  TTAE_CACHE is used as a cache in
+   tree_to_aff_combination_expand.  */
+
+static bool
+mem_refs_may_alias_p (im_mem_ref *mem1, im_mem_ref *mem2,
+		      hash_map<tree, name_expansion *> **ttae_cache,
+		      bool tbaa_p)
+{
+  gcc_checking_assert (mem1->mem.ref != error_mark_node
+		       && mem2->mem.ref != error_mark_node);
+
+  /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the same
+     object and their offset differ in such a way that the locations cannot
+     overlap, then they cannot alias.  */
+  poly_widest_int size1, size2;
+  aff_tree off1, off2;
+
+  /* Perform basic offset and type-based disambiguation.  */
+  if (!refs_may_alias_p_1 (&mem1->mem, &mem2->mem, tbaa_p))
+    return false;
+
+  /* The expansion of addresses may be a bit expensive, thus we only do
+     the check at -O2 and higher optimization levels.  */
+  if (optimize < 2)
+    return true;
+
+  get_inner_reference_aff (mem1->mem.ref, &off1, &size1);
+  get_inner_reference_aff (mem2->mem.ref, &off2, &size2);
+  aff_combination_expand (&off1, ttae_cache);
+  aff_combination_expand (&off2, ttae_cache);
+  aff_combination_scale (&off1, -1);
+  aff_combination_add (&off2, &off1);
+
+  if (aff_comb_cannot_overlap_p (&off2, size1, size2))
+    return false;
+
+  return true;
+}
+
+/* Compare function for bsearch searching for reference locations
+   in a loop.  */
+
+static int
+find_ref_loc_in_loop_cmp (const void *loop_, const void *loc_,
+			  void *bb_loop_postorder_)
+{
+  unsigned *bb_loop_postorder = (unsigned *)bb_loop_postorder_;
+  class loop *loop = (class loop *)const_cast<void *>(loop_);
+  mem_ref_loc *loc = (mem_ref_loc *)const_cast<void *>(loc_);
+  class loop *loc_loop = gimple_bb (loc->stmt)->loop_father;
+  if (loop->num  == loc_loop->num
+      || flow_loop_nested_p (loop, loc_loop))
+    return 0;
+  return (bb_loop_postorder[loop->num] < bb_loop_postorder[loc_loop->num]
+	  ? -1 : 1);
+}
+
+/* Iterates over all locations of REF in LOOP and its subloops calling
+   fn.operator() with the location as argument.  When that operator
+   returns true the iteration is stopped and true is returned.
+   Otherwise false is returned.  */
+
+template <typename FN>
+static bool
+for_all_locs_in_loop (class loop *loop, im_mem_ref *ref, FN fn)
+{
+  unsigned i;
+  mem_ref_loc *loc;
+
+  /* Search for the cluster of locs in the accesses_in_loop vector
+     which is sorted after postorder index of the loop father.  */
+  loc = ref->accesses_in_loop.bsearch (loop, find_ref_loc_in_loop_cmp,
+				       bb_loop_postorder);
+  if (!loc)
+    return false;
+
+  /* We have found one location inside loop or its sub-loops.  Iterate
+     both forward and backward to cover the whole cluster.  */
+  i = loc - ref->accesses_in_loop.address ();
+  while (i > 0)
+    {
+      --i;
+      mem_ref_loc *l = &ref->accesses_in_loop[i];
+      if (!flow_bb_inside_loop_p (loop, gimple_bb (l->stmt)))
+	break;
+      if (fn (l))
+	return true;
+    }
+  for (i = loc - ref->accesses_in_loop.address ();
+       i < ref->accesses_in_loop.length (); ++i)
+    {
+      mem_ref_loc *l = &ref->accesses_in_loop[i];
+      if (!flow_bb_inside_loop_p (loop, gimple_bb (l->stmt)))
+	break;
+      if (fn (l))
+	return true;
+    }
+
+  return false;
+}
+
+/* Rewrites location LOC by TMP_VAR.  */
+
+class rewrite_mem_ref_loc
+{
+public:
+  rewrite_mem_ref_loc (tree tmp_var_) : tmp_var (tmp_var_) {}
+  bool operator () (mem_ref_loc *loc);
+  tree tmp_var;
+};
+
+bool
+rewrite_mem_ref_loc::operator () (mem_ref_loc *loc)
+{
+  *loc->ref = tmp_var;
+  update_stmt (loc->stmt);
+  return false;
+}
+
+/* Rewrites all references to REF in LOOP by variable TMP_VAR.  */
+
+static void
+rewrite_mem_refs (class loop *loop, im_mem_ref *ref, tree tmp_var)
+{
+  for_all_locs_in_loop (loop, ref, rewrite_mem_ref_loc (tmp_var));
+}
+
+/* Stores the first reference location in LOCP.  */
+
+class first_mem_ref_loc_1
+{
+public:
+  first_mem_ref_loc_1 (mem_ref_loc **locp_) : locp (locp_) {}
+  bool operator () (mem_ref_loc *loc);
+  mem_ref_loc **locp;
+};
+
+bool
+first_mem_ref_loc_1::operator () (mem_ref_loc *loc)
+{
+  *locp = loc;
+  return true;
+}
+
+/* Returns the first reference location to REF in LOOP.  */
+
+static mem_ref_loc *
+first_mem_ref_loc (class loop *loop, im_mem_ref *ref)
+{
+  mem_ref_loc *locp = NULL;
+  for_all_locs_in_loop (loop, ref, first_mem_ref_loc_1 (&locp));
+  return locp;
+}
+
+/* Helper function for execute_sm.  Emit code to store TMP_VAR into
+   MEM along edge EX.
+
+   The store is only done if MEM has changed.  We do this so no
+   changes to MEM occur on code paths that did not originally store
+   into it.
+
+   The common case for execute_sm will transform:
+
+     for (...) {
+       if (foo)
+         stuff;
+       else
+         MEM = TMP_VAR;
+     }
+
+   into:
+
+     lsm = MEM;
+     for (...) {
+       if (foo)
+         stuff;
+       else
+         lsm = TMP_VAR;
+     }
+     MEM = lsm;
+
+  This function will generate:
+
+     lsm = MEM;
+
+     lsm_flag = false;
+     ...
+     for (...) {
+       if (foo)
+         stuff;
+       else {
+         lsm = TMP_VAR;
+         lsm_flag = true;
+       }
+     }
+     if (lsm_flag)	<--
+       MEM = lsm;	<-- (X)
+
+  In case MEM and TMP_VAR are NULL the function will return the then
+  block so the caller can insert (X) and other related stmts. 
+*/
+
+static basic_block
+execute_sm_if_changed (edge ex, tree mem, tree tmp_var, tree flag,
+		       edge preheader, hash_set <basic_block> *flag_bbs,
+		       edge &append_cond_position, edge &last_cond_fallthru)
+{
+  basic_block new_bb, then_bb, old_dest;
+  bool loop_has_only_one_exit;
+  edge then_old_edge;
+  gimple_stmt_iterator gsi;
+  gimple *stmt;
+  bool irr = ex->flags & EDGE_IRREDUCIBLE_LOOP;
+
+  profile_count count_sum = profile_count::zero ();
+  int nbbs = 0, ncount = 0;
+  profile_probability flag_probability = profile_probability::uninitialized ();
+
+  /* Flag is set in FLAG_BBS. Determine probability that flag will be true
+     at loop exit.
+
+     This code may look fancy, but it cannot update profile very realistically
+     because we do not know the probability that flag will be true at given
+     loop exit.
+
+     We look for two interesting extremes
+       - when exit is dominated by block setting the flag, we know it will
+         always be true.  This is a common case.
+       - when all blocks setting the flag have very low frequency we know
+         it will likely be false.
+     In all other cases we default to 2/3 for flag being true.  */
+
+  for (hash_set<basic_block>::iterator it = flag_bbs->begin ();
+       it != flag_bbs->end (); ++it)
+    {
+       if ((*it)->count.initialized_p ())
+         count_sum += (*it)->count, ncount ++;
+       if (dominated_by_p (CDI_DOMINATORS, ex->src, *it))
+	 flag_probability = profile_probability::always ();
+       nbbs++;
+    }
+
+  profile_probability cap = profile_probability::always ().apply_scale (2, 3);
+
+  if (flag_probability.initialized_p ())
+    ;
+  else if (ncount == nbbs
+	   && preheader->count () >= count_sum && preheader->count ().nonzero_p ())
+    {
+      flag_probability = count_sum.probability_in (preheader->count ());
+      if (flag_probability > cap)
+	flag_probability = cap;
+    }
+
+  if (!flag_probability.initialized_p ())
+    flag_probability = cap;
+
+  /* ?? Insert store after previous store if applicable.  See note
+     below.  */
+  if (append_cond_position)
+    ex = append_cond_position;
+
+  loop_has_only_one_exit = single_pred_p (ex->dest);
+
+  if (loop_has_only_one_exit)
+    ex = split_block_after_labels (ex->dest);
+  else
+    {
+      for (gphi_iterator gpi = gsi_start_phis (ex->dest);
+	   !gsi_end_p (gpi); gsi_next (&gpi))
+	{
+	  gphi *phi = gpi.phi ();
+	  if (virtual_operand_p (gimple_phi_result (phi)))
+	    continue;
+
+	  /* When the destination has a non-virtual PHI node with multiple
+	     predecessors make sure we preserve the PHI structure by
+	     forcing a forwarder block so that hoisting of that PHI will
+	     still work.  */
+	  split_edge (ex);
+	  break;
+	}
+    }
+
+  old_dest = ex->dest;
+  new_bb = split_edge (ex);
+  then_bb = create_empty_bb (new_bb);
+  then_bb->count = new_bb->count.apply_probability (flag_probability);
+  if (irr)
+    then_bb->flags = BB_IRREDUCIBLE_LOOP;
+  add_bb_to_loop (then_bb, new_bb->loop_father);
+
+  gsi = gsi_start_bb (new_bb);
+  stmt = gimple_build_cond (NE_EXPR, flag, boolean_false_node,
+			    NULL_TREE, NULL_TREE);
+  gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);
+
+  /* Insert actual store.  */
+  if (mem)
+    {
+      gsi = gsi_start_bb (then_bb);
+      stmt = gimple_build_assign (unshare_expr (mem), tmp_var);
+      gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);
+    }
+
+  edge e1 = single_succ_edge (new_bb);
+  edge e2 = make_edge (new_bb, then_bb,
+	               EDGE_TRUE_VALUE | (irr ? EDGE_IRREDUCIBLE_LOOP : 0));
+  e2->probability = flag_probability;
+
+  e1->flags |= EDGE_FALSE_VALUE | (irr ? EDGE_IRREDUCIBLE_LOOP : 0);
+  e1->flags &= ~EDGE_FALLTHRU;
+
+  e1->probability = flag_probability.invert ();
+
+  then_old_edge = make_single_succ_edge (then_bb, old_dest,
+			     EDGE_FALLTHRU | (irr ? EDGE_IRREDUCIBLE_LOOP : 0));
+
+  set_immediate_dominator (CDI_DOMINATORS, then_bb, new_bb);
+
+  if (append_cond_position)
+    {
+      basic_block prevbb = last_cond_fallthru->src;
+      redirect_edge_succ (last_cond_fallthru, new_bb);
+      set_immediate_dominator (CDI_DOMINATORS, new_bb, prevbb);
+      set_immediate_dominator (CDI_DOMINATORS, old_dest,
+			       recompute_dominator (CDI_DOMINATORS, old_dest));
+    }
+
+  /* ?? Because stores may alias, they must happen in the exact
+     sequence they originally happened.  Save the position right after
+     the (_lsm) store we just created so we can continue appending after
+     it and maintain the original order.  */
+  append_cond_position = then_old_edge;
+  last_cond_fallthru = find_edge (new_bb, old_dest);
+
+  if (!loop_has_only_one_exit)
+    for (gphi_iterator gpi = gsi_start_phis (old_dest);
+	 !gsi_end_p (gpi); gsi_next (&gpi))
+      {
+	gphi *phi = gpi.phi ();
+	unsigned i;
+
+	for (i = 0; i < gimple_phi_num_args (phi); i++)
+	  if (gimple_phi_arg_edge (phi, i)->src == new_bb)
+	    {
+	      tree arg = gimple_phi_arg_def (phi, i);
+	      add_phi_arg (phi, arg, then_old_edge, UNKNOWN_LOCATION);
+	      update_stmt (phi);
+	    }
+      }
+
+  return then_bb;
+}
+
+/* When REF is set on the location, set flag indicating the store.  */
+
+class sm_set_flag_if_changed
+{
+public:
+  sm_set_flag_if_changed (tree flag_, hash_set <basic_block> *bbs_)
+	 : flag (flag_), bbs (bbs_) {}
+  bool operator () (mem_ref_loc *loc);
+  tree flag;
+  hash_set <basic_block> *bbs;
+};
+
+bool
+sm_set_flag_if_changed::operator () (mem_ref_loc *loc)
+{
+  /* Only set the flag for writes.  */
+  if (is_gimple_assign (loc->stmt)
+      && gimple_assign_lhs_ptr (loc->stmt) == loc->ref)
+    {
+      gimple_stmt_iterator gsi = gsi_for_stmt (loc->stmt);
+      gimple *stmt = gimple_build_assign (flag, boolean_true_node);
+      gsi_insert_after (&gsi, stmt, GSI_CONTINUE_LINKING);
+      bbs->add (gimple_bb (stmt));
+    }
+  return false;
+}
+
+/* Helper function for execute_sm.  On every location where REF is
+   set, set an appropriate flag indicating the store.  */
+
+static tree
+execute_sm_if_changed_flag_set (class loop *loop, im_mem_ref *ref,
+				hash_set <basic_block> *bbs)
+{
+  tree flag;
+  char *str = get_lsm_tmp_name (ref->mem.ref, ~0, "_flag");
+  flag = create_tmp_reg (boolean_type_node, str);
+  for_all_locs_in_loop (loop, ref, sm_set_flag_if_changed (flag, bbs));
+  return flag;
+}
+
+struct sm_aux
+{
+  tree tmp_var;
+  tree store_flag;
+  hash_set <basic_block> flag_bbs;
+};
+
+/* Executes store motion of memory reference REF from LOOP.
+   Exits from the LOOP are stored in EXITS.  The initialization of the
+   temporary variable is put to the preheader of the loop, and assignments
+   to the reference from the temporary variable are emitted to exits.  */
+
+static void
+execute_sm (class loop *loop, im_mem_ref *ref,
+	    hash_map<im_mem_ref *, sm_aux *> &aux_map, bool maybe_mt,
+	    bool use_other_flag_var)
+{
+  gassign *load;
+  struct fmt_data fmt_data;
+  struct lim_aux_data *lim_data;
+  bool multi_threaded_model_p = false;
+  gimple_stmt_iterator gsi;
+  sm_aux *aux = new sm_aux;
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "Executing store motion of ");
+      print_generic_expr (dump_file, ref->mem.ref);
+      fprintf (dump_file, " from loop %d\n", loop->num);
+    }
+
+  aux->tmp_var = create_tmp_reg (TREE_TYPE (ref->mem.ref),
+				 get_lsm_tmp_name (ref->mem.ref, ~0));
+
+  fmt_data.loop = loop;
+  fmt_data.orig_loop = loop;
+  for_each_index (&ref->mem.ref, force_move_till, &fmt_data);
+
+  bool always_stored = ref_always_accessed_p (loop, ref, true);
+  if (maybe_mt
+      && (bb_in_transaction (loop_preheader_edge (loop)->src)
+	  || (! flag_store_data_races && ! always_stored)))
+    multi_threaded_model_p = true;
+
+  if (multi_threaded_model_p && !use_other_flag_var)
+    aux->store_flag
+      = execute_sm_if_changed_flag_set (loop, ref, &aux->flag_bbs);
+  else
+    aux->store_flag = NULL_TREE;
+
+  /* Remember variable setup.  */
+  aux_map.put (ref, aux);
+
+  rewrite_mem_refs (loop, ref, aux->tmp_var);
+
+  /* Emit the load code on a random exit edge or into the latch if
+     the loop does not exit, so that we are sure it will be processed
+     by move_computations after all dependencies.  */
+  gsi = gsi_for_stmt (first_mem_ref_loc (loop, ref)->stmt);
+
+  /* Avoid doing a load if there was no load of the ref in the loop.
+     Esp. when the ref is not always stored we cannot optimize it
+     away later.  But when it is not always stored we must use a conditional
+     store then.  */
+  if ((!always_stored && !multi_threaded_model_p)
+      || (ref->loaded && bitmap_bit_p (ref->loaded, loop->num)))
+    load = gimple_build_assign (aux->tmp_var, unshare_expr (ref->mem.ref));
+  else
+    {
+      /* If not emitting a load mark the uninitialized state on the
+	 loop entry as not to be warned for.  */
+      tree uninit = create_tmp_reg (TREE_TYPE (aux->tmp_var));
+      suppress_warning (uninit, OPT_Wuninitialized);
+      load = gimple_build_assign (aux->tmp_var, uninit);
+    }
+  lim_data = init_lim_data (load);
+  lim_data->max_loop = loop;
+  lim_data->tgt_loop = loop;
+  gsi_insert_before (&gsi, load, GSI_SAME_STMT);
+
+  if (aux->store_flag)
+    {
+      load = gimple_build_assign (aux->store_flag, boolean_false_node);
+      lim_data = init_lim_data (load);
+      lim_data->max_loop = loop;
+      lim_data->tgt_loop = loop;
+      gsi_insert_before (&gsi, load, GSI_SAME_STMT);
+    }
+}
+
+/* sm_ord is used for ordinary stores we can retain order with respect
+       to other stores
+   sm_unord is used for conditional executed stores which need to be
+       able to execute in arbitrary order with respect to other stores
+   sm_other is used for stores we do not try to apply store motion to.  */
+enum sm_kind { sm_ord, sm_unord, sm_other };
+struct seq_entry
+{
+  seq_entry () {}
+  seq_entry (unsigned f, sm_kind k, tree fr = NULL)
+    : first (f), second (k), from (fr) {}
+  unsigned first;
+  sm_kind second;
+  tree from;
+};
+
+static void
+execute_sm_exit (class loop *loop, edge ex, vec<seq_entry> &seq,
+		 hash_map<im_mem_ref *, sm_aux *> &aux_map, sm_kind kind,
+		 edge &append_cond_position, edge &last_cond_fallthru)
+{
+  /* Sink the stores to exit from the loop.  */
+  for (unsigned i = seq.length (); i > 0; --i)
+    {
+      im_mem_ref *ref = memory_accesses.refs_list[seq[i-1].first];
+      if (seq[i-1].second == sm_other)
+	{
+	  gcc_assert (kind == sm_ord && seq[i-1].from != NULL_TREE);
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "Re-issueing dependent store of ");
+	      print_generic_expr (dump_file, ref->mem.ref);
+	      fprintf (dump_file, " from loop %d on exit %d -> %d\n",
+		       loop->num, ex->src->index, ex->dest->index);
+	    }
+	  gassign *store = gimple_build_assign (unshare_expr (ref->mem.ref),
+						seq[i-1].from);
+	  gsi_insert_on_edge (ex, store);
+	}
+      else
+	{
+	  sm_aux *aux = *aux_map.get (ref);
+	  if (!aux->store_flag || kind == sm_ord)
+	    {
+	      gassign *store;
+	      store = gimple_build_assign (unshare_expr (ref->mem.ref),
+					   aux->tmp_var);
+	      gsi_insert_on_edge (ex, store);
+	    }
+	  else
+	    execute_sm_if_changed (ex, ref->mem.ref, aux->tmp_var,
+				   aux->store_flag,
+				   loop_preheader_edge (loop), &aux->flag_bbs,
+				   append_cond_position, last_cond_fallthru);
+	}
+    }
+}
+
+/* Push the SM candidate at index PTR in the sequence SEQ down until
+   we hit the next SM candidate.  Return true if that went OK and
+   false if we could not disambiguate agains another unrelated ref.
+   Update *AT to the index where the candidate now resides.  */
+
+static bool
+sm_seq_push_down (vec<seq_entry> &seq, unsigned ptr, unsigned *at)
+{
+  *at = ptr;
+  for (; ptr > 0; --ptr)
+    {
+      seq_entry &new_cand = seq[ptr];
+      seq_entry &against = seq[ptr-1];
+      if (against.second == sm_ord
+	  || (against.second == sm_other && against.from != NULL_TREE))
+	/* Found the tail of the sequence.  */
+	break;
+      /* We may not ignore self-dependences here.  */
+      if (new_cand.first == against.first
+	  || !refs_independent_p (memory_accesses.refs_list[new_cand.first],
+				  memory_accesses.refs_list[against.first],
+				  false))
+	/* ???  Prune new_cand from the list of refs to apply SM to.  */
+	return false;
+      std::swap (new_cand, against);
+      *at = ptr - 1;
+    }
+  return true;
+}
+
+/* Computes the sequence of stores from candidates in REFS_NOT_IN_SEQ to SEQ
+   walking backwards from VDEF (or the end of BB if VDEF is NULL).  */
+
+static int
+sm_seq_valid_bb (class loop *loop, basic_block bb, tree vdef,
+		 vec<seq_entry> &seq, bitmap refs_not_in_seq,
+		 bitmap refs_not_supported, bool forked,
+		 bitmap fully_visited)
+{
+  if (!vdef)
+    for (gimple_stmt_iterator gsi = gsi_last_bb (bb); !gsi_end_p (gsi);
+	 gsi_prev (&gsi))
+      {
+	vdef = gimple_vdef (gsi_stmt (gsi));
+	if (vdef)
+	  break;
+      }
+  if (!vdef)
+    {
+      gphi *vphi = get_virtual_phi (bb);
+      if (vphi)
+	vdef = gimple_phi_result (vphi);
+    }
+  if (!vdef)
+    {
+      if (single_pred_p (bb))
+	/* This handles the perfect nest case.  */
+	return sm_seq_valid_bb (loop, single_pred (bb), vdef,
+				seq, refs_not_in_seq, refs_not_supported,
+				forked, fully_visited);
+      return 0;
+    }
+  do
+    {
+      gimple *def = SSA_NAME_DEF_STMT (vdef);
+      if (gimple_bb (def) != bb)
+	{
+	  /* If we forked by processing a PHI do not allow our walk to
+	     merge again until we handle that robustly.  */
+	  if (forked)
+	    {
+	      /* Mark refs_not_in_seq as unsupported.  */
+	      bitmap_ior_into (refs_not_supported, refs_not_in_seq);
+	      return 1;
+	    }
+	  /* Otherwise it doesn't really matter if we end up in different
+	     BBs.  */
+	  bb = gimple_bb (def);
+	}
+      if (gphi *phi = dyn_cast <gphi *> (def))
+	{
+	  /* Handle CFG merges.  Until we handle forks (gimple_bb (def) != bb)
+	     this is still linear.
+	     Eventually we want to cache intermediate results per BB
+	     (but we can't easily cache for different exits?).  */
+	  /* Stop at PHIs with possible backedges.  */
+	  if (bb == bb->loop_father->header
+	      || bb->flags & BB_IRREDUCIBLE_LOOP)
+	    {
+	      /* Mark refs_not_in_seq as unsupported.  */
+	      bitmap_ior_into (refs_not_supported, refs_not_in_seq);
+	      return 1;
+	    }
+	  if (gimple_phi_num_args (phi) == 1)
+	    return sm_seq_valid_bb (loop, gimple_phi_arg_edge (phi, 0)->src,
+				    gimple_phi_arg_def (phi, 0), seq,
+				    refs_not_in_seq, refs_not_supported,
+				    false, fully_visited);
+	  if (bitmap_bit_p (fully_visited,
+			    SSA_NAME_VERSION (gimple_phi_result (phi))))
+	    return 1;
+	  auto_vec<seq_entry> first_edge_seq;
+	  auto_bitmap tem_refs_not_in_seq (&lim_bitmap_obstack);
+	  int eret;
+	  bitmap_copy (tem_refs_not_in_seq, refs_not_in_seq);
+	  eret = sm_seq_valid_bb (loop, gimple_phi_arg_edge (phi, 0)->src,
+				  gimple_phi_arg_def (phi, 0),
+				  first_edge_seq,
+				  tem_refs_not_in_seq, refs_not_supported,
+				  true, fully_visited);
+	  if (eret != 1)
+	    return -1;
+	  /* Simplify our lives by pruning the sequence of !sm_ord.  */
+	  while (!first_edge_seq.is_empty ()
+		 && first_edge_seq.last ().second != sm_ord)
+	    first_edge_seq.pop ();
+	  for (unsigned int i = 1; i < gimple_phi_num_args (phi); ++i)
+	    {
+	      tree vuse = gimple_phi_arg_def (phi, i);
+	      edge e = gimple_phi_arg_edge (phi, i);
+	      auto_vec<seq_entry> edge_seq;
+	      bitmap_and_compl (tem_refs_not_in_seq,
+				refs_not_in_seq, refs_not_supported);
+	      /* If we've marked all refs we search for as unsupported
+		 we can stop processing and use the sequence as before
+		 the PHI.  */
+	      if (bitmap_empty_p (tem_refs_not_in_seq))
+		return 1;
+	      eret = sm_seq_valid_bb (loop, e->src, vuse, edge_seq,
+				      tem_refs_not_in_seq, refs_not_supported,
+				      true, fully_visited);
+	      if (eret != 1)
+		return -1;
+	      /* Simplify our lives by pruning the sequence of !sm_ord.  */
+	      while (!edge_seq.is_empty ()
+		     && edge_seq.last ().second != sm_ord)
+		edge_seq.pop ();
+	      unsigned min_len = MIN(first_edge_seq.length (),
+				     edge_seq.length ());
+	      /* Incrementally merge seqs into first_edge_seq.  */
+	      int first_uneq = -1;
+	      auto_vec<seq_entry, 2> extra_refs;
+	      for (unsigned int i = 0; i < min_len; ++i)
+		{
+		  /* ???  We can more intelligently merge when we face different
+		     order by additional sinking operations in one sequence.
+		     For now we simply mark them as to be processed by the
+		     not order-preserving SM code.  */
+		  if (first_edge_seq[i].first != edge_seq[i].first)
+		    {
+		      if (first_edge_seq[i].second == sm_ord)
+			bitmap_set_bit (refs_not_supported,
+					first_edge_seq[i].first);
+		      if (edge_seq[i].second == sm_ord)
+			bitmap_set_bit (refs_not_supported, edge_seq[i].first);
+		      first_edge_seq[i].second = sm_other;
+		      first_edge_seq[i].from = NULL_TREE;
+		      /* Record the dropped refs for later processing.  */
+		      if (first_uneq == -1)
+			first_uneq = i;
+		      extra_refs.safe_push (seq_entry (edge_seq[i].first,
+						       sm_other, NULL_TREE));
+		    }
+		  /* sm_other prevails.  */
+		  else if (first_edge_seq[i].second != edge_seq[i].second)
+		    {
+		      /* Make sure the ref is marked as not supported.  */
+		      bitmap_set_bit (refs_not_supported,
+				      first_edge_seq[i].first);
+		      first_edge_seq[i].second = sm_other;
+		      first_edge_seq[i].from = NULL_TREE;
+		    }
+		  else if (first_edge_seq[i].second == sm_other
+			   && first_edge_seq[i].from != NULL_TREE
+			   && (edge_seq[i].from == NULL_TREE
+			       || !operand_equal_p (first_edge_seq[i].from,
+						    edge_seq[i].from, 0)))
+		    first_edge_seq[i].from = NULL_TREE;
+		}
+	      /* Any excess elements become sm_other since they are now
+		 coonditionally executed.  */
+	      if (first_edge_seq.length () > edge_seq.length ())
+		{
+		  for (unsigned i = edge_seq.length ();
+		       i < first_edge_seq.length (); ++i)
+		    {
+		      if (first_edge_seq[i].second == sm_ord)
+			bitmap_set_bit (refs_not_supported,
+					first_edge_seq[i].first);
+		      first_edge_seq[i].second = sm_other;
+		    }
+		}
+	      else if (edge_seq.length () > first_edge_seq.length ())
+		{
+		  if (first_uneq == -1)
+		    first_uneq = first_edge_seq.length ();
+		  for (unsigned i = first_edge_seq.length ();
+		       i < edge_seq.length (); ++i)
+		    {
+		      if (edge_seq[i].second == sm_ord)
+			bitmap_set_bit (refs_not_supported, edge_seq[i].first);
+		      extra_refs.safe_push (seq_entry (edge_seq[i].first,
+						       sm_other, NULL_TREE));
+		    }
+		}
+	      /* Put unmerged refs at first_uneq to force dependence checking
+		 on them.  */
+	      if (first_uneq != -1)
+		{
+		  /* Missing ordered_splice_at.  */
+		  if ((unsigned)first_uneq == first_edge_seq.length ())
+		    first_edge_seq.safe_splice (extra_refs);
+		  else
+		    {
+		      unsigned fes_length = first_edge_seq.length ();
+		      first_edge_seq.safe_grow (fes_length
+						+ extra_refs.length ());
+		      memmove (&first_edge_seq[first_uneq + extra_refs.length ()],
+			       &first_edge_seq[first_uneq],
+			       (fes_length - first_uneq) * sizeof (seq_entry));
+		      memcpy (&first_edge_seq[first_uneq],
+			      extra_refs.address (),
+			      extra_refs.length () * sizeof (seq_entry));
+		    }
+		}
+	    }
+	  /* Use the sequence from the first edge and push SMs down.  */
+	  for (unsigned i = 0; i < first_edge_seq.length (); ++i)
+	    {
+	      unsigned id = first_edge_seq[i].first;
+	      seq.safe_push (first_edge_seq[i]);
+	      unsigned new_idx;
+	      if ((first_edge_seq[i].second == sm_ord
+		   || (first_edge_seq[i].second == sm_other
+		       && first_edge_seq[i].from != NULL_TREE))
+		  && !sm_seq_push_down (seq, seq.length () - 1, &new_idx))
+		{
+		  if (first_edge_seq[i].second == sm_ord)
+		    bitmap_set_bit (refs_not_supported, id);
+		  /* Mark it sm_other.  */
+		  seq[new_idx].second = sm_other;
+		  seq[new_idx].from = NULL_TREE;
+		}
+	    }
+	  bitmap_set_bit (fully_visited,
+			  SSA_NAME_VERSION (gimple_phi_result (phi)));
+	  return 1;
+	}
+      lim_aux_data *data = get_lim_data (def);
+      gcc_assert (data);
+      if (data->ref == UNANALYZABLE_MEM_ID)
+	return -1;
+      /* Stop at memory references which we can't move.  */
+      else if (memory_accesses.refs_list[data->ref]->mem.ref == error_mark_node)
+	{
+	  /* Mark refs_not_in_seq as unsupported.  */
+	  bitmap_ior_into (refs_not_supported, refs_not_in_seq);
+	  return 1;
+	}
+      /* One of the stores we want to apply SM to and we've not yet seen.  */
+      else if (bitmap_clear_bit (refs_not_in_seq, data->ref))
+	{
+	  seq.safe_push (seq_entry (data->ref, sm_ord));
+
+	  /* 1) push it down the queue until a SMed
+	     and not ignored ref is reached, skipping all not SMed refs
+	     and ignored refs via non-TBAA disambiguation.  */
+	  unsigned new_idx;
+	  if (!sm_seq_push_down (seq, seq.length () - 1, &new_idx)
+	      /* If that fails but we did not fork yet continue, we'll see
+		 to re-materialize all of the stores in the sequence then.
+		 Further stores will only be pushed up to this one.  */
+	      && forked)
+	    {
+	      bitmap_set_bit (refs_not_supported, data->ref);
+	      /* Mark it sm_other.  */
+	      seq[new_idx].second = sm_other;
+	    }
+
+	  /* 2) check whether we've seen all refs we want to SM and if so
+	     declare success for the active exit  */
+	  if (bitmap_empty_p (refs_not_in_seq))
+	    return 1;
+	}
+      else
+	/* Another store not part of the final sequence.  Simply push it.  */
+	seq.safe_push (seq_entry (data->ref, sm_other,
+				  gimple_assign_rhs1 (def)));
+
+      vdef = gimple_vuse (def);
+    }
+  while (1);
+}
+
+/* Hoists memory references MEM_REFS out of LOOP.  EXITS is the list of exit
+   edges of the LOOP.  */
+
+static void
+hoist_memory_references (class loop *loop, bitmap mem_refs,
+			 const vec<edge> &exits)
+{
+  im_mem_ref *ref;
+  unsigned  i;
+  bitmap_iterator bi;
+
+  /* There's a special case we can use ordered re-materialization for
+     conditionally excuted stores which is when all stores in the loop
+     happen in the same basic-block.  In that case we know we'll reach
+     all stores and thus can simply process that BB and emit a single
+     conditional block of ordered materializations.  See PR102436.  */
+  basic_block single_store_bb = NULL;
+  EXECUTE_IF_SET_IN_BITMAP (&memory_accesses.all_refs_stored_in_loop[loop->num],
+			    0, i, bi)
+    {
+      bool fail = false;
+      ref = memory_accesses.refs_list[i];
+      for (auto loc : ref->accesses_in_loop)
+	if (!gimple_vdef (loc.stmt))
+	  ;
+	else if (!single_store_bb)
+	  {
+	    single_store_bb = gimple_bb (loc.stmt);
+	    bool conditional = false;
+	    for (edge e : exits)
+	      if (!dominated_by_p (CDI_DOMINATORS, e->src, single_store_bb))
+		{
+		  /* Conditional as seen from e.  */
+		  conditional = true;
+		  break;
+		}
+	    if (!conditional)
+	      {
+		fail = true;
+		break;
+	      }
+	  }
+	else if (single_store_bb != gimple_bb (loc.stmt))
+	  {
+	    fail = true;
+	    break;
+	  }
+      if (fail)
+	{
+	  single_store_bb = NULL;
+	  break;
+	}
+    }
+  if (single_store_bb)
+    {
+      /* Analyze the single block with stores.  */
+      auto_bitmap fully_visited;
+      auto_bitmap refs_not_supported;
+      auto_bitmap refs_not_in_seq;
+      auto_vec<seq_entry> seq;
+      bitmap_copy (refs_not_in_seq, mem_refs);
+      int res = sm_seq_valid_bb (loop, single_store_bb, NULL_TREE,
+				 seq, refs_not_in_seq, refs_not_supported,
+				 false, fully_visited);
+      if (res != 1)
+	{
+	  /* Unhandled refs can still fail this.  */
+	  bitmap_clear (mem_refs);
+	  return;
+	}
+
+      /* We cannot handle sm_other since we neither remember the
+	 stored location nor the value at the point we execute them.  */
+      for (unsigned i = 0; i < seq.length (); ++i)
+	{
+	  unsigned new_i;
+	  if (seq[i].second == sm_other
+	      && seq[i].from != NULL_TREE)
+	    seq[i].from = NULL_TREE;
+	  else if ((seq[i].second == sm_ord
+		    || (seq[i].second == sm_other
+			&& seq[i].from != NULL_TREE))
+		   && !sm_seq_push_down (seq, i, &new_i))
+	    {
+	      bitmap_set_bit (refs_not_supported, seq[new_i].first);
+	      seq[new_i].second = sm_other;
+	      seq[new_i].from = NULL_TREE;
+	    }
+	}
+      bitmap_and_compl_into (mem_refs, refs_not_supported);
+      if (bitmap_empty_p (mem_refs))
+	return;
+
+      /* Prune seq.  */
+      while (seq.last ().second == sm_other
+	     && seq.last ().from == NULL_TREE)
+	seq.pop ();
+
+      hash_map<im_mem_ref *, sm_aux *> aux_map;
+
+      /* Execute SM but delay the store materialization for ordered
+	 sequences on exit.  */
+      bool first_p = true;
+      EXECUTE_IF_SET_IN_BITMAP (mem_refs, 0, i, bi)
+	{
+	  ref = memory_accesses.refs_list[i];
+	  execute_sm (loop, ref, aux_map, true, !first_p);
+	  first_p = false;
+	}
+
+      /* Get at the single flag variable we eventually produced.  */
+      im_mem_ref *ref
+	= memory_accesses.refs_list[bitmap_first_set_bit (mem_refs)];
+      sm_aux *aux = *aux_map.get (ref);
+
+      /* Materialize ordered store sequences on exits.  */
+      edge e;
+      FOR_EACH_VEC_ELT (exits, i, e)
+	{
+	  edge append_cond_position = NULL;
+	  edge last_cond_fallthru = NULL;
+	  edge insert_e = e;
+	  /* Construct the single flag variable control flow and insert
+	     the ordered seq of stores in the then block.  With
+	     -fstore-data-races we can do the stores unconditionally.  */
+	  if (aux->store_flag)
+	    insert_e
+	      = single_pred_edge
+		  (execute_sm_if_changed (e, NULL_TREE, NULL_TREE,
+					  aux->store_flag,
+					  loop_preheader_edge (loop),
+					  &aux->flag_bbs, append_cond_position,
+					  last_cond_fallthru));
+	  execute_sm_exit (loop, insert_e, seq, aux_map, sm_ord,
+			   append_cond_position, last_cond_fallthru);
+	  gsi_commit_one_edge_insert (insert_e, NULL);
+	}
+
+      for (hash_map<im_mem_ref *, sm_aux *>::iterator iter = aux_map.begin ();
+	   iter != aux_map.end (); ++iter)
+	delete (*iter).second;
+
+      return;
+    }
+
+  /* To address PR57359 before actually applying store-motion check
+     the candidates found for validity with regards to reordering
+     relative to other stores which we until here disambiguated using
+     TBAA which isn't valid.
+     What matters is the order of the last stores to the mem_refs
+     with respect to the other stores of the loop at the point of the
+     loop exits.  */
+
+  /* For each exit compute the store order, pruning from mem_refs
+     on the fly.  */
+  /* The complexity of this is at least
+     O(number of exits * number of SM refs) but more approaching
+     O(number of exits * number of SM refs * number of stores).  */
+  /* ???  Somehow do this in a single sweep over the loop body.  */
+  auto_vec<std::pair<edge, vec<seq_entry> > > sms;
+  auto_bitmap refs_not_supported (&lim_bitmap_obstack);
+  edge e;
+  FOR_EACH_VEC_ELT (exits, i, e)
+    {
+      vec<seq_entry> seq;
+      seq.create (4);
+      auto_bitmap refs_not_in_seq (&lim_bitmap_obstack);
+      bitmap_and_compl (refs_not_in_seq, mem_refs, refs_not_supported);
+      if (bitmap_empty_p (refs_not_in_seq))
+	{
+	  seq.release ();
+	  break;
+	}
+      auto_bitmap fully_visited;
+      int res = sm_seq_valid_bb (loop, e->src, NULL_TREE,
+				 seq, refs_not_in_seq,
+				 refs_not_supported, false,
+				 fully_visited);
+      if (res != 1)
+	{
+	  bitmap_copy (refs_not_supported, mem_refs);
+	  seq.release ();
+	  break;
+	}
+      sms.safe_push (std::make_pair (e, seq));
+    }
+
+  /* Prune pruned mem_refs from earlier processed exits.  */
+  bool changed = !bitmap_empty_p (refs_not_supported);
+  while (changed)
+    {
+      changed = false;
+      std::pair<edge, vec<seq_entry> > *seq;
+      FOR_EACH_VEC_ELT (sms, i, seq)
+	{
+	  bool need_to_push = false;
+	  for (unsigned i = 0; i < seq->second.length (); ++i)
+	    {
+	      sm_kind kind = seq->second[i].second;
+	      if (kind == sm_other && seq->second[i].from == NULL_TREE)
+		break;
+	      unsigned id = seq->second[i].first;
+	      unsigned new_idx;
+	      if (kind == sm_ord
+		  && bitmap_bit_p (refs_not_supported, id))
+		{
+		  seq->second[i].second = sm_other;
+		  gcc_assert (seq->second[i].from == NULL_TREE);
+		  need_to_push = true;
+		}
+	      else if (need_to_push
+		       && !sm_seq_push_down (seq->second, i, &new_idx))
+		{
+		  /* We need to push down both sm_ord and sm_other
+		     but for the latter we need to disqualify all
+		     following refs.  */
+		  if (kind == sm_ord)
+		    {
+		      if (bitmap_set_bit (refs_not_supported, id))
+			changed = true;
+		      seq->second[new_idx].second = sm_other;
+		    }
+		  else
+		    {
+		      for (unsigned j = seq->second.length () - 1;
+			   j > new_idx; --j)
+			if (seq->second[j].second == sm_ord
+			    && bitmap_set_bit (refs_not_supported,
+					       seq->second[j].first))
+			  changed = true;
+		      seq->second.truncate (new_idx);
+		      break;
+		    }
+		}
+	    }
+	}
+    }
+  std::pair<edge, vec<seq_entry> > *seq;
+  FOR_EACH_VEC_ELT (sms, i, seq)
+    {
+      /* Prune sm_other from the end.  */
+      while (!seq->second.is_empty ()
+	     && seq->second.last ().second == sm_other)
+	seq->second.pop ();
+      /* Prune duplicates from the start.  */
+      auto_bitmap seen (&lim_bitmap_obstack);
+      unsigned j, k;
+      for (j = k = 0; j < seq->second.length (); ++j)
+	if (bitmap_set_bit (seen, seq->second[j].first))
+	  {
+	    if (k != j)
+	      seq->second[k] = seq->second[j];
+	    ++k;
+	  }
+      seq->second.truncate (k);
+      /* And verify.  */
+      seq_entry *e;
+      FOR_EACH_VEC_ELT (seq->second, j, e)
+	gcc_assert (e->second == sm_ord
+		    || (e->second == sm_other && e->from != NULL_TREE));
+    }
+
+  /* Verify dependence for refs we cannot handle with the order preserving
+     code (refs_not_supported) or prune them from mem_refs.  */
+  auto_vec<seq_entry> unord_refs;
+  EXECUTE_IF_SET_IN_BITMAP (refs_not_supported, 0, i, bi)
+    {
+      ref = memory_accesses.refs_list[i];
+      if (!ref_indep_loop_p (loop, ref, sm_waw))
+	bitmap_clear_bit (mem_refs, i);
+      /* We've now verified store order for ref with respect to all other
+	 stores in the loop does not matter.  */
+      else
+	unord_refs.safe_push (seq_entry (i, sm_unord));
+    }
+
+  hash_map<im_mem_ref *, sm_aux *> aux_map;
+
+  /* Execute SM but delay the store materialization for ordered
+     sequences on exit.  */
+  EXECUTE_IF_SET_IN_BITMAP (mem_refs, 0, i, bi)
+    {
+      ref = memory_accesses.refs_list[i];
+      execute_sm (loop, ref, aux_map, bitmap_bit_p (refs_not_supported, i),
+		  false);
+    }
+
+  /* Materialize ordered store sequences on exits.  */
+  FOR_EACH_VEC_ELT (exits, i, e)
+    {
+      edge append_cond_position = NULL;
+      edge last_cond_fallthru = NULL;
+      if (i < sms.length ())
+	{
+	  gcc_assert (sms[i].first == e);
+	  execute_sm_exit (loop, e, sms[i].second, aux_map, sm_ord,
+			   append_cond_position, last_cond_fallthru);
+	  sms[i].second.release ();
+	}
+      if (!unord_refs.is_empty ())
+	execute_sm_exit (loop, e, unord_refs, aux_map, sm_unord,
+			 append_cond_position, last_cond_fallthru);
+      /* Commit edge inserts here to preserve the order of stores
+	 when an exit exits multiple loops.  */
+      gsi_commit_one_edge_insert (e, NULL);
+    }
+
+  for (hash_map<im_mem_ref *, sm_aux *>::iterator iter = aux_map.begin ();
+       iter != aux_map.end (); ++iter)
+    delete (*iter).second;
+}
+
+class ref_always_accessed
+{
+public:
+  ref_always_accessed (class loop *loop_, bool stored_p_)
+      : loop (loop_), stored_p (stored_p_) {}
+  bool operator () (mem_ref_loc *loc);
+  class loop *loop;
+  bool stored_p;
+};
+
+bool
+ref_always_accessed::operator () (mem_ref_loc *loc)
+{
+  class loop *must_exec;
+
+  struct lim_aux_data *lim_data = get_lim_data (loc->stmt);
+  if (!lim_data)
+    return false;
+
+  /* If we require an always executed store make sure the statement
+     is a store.  */
+  if (stored_p)
+    {
+      tree lhs = gimple_get_lhs (loc->stmt);
+      if (!lhs
+	  || !(DECL_P (lhs) || REFERENCE_CLASS_P (lhs)))
+	return false;
+    }
+
+  must_exec = lim_data->always_executed_in;
+  if (!must_exec)
+    return false;
+
+  if (must_exec == loop
+      || flow_loop_nested_p (must_exec, loop))
+    return true;
+
+  return false;
+}
+
+/* Returns true if REF is always accessed in LOOP.  If STORED_P is true
+   make sure REF is always stored to in LOOP.  */
+
+static bool
+ref_always_accessed_p (class loop *loop, im_mem_ref *ref, bool stored_p)
+{
+  return for_all_locs_in_loop (loop, ref,
+			       ref_always_accessed (loop, stored_p));
+}
+
+/* Returns true if REF1 and REF2 are independent.  */
+
+static bool
+refs_independent_p (im_mem_ref *ref1, im_mem_ref *ref2, bool tbaa_p)
+{
+  if (ref1 == ref2)
+    return true;
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    fprintf (dump_file, "Querying dependency of refs %u and %u: ",
+	     ref1->id, ref2->id);
+
+  if (mem_refs_may_alias_p (ref1, ref2, &memory_accesses.ttae_cache, tbaa_p))
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "dependent.\n");
+      return false;
+    }
+  else
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "independent.\n");
+      return true;
+    }
+}
+
+/* Returns true if REF is independent on all other accessess in LOOP.
+   KIND specifies the kind of dependence to consider.
+     lim_raw assumes REF is not stored in LOOP and disambiguates RAW
+	     dependences so if true REF can be hoisted out of LOOP
+     sm_war disambiguates a store REF against all other loads to see
+	    whether the store can be sunk across loads out of LOOP
+     sm_waw disambiguates a store REF against all other stores to see
+	    whether the store can be sunk across stores out of LOOP.  */
+
+static bool
+ref_indep_loop_p (class loop *loop, im_mem_ref *ref, dep_kind kind)
+{
+  bool indep_p = true;
+  bitmap refs_to_check;
+
+  if (kind == sm_war)
+    refs_to_check = &memory_accesses.refs_loaded_in_loop[loop->num];
+  else
+    refs_to_check = &memory_accesses.refs_stored_in_loop[loop->num];
+
+  if (bitmap_bit_p (refs_to_check, UNANALYZABLE_MEM_ID)
+      || ref->mem.ref == error_mark_node)
+    indep_p = false;
+  else
+    {
+      /* tri-state, { unknown, independent, dependent }  */
+      dep_state state = query_loop_dependence (loop, ref, kind);
+      if (state != dep_unknown)
+	return state == dep_independent ? true : false;
+
+      class loop *inner = loop->inner;
+      while (inner)
+	{
+	  if (!ref_indep_loop_p (inner, ref, kind))
+	    {
+	      indep_p = false;
+	      break;
+	    }
+	  inner = inner->next;
+	}
+
+      if (indep_p)
+	{
+	  unsigned i;
+	  bitmap_iterator bi;
+	  EXECUTE_IF_SET_IN_BITMAP (refs_to_check, 0, i, bi)
+	    {
+	      im_mem_ref *aref = memory_accesses.refs_list[i];
+	      if (aref->mem.ref == error_mark_node)
+		{
+		  gimple *stmt = aref->accesses_in_loop[0].stmt;
+		  if ((kind == sm_war
+		       && ref_maybe_used_by_stmt_p (stmt, &ref->mem,
+						    kind != sm_waw))
+		      || stmt_may_clobber_ref_p_1 (stmt, &ref->mem,
+						   kind != sm_waw))
+		    {
+		      indep_p = false;
+		      break;
+		    }
+		}
+	      else if (!refs_independent_p (ref, aref, kind != sm_waw))
+		{
+		  indep_p = false;
+		  break;
+		}
+	    }
+	}
+    }
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    fprintf (dump_file, "Querying %s dependencies of ref %u in loop %d: %s\n",
+	     kind == lim_raw ? "RAW" : (kind == sm_war ? "SM WAR" : "SM WAW"),
+	     ref->id, loop->num, indep_p ? "independent" : "dependent");
+
+  /* Record the computed result in the cache.  */
+  record_loop_dependence (loop, ref, kind,
+			  indep_p ? dep_independent : dep_dependent);
+
+  return indep_p;
+}
+
+class ref_in_loop_hot_body
+{
+public:
+  ref_in_loop_hot_body (class loop *loop_) : l (loop_) {}
+  bool operator () (mem_ref_loc *loc);
+  class loop *l;
+};
+
+/* Check the coldest loop between loop L and innermost loop.  If there is one
+   cold loop between L and INNER_LOOP, store motion can be performed, otherwise
+   no cold loop means no store motion.  get_coldest_out_loop also handles cases
+   when l is inner_loop.  */
+bool
+ref_in_loop_hot_body::operator () (mem_ref_loc *loc)
+{
+  basic_block curr_bb = gimple_bb (loc->stmt);
+  class loop *inner_loop = curr_bb->loop_father;
+  return get_coldest_out_loop (l, inner_loop, curr_bb);
+}
+
+
+/* Returns true if we can perform store motion of REF from LOOP.  */
+
+static bool
+can_sm_ref_p (class loop *loop, im_mem_ref *ref)
+{
+  tree base;
+
+  /* Can't hoist unanalyzable refs.  */
+  if (!MEM_ANALYZABLE (ref))
+    return false;
+
+  /* Can't hoist/sink aggregate copies.  */
+  if (ref->mem.ref == error_mark_node)
+    return false;
+
+  /* It should be movable.  */
+  if (!is_gimple_reg_type (TREE_TYPE (ref->mem.ref))
+      || TREE_THIS_VOLATILE (ref->mem.ref)
+      || !for_each_index (&ref->mem.ref, may_move_till, loop))
+    return false;
+
+  /* If it can throw fail, we do not properly update EH info.  */
+  if (tree_could_throw_p (ref->mem.ref))
+    return false;
+
+  /* If it can trap, it must be always executed in LOOP.
+     Readonly memory locations may trap when storing to them, but
+     tree_could_trap_p is a predicate for rvalues, so check that
+     explicitly.  */
+  base = get_base_address (ref->mem.ref);
+  if ((tree_could_trap_p (ref->mem.ref)
+       || (DECL_P (base) && TREE_READONLY (base)))
+      /* ???  We can at least use false here, allowing loads?  We
+	 are forcing conditional stores if the ref is not always
+	 stored to later anyway.  So this would only guard
+	 the load we need to emit.  Thus when the ref is not
+	 loaded we can elide this completely?  */
+      && !ref_always_accessed_p (loop, ref, true))
+    return false;
+
+  /* Verify all loads of ref can be hoisted.  */
+  if (ref->loaded
+      && bitmap_bit_p (ref->loaded, loop->num)
+      && !ref_indep_loop_p (loop, ref, lim_raw))
+    return false;
+
+  /* Verify the candidate can be disambiguated against all loads,
+     that is, we can elide all in-loop stores.  Disambiguation
+     against stores is done later when we cannot guarantee preserving
+     the order of stores.  */
+  if (!ref_indep_loop_p (loop, ref, sm_war))
+    return false;
+
+  /* Verify whether the candidate is hot for LOOP.  Only do store motion if the
+    candidate's profile count is hot.  Statement in cold BB shouldn't be moved
+    out of it's loop_father.  */
+  if (!for_all_locs_in_loop (loop, ref, ref_in_loop_hot_body (loop)))
+    return false;
+
+  return true;
+}
+
+/* Marks the references in LOOP for that store motion should be performed
+   in REFS_TO_SM.  SM_EXECUTED is the set of references for that store
+   motion was performed in one of the outer loops.  */
+
+static void
+find_refs_for_sm (class loop *loop, bitmap sm_executed, bitmap refs_to_sm)
+{
+  bitmap refs = &memory_accesses.all_refs_stored_in_loop[loop->num];
+  unsigned i;
+  bitmap_iterator bi;
+  im_mem_ref *ref;
+
+  EXECUTE_IF_AND_COMPL_IN_BITMAP (refs, sm_executed, 0, i, bi)
+    {
+      ref = memory_accesses.refs_list[i];
+      if (can_sm_ref_p (loop, ref) && dbg_cnt (lim))
+	bitmap_set_bit (refs_to_sm, i);
+    }
+}
+
+/* Checks whether LOOP (with exits stored in EXITS array) is suitable
+   for a store motion optimization (i.e. whether we can insert statement
+   on its exits).  */
+
+static bool
+loop_suitable_for_sm (class loop *loop ATTRIBUTE_UNUSED,
+		      const vec<edge> &exits)
+{
+  unsigned i;
+  edge ex;
+
+  FOR_EACH_VEC_ELT (exits, i, ex)
+    if (ex->flags & (EDGE_ABNORMAL | EDGE_EH))
+      return false;
+
+  return true;
+}
+
+/* Try to perform store motion for all memory references modified inside
+   LOOP.  SM_EXECUTED is the bitmap of the memory references for that
+   store motion was executed in one of the outer loops.  */
+
+static void
+store_motion_loop (class loop *loop, bitmap sm_executed)
+{
+  auto_vec<edge> exits = get_loop_exit_edges (loop);
+  class loop *subloop;
+  bitmap sm_in_loop = BITMAP_ALLOC (&lim_bitmap_obstack);
+
+  if (loop_suitable_for_sm (loop, exits))
+    {
+      find_refs_for_sm (loop, sm_executed, sm_in_loop);
+      if (!bitmap_empty_p (sm_in_loop))
+	hoist_memory_references (loop, sm_in_loop, exits);
+    }
+
+  bitmap_ior_into (sm_executed, sm_in_loop);
+  for (subloop = loop->inner; subloop != NULL; subloop = subloop->next)
+    store_motion_loop (subloop, sm_executed);
+  bitmap_and_compl_into (sm_executed, sm_in_loop);
+  BITMAP_FREE (sm_in_loop);
+}
+
+/* Try to perform store motion for all memory references modified inside
+   loops.  */
+
+static void
+do_store_motion (void)
+{
+  class loop *loop;
+  bitmap sm_executed = BITMAP_ALLOC (&lim_bitmap_obstack);
+
+  for (loop = current_loops->tree_root->inner; loop != NULL; loop = loop->next)
+    store_motion_loop (loop, sm_executed);
+
+  BITMAP_FREE (sm_executed);
+}
+
+/* Fills ALWAYS_EXECUTED_IN information for basic blocks of LOOP, i.e.
+   for each such basic block bb records the outermost loop for that execution
+   of its header implies execution of bb.  CONTAINS_CALL is the bitmap of
+   blocks that contain a nonpure call.  */
+
+static void
+fill_always_executed_in_1 (class loop *loop, sbitmap contains_call)
+{
+  basic_block bb = NULL, last = NULL;
+  edge e;
+  class loop *inn_loop = loop;
+
+  if (ALWAYS_EXECUTED_IN (loop->header) == NULL)
+    {
+      auto_vec<basic_block, 64> worklist;
+      worklist.reserve_exact (loop->num_nodes);
+      worklist.quick_push (loop->header);
+      do
+	{
+	  edge_iterator ei;
+	  bb = worklist.pop ();
+
+	  if (!flow_bb_inside_loop_p (inn_loop, bb))
+	    {
+	      /* When we are leaving a possibly infinite inner loop
+		 we have to stop processing.  */
+	      if (!finite_loop_p (inn_loop))
+		break;
+	      /* If the loop was finite we can continue with processing
+		 the loop we exited to.  */
+	      inn_loop = bb->loop_father;
+	    }
+
+	  if (dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
+	    last = bb;
+
+	  if (bitmap_bit_p (contains_call, bb->index))
+	    break;
+
+	  /* If LOOP exits from this BB stop processing.  */
+	  FOR_EACH_EDGE (e, ei, bb->succs)
+	    if (!flow_bb_inside_loop_p (loop, e->dest))
+	      break;
+	  if (e)
+	    break;
+
+	  /* A loop might be infinite (TODO use simple loop analysis
+	     to disprove this if possible).  */
+	  if (bb->flags & BB_IRREDUCIBLE_LOOP)
+	    break;
+
+	  if (bb->loop_father->header == bb)
+	    /* Record that we enter into a subloop since it might not
+	       be finite.  */
+	    /* ???  Entering into a not always executed subloop makes
+	       fill_always_executed_in quadratic in loop depth since
+	       we walk those loops N times.  This is not a problem
+	       in practice though, see PR102253 for a worst-case testcase.  */
+	    inn_loop = bb->loop_father;
+
+	  /* Walk the body of LOOP sorted by dominance relation.  Additionally,
+	     if a basic block S dominates the latch, then only blocks dominated
+	     by S are after it.
+	     This is get_loop_body_in_dom_order using a worklist algorithm and
+	     stopping once we are no longer interested in visiting further
+	     blocks.  */
+	  unsigned old_len = worklist.length ();
+	  unsigned postpone = 0;
+	  for (basic_block son = first_dom_son (CDI_DOMINATORS, bb);
+	       son;
+	       son = next_dom_son (CDI_DOMINATORS, son))
+	    {
+	      if (!flow_bb_inside_loop_p (loop, son))
+		continue;
+	      if (dominated_by_p (CDI_DOMINATORS, loop->latch, son))
+		postpone = worklist.length ();
+	      worklist.quick_push (son);
+	    }
+	  if (postpone)
+	    /* Postponing the block that dominates the latch means
+	       processing it last and thus putting it earliest in the
+	       worklist.  */
+	    std::swap (worklist[old_len], worklist[postpone]);
+	}
+      while (!worklist.is_empty ());
+
+      while (1)
+	{
+	  if (dump_enabled_p ())
+	    dump_printf (MSG_NOTE, "BB %d is always executed in loop %d\n",
+			 last->index, loop->num);
+	  SET_ALWAYS_EXECUTED_IN (last, loop);
+	  if (last == loop->header)
+	    break;
+	  last = get_immediate_dominator (CDI_DOMINATORS, last);
+	}
+    }
+
+  for (loop = loop->inner; loop; loop = loop->next)
+    fill_always_executed_in_1 (loop, contains_call);
+}
+
+/* Fills ALWAYS_EXECUTED_IN information for basic blocks, i.e.
+   for each such basic block bb records the outermost loop for that execution
+   of its header implies execution of bb.  */
+
+static void
+fill_always_executed_in (void)
+{
+  basic_block bb;
+  class loop *loop;
+
+  auto_sbitmap contains_call (last_basic_block_for_fn (cfun));
+  bitmap_clear (contains_call);
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      gimple_stmt_iterator gsi;
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  if (nonpure_call_p (gsi_stmt (gsi)))
+	    break;
+	}
+
+      if (!gsi_end_p (gsi))
+	bitmap_set_bit (contains_call, bb->index);
+    }
+
+  for (loop = current_loops->tree_root->inner; loop; loop = loop->next)
+    fill_always_executed_in_1 (loop, contains_call);
+}
+
+/* Find the coldest loop preheader for LOOP, also find the nearest hotter loop
+   to LOOP.  Then recursively iterate each inner loop.  */
+
+void
+fill_coldest_and_hotter_out_loop (class loop *coldest_loop,
+				  class loop *hotter_loop, class loop *loop)
+{
+  if (bb_colder_than_loop_preheader (loop_preheader_edge (loop)->src,
+				     coldest_loop))
+    coldest_loop = loop;
+
+  coldest_outermost_loop[loop->num] = coldest_loop;
+
+  hotter_than_inner_loop[loop->num] = NULL;
+  class loop *outer_loop = loop_outer (loop);
+  if (hotter_loop
+      && bb_colder_than_loop_preheader (loop_preheader_edge (loop)->src,
+					hotter_loop))
+    hotter_than_inner_loop[loop->num] = hotter_loop;
+
+  if (outer_loop && outer_loop != current_loops->tree_root
+      && bb_colder_than_loop_preheader (loop_preheader_edge (loop)->src,
+					outer_loop))
+    hotter_than_inner_loop[loop->num] = outer_loop;
+
+  if (dump_enabled_p ())
+    {
+      dump_printf (MSG_NOTE, "loop %d's coldest_outermost_loop is %d, ",
+		   loop->num, coldest_loop->num);
+      if (hotter_than_inner_loop[loop->num])
+	dump_printf (MSG_NOTE, "hotter_than_inner_loop is %d\n",
+		     hotter_than_inner_loop[loop->num]->num);
+      else
+	dump_printf (MSG_NOTE, "hotter_than_inner_loop is NULL\n");
+    }
+
+  class loop *inner_loop;
+  for (inner_loop = loop->inner; inner_loop; inner_loop = inner_loop->next)
+    fill_coldest_and_hotter_out_loop (coldest_loop,
+				      hotter_than_inner_loop[loop->num],
+				      inner_loop);
+}
+
+/* Compute the global information needed by the loop invariant motion pass.  */
+
+static void
+tree_ssa_lim_initialize (bool store_motion)
+{
+  unsigned i;
+
+  bitmap_obstack_initialize (&lim_bitmap_obstack);
+  gcc_obstack_init (&mem_ref_obstack);
+  lim_aux_data_map = new hash_map<gimple *, lim_aux_data *>;
+
+  if (flag_tm)
+    compute_transaction_bits ();
+
+  memory_accesses.refs = new hash_table<mem_ref_hasher> (100);
+  memory_accesses.refs_list.create (100);
+  /* Allocate a special, unanalyzable mem-ref with ID zero.  */
+  memory_accesses.refs_list.quick_push
+    (mem_ref_alloc (NULL, 0, UNANALYZABLE_MEM_ID));
+
+  memory_accesses.refs_loaded_in_loop.create (number_of_loops (cfun));
+  memory_accesses.refs_loaded_in_loop.quick_grow (number_of_loops (cfun));
+  memory_accesses.refs_stored_in_loop.create (number_of_loops (cfun));
+  memory_accesses.refs_stored_in_loop.quick_grow (number_of_loops (cfun));
+  if (store_motion)
+    {
+      memory_accesses.all_refs_stored_in_loop.create (number_of_loops (cfun));
+      memory_accesses.all_refs_stored_in_loop.quick_grow
+						      (number_of_loops (cfun));
+    }
+
+  for (i = 0; i < number_of_loops (cfun); i++)
+    {
+      bitmap_initialize (&memory_accesses.refs_loaded_in_loop[i],
+			 &lim_bitmap_obstack);
+      bitmap_initialize (&memory_accesses.refs_stored_in_loop[i],
+			 &lim_bitmap_obstack);
+      if (store_motion)
+	bitmap_initialize (&memory_accesses.all_refs_stored_in_loop[i],
+			   &lim_bitmap_obstack);
+    }
+
+  memory_accesses.ttae_cache = NULL;
+
+  /* Initialize bb_loop_postorder with a mapping from loop->num to
+     its postorder index.  */
+  i = 0;
+  bb_loop_postorder = XNEWVEC (unsigned, number_of_loops (cfun));
+  for (auto loop : loops_list (cfun, LI_FROM_INNERMOST))
+    bb_loop_postorder[loop->num] = i++;
+}
+
+/* Cleans up after the invariant motion pass.  */
+
+static void
+tree_ssa_lim_finalize (void)
+{
+  basic_block bb;
+  unsigned i;
+  im_mem_ref *ref;
+
+  FOR_EACH_BB_FN (bb, cfun)
+    SET_ALWAYS_EXECUTED_IN (bb, NULL);
+
+  bitmap_obstack_release (&lim_bitmap_obstack);
+  delete lim_aux_data_map;
+
+  delete memory_accesses.refs;
+  memory_accesses.refs = NULL;
+
+  FOR_EACH_VEC_ELT (memory_accesses.refs_list, i, ref)
+    memref_free (ref);
+  memory_accesses.refs_list.release ();
+  obstack_free (&mem_ref_obstack, NULL);
+
+  memory_accesses.refs_loaded_in_loop.release ();
+  memory_accesses.refs_stored_in_loop.release ();
+  memory_accesses.all_refs_stored_in_loop.release ();
+
+  if (memory_accesses.ttae_cache)
+    free_affine_expand_cache (&memory_accesses.ttae_cache);
+
+  free (bb_loop_postorder);
+
+  coldest_outermost_loop.release ();
+  hotter_than_inner_loop.release ();
+}
+
+/* Moves invariants from loops.  Only "expensive" invariants are moved out --
+   i.e. those that are likely to be win regardless of the register pressure.
+   Only perform store motion if STORE_MOTION is true.  */
+
+unsigned int
+loop_invariant_motion_in_fun (function *fun, bool store_motion)
+{
+  unsigned int todo = 0;
+
+  tree_ssa_lim_initialize (store_motion);
+
+  /* Gathers information about memory accesses in the loops.  */
+  analyze_memory_references (store_motion);
+
+  /* Fills ALWAYS_EXECUTED_IN information for basic blocks.  */
+  fill_always_executed_in ();
+
+  /* Pre-compute coldest outermost loop and nearest hotter loop of each loop.
+   */
+  class loop *loop;
+  coldest_outermost_loop.create (number_of_loops (cfun));
+  coldest_outermost_loop.safe_grow_cleared (number_of_loops (cfun));
+  hotter_than_inner_loop.create (number_of_loops (cfun));
+  hotter_than_inner_loop.safe_grow_cleared (number_of_loops (cfun));
+  for (loop = current_loops->tree_root->inner; loop != NULL; loop = loop->next)
+    fill_coldest_and_hotter_out_loop (loop, NULL, loop);
+
+  int *rpo = XNEWVEC (int, last_basic_block_for_fn (fun));
+  int n = pre_and_rev_post_order_compute_fn (fun, NULL, rpo, false);
+
+  /* For each statement determine the outermost loop in that it is
+     invariant and cost for computing the invariant.  */
+  for (int i = 0; i < n; ++i)
+    compute_invariantness (BASIC_BLOCK_FOR_FN (fun, rpo[i]));
+
+  /* Execute store motion.  Force the necessary invariants to be moved
+     out of the loops as well.  */
+  if (store_motion)
+    do_store_motion ();
+
+  free (rpo);
+  rpo = XNEWVEC (int, last_basic_block_for_fn (fun));
+  n = pre_and_rev_post_order_compute_fn (fun, NULL, rpo, false);
+
+  /* Move the expressions that are expensive enough.  */
+  for (int i = 0; i < n; ++i)
+    todo |= move_computations_worker (BASIC_BLOCK_FOR_FN (fun, rpo[i]));
+
+  free (rpo);
+
+  gsi_commit_edge_inserts ();
+  if (need_ssa_update_p (fun))
+    rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
+
+  tree_ssa_lim_finalize ();
+
+  return todo;
+}
+
+/* Loop invariant motion pass.  */
+
+namespace {
+
+const pass_data pass_data_lim =
+{
+  GIMPLE_PASS, /* type */
+  "lim", /* name */
+  OPTGROUP_LOOP, /* optinfo_flags */
+  TV_LIM, /* tv_id */
+  PROP_cfg, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  0, /* todo_flags_finish */
+};
+
+class pass_lim : public gimple_opt_pass
+{
+public:
+  pass_lim (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_lim, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  opt_pass * clone () { return new pass_lim (m_ctxt); }
+  virtual bool gate (function *) { return flag_tree_loop_im != 0; }
+  virtual unsigned int execute (function *);
+
+}; // class pass_lim
+
+unsigned int
+pass_lim::execute (function *fun)
+{
+  bool in_loop_pipeline = scev_initialized_p ();
+  if (!in_loop_pipeline)
+    loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
+
+  if (number_of_loops (fun) <= 1)
+    return 0;
+  unsigned int todo = loop_invariant_motion_in_fun (fun, flag_move_loop_stores);
+
+  if (!in_loop_pipeline)
+    loop_optimizer_finalize ();
+  else
+    scev_reset ();
+  return todo;
+}
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_lim (gcc::context *ctxt)
+{
+  return new pass_lim (ctxt);
+}
+
+