--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/tree-ssa-alias.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,3799 @@
+/* Alias analysis for trees.
+   Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009
+   Free Software Foundation, Inc.
+   Contributed by Diego Novillo <dnovillo@redhat.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "timevar.h"
+#include "expr.h"
+#include "ggc.h"
+#include "langhooks.h"
+#include "flags.h"
+#include "function.h"
+#include "diagnostic.h"
+#include "tree-dump.h"
+#include "gimple.h"
+#include "tree-flow.h"
+#include "tree-inline.h"
+#include "tree-pass.h"
+#include "tree-ssa-structalias.h"
+#include "convert.h"
+#include "params.h"
+#include "ipa-type-escape.h"
+#include "vec.h"
+#include "bitmap.h"
+#include "vecprim.h"
+#include "pointer-set.h"
+#include "alloc-pool.h"
+
+/* Broad overview of how aliasing works:
+   
+   First we compute points-to sets, which is done in
+   tree-ssa-structalias.c
+      
+   During points-to set constraint finding, a bunch of little bits of
+   information is collected.
+   This is not done because it is necessary for points-to, but because
+   points-to has to walk every statement anyway.  The function performing
+   this collecting is update_alias_info.
+
+   Bits update_alias_info collects include:
+   1. Directly escaping variables and variables whose value escapes
+   (using is_escape_site).  This is the set of variables and values that
+   escape prior to transitive closure of the clobbers.
+   2.  The set of variables dereferenced on the LHS (into
+   dereferenced_ptr_stores) 
+   3. The set of variables dereferenced on the RHS (into
+   dereferenced_ptr_loads) 
+   4. The set of all pointers we saw.
+   5. The number of loads and stores for each variable
+   6. The number of statements touching memory
+   7. The set of address taken variables.
+   
+   
+   #1 is computed by a combination of is_escape_site, and counting the
+   number of uses/deref operators.  This function properly accounts for
+   situations like &ptr->field, which is *not* a dereference.
+   
+   After points-to sets are computed, the sets themselves still
+   contain points-to specific variables, such as a variable that says
+   the pointer points to anything, a variable that says the pointer
+   points to readonly memory, etc.
+
+   These are eliminated in a later phase, as we will see.
+
+   The rest of the phases are located in tree-ssa-alias.c
+
+   The next phase after points-to set computation is called
+   "setup_pointers_and_addressables"
+
+   This pass does 3 main things:
+   
+   1. All variables that can have TREE_ADDRESSABLE removed safely (IE
+   non-globals whose address is not taken), have TREE_ADDRESSABLE
+   removed.
+   2. All variables that may be aliased (which is the set of addressable
+   variables and globals) at all, are marked for renaming, and have
+   symbol memory tags created for them.
+   3. All variables which are stored into have their SMT's added to
+   written vars. 
+
+
+   After this function is run, all variables that will ever have an
+   SMT, have one, though its aliases are not filled in.
+
+   The next phase is to compute flow-insensitive aliasing, which in
+   our case, is a misnomer.  it is really computing aliasing that
+   requires no transitive closure to be correct.  In particular, it
+   uses stack vs non-stack, TBAA, etc, to determine whether two
+   symbols could *ever* alias .  This phase works by going through all
+   the pointers we collected during update_alias_info, and for every
+   addressable variable in the program, seeing if they alias.  If so,
+   the addressable variable is added to the symbol memory tag for the
+   pointer.
+
+   As part of this, we handle symbol memory tags that conflict but
+   have no aliases in common, by forcing them to have a symbol in
+   common (through unioning alias sets or adding one as an alias of
+   the other), or by adding one as an alias of another.  The case of
+   conflicts with no aliases in common occurs mainly due to aliasing
+   we cannot see.  In particular, it generally means we have a load
+   through a pointer whose value came from outside the function.
+   Without an addressable symbol to point to, they would get the wrong
+   answer.
+
+   After flow insensitive aliasing is computed, we compute name tags
+   (called compute_flow_sensitive_info).  We walk each pointer we
+   collected and see if it has a usable points-to set.  If so, we
+   generate a name tag using that pointer, and make an alias bitmap for
+   it.  Name tags are shared between all things with the same alias
+   bitmap.  The alias bitmap will be translated from what points-to
+   computed.  In particular, the "anything" variable in points-to will be
+   transformed into a pruned set of SMT's and their aliases that
+   compute_flow_insensitive_aliasing computed.
+   Note that since 4.3, every pointer that points-to computed a solution for
+   will get a name tag (whereas before 4.3, only those whose set did
+   *not* include the anything variable would).  At the point where name
+   tags are all assigned, symbol memory tags are dead, and could be
+   deleted, *except* on global variables.  Global variables still use
+   symbol memory tags as of right now.
+
+   After name tags are computed, the set of clobbered variables is
+   transitively closed.  In particular, we compute the set of clobbered
+   variables based on the initial set of clobbers, plus the aliases of
+   pointers which either escape, or have their value escape.
+
+   After this, maybe_create_global_var is run, which handles a corner
+   case where we have no call clobbered variables, but have pure and
+   non-pure functions.
+   
+   Staring at this function, I now remember it is a hack for the fact
+   that we do not mark all globals in the program as call clobbered for a
+   function unless they are actually used in that function.  Instead,  we
+   only mark the set that is actually clobbered.  As a result, you can
+   end up with situations where you have no call clobbered vars set.
+   
+   After maybe_create_global_var, we set pointers with the REF_ALL flag
+   to have alias sets that include all clobbered
+   memory tags and variables.
+   
+   After this, memory partitioning is computed (by the function
+   compute_memory_partitions) and alias sets are reworked accordingly.
+
+   Lastly, we delete partitions with no symbols, and clean up after
+   ourselves.  */
+
+
+/* Alias information used by compute_may_aliases and its helpers.  */
+struct alias_info
+{
+  /* SSA names visited while collecting points-to information.  If bit I
+     is set, it means that SSA variable with version I has already been
+     visited.  */
+  sbitmap ssa_names_visited;
+
+  /* Array of SSA_NAME pointers processed by the points-to collector.  */
+  VEC(tree,heap) *processed_ptrs;
+
+  /* ADDRESSABLE_VARS contains all the global variables and locals that
+     have had their address taken.  */
+  struct alias_map_d **addressable_vars;
+  size_t num_addressable_vars;
+
+  /* POINTERS contains all the _DECL pointers with unique memory tags
+     that have been referenced in the program.  */
+  struct alias_map_d **pointers;
+  size_t num_pointers;
+
+  /* Pointers that have been used in an indirect load/store operation.  */
+  struct pointer_set_t *dereferenced_ptrs;
+};
+
+
+/* Structure to map a variable to its alias set.  */
+struct alias_map_d
+{
+  /* Variable and its alias set.  */
+  tree var;
+  alias_set_type set;
+};
+
+
+/* Counters used to display statistics on alias analysis.  */
+struct alias_stats_d
+{
+  unsigned int alias_queries;
+  unsigned int alias_mayalias;
+  unsigned int alias_noalias;
+  unsigned int simple_queries;
+  unsigned int simple_resolved;
+  unsigned int tbaa_queries;
+  unsigned int tbaa_resolved;
+  unsigned int structnoaddress_queries;
+  unsigned int structnoaddress_resolved;
+};
+
+
+/* Local variables.  */
+static struct alias_stats_d alias_stats;
+static bitmap_obstack alias_bitmap_obstack;
+
+/* Local functions.  */
+static void compute_flow_insensitive_aliasing (struct alias_info *);
+static void dump_alias_stats (FILE *);
+static tree create_memory_tag (tree type, bool is_type_tag);
+static tree get_smt_for (tree, struct alias_info *);
+static tree get_nmt_for (tree);
+static void add_may_alias (tree, tree);
+static struct alias_info *init_alias_info (void);
+static void delete_alias_info (struct alias_info *);
+static void compute_flow_sensitive_aliasing (struct alias_info *);
+static void setup_pointers_and_addressables (struct alias_info *);
+static void update_alias_info (struct alias_info *);
+static void create_global_var (void);
+static void maybe_create_global_var (void);
+static void set_pt_anything (tree);
+
+void debug_mp_info (VEC(mem_sym_stats_t,heap) *);
+
+static alloc_pool mem_sym_stats_pool;
+
+/* Return memory reference stats for symbol VAR.  Create a new slot in
+   cfun->gimple_df->mem_sym_stats if needed.  */
+
+static struct mem_sym_stats_d *
+get_mem_sym_stats_for (tree var)
+{
+  void **slot;
+  struct mem_sym_stats_d *stats;
+  struct pointer_map_t *map = gimple_mem_ref_stats (cfun)->mem_sym_stats;
+  
+  gcc_assert (map);
+
+  slot = pointer_map_insert (map, var);
+  if (*slot == NULL)
+    {
+      stats = (struct mem_sym_stats_d *) pool_alloc (mem_sym_stats_pool);
+      memset (stats, 0, sizeof (*stats));
+      stats->var = var;
+      *slot = (void *) stats;
+    }
+  else
+    stats = (struct mem_sym_stats_d *) *slot;
+
+  return stats;
+}
+
+
+/* Return memory reference statistics for variable VAR in function FN.
+   This is computed by alias analysis, but it is not kept
+   incrementally up-to-date.  So, these stats are only accurate if
+   pass_may_alias has been run recently.  If no alias information
+   exists, this function returns NULL.  */
+
+static mem_sym_stats_t
+mem_sym_stats (struct function *fn, tree var)
+{
+  void **slot;
+  struct pointer_map_t *stats_map = gimple_mem_ref_stats (fn)->mem_sym_stats;
+
+  if (stats_map == NULL)
+    return NULL;
+
+  slot = pointer_map_contains (stats_map, var);
+  if (slot == NULL)
+    return NULL;
+
+  return (mem_sym_stats_t) *slot;
+}
+
+
+/* Set MPT to be the memory partition associated with symbol SYM.  */
+
+static inline void
+set_memory_partition (tree sym, tree mpt)
+{
+#if defined ENABLE_CHECKING
+  if (mpt)
+    gcc_assert (TREE_CODE (mpt) == MEMORY_PARTITION_TAG
+	        && !is_gimple_reg (sym));
+#endif
+
+  var_ann (sym)->mpt = mpt;
+  if (mpt)
+    {
+      if (MPT_SYMBOLS (mpt) == NULL)
+	MPT_SYMBOLS (mpt) = BITMAP_ALLOC (&alias_bitmap_obstack);
+
+      bitmap_set_bit (MPT_SYMBOLS (mpt), DECL_UID (sym));
+
+      /* MPT inherits the call-clobbering attributes from SYM.  */
+      if (is_call_clobbered (sym))
+	{
+	  MTAG_GLOBAL (mpt) = 1;
+	  mark_call_clobbered (mpt, ESCAPE_IS_GLOBAL);
+	}
+    }
+}
+
+
+/* Mark variable VAR as being non-addressable.  */
+
+static void
+mark_non_addressable (tree var)
+{
+  tree mpt;
+
+  if (!TREE_ADDRESSABLE (var))
+    return;
+
+  mpt = memory_partition (var);
+
+  clear_call_clobbered (var);
+  TREE_ADDRESSABLE (var) = 0;
+
+  if (mpt)
+    {
+      /* Note that it's possible for a symbol to have an associated
+	 MPT and the MPT have a NULL empty set.  During
+	 init_alias_info, all MPTs get their sets cleared out, but the
+	 symbols still point to the old MPTs that used to hold them.
+	 This is done so that compute_memory_partitions can now which
+	 symbols are losing or changing partitions and mark them for
+	 renaming.  */
+      if (MPT_SYMBOLS (mpt))
+	bitmap_clear_bit (MPT_SYMBOLS (mpt), DECL_UID (var));
+      set_memory_partition (var, NULL_TREE);
+    }
+}
+
+
+/* qsort comparison function to sort type/name tags by DECL_UID.  */
+
+static int
+sort_tags_by_id (const void *pa, const void *pb)
+{
+  const_tree const a = *(const_tree const *)pa;
+  const_tree const b = *(const_tree const *)pb;
+ 
+  return DECL_UID (a) - DECL_UID (b);
+}
+
+/* Initialize WORKLIST to contain those memory tags that are marked call
+   clobbered.  Initialized WORKLIST2 to contain the reasons these
+   memory tags escaped.  */
+
+static void
+init_transitive_clobber_worklist (VEC (tree, heap) **worklist,
+				  VEC (int, heap) **worklist2,
+				  bitmap on_worklist)
+{
+  referenced_var_iterator rvi;
+  tree curr;
+
+  FOR_EACH_REFERENCED_VAR (curr, rvi)
+    {
+      if (MTAG_P (curr) && is_call_clobbered (curr))
+	{
+	  VEC_safe_push (tree, heap, *worklist, curr);
+	  VEC_safe_push (int, heap, *worklist2,
+			 var_ann (curr)->escape_mask);
+	  bitmap_set_bit (on_worklist, DECL_UID (curr));
+	}
+    }
+}
+
+/* Add ALIAS to WORKLIST (and the reason for escaping REASON to WORKLIST2) if
+   ALIAS is not already marked call clobbered, and is a memory
+   tag.  */
+
+static void
+add_to_worklist (tree alias, VEC (tree, heap) **worklist,
+		 VEC (int, heap) **worklist2, int reason,
+		 bitmap on_worklist)
+{
+  if (MTAG_P (alias) && !is_call_clobbered (alias)
+      && !bitmap_bit_p (on_worklist, DECL_UID (alias)))
+    {
+      VEC_safe_push (tree, heap, *worklist, alias);
+      VEC_safe_push (int, heap, *worklist2, reason);
+      bitmap_set_bit (on_worklist, DECL_UID (alias));
+    }
+}
+
+/* Mark aliases of TAG as call clobbered, and place any tags on the
+   alias list that were not already call clobbered on WORKLIST.  */
+
+static void
+mark_aliases_call_clobbered (tree tag, VEC (tree, heap) **worklist,
+			     VEC (int, heap) **worklist2, bitmap on_worklist)
+{
+  bitmap aliases;
+  bitmap_iterator bi;
+  unsigned int i;
+  tree entry;
+  var_ann_t ta = var_ann (tag);
+
+  if (!MTAG_P (tag))
+    return;
+  aliases = may_aliases (tag);
+  if (!aliases)
+    return;
+
+  EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
+    {
+      entry = referenced_var (i);
+      /* If you clobber one part of a structure, you
+	 clobber the entire thing.  While this does not make
+	 the world a particularly nice place, it is necessary
+	 in order to allow C/C++ tricks that involve
+	 pointer arithmetic to work.  */
+      if (!unmodifiable_var_p (entry))
+	{
+	  add_to_worklist (entry, worklist, worklist2, ta->escape_mask,
+			   on_worklist);
+	  mark_call_clobbered (entry, ta->escape_mask);
+	}
+    }
+}
+
+/* Tags containing global vars need to be marked as global.
+   Tags containing call clobbered vars need to be marked as call
+   clobbered. */
+
+static void
+compute_tag_properties (void)
+{
+  referenced_var_iterator rvi;
+  tree tag;
+  bool changed = true;
+  VEC (tree, heap) *taglist = NULL;
+
+  FOR_EACH_REFERENCED_VAR (tag, rvi)
+    {
+      if (!MTAG_P (tag))
+	continue;
+      VEC_safe_push (tree, heap, taglist, tag);
+    }
+
+  /* We sort the taglist by DECL_UID, for two reasons.
+     1. To get a sequential ordering to make the bitmap accesses
+     faster.
+     2. Because of the way we compute aliases, it's more likely that
+     an earlier tag is included in a later tag, and this will reduce
+     the number of iterations.
+
+     If we had a real tag graph, we would just topo-order it and be
+     done with it.  */
+  qsort (VEC_address (tree, taglist),
+	 VEC_length (tree, taglist),
+	 sizeof (tree),
+	 sort_tags_by_id);
+
+  /* Go through each tag not marked as global, and if it aliases
+     global vars, mark it global. 
+     
+     If the tag contains call clobbered vars, mark it call
+     clobbered.  
+
+     This loop iterates because tags may appear in the may-aliases
+     list of other tags when we group.  */
+
+  while (changed)
+    {
+      unsigned int k;
+
+      changed = false;      
+      for (k = 0; VEC_iterate (tree, taglist, k, tag); k++)
+	{
+	  bitmap ma;
+	  bitmap_iterator bi;
+	  unsigned int i;
+	  tree entry;
+	  bool tagcc = is_call_clobbered (tag);
+	  bool tagglobal = MTAG_GLOBAL (tag);
+	  
+	  if (tagcc && tagglobal)
+	    continue;
+	  
+	  ma = may_aliases (tag);
+	  if (!ma)
+	    continue;
+
+	  EXECUTE_IF_SET_IN_BITMAP (ma, 0, i, bi)
+	    {
+	      entry = referenced_var (i);
+	      /* Call clobbered entries cause the tag to be marked
+		 call clobbered.  */
+	      if (!tagcc && is_call_clobbered (entry))
+		{
+		  mark_call_clobbered (tag, var_ann (entry)->escape_mask);
+		  tagcc = true;
+		  changed = true;
+		}
+
+	      /* Global vars cause the tag to be marked global.  */
+	      if (!tagglobal && is_global_var (entry))
+		{
+		  MTAG_GLOBAL (tag) = true;
+		  changed = true;
+		  tagglobal = true;
+		}
+
+	      /* Early exit once both global and cc are set, since the
+		 loop can't do any more than that.  */
+	      if (tagcc && tagglobal)
+		break;
+	    }
+	}
+    }
+  VEC_free (tree, heap, taglist);
+}
+
+/* Set up the initial variable clobbers, call-uses and globalness.
+   When this function completes, only tags whose aliases need to be
+   clobbered will be set clobbered.  Tags clobbered because they   
+   contain call clobbered vars are handled in compute_tag_properties.  */
+
+static void
+set_initial_properties (struct alias_info *ai)
+{
+  unsigned int i;
+  referenced_var_iterator rvi;
+  tree var;
+  tree ptr;
+  bool any_pt_anything = false;
+  enum escape_type pt_anything_mask = 0;
+
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (is_global_var (var))
+	{
+	  if (!unmodifiable_var_p (var))
+	    mark_call_clobbered (var, ESCAPE_IS_GLOBAL);
+	}
+      else if (TREE_CODE (var) == PARM_DECL
+	       && gimple_default_def (cfun, var)
+	       && POINTER_TYPE_P (TREE_TYPE (var)))
+	{
+	  tree def = gimple_default_def (cfun, var);
+	  get_ptr_info (def)->value_escapes_p = 1;
+	  get_ptr_info (def)->escape_mask |= ESCAPE_IS_PARM;	  
+	}
+    }
+
+  if (!clobber_what_escaped ())
+    {
+      any_pt_anything = true;
+      pt_anything_mask |= ESCAPE_TO_CALL;
+    }
+
+  compute_call_used_vars ();
+
+  for (i = 0; VEC_iterate (tree, ai->processed_ptrs, i, ptr); i++)
+    {
+      struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
+      tree tag = symbol_mem_tag (SSA_NAME_VAR (ptr));
+
+      /* A pointer that only escapes via a function return does not
+         add to the call clobber or call used solution.
+	 To exclude ESCAPE_TO_PURE_CONST we would need to track
+	 call used variables separately or compute those properly
+	 in the operand scanner.  */
+      if (pi->value_escapes_p
+	  && pi->escape_mask & ~ESCAPE_TO_RETURN)
+	{
+	  /* If PTR escapes then its associated memory tags and
+	     pointed-to variables are call-clobbered.  */
+	  if (pi->name_mem_tag)
+	    mark_call_clobbered (pi->name_mem_tag, pi->escape_mask);
+
+	  if (tag)
+	    mark_call_clobbered (tag, pi->escape_mask);
+	}
+
+      /* If the name tag is call clobbered, so is the symbol tag
+	 associated with the base VAR_DECL.  */
+      if (pi->name_mem_tag
+	  && tag
+	  && is_call_clobbered (pi->name_mem_tag))
+	mark_call_clobbered (tag, pi->escape_mask);
+
+      /* Name tags and symbol tags that we don't know where they point
+	 to, might point to global memory, and thus, are clobbered.
+
+         FIXME:  This is not quite right.  They should only be
+         clobbered if value_escapes_p is true, regardless of whether
+         they point to global memory or not.
+         So removing this code and fixing all the bugs would be nice.
+         It is the cause of a bunch of clobbering.  */
+      if ((pi->pt_global_mem || pi->pt_anything) 
+	  && pi->memory_tag_needed && pi->name_mem_tag)
+	{
+	  mark_call_clobbered (pi->name_mem_tag, ESCAPE_IS_GLOBAL);
+	  MTAG_GLOBAL (pi->name_mem_tag) = true;
+	}
+      
+      if ((pi->pt_global_mem || pi->pt_anything) 
+	  && pi->memory_tag_needed
+	  && tag)
+	{
+	  mark_call_clobbered (tag, ESCAPE_IS_GLOBAL);
+	  MTAG_GLOBAL (tag) = true;
+	}
+    }
+
+  /* If a pt_anything pointer escaped we need to mark all addressable
+     variables call clobbered.  */
+  if (any_pt_anything)
+    {
+      bitmap_iterator bi;
+      unsigned int j;
+
+      EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, j, bi)
+	{
+	  tree var = referenced_var (j);
+	  if (!unmodifiable_var_p (var))
+	    mark_call_clobbered (var, pt_anything_mask);
+	}
+    }
+}
+
+/* Compute which variables need to be marked call clobbered because
+   their tag is call clobbered, and which tags need to be marked
+   global because they contain global variables.  */
+
+static void
+compute_call_clobbered (struct alias_info *ai)
+{
+  VEC (tree, heap) *worklist = NULL;
+  VEC (int,heap) *worklist2 = NULL;
+  bitmap on_worklist;
+
+  timevar_push (TV_CALL_CLOBBER);
+  on_worklist = BITMAP_ALLOC (NULL);
+    
+  set_initial_properties (ai);
+  init_transitive_clobber_worklist (&worklist, &worklist2, on_worklist);
+  while (VEC_length (tree, worklist) != 0)
+    {
+      tree curr = VEC_pop (tree, worklist);
+      int reason = VEC_pop (int, worklist2);
+
+      bitmap_clear_bit (on_worklist, DECL_UID (curr));
+      mark_call_clobbered (curr, reason);
+      mark_aliases_call_clobbered (curr, &worklist, &worklist2, on_worklist);
+    }
+  VEC_free (tree, heap, worklist);
+  VEC_free (int, heap, worklist2);
+  BITMAP_FREE (on_worklist);
+  compute_tag_properties ();
+  timevar_pop (TV_CALL_CLOBBER);
+}
+
+
+/* Dump memory partition information to FILE.  */
+
+static void
+dump_memory_partitions (FILE *file)
+{
+  unsigned i, npart;
+  unsigned long nsyms;
+  tree mpt;
+
+  fprintf (file, "\nMemory partitions\n\n");
+  for (i = 0, npart = 0, nsyms = 0;
+       VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, i, mpt);
+       i++)
+    {
+      if (mpt)
+	{
+	  bitmap syms = MPT_SYMBOLS (mpt);
+	  unsigned long n = (syms) ? bitmap_count_bits (syms) : 0;
+
+	  fprintf (file, "#%u: ", i);
+	  print_generic_expr (file, mpt, 0);
+	  fprintf (file, ": %lu elements: ", n);
+	  dump_decl_set (file, syms);
+	  npart++;
+	  nsyms += n;
+	}
+    }
+
+  fprintf (file, "\n%u memory partitions holding %lu symbols\n", npart, nsyms);
+}
+
+
+/* Dump memory partition information to stderr.  */
+
+void
+debug_memory_partitions (void)
+{
+  dump_memory_partitions (stderr);
+}
+
+
+/* Return true if memory partitioning is required given the memory
+   reference estimates in STATS.  */
+
+static inline bool
+need_to_partition_p (struct mem_ref_stats_d *stats)
+{
+  long num_vops = stats->num_vuses + stats->num_vdefs;
+  long avg_vops = CEIL (num_vops, stats->num_mem_stmts);
+  return (num_vops > (long) MAX_ALIASED_VOPS
+          && avg_vops > (long) AVG_ALIASED_VOPS);
+}
+
+
+/* Count the actual number of virtual operators in CFUN.  Note that
+   this is only meaningful after virtual operands have been populated,
+   so it should be invoked at the end of compute_may_aliases.
+
+   The number of virtual operators are stored in *NUM_VDEFS_P and
+   *NUM_VUSES_P, the number of partitioned symbols in
+   *NUM_PARTITIONED_P and the number of unpartitioned symbols in
+   *NUM_UNPARTITIONED_P.
+
+   If any of these pointers is NULL the corresponding count is not
+   computed.  */
+
+static void
+count_mem_refs (long *num_vuses_p, long *num_vdefs_p,
+		long *num_partitioned_p, long *num_unpartitioned_p)
+{
+  gimple_stmt_iterator gsi;
+  basic_block bb;
+  long num_vdefs, num_vuses, num_partitioned, num_unpartitioned;
+  referenced_var_iterator rvi;
+  tree sym;
+
+  num_vuses = num_vdefs = num_partitioned = num_unpartitioned = 0;
+
+  if (num_vuses_p || num_vdefs_p)
+    FOR_EACH_BB (bb)
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  gimple stmt = gsi_stmt (gsi);
+	  if (gimple_references_memory_p (stmt))
+	    {
+	      num_vuses += NUM_SSA_OPERANDS (stmt, SSA_OP_VUSE);
+	      num_vdefs += NUM_SSA_OPERANDS (stmt, SSA_OP_VDEF);
+	    }
+	}
+
+  if (num_partitioned_p || num_unpartitioned_p)
+    FOR_EACH_REFERENCED_VAR (sym, rvi)
+      {
+	if (is_gimple_reg (sym))
+	  continue;
+
+	if (memory_partition (sym))
+	  num_partitioned++;
+	else
+	  num_unpartitioned++;
+      }
+
+  if (num_vdefs_p)
+    *num_vdefs_p = num_vdefs;
+
+  if (num_vuses_p)
+    *num_vuses_p = num_vuses;
+
+  if (num_partitioned_p)
+    *num_partitioned_p = num_partitioned;
+
+  if (num_unpartitioned_p)
+    *num_unpartitioned_p = num_unpartitioned;
+}
+
+
+/* The list is sorted by increasing partitioning score (PSCORE).
+   This score is computed such that symbols with high scores are
+   those that are least likely to be partitioned.  Given a symbol
+   MP->VAR, PSCORE(S) is the result of the following weighted sum
+
+   PSCORE(S) =   FW * 64 + FR * 32
+   	       + DW * 16 + DR *  8 
+   	       + IW *  4 + IR *  2
+               + NO_ALIAS
+
+   where
+
+   FW		Execution frequency of writes to S
+   FR		Execution frequency of reads from S
+   DW		Number of direct writes to S
+   DR		Number of direct reads from S
+   IW		Number of indirect writes to S
+   IR		Number of indirect reads from S
+   NO_ALIAS	State of the NO_ALIAS* flags
+
+   The basic idea here is that symbols that are frequently
+   written-to in hot paths of the code are the last to be considered
+   for partitioning.  */
+
+static inline long
+mem_sym_score (mem_sym_stats_t mp)
+{
+  return mp->frequency_writes * 64 + mp->frequency_reads * 32
+         + mp->num_direct_writes * 16 + mp->num_direct_reads * 8
+	 + mp->num_indirect_writes * 4 + mp->num_indirect_reads * 2
+	 + var_ann (mp->var)->noalias_state;
+}
+
+
+/* Dump memory reference stats for function CFUN to FILE.  */
+
+void
+dump_mem_ref_stats (FILE *file)
+{
+  long actual_num_vuses, actual_num_vdefs;
+  long num_partitioned, num_unpartitioned;
+  struct mem_ref_stats_d *stats;
+  
+  stats = gimple_mem_ref_stats (cfun);
+
+  count_mem_refs (&actual_num_vuses, &actual_num_vdefs, &num_partitioned,
+                  &num_unpartitioned);
+
+  fprintf (file, "\nMemory reference statistics for %s\n\n", 
+	   lang_hooks.decl_printable_name (current_function_decl, 2));
+
+  fprintf (file, "Number of memory statements:     %ld\n",
+           stats->num_mem_stmts);
+  fprintf (file, "Number of call sites:            %ld\n",
+	   stats->num_call_sites);
+  fprintf (file, "Number of pure/const call sites: %ld\n",
+	   stats->num_pure_const_call_sites);
+  fprintf (file, "Number of asm sites:             %ld\n",
+	   stats->num_asm_sites);
+  fprintf (file, "Estimated number of loads:       %ld (%ld/stmt)\n",
+	   stats->num_vuses,
+	   (stats->num_mem_stmts)
+	   ? CEIL (stats->num_vuses, stats->num_mem_stmts)
+	   : 0);
+  fprintf (file, "Actual number of loads:          %ld (%ld/stmt)\n",
+	   actual_num_vuses, 
+	   (stats->num_mem_stmts)
+	   ? CEIL (actual_num_vuses, stats->num_mem_stmts)
+	   : 0);
+
+  if (actual_num_vuses > stats->num_vuses + (stats->num_vuses / 25))
+    fprintf (file, "\t(warning: estimation is lower by more than 25%%)\n");
+
+  fprintf (file, "Estimated number of stores:      %ld (%ld/stmt)\n",
+	   stats->num_vdefs,
+	   (stats->num_mem_stmts)
+	   ? CEIL (stats->num_vdefs, stats->num_mem_stmts)
+	   : 0);
+  fprintf (file, "Actual number of stores:         %ld (%ld/stmt)\n",
+	   actual_num_vdefs, 
+	   (stats->num_mem_stmts)
+	   ? CEIL (actual_num_vdefs, stats->num_mem_stmts)
+	   : 0);
+
+  if (actual_num_vdefs > stats->num_vdefs + (stats->num_vdefs / 25))
+    fprintf (file, "\t(warning: estimation is lower by more than 25%%)\n");
+
+  fprintf (file, "Partitioning thresholds:         MAX = %d   AVG = %d "
+           "(%sNEED TO PARTITION)\n", MAX_ALIASED_VOPS, AVG_ALIASED_VOPS,
+	   stats->num_mem_stmts && need_to_partition_p (stats) ? "" : "NO ");
+  fprintf (file, "Number of partitioned symbols:   %ld\n", num_partitioned);
+  fprintf (file, "Number of unpartitioned symbols: %ld\n", num_unpartitioned);
+}
+
+
+/* Dump memory reference stats for function FN to stderr.  */
+
+void
+debug_mem_ref_stats (void)
+{
+  dump_mem_ref_stats (stderr);
+}
+
+
+/* Dump memory reference stats for variable VAR to FILE.  */
+
+static void
+dump_mem_sym_stats (FILE *file, tree var)
+{
+  mem_sym_stats_t stats = mem_sym_stats (cfun, var);
+
+  if (stats == NULL)
+    return;
+
+  fprintf (file, "read frequency: %6ld, write frequency: %6ld, "
+           "direct reads: %3ld, direct writes: %3ld, "
+	   "indirect reads: %4ld, indirect writes: %4ld, symbol: ",
+	   stats->frequency_reads, stats->frequency_writes,
+	   stats->num_direct_reads, stats->num_direct_writes,
+	   stats->num_indirect_reads, stats->num_indirect_writes);
+  print_generic_expr (file, stats->var, 0);
+  fprintf (file, ", tags: ");
+  dump_decl_set (file, stats->parent_tags);
+}
+
+
+/* Dump memory reference stats for variable VAR to stderr.  */
+
+void
+debug_mem_sym_stats (tree var)
+{
+  dump_mem_sym_stats (stderr, var);
+}
+
+/* Dump memory reference stats for variable VAR to FILE.  For use
+   of tree-dfa.c:dump_variable.  */
+
+void
+dump_mem_sym_stats_for_var (FILE *file, tree var)
+{
+  mem_sym_stats_t stats = mem_sym_stats (cfun, var);
+
+  if (stats == NULL)
+    return;
+
+  fprintf (file, ", score: %ld", mem_sym_score (stats));
+  fprintf (file, ", direct reads: %ld", stats->num_direct_reads);
+  fprintf (file, ", direct writes: %ld", stats->num_direct_writes);
+  fprintf (file, ", indirect reads: %ld", stats->num_indirect_reads);
+  fprintf (file, ", indirect writes: %ld", stats->num_indirect_writes);
+}
+
+/* Dump memory reference stats for all memory symbols to FILE.  */
+
+static void
+dump_all_mem_sym_stats (FILE *file)
+{
+  referenced_var_iterator rvi;
+  tree sym;
+
+  FOR_EACH_REFERENCED_VAR (sym, rvi)
+    {
+      if (is_gimple_reg (sym))
+	continue;
+
+      dump_mem_sym_stats (file, sym);
+    }
+}
+
+
+/* Dump memory reference stats for all memory symbols to stderr.  */
+
+void
+debug_all_mem_sym_stats (void)
+{
+  dump_all_mem_sym_stats (stderr);
+}
+
+
+/* Dump the MP_INFO array to FILE.  */
+
+static void
+dump_mp_info (FILE *file, VEC(mem_sym_stats_t,heap) *mp_info)
+{
+  unsigned i;
+  mem_sym_stats_t mp_p;
+
+  for (i = 0; VEC_iterate (mem_sym_stats_t, mp_info, i, mp_p); i++)
+    if (!mp_p->partitioned_p)
+      dump_mem_sym_stats (file, mp_p->var);
+}
+
+
+/* Dump the MP_INFO array to stderr.  */
+
+void
+debug_mp_info (VEC(mem_sym_stats_t,heap) *mp_info)
+{
+  dump_mp_info (stderr, mp_info);
+}
+
+
+/* Update memory reference stats for symbol VAR in statement STMT.
+   NUM_DIRECT_READS and NUM_DIRECT_WRITES specify the number of times
+   that VAR is read/written in STMT (indirect reads/writes are not
+   recorded by this function, see compute_memory_partitions).  */
+
+void
+update_mem_sym_stats_from_stmt (tree var, gimple stmt, long num_direct_reads,
+                                long num_direct_writes)
+{
+  mem_sym_stats_t stats;
+
+  gcc_assert (num_direct_reads >= 0 && num_direct_writes >= 0);
+
+  stats = get_mem_sym_stats_for (var);
+
+  stats->num_direct_reads += num_direct_reads;
+  stats->frequency_reads += ((long) gimple_bb (stmt)->frequency
+                             * num_direct_reads);
+
+  stats->num_direct_writes += num_direct_writes;
+  stats->frequency_writes += ((long) gimple_bb (stmt)->frequency
+                              * num_direct_writes);
+}
+
+
+/* Given two MP_INFO entries MP1 and MP2, return -1 if MP1->VAR should
+   be partitioned before MP2->VAR, 0 if they are the same or 1 if
+   MP1->VAR should be partitioned after MP2->VAR.  */
+
+static inline int
+compare_mp_info_entries (mem_sym_stats_t mp1, mem_sym_stats_t mp2)
+{
+  long pscore1 = mem_sym_score (mp1);
+  long pscore2 = mem_sym_score (mp2);
+
+  if (pscore1 < pscore2)
+    return -1;
+  else if (pscore1 > pscore2)
+    return 1;
+  else
+    return DECL_UID (mp1->var) - DECL_UID (mp2->var);
+}
+
+
+/* Comparison routine for qsort.  The list is sorted by increasing
+   partitioning score (PSCORE).  This score is computed such that
+   symbols with high scores are those that are least likely to be
+   partitioned.  */
+
+static int
+mp_info_cmp (const void *p, const void *q)
+{
+  mem_sym_stats_t e1 = *((const mem_sym_stats_t *) p);
+  mem_sym_stats_t e2 = *((const mem_sym_stats_t *) q);
+  return compare_mp_info_entries (e1, e2);
+}
+
+
+/* Sort the array of reference counts used to compute memory partitions.
+   Elements are sorted in ascending order of execution frequency and 
+   descending order of virtual operators needed.  */
+
+static inline void
+sort_mp_info (VEC(mem_sym_stats_t,heap) *list)
+{
+  unsigned num = VEC_length (mem_sym_stats_t, list);
+
+  if (num < 2)
+    return;
+
+  if (num == 2)
+    {
+      if (compare_mp_info_entries (VEC_index (mem_sym_stats_t, list, 0),
+	                           VEC_index (mem_sym_stats_t, list, 1)) > 0)
+	{  
+	  /* Swap elements if they are in the wrong order.  */
+	  mem_sym_stats_t tmp = VEC_index (mem_sym_stats_t, list, 0);
+	  VEC_replace (mem_sym_stats_t, list, 0,
+	               VEC_index (mem_sym_stats_t, list, 1));
+	  VEC_replace (mem_sym_stats_t, list, 1, tmp);
+	}
+
+      return;
+    }
+
+  /* There are 3 or more elements, call qsort.  */
+  qsort (VEC_address (mem_sym_stats_t, list),
+         VEC_length (mem_sym_stats_t, list), 
+	 sizeof (mem_sym_stats_t),
+	 mp_info_cmp);
+}
+
+
+/* Return the memory partition tag (MPT) associated with memory
+   symbol SYM.  */
+
+static tree
+get_mpt_for (tree sym)
+{
+  tree mpt;
+
+  /* Don't create a new tag unnecessarily.  */
+  mpt = memory_partition (sym);
+  if (mpt == NULL_TREE)
+    {
+      mpt = create_tag_raw (MEMORY_PARTITION_TAG, TREE_TYPE (sym), "MPT");
+      TREE_ADDRESSABLE (mpt) = 0;
+      add_referenced_var (mpt);
+      VEC_safe_push (tree, heap, gimple_ssa_operands (cfun)->mpt_table, mpt);
+      gcc_assert (MPT_SYMBOLS (mpt) == NULL);
+      set_memory_partition (sym, mpt);
+    }
+
+  return mpt;
+}
+
+
+/* Add MP_P->VAR to a memory partition and return the partition.  */
+
+static tree
+find_partition_for (mem_sym_stats_t mp_p)
+{
+  unsigned i;
+  VEC(tree,heap) *mpt_table;
+  tree mpt;
+
+  mpt_table = gimple_ssa_operands (cfun)->mpt_table;
+  mpt = NULL_TREE;
+
+  /* Find an existing partition for MP_P->VAR.  */
+  for (i = 0; VEC_iterate (tree, mpt_table, i, mpt); i++)
+    {
+      mem_sym_stats_t mpt_stats;
+
+      /* If MPT does not have any symbols yet, use it.  */
+      if (MPT_SYMBOLS (mpt) == NULL)
+	break;
+
+      /* Otherwise, see if MPT has common parent tags with MP_P->VAR,
+	 but avoid grouping clobbered variables with non-clobbered
+	 variables (otherwise, this tends to creates a single memory
+	 partition because other call-clobbered variables may have
+	 common parent tags with non-clobbered ones).  */
+      mpt_stats = get_mem_sym_stats_for (mpt);
+      if (mp_p->parent_tags
+	  && mpt_stats->parent_tags
+	  && is_call_clobbered (mpt) == is_call_clobbered (mp_p->var)
+	  && bitmap_intersect_p (mpt_stats->parent_tags, mp_p->parent_tags))
+	break;
+
+      /* If no common parent tags are found, see if both MPT and
+	 MP_P->VAR are call-clobbered.  */
+      if (is_call_clobbered (mpt) && is_call_clobbered (mp_p->var))
+	break;
+    }
+
+  if (mpt == NULL_TREE)
+    mpt = get_mpt_for (mp_p->var);
+  else
+    set_memory_partition (mp_p->var, mpt);
+
+  mp_p->partitioned_p = true;
+
+  mark_sym_for_renaming (mp_p->var);
+  mark_sym_for_renaming (mpt);
+
+  return mpt;
+}
+
+
+/* Rewrite the alias set for TAG to use the newly created partitions.
+   If TAG is NULL, rewrite the set of call-clobbered variables.
+   NEW_ALIASES is a scratch bitmap to build the new set of aliases for
+   TAG.  */
+
+static void
+rewrite_alias_set_for (tree tag, bitmap new_aliases)
+{
+  bitmap_iterator bi;
+  unsigned i;
+  tree mpt, sym;
+
+  EXECUTE_IF_SET_IN_BITMAP (MTAG_ALIASES (tag), 0, i, bi)
+    {
+      sym = referenced_var (i);
+      mpt = memory_partition (sym);
+      if (mpt)
+	bitmap_set_bit (new_aliases, DECL_UID (mpt));
+      else
+	bitmap_set_bit (new_aliases, DECL_UID (sym));
+    }
+
+  /* Rebuild the may-alias array for TAG.  */
+  bitmap_copy (MTAG_ALIASES (tag), new_aliases);
+}
+
+
+/* Determine how many virtual operands can be saved by partitioning
+   MP_P->VAR into MPT.  When a symbol S is thrown inside a partition
+   P, every virtual operand that used to reference S will now
+   reference P.  Whether it reduces the number of virtual operands
+   depends on:
+
+   1- Direct references to S are never saved.  Instead of the virtual
+      operand to S, we will now have a virtual operand to P.
+
+   2- Indirect references to S are reduced only for those memory tags
+      holding S that already had other symbols partitioned into P.
+      For instance, if a memory tag T has the alias set { a b S c },
+      the first time we partition S into P, the alias set will become
+      { a b P c }, so no virtual operands will be saved. However, if
+      we now partition symbol 'c' into P, then the alias set for T
+      will become { a b P }, so we will be saving one virtual operand
+      for every indirect reference to 'c'.
+
+   3- Is S is call-clobbered, we save as many virtual operands as
+      call/asm sites exist in the code, but only if other
+      call-clobbered symbols have been grouped into P.  The first
+      call-clobbered symbol that we group does not produce any
+      savings.
+
+   MEM_REF_STATS points to CFUN's memory reference information.  */
+
+static void
+estimate_vop_reduction (struct mem_ref_stats_d *mem_ref_stats,
+                        mem_sym_stats_t mp_p, tree mpt)
+{
+  unsigned i;
+  bitmap_iterator bi;
+  mem_sym_stats_t mpt_stats;
+
+  /* We should only get symbols with indirect references here.  */
+  gcc_assert (mp_p->num_indirect_reads > 0 || mp_p->num_indirect_writes > 0);
+
+  /* Note that the only statistics we keep for MPT is the set of
+     parent tags to know which memory tags have had alias members
+     partitioned, and the indicator has_call_clobbered_vars.
+     Reference counts are not important for MPT.  */
+  mpt_stats = get_mem_sym_stats_for (mpt);
+
+  /* Traverse all the parent tags for MP_P->VAR.  For every tag T, if
+     partition P is already grouping aliases of T, then reduce the
+     number of virtual operands by the number of direct references
+     to T.  */
+  if (mp_p->parent_tags)
+    {
+      if (mpt_stats->parent_tags == NULL)
+	mpt_stats->parent_tags = BITMAP_ALLOC (&alias_bitmap_obstack);
+
+      EXECUTE_IF_SET_IN_BITMAP (mp_p->parent_tags, 0, i, bi)
+	{
+	  if (bitmap_bit_p (mpt_stats->parent_tags, i))
+	    {
+	      /* Partition MPT is already partitioning symbols in the
+		 alias set for TAG.  This means that we are now saving
+		 1 virtual operand for every direct reference to TAG.  */
+	      tree tag = referenced_var (i);
+	      mem_sym_stats_t tag_stats = mem_sym_stats (cfun, tag);
+	      mem_ref_stats->num_vuses -= tag_stats->num_direct_reads;
+	      mem_ref_stats->num_vdefs -= tag_stats->num_direct_writes;
+	    }
+	  else
+	    {
+	      /* This is the first symbol in tag I's alias set that is
+		 being grouped under MPT.  We will not save any
+		 virtual operands this time, but record that MPT is
+		 grouping a symbol from TAG's alias set so that the
+		 next time we get the savings.  */
+	      bitmap_set_bit (mpt_stats->parent_tags, i);
+	    }
+	}
+    }
+
+  /* If MP_P->VAR is call-clobbered, and MPT is already grouping
+     call-clobbered symbols, then we will save as many virtual
+     operands as asm/call sites there are.  */
+  if (is_call_clobbered (mp_p->var))
+    {
+      if (mpt_stats->has_call_clobbered_vars)
+	mem_ref_stats->num_vdefs -= mem_ref_stats->num_call_sites
+	                            + mem_ref_stats->num_asm_sites;
+      else
+	mpt_stats->has_call_clobbered_vars = true;
+    }
+}
+
+
+/* Helper for compute_memory_partitions.  Transfer reference counts
+   from pointers to their pointed-to sets.  Counters for pointers were
+   computed by update_alias_info.  MEM_REF_STATS points to CFUN's
+   memory reference information.  */
+
+static void
+update_reference_counts (struct mem_ref_stats_d *mem_ref_stats)
+{
+  unsigned i;
+  bitmap_iterator bi;
+  mem_sym_stats_t sym_stats;
+
+  for (i = 1; i < num_ssa_names; i++)
+    {
+      tree ptr;
+      struct ptr_info_def *pi;
+
+      ptr = ssa_name (i);
+      if (ptr
+	  && POINTER_TYPE_P (TREE_TYPE (ptr))
+	  && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
+	  && pi->memory_tag_needed)
+	{
+	  unsigned j;
+	  bitmap_iterator bj;
+	  tree tag;
+	  mem_sym_stats_t ptr_stats, tag_stats;
+
+	  /* If PTR has flow-sensitive points-to information, use
+	     PTR's name tag, otherwise use the symbol tag associated
+	     with PTR's symbol.  */
+	  if (pi->name_mem_tag)
+	    tag = pi->name_mem_tag;
+	  else
+	    tag = symbol_mem_tag (SSA_NAME_VAR (ptr));
+
+	  ptr_stats = get_mem_sym_stats_for (ptr);
+	  tag_stats = get_mem_sym_stats_for (tag);
+
+	  /* TAG has as many direct references as dereferences we
+	     found for its parent pointer.  */
+	  tag_stats->num_direct_reads += ptr_stats->num_direct_reads;
+	  tag_stats->num_direct_writes += ptr_stats->num_direct_writes;
+
+	  /* All the dereferences of pointer PTR are considered direct
+	     references to PTR's memory tag (TAG).  In turn,
+	     references to TAG will become virtual operands for every
+	     symbol in TAG's alias set.  So, for every symbol ALIAS in
+	     TAG's alias set, add as many indirect references to ALIAS
+	     as direct references there are for TAG.  */
+	  if (MTAG_ALIASES (tag))
+	    EXECUTE_IF_SET_IN_BITMAP (MTAG_ALIASES (tag), 0, j, bj)
+	      {
+		tree alias = referenced_var (j);
+		sym_stats = get_mem_sym_stats_for (alias);
+
+		/* All the direct references to TAG are indirect references
+		   to ALIAS.  */
+		sym_stats->num_indirect_reads += ptr_stats->num_direct_reads;
+		sym_stats->num_indirect_writes += ptr_stats->num_direct_writes;
+		sym_stats->frequency_reads += ptr_stats->frequency_reads;
+		sym_stats->frequency_writes += ptr_stats->frequency_writes;
+
+		/* Indicate that TAG is one of ALIAS's parent tags.  */
+		if (sym_stats->parent_tags == NULL)
+		  sym_stats->parent_tags = BITMAP_ALLOC (&alias_bitmap_obstack);
+		bitmap_set_bit (sym_stats->parent_tags, DECL_UID (tag));
+	      }
+	}
+    }
+
+  /* Call-clobbered symbols are indirectly written at every
+     call/asm site.  */
+  EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
+    {
+      tree sym = referenced_var (i);
+      sym_stats = get_mem_sym_stats_for (sym);
+      sym_stats->num_indirect_writes += mem_ref_stats->num_call_sites
+	                                + mem_ref_stats->num_asm_sites;
+    }
+
+  /* Addressable symbols are indirectly written at some ASM sites.
+     Since only ASM sites that clobber memory actually affect
+     addressable symbols, this is an over-estimation.  */
+  EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
+    {
+      tree sym = referenced_var (i);
+      sym_stats = get_mem_sym_stats_for (sym);
+      sym_stats->num_indirect_writes += mem_ref_stats->num_asm_sites;
+    }
+}
+
+
+/* Helper for compute_memory_partitions.  Add all memory symbols to
+   *MP_INFO_P and compute the initial estimate for the total number of
+   virtual operands needed.  MEM_REF_STATS points to CFUN's memory
+   reference information.  On exit, *TAGS_P will contain the list of
+   memory tags whose alias set need to be rewritten after
+   partitioning.  */
+
+static void
+build_mp_info (struct mem_ref_stats_d *mem_ref_stats,
+               VEC(mem_sym_stats_t,heap) **mp_info_p,
+	       VEC(tree,heap) **tags_p)
+{
+  tree var;
+  referenced_var_iterator rvi;
+
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      mem_sym_stats_t sym_stats;
+      tree old_mpt;
+
+      /* We are only interested in memory symbols other than MPTs.  */
+      if (is_gimple_reg (var) || TREE_CODE (var) == MEMORY_PARTITION_TAG)
+	continue;
+
+      /* Collect memory tags into the TAGS array so that we can
+	 rewrite their alias sets after partitioning.  */
+      if (MTAG_P (var) && MTAG_ALIASES (var))
+	VEC_safe_push (tree, heap, *tags_p, var);
+
+      /* Since we are going to re-compute partitions, any symbols that
+	 used to belong to a partition must be detached from it and
+	 marked for renaming.  */
+      if ((old_mpt = memory_partition (var)) != NULL)
+	{
+	  mark_sym_for_renaming (old_mpt);
+	  set_memory_partition (var, NULL_TREE);
+	  mark_sym_for_renaming (var);
+	}
+
+      sym_stats = get_mem_sym_stats_for (var);
+
+      /* Add VAR's reference info to MP_INFO.  Note that the only
+	 symbols that make sense to partition are those that have
+	 indirect references.  If a symbol S is always directly
+	 referenced, partitioning it will not reduce the number of
+	 virtual operators.  The only symbols that are profitable to
+	 partition are those that belong to alias sets and/or are
+	 call-clobbered.  */
+      if (sym_stats->num_indirect_reads > 0
+	  || sym_stats->num_indirect_writes > 0)
+	VEC_safe_push (mem_sym_stats_t, heap, *mp_info_p, sym_stats);
+
+      /* Update the number of estimated VOPS.  Note that direct
+	 references to memory tags are always counted as indirect
+	 references to their alias set members, so if a memory tag has
+	 aliases, do not count its direct references to avoid double
+	 accounting.  */
+      if (!MTAG_P (var) || !MTAG_ALIASES (var))
+	{
+	  mem_ref_stats->num_vuses += sym_stats->num_direct_reads;
+	  mem_ref_stats->num_vdefs += sym_stats->num_direct_writes;
+	}
+
+      mem_ref_stats->num_vuses += sym_stats->num_indirect_reads;
+      mem_ref_stats->num_vdefs += sym_stats->num_indirect_writes;
+    }
+}
+
+
+/* Compute memory partitions.  A memory partition (MPT) is an
+   arbitrary grouping of memory symbols, such that references to one
+   member of the group is considered a reference to all the members of
+   the group.
+   
+   As opposed to alias sets in memory tags, the grouping into
+   partitions is completely arbitrary and only done to reduce the
+   number of virtual operands.  The only rule that needs to be
+   observed when creating memory partitions is that given two memory
+   partitions MPT.i and MPT.j, they must not contain symbols in
+   common.
+
+   Memory partitions are used when putting the program into Memory-SSA
+   form.  In particular, in Memory-SSA PHI nodes are not computed for
+   individual memory symbols.  They are computed for memory
+   partitions.  This reduces the amount of PHI nodes in the SSA graph
+   at the expense of precision (i.e., it makes unrelated stores affect
+   each other).
+   
+   However, it is possible to increase precision by changing this
+   partitioning scheme.  For instance, if the partitioning scheme is
+   such that get_mpt_for is the identity function (that is,
+   get_mpt_for (s) = s), this will result in ultimate precision at the
+   expense of huge SSA webs.
+
+   At the other extreme, a partitioning scheme that groups all the
+   symbols in the same set results in minimal SSA webs and almost
+   total loss of precision.
+
+   There partitioning heuristic uses three parameters to decide the
+   order in which symbols are processed.  The list of symbols is
+   sorted so that symbols that are more likely to be partitioned are
+   near the top of the list:
+
+   - Execution frequency.  If a memory references is in a frequently
+     executed code path, grouping it into a partition may block useful
+     transformations and cause sub-optimal code generation.  So, the
+     partition heuristic tries to avoid grouping symbols with high
+     execution frequency scores.  Execution frequency is taken
+     directly from the basic blocks where every reference is made (see
+     update_mem_sym_stats_from_stmt), which in turn uses the
+     profile guided machinery, so if the program is compiled with PGO
+     enabled, more accurate partitioning decisions will be made.
+
+   - Number of references.  Symbols with few references in the code,
+     are partitioned before symbols with many references.
+
+   - NO_ALIAS attributes.  Symbols with any of the NO_ALIAS*
+     attributes are partitioned after symbols marked MAY_ALIAS.
+
+   Once the list is sorted, the partitioning proceeds as follows:
+
+   1- For every symbol S in MP_INFO, create a new memory partition MP,
+      if necessary.  To avoid memory partitions that contain symbols
+      from non-conflicting alias sets, memory partitions are
+      associated to the memory tag that holds S in its alias set.  So,
+      when looking for a memory partition for S, the memory partition
+      associated with one of the memory tags holding S is chosen.  If
+      none exists, a new one is created.
+
+   2- Add S to memory partition MP.
+
+   3- Reduce by 1 the number of VOPS for every memory tag holding S.
+
+   4- If the total number of VOPS is less than MAX_ALIASED_VOPS or the
+      average number of VOPS per statement is less than
+      AVG_ALIASED_VOPS, stop.  Otherwise, go to the next symbol in the
+      list.  */
+
+static void
+compute_memory_partitions (void)
+{
+  tree tag;
+  unsigned i;
+  mem_sym_stats_t mp_p;
+  VEC(mem_sym_stats_t,heap) *mp_info;
+  bitmap new_aliases;
+  VEC(tree,heap) *tags;
+  struct mem_ref_stats_d *mem_ref_stats;
+  int prev_max_aliased_vops;
+
+  mem_ref_stats = gimple_mem_ref_stats (cfun);
+  gcc_assert (mem_ref_stats->num_vuses == 0 && mem_ref_stats->num_vdefs == 0);
+
+  if (mem_ref_stats->num_mem_stmts == 0)
+    return;
+
+  timevar_push (TV_MEMORY_PARTITIONING);
+
+  mp_info = NULL;
+  tags = NULL;
+  prev_max_aliased_vops = MAX_ALIASED_VOPS;
+
+  /* Since we clearly cannot lower the number of virtual operators
+     below the total number of memory statements in the function, we
+     may need to adjust MAX_ALIASED_VOPS beforehand.  */
+  if (MAX_ALIASED_VOPS < mem_ref_stats->num_mem_stmts)
+    MAX_ALIASED_VOPS = mem_ref_stats->num_mem_stmts;
+
+  /* Update reference stats for all the pointed-to variables and
+     memory tags.  */
+  update_reference_counts (mem_ref_stats);
+
+  /* Add all the memory symbols to MP_INFO.  */
+  build_mp_info (mem_ref_stats, &mp_info, &tags);
+
+  /* No partitions required if we are below the threshold.  */
+  if (!need_to_partition_p (mem_ref_stats))
+    {
+      if (dump_file)
+	fprintf (dump_file, "\nMemory partitioning NOT NEEDED for %s\n",
+	         get_name (current_function_decl));
+      goto done;
+    }
+
+  /* Sort the MP_INFO array so that symbols that should be partitioned
+     first are near the top of the list.  */
+  sort_mp_info (mp_info);
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "\nMemory partitioning NEEDED for %s\n\n",
+	       get_name (current_function_decl));
+      fprintf (dump_file, "Memory symbol references before partitioning:\n");
+      dump_mp_info (dump_file, mp_info);
+    }
+
+  /* Create partitions for variables in MP_INFO until we have enough
+     to lower the total number of VOPS below MAX_ALIASED_VOPS or if
+     the average number of VOPS per statement is below
+     AVG_ALIASED_VOPS.  */
+  for (i = 0; VEC_iterate (mem_sym_stats_t, mp_info, i, mp_p); i++)
+    {
+      tree mpt;
+
+      /* If we are below the threshold, stop.  */
+      if (!need_to_partition_p (mem_ref_stats))
+	break;
+
+      mpt = find_partition_for (mp_p);
+      estimate_vop_reduction (mem_ref_stats, mp_p, mpt);
+    }
+
+  /* After partitions have been created, rewrite alias sets to use
+     them instead of the original symbols.  This way, if the alias set
+     was computed as { a b c d e f }, and the subset { b e f } was
+     grouped into partition MPT.3, then the new alias set for the tag
+     will be  { a c d MPT.3 }.
+     
+     Note that this is not strictly necessary.  The operand scanner
+     will always check if a symbol belongs to a partition when adding
+     virtual operands.  However, by reducing the size of the alias
+     sets to be scanned, the work needed inside the operand scanner is
+     significantly reduced.  */
+  new_aliases = BITMAP_ALLOC (&alias_bitmap_obstack);
+
+  for (i = 0; VEC_iterate (tree, tags, i, tag); i++)
+    {
+      rewrite_alias_set_for (tag, new_aliases);
+      bitmap_clear (new_aliases);
+    }
+
+  BITMAP_FREE (new_aliases);
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "\nMemory symbol references after partitioning:\n");
+      dump_mp_info (dump_file, mp_info);
+    }
+
+done:
+  /* Free allocated memory.  */
+  VEC_free (mem_sym_stats_t, heap, mp_info);
+  VEC_free (tree, heap, tags);
+
+  MAX_ALIASED_VOPS = prev_max_aliased_vops;
+
+  timevar_pop (TV_MEMORY_PARTITIONING);
+}
+
+/* Compute may-alias information for every variable referenced in function
+   FNDECL.
+
+   Alias analysis proceeds in 3 main phases:
+
+   1- Points-to and escape analysis.
+
+   This phase walks the use-def chains in the SSA web looking for three
+   things:
+
+	* Assignments of the form P_i = &VAR
+	* Assignments of the form P_i = malloc()
+	* Pointers and ADDR_EXPR that escape the current function.
+
+   The concept of 'escaping' is the same one used in the Java world.  When
+   a pointer or an ADDR_EXPR escapes, it means that it has been exposed
+   outside of the current function.  So, assignment to global variables,
+   function arguments and returning a pointer are all escape sites, as are
+   conversions between pointers and integers.
+
+   This is where we are currently limited.  Since not everything is renamed
+   into SSA, we lose track of escape properties when a pointer is stashed
+   inside a field in a structure, for instance.  In those cases, we are
+   assuming that the pointer does escape.
+
+   We use escape analysis to determine whether a variable is
+   call-clobbered.  Simply put, if an ADDR_EXPR escapes, then the variable
+   is call-clobbered.  If a pointer P_i escapes, then all the variables
+   pointed-to by P_i (and its memory tag) also escape.
+
+   2- Compute flow-sensitive aliases
+
+   We have two classes of memory tags.  Memory tags associated with the
+   pointed-to data type of the pointers in the program.  These tags are
+   called "symbol memory tag" (SMT).  The other class are those associated
+   with SSA_NAMEs, called "name memory tag" (NMT). The basic idea is that
+   when adding operands for an INDIRECT_REF *P_i, we will first check
+   whether P_i has a name tag, if it does we use it, because that will have
+   more precise aliasing information.  Otherwise, we use the standard symbol
+   tag.
+
+   In this phase, we go through all the pointers we found in points-to
+   analysis and create alias sets for the name memory tags associated with
+   each pointer P_i.  If P_i escapes, we mark call-clobbered the variables
+   it points to and its tag.
+
+
+   3- Compute flow-insensitive aliases
+
+   This pass will compare the alias set of every symbol memory tag and
+   every addressable variable found in the program.  Given a symbol
+   memory tag SMT and an addressable variable V.  If the alias sets of
+   SMT and V conflict (as computed by may_alias_p), then V is marked
+   as an alias tag and added to the alias set of SMT.
+
+   For instance, consider the following function:
+
+	    foo (int i)
+	    {
+	      int *p, a, b;
+	    
+	      if (i > 10)
+	        p = &a;
+	      else
+	        p = &b;
+	    
+	      *p = 3;
+	      a = b + 2;
+	      return *p;
+	    }
+
+   After aliasing analysis has finished, the symbol memory tag for pointer
+   'p' will have two aliases, namely variables 'a' and 'b'.  Every time
+   pointer 'p' is dereferenced, we want to mark the operation as a
+   potential reference to 'a' and 'b'.
+
+	    foo (int i)
+	    {
+	      int *p, a, b;
+
+	      if (i_2 > 10)
+		p_4 = &a;
+	      else
+		p_6 = &b;
+	      # p_1 = PHI <p_4(1), p_6(2)>;
+
+	      # a_7 = VDEF <a_3>;
+	      # b_8 = VDEF <b_5>;
+	      *p_1 = 3;
+
+	      # a_9 = VDEF <a_7>
+	      # VUSE <b_8>
+	      a_9 = b_8 + 2;
+
+	      # VUSE <a_9>;
+	      # VUSE <b_8>;
+	      return *p_1;
+	    }
+
+   In certain cases, the list of may aliases for a pointer may grow too
+   large.  This may cause an explosion in the number of virtual operands
+   inserted in the code.  Resulting in increased memory consumption and
+   compilation time.
+
+   When the number of virtual operands needed to represent aliased
+   loads and stores grows too large (configurable with option --param
+   max-aliased-vops and --param avg-aliased-vops), alias sets are
+   grouped to avoid severe compile-time slow downs and memory
+   consumption. See compute_memory_partitions.  */
+
+unsigned int
+compute_may_aliases (void)
+{
+  struct alias_info *ai;
+
+  timevar_push (TV_TREE_MAY_ALIAS);
+  
+  memset (&alias_stats, 0, sizeof (alias_stats));
+
+  /* Initialize aliasing information.  */
+  ai = init_alias_info ();
+
+  /* For each pointer P_i, determine the sets of variables that P_i may
+     point-to.  For every addressable variable V, determine whether the
+     address of V escapes the current function, making V call-clobbered
+     (i.e., whether &V is stored in a global variable or if its passed as a
+     function call argument).  */
+  compute_points_to_sets ();
+
+  /* Update various related attributes like escaped addresses,
+     pointer dereferences for loads and stores.  This is used
+     when creating name tags and alias sets.  */
+  update_alias_info (ai);
+
+  /* Collect all pointers and addressable variables, compute alias sets,
+     create memory tags for pointers and promote variables whose address is
+     not needed anymore.  */
+  setup_pointers_and_addressables (ai);
+
+  /* Compute type-based flow-insensitive aliasing for all the type
+     memory tags.  */
+  compute_flow_insensitive_aliasing (ai);
+
+  /* Compute flow-sensitive, points-to based aliasing for all the name
+     memory tags.  */
+  compute_flow_sensitive_aliasing (ai);
+  
+  /* Compute call clobbering information.  */
+  compute_call_clobbered (ai);
+
+  /* If the program makes no reference to global variables, but it
+     contains a mixture of pure and non-pure functions, then we need
+     to create use-def and def-def links between these functions to
+     avoid invalid transformations on them.  */
+  maybe_create_global_var ();
+
+  /* Compute memory partitions for every memory variable.  */
+  compute_memory_partitions ();
+
+  /* Remove partitions with no symbols.  Partitions may end up with an
+     empty MPT_SYMBOLS set if a previous round of alias analysis
+     needed to partition more symbols.  Since we don't need those
+     partitions anymore, remove them to free up the space.  */
+  {
+    tree mpt;
+    unsigned i;
+    VEC(tree,heap) *mpt_table;
+
+    mpt_table = gimple_ssa_operands (cfun)->mpt_table;
+    i = 0;
+    while (i < VEC_length (tree, mpt_table))
+      {
+	mpt = VEC_index (tree, mpt_table, i);
+	if (MPT_SYMBOLS (mpt) == NULL)
+	  VEC_unordered_remove (tree, mpt_table, i);
+	else
+	  i++;
+      }
+  }
+
+  /* Populate all virtual operands and newly promoted register operands.  */
+  {
+    gimple_stmt_iterator gsi;
+    basic_block bb;
+    FOR_EACH_BB (bb)
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	update_stmt_if_modified (gsi_stmt (gsi));
+  }
+
+  /* Debugging dumps.  */
+  if (dump_file)
+    {
+      dump_mem_ref_stats (dump_file);
+      dump_alias_info (dump_file);
+      dump_points_to_info (dump_file);
+
+      if (dump_flags & TDF_STATS)
+	dump_alias_stats (dump_file);
+
+      if (dump_flags & TDF_DETAILS)
+	dump_referenced_vars (dump_file);
+    }
+
+  /* Deallocate memory used by aliasing data structures.  */
+  delete_alias_info (ai);
+
+  if (need_ssa_update_p ())
+    update_ssa (TODO_update_ssa);
+
+  timevar_pop (TV_TREE_MAY_ALIAS);
+  
+  return 0;
+}
+
+/* Data structure used to count the number of dereferences to PTR
+   inside an expression.  */
+struct count_ptr_d
+{
+  tree ptr;
+  unsigned num_stores;
+  unsigned num_loads;
+};
+
+
+/* Helper for count_uses_and_derefs.  Called by walk_tree to look for
+   (ALIGN/MISALIGNED_)INDIRECT_REF nodes for the pointer passed in DATA.  */
+
+static tree
+count_ptr_derefs (tree *tp, int *walk_subtrees, void *data)
+{
+  struct walk_stmt_info *wi_p = (struct walk_stmt_info *) data;
+  struct count_ptr_d *count_p = (struct count_ptr_d *) wi_p->info;
+
+  /* Do not walk inside ADDR_EXPR nodes.  In the expression &ptr->fld,
+     pointer 'ptr' is *not* dereferenced, it is simply used to compute
+     the address of 'fld' as 'ptr + offsetof(fld)'.  */
+  if (TREE_CODE (*tp) == ADDR_EXPR)
+    {
+      *walk_subtrees = 0;
+      return NULL_TREE;
+    }
+
+  if (INDIRECT_REF_P (*tp) && TREE_OPERAND (*tp, 0) == count_p->ptr)
+    {
+      if (wi_p->is_lhs)
+	count_p->num_stores++;
+      else
+	count_p->num_loads++;
+    }
+
+  return NULL_TREE;
+}
+
+
+/* Count the number of direct and indirect uses for pointer PTR in
+   statement STMT.  The number of direct uses is stored in
+   *NUM_USES_P.  Indirect references are counted separately depending
+   on whether they are store or load operations.  The counts are
+   stored in *NUM_STORES_P and *NUM_LOADS_P.  */
+
+void
+count_uses_and_derefs (tree ptr, gimple stmt, unsigned *num_uses_p,
+		       unsigned *num_loads_p, unsigned *num_stores_p)
+{
+  ssa_op_iter i;
+  tree use;
+
+  *num_uses_p = 0;
+  *num_loads_p = 0;
+  *num_stores_p = 0;
+
+  /* Find out the total number of uses of PTR in STMT.  */
+  FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
+    if (use == ptr)
+      (*num_uses_p)++;
+
+  /* Now count the number of indirect references to PTR.  This is
+     truly awful, but we don't have much choice.  There are no parent
+     pointers inside INDIRECT_REFs, so an expression like
+     '*x_1 = foo (x_1, *x_1)' needs to be traversed piece by piece to
+     find all the indirect and direct uses of x_1 inside.  The only
+     shortcut we can take is the fact that GIMPLE only allows
+     INDIRECT_REFs inside the expressions below.  */
+  if (is_gimple_assign (stmt)
+      || gimple_code (stmt) == GIMPLE_RETURN
+      || gimple_code (stmt) == GIMPLE_ASM
+      || is_gimple_call (stmt))
+    {
+      struct walk_stmt_info wi;
+      struct count_ptr_d count;
+
+      count.ptr = ptr;
+      count.num_stores = 0;
+      count.num_loads = 0;
+
+      memset (&wi, 0, sizeof (wi));
+      wi.info = &count;
+      walk_gimple_op (stmt, count_ptr_derefs, &wi);
+
+      *num_stores_p = count.num_stores;
+      *num_loads_p = count.num_loads;
+    }
+
+  gcc_assert (*num_uses_p >= *num_loads_p + *num_stores_p);
+}
+
+/* Remove memory references stats for function FN.  */
+
+void
+delete_mem_ref_stats (struct function *fn)
+{
+  if (gimple_mem_ref_stats (fn)->mem_sym_stats)
+    {
+      free_alloc_pool (mem_sym_stats_pool);
+      pointer_map_destroy (gimple_mem_ref_stats (fn)->mem_sym_stats);
+    }
+  gimple_mem_ref_stats (fn)->mem_sym_stats = NULL;
+}
+
+
+/* Initialize memory reference stats.  */
+
+static void
+init_mem_ref_stats (void)
+{
+  struct mem_ref_stats_d *mem_ref_stats = gimple_mem_ref_stats (cfun);
+
+  mem_sym_stats_pool = create_alloc_pool ("Mem sym stats",
+					  sizeof (struct mem_sym_stats_d),
+					  100);
+  memset (mem_ref_stats, 0, sizeof (struct mem_ref_stats_d));
+  mem_ref_stats->mem_sym_stats = pointer_map_create ();
+}
+
+
+/* Helper for init_alias_info.  Reset existing aliasing information.  */
+
+static void
+reset_alias_info (void)
+{
+  referenced_var_iterator rvi;
+  tree var;
+  unsigned i;
+  bitmap active_nmts, all_nmts;
+
+  /* Clear the set of addressable variables.  We do not need to clear
+     the TREE_ADDRESSABLE bit on every symbol because we are going to
+     re-compute addressability here.  */
+  bitmap_clear (gimple_addressable_vars (cfun));
+
+  active_nmts = BITMAP_ALLOC (&alias_bitmap_obstack);
+  all_nmts = BITMAP_ALLOC (&alias_bitmap_obstack);
+
+  /* Clear flow-insensitive alias information from each symbol.  */
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (is_gimple_reg (var))
+	continue;
+
+      if (MTAG_P (var))
+	MTAG_ALIASES (var) = NULL;
+
+      /* Memory partition information will be computed from scratch.  */
+      if (TREE_CODE (var) == MEMORY_PARTITION_TAG)
+	MPT_SYMBOLS (var) = NULL;
+
+      /* Collect all the name tags to determine if we have any
+	 orphaned that need to be removed from the IL.  A name tag
+	 will be orphaned if it is not associated with any active SSA
+	 name.  */
+      if (TREE_CODE (var) == NAME_MEMORY_TAG)
+	bitmap_set_bit (all_nmts, DECL_UID (var));
+
+      /* Since we are about to re-discover call-clobbered
+	 variables, clear the call-clobbered flag.  */
+      clear_call_clobbered (var);
+    }
+
+  /* There should be no call-clobbered variable left.  */
+  gcc_assert (bitmap_empty_p (gimple_call_clobbered_vars (cfun)));
+
+  /* Clear the call-used variables.  */
+  bitmap_clear (gimple_call_used_vars (cfun));
+
+  /* Clear flow-sensitive points-to information from each SSA name.  */
+  for (i = 1; i < num_ssa_names; i++)
+    {
+      tree name = ssa_name (i);
+
+      if (!name || !POINTER_TYPE_P (TREE_TYPE (name)))
+	continue;
+
+      if (SSA_NAME_PTR_INFO (name))
+	{
+	  struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name);
+
+	  /* Clear all the flags but keep the name tag to
+	     avoid creating new temporaries unnecessarily.  If
+	     this pointer is found to point to a subset or
+	     superset of its former points-to set, then a new
+	     tag will need to be created in create_name_tags.  */
+	  pi->pt_anything = 0;
+	  pi->pt_null = 0;
+	  pi->value_escapes_p = 0;
+	  pi->memory_tag_needed = 0;
+	  pi->is_dereferenced = 0;
+	  if (pi->pt_vars)
+	    bitmap_clear (pi->pt_vars);
+
+	  /* Add NAME's name tag to the set of active tags.  */
+	  if (pi->name_mem_tag)
+	    bitmap_set_bit (active_nmts, DECL_UID (pi->name_mem_tag));
+	}
+    }
+
+  /* Name memory tags that are no longer associated with an SSA name
+     are considered stale and should be removed from the IL.  All the
+     name tags that are in the set ALL_NMTS but not in ACTIVE_NMTS are
+     considered stale and marked for renaming.  */
+  bitmap_and_compl_into (all_nmts, active_nmts);
+  mark_set_for_renaming (all_nmts);
+
+  BITMAP_FREE (all_nmts);
+  BITMAP_FREE (active_nmts);
+}
+
+
+/* Initialize the data structures used for alias analysis.  */
+
+static struct alias_info *
+init_alias_info (void)
+{
+  struct alias_info *ai;
+  referenced_var_iterator rvi;
+  tree var;
+  static bool alias_bitmap_obstack_initialized;
+
+  ai = XCNEW (struct alias_info);
+  ai->ssa_names_visited = sbitmap_alloc (num_ssa_names);
+  sbitmap_zero (ai->ssa_names_visited);
+  ai->processed_ptrs = VEC_alloc (tree, heap, 50);
+  ai->dereferenced_ptrs = pointer_set_create ();
+
+  /* Clear out all memory reference stats.  */
+  init_mem_ref_stats ();
+
+  /* If aliases have been computed before, clear existing information.  */
+  if (gimple_aliases_computed_p (cfun))
+    reset_alias_info ();
+  else
+    {
+      /* If this is the first time we compute aliasing information,
+	 every non-register symbol will need to be put into SSA form
+	 (the initial SSA form only operates on GIMPLE registers).  */
+      FOR_EACH_REFERENCED_VAR (var, rvi)
+	if (!is_gimple_reg (var))
+	  mark_sym_for_renaming (var);
+    }
+
+  /* Next time, we will need to reset alias information.  */
+  cfun->gimple_df->aliases_computed_p = true;
+  if (alias_bitmap_obstack_initialized)
+    bitmap_obstack_release (&alias_bitmap_obstack);    
+  bitmap_obstack_initialize (&alias_bitmap_obstack);
+  alias_bitmap_obstack_initialized = true;
+
+  return ai;
+}
+
+
+/* Deallocate memory used by alias analysis.  */
+
+static void
+delete_alias_info (struct alias_info *ai)
+{
+  size_t i;
+
+  sbitmap_free (ai->ssa_names_visited);
+
+  VEC_free (tree, heap, ai->processed_ptrs);
+
+  for (i = 0; i < ai->num_addressable_vars; i++)
+    free (ai->addressable_vars[i]);
+  free (ai->addressable_vars);
+  
+  for (i = 0; i < ai->num_pointers; i++)
+    free (ai->pointers[i]);
+  free (ai->pointers);
+
+  pointer_set_destroy (ai->dereferenced_ptrs);
+  free (ai);
+
+  delete_mem_ref_stats (cfun);
+  delete_points_to_sets ();
+}
+
+
+/* Used for hashing to identify pointer infos with identical
+   pt_vars bitmaps.  */
+
+static int
+eq_ptr_info (const void *p1, const void *p2)
+{
+  const struct ptr_info_def *n1 = (const struct ptr_info_def *) p1;
+  const struct ptr_info_def *n2 = (const struct ptr_info_def *) p2;
+  return bitmap_equal_p (n1->pt_vars, n2->pt_vars);
+}
+
+static hashval_t
+ptr_info_hash (const void *p)
+{
+  const struct ptr_info_def *n = (const struct ptr_info_def *) p;
+  return bitmap_hash (n->pt_vars);
+}
+
+
+/* Create name tags for all the pointers that have been dereferenced.
+   We only create a name tag for a pointer P if P is found to point to
+   a set of variables (so that we can alias them to *P) or if it is
+   the result of a call to malloc (which means that P cannot point to
+   anything else nor alias any other variable).
+
+   If two pointers P and Q point to the same set of variables, they
+   are assigned the same name tag.  */
+
+static void
+create_name_tags (void)
+{
+  size_t i;
+  VEC (tree, heap) *with_ptvars = NULL;
+  tree ptr;
+  htab_t ptr_hash;
+
+  /* Collect the list of pointers with a non-empty points to set.  */
+  for (i = 1; i < num_ssa_names; i++)
+    {
+      tree ptr = ssa_name (i);
+      struct ptr_info_def *pi;
+
+      if (!ptr
+	  || !POINTER_TYPE_P (TREE_TYPE (ptr))
+	  || !SSA_NAME_PTR_INFO (ptr))
+	continue;
+
+      pi = SSA_NAME_PTR_INFO (ptr);
+
+      if (pi->pt_anything || !pi->memory_tag_needed)
+	{
+	  /* No name tags for pointers that have not been
+	     dereferenced or point to an arbitrary location.  */
+	  pi->name_mem_tag = NULL_TREE;
+	  continue;
+	}
+
+      /* Set pt_anything on the pointers without pt_vars filled in so
+	 that they are assigned a symbol tag.  */
+      if (pi->pt_vars && !bitmap_empty_p (pi->pt_vars))	
+	VEC_safe_push (tree, heap, with_ptvars, ptr);
+      else
+	set_pt_anything (ptr);
+    }
+  
+  /* If we didn't find any pointers with pt_vars set, we're done.  */
+  if (!with_ptvars)
+    return;
+
+  ptr_hash = htab_create (10, ptr_info_hash, eq_ptr_info, NULL);
+
+  /* Now go through the pointers with pt_vars, and find a name tag
+     with the same pt_vars as this pointer, or create one if one
+     doesn't exist.  */
+  for (i = 0; VEC_iterate (tree, with_ptvars, i, ptr); i++)
+    {
+      struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
+      tree old_name_tag = pi->name_mem_tag;
+      struct ptr_info_def **slot;
+      
+      /* If PTR points to a set of variables, check if we don't
+	 have another pointer Q with the same points-to set before
+	 creating a tag.  If so, use Q's tag instead of creating a
+	 new one.
+	 
+	 This is important for not creating unnecessary symbols
+	 and also for copy propagation.  If we ever need to
+	 propagate PTR into Q or vice-versa, we would run into
+	 problems if they both had different name tags because
+	 they would have different SSA version numbers (which
+	 would force us to take the name tags in and out of SSA).  */
+      slot = (struct ptr_info_def **) htab_find_slot (ptr_hash, pi, INSERT);
+      if (*slot)
+        pi->name_mem_tag = (*slot)->name_mem_tag;
+      else
+	{
+	  *slot = pi;
+
+	  /* If we didn't find a pointer with the same points-to set
+	     as PTR, create a new name tag if needed.  */
+	  if (pi->name_mem_tag == NULL_TREE)
+	    pi->name_mem_tag = get_nmt_for (ptr);
+	}
+      
+      /* If the new name tag computed for PTR is different than
+	 the old name tag that it used to have, then the old tag
+	 needs to be removed from the IL, so we mark it for
+	 renaming.  */
+      if (old_name_tag && old_name_tag != pi->name_mem_tag)
+	mark_sym_for_renaming (old_name_tag);
+
+      /* Inherit volatility from the pointed-to type.  */
+      TREE_THIS_VOLATILE (pi->name_mem_tag)
+	|= TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (ptr)));
+      
+      /* Mark the new name tag for renaming.  */
+      mark_sym_for_renaming (pi->name_mem_tag);
+    }
+
+  htab_delete (ptr_hash);
+
+  VEC_free (tree, heap, with_ptvars);
+}
+
+
+/* Union the alias set SET into the may-aliases for TAG.  */
+
+static void
+union_alias_set_into (tree tag, bitmap set)
+{
+  bitmap ma = MTAG_ALIASES (tag);
+  
+  if (bitmap_empty_p (set))
+    return;
+  
+  if (!ma)
+    ma = MTAG_ALIASES (tag) = BITMAP_ALLOC (&alias_bitmap_obstack);
+  bitmap_ior_into (ma, set);
+}
+
+
+/* For every pointer P_i in AI->PROCESSED_PTRS, create may-alias sets for
+   the name memory tag (NMT) associated with P_i.  If P_i escapes, then its
+   name tag and the variables it points-to are call-clobbered.  Finally, if
+   P_i escapes and we could not determine where it points to, then all the
+   variables in the same alias set as *P_i are marked call-clobbered.  This
+   is necessary because we must assume that P_i may take the address of any
+   variable in the same alias set.  */
+
+static void
+compute_flow_sensitive_aliasing (struct alias_info *ai)
+{
+  size_t i;
+  tree ptr;
+  
+  timevar_push (TV_FLOW_SENSITIVE);
+  
+  for (i = 0; VEC_iterate (tree, ai->processed_ptrs, i, ptr); i++)
+    {
+      if (!find_what_p_points_to (ptr))
+	set_pt_anything (ptr);
+    }
+
+  create_name_tags ();
+
+  for (i = 0; VEC_iterate (tree, ai->processed_ptrs, i, ptr); i++)
+    {
+      struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
+
+      /* Set up aliasing information for PTR's name memory tag (if it has
+	 one).  Note that only pointers that have been dereferenced will
+	 have a name memory tag.  */
+      if (pi->name_mem_tag && pi->pt_vars)
+	{
+	  if (!bitmap_empty_p (pi->pt_vars))
+	    union_alias_set_into (pi->name_mem_tag, pi->pt_vars);
+	}
+    }
+  timevar_pop (TV_FLOW_SENSITIVE);
+}
+
+
+/* Return TRUE if at least one symbol in TAG2's alias set is also
+   present in TAG1's alias set.  */
+
+static bool
+have_common_aliases_p (bitmap tag1aliases, bitmap tag2aliases)
+{
+
+  /* This is the old behavior of have_common_aliases_p, which is to
+     return false if both sets are empty, or one set is and the other
+     isn't.  */
+  if (tag1aliases == NULL || tag2aliases == NULL)
+    return false;
+
+  return bitmap_intersect_p (tag1aliases, tag2aliases);
+}
+
+/* Compute type-based alias sets.  Traverse all the pointers and
+   addressable variables found in setup_pointers_and_addressables.
+   
+   For every pointer P in AI->POINTERS and addressable variable V in
+   AI->ADDRESSABLE_VARS, add V to the may-alias sets of P's symbol
+   memory tag (SMT) if their alias sets conflict.  V is then marked as
+   an aliased symbol so that the operand scanner knows that statements
+   containing V have aliased operands.  */
+
+static void
+compute_flow_insensitive_aliasing (struct alias_info *ai)
+{
+  referenced_var_iterator rvi;
+  tree var;
+  size_t i;
+
+  timevar_push (TV_FLOW_INSENSITIVE);
+  /* For every pointer P, determine which addressable variables may alias
+     with P's symbol memory tag.  */
+  for (i = 0; i < ai->num_pointers; i++)
+    {
+      size_t j;
+      struct alias_map_d *p_map = ai->pointers[i];
+      tree tag = symbol_mem_tag (p_map->var);
+      tree var;
+
+      for (j = 0; j < ai->num_addressable_vars; j++)
+	{
+	  struct alias_map_d *v_map;
+	  var_ann_t v_ann;
+	  
+	  v_map = ai->addressable_vars[j];
+	  var = v_map->var;
+	  v_ann = var_ann (var);
+
+	  /* We used to skip variables that have never been written to
+	     if the memory tag has been never written to directly (or
+	     either of them were call clobbered).  This is not enough
+	     though, as this misses writes through the tags aliases.
+	     So, for correctness we need to include any aliased
+	     variable here.  */
+
+	  if (may_alias_p (p_map->var, p_map->set, var, v_map->set, false))
+	    {
+	      /* Add VAR to TAG's may-aliases set.  */
+	      add_may_alias (tag, var);
+	    }
+	}
+    }
+
+  /* Since this analysis is based exclusively on symbols, it fails to
+     handle cases where two pointers P and Q have different memory
+     tags with conflicting alias set numbers but no aliased symbols in
+     common.
+
+     For example, suppose that we have two memory tags SMT.1 and SMT.2
+     such that
+     
+     		may-aliases (SMT.1) = { a }
+		may-aliases (SMT.2) = { b }
+
+     and the alias set number of SMT.1 conflicts with that of SMT.2.
+     Since they don't have symbols in common, loads and stores from
+     SMT.1 and SMT.2 will seem independent of each other, which will
+     lead to the optimizers making invalid transformations (see
+     testsuite/gcc.c-torture/execute/pr15262-[12].c).
+
+     To avoid this problem, we do a final traversal of AI->POINTERS
+     looking for pairs of pointers that have no aliased symbols in
+     common and yet have conflicting alias set numbers.  */
+  for (i = 0; i < ai->num_pointers; i++)
+    {
+      size_t j;
+      struct alias_map_d *p_map1 = ai->pointers[i];
+      tree tag1 = symbol_mem_tag (p_map1->var);
+      bitmap may_aliases1 = MTAG_ALIASES (tag1);
+
+      for (j = 0; j < ai->num_pointers; j++)
+	{
+	  struct alias_map_d *p_map2 = ai->pointers[j];
+	  tree tag2 = symbol_mem_tag (p_map2->var);
+	  bitmap may_aliases2 = may_aliases (tag2);
+
+	  /* By convention tags don't alias themselves.  */
+	  if (tag1 == tag2)
+	    continue;
+
+	  /* If the pointers may not point to each other, do nothing.  */
+	  if (!may_alias_p (p_map1->var, p_map1->set, tag2, p_map2->set, true))
+	    continue;
+
+	  /* The two pointers may alias each other.  If they already have
+	     symbols in common, do nothing.  */
+	  if (have_common_aliases_p (may_aliases1, may_aliases2))
+	    continue;
+
+	  add_may_alias (tag1, tag2);
+	}
+    }
+
+  /* We have to add all HEAP variables to all SMTs aliases bitmaps.
+     As we don't know which effective type the HEAP will have we cannot
+     do better here and we need the conflicts with obfuscated pointers
+     (a simple (*(int[n] *)ptr)[i] will do, with ptr from a VLA array
+     allocation).  */
+  for (i = 0; i < ai->num_pointers; i++)
+    {
+      struct alias_map_d *p_map = ai->pointers[i];
+      tree tag = symbol_mem_tag (p_map->var);
+
+      FOR_EACH_REFERENCED_VAR (var, rvi)
+	{
+	  if (var_ann (var)->is_heapvar)
+	    add_may_alias (tag, var);
+	}
+    }
+
+  timevar_pop (TV_FLOW_INSENSITIVE);
+}
+
+
+/* Create a new alias set entry for VAR in AI->ADDRESSABLE_VARS.  */
+
+static void
+create_alias_map_for (tree var, struct alias_info *ai)
+{
+  struct alias_map_d *alias_map;
+  alias_map = XCNEW (struct alias_map_d);
+  alias_map->var = var;
+  alias_map->set = get_alias_set (var);
+  ai->addressable_vars[ai->num_addressable_vars++] = alias_map;
+}
+
+
+/* Update related alias information kept in AI.  This is used when
+   building name tags, alias sets and deciding grouping heuristics.
+   STMT is the statement to process.  This function also updates
+   ADDRESSABLE_VARS.  */
+
+static void
+update_alias_info_1 (gimple stmt, struct alias_info *ai)
+{
+  bitmap addr_taken;
+  use_operand_p use_p;
+  ssa_op_iter iter;
+  bool stmt_dereferences_ptr_p;
+  enum escape_type stmt_escape_type = is_escape_site (stmt);
+  struct mem_ref_stats_d *mem_ref_stats = gimple_mem_ref_stats (cfun);
+
+  stmt_dereferences_ptr_p = false;
+
+  if (stmt_escape_type == ESCAPE_TO_CALL
+      || stmt_escape_type == ESCAPE_TO_PURE_CONST)
+    {
+      mem_ref_stats->num_call_sites++;
+      if (stmt_escape_type == ESCAPE_TO_PURE_CONST)
+	mem_ref_stats->num_pure_const_call_sites++;
+    }
+  else if (stmt_escape_type == ESCAPE_TO_ASM)
+    mem_ref_stats->num_asm_sites++;
+
+  /* Mark all the variables whose address are taken by the statement.  */
+  addr_taken = gimple_addresses_taken (stmt);
+  if (addr_taken)
+    bitmap_ior_into (gimple_addressable_vars (cfun), addr_taken);
+
+  /* If we have a call or an assignment, see if the lhs contains
+     a local decl that requires not to be a gimple register.  */
+  if (gimple_code (stmt) == GIMPLE_ASSIGN
+      || gimple_code (stmt) == GIMPLE_CALL)
+    {
+      tree lhs = gimple_get_lhs (stmt);
+      /* A plain decl does not need it set.  */
+      if (lhs && handled_component_p (lhs))
+	{
+	  tree var = get_base_address (lhs);
+	  if (DECL_P (var)
+	      /* We are not going to mess with RESULT_DECL anyway.  */
+	      && TREE_CODE (var) != RESULT_DECL
+	      && is_gimple_reg_type (TREE_TYPE (var)))
+	    bitmap_set_bit (gimple_addressable_vars (cfun), DECL_UID (var));
+	}
+    }
+
+  /* Process each operand use.  For pointers, determine whether they
+     are dereferenced by the statement, or whether their value
+     escapes, etc.  */
+  FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE)
+    {
+      tree op, var;
+      var_ann_t v_ann;
+      struct ptr_info_def *pi;
+      unsigned num_uses, num_loads, num_stores;
+
+      op = USE_FROM_PTR (use_p);
+
+      /* If STMT is a PHI node, OP may be an ADDR_EXPR.  If so, add it
+	 to the set of addressable variables.  */
+      if (TREE_CODE (op) == ADDR_EXPR)
+	{
+	  bitmap addressable_vars = gimple_addressable_vars (cfun);
+
+	  gcc_assert (gimple_code (stmt) == GIMPLE_PHI);
+	  gcc_assert (addressable_vars);
+
+	  /* PHI nodes don't have annotations for pinning the set
+	     of addresses taken, so we collect them here.
+
+	     FIXME, should we allow PHI nodes to have annotations
+	     so that they can be treated like regular statements?
+	     Currently, they are treated as second-class
+	     statements.  */
+	  add_to_addressable_set (TREE_OPERAND (op, 0), &addressable_vars);
+	  continue;
+	}
+
+      /* Ignore constants (they may occur in PHI node arguments).  */
+      if (TREE_CODE (op) != SSA_NAME)
+	continue;
+
+      var = SSA_NAME_VAR (op);
+      v_ann = var_ann (var);
+
+      /* The base variable of an SSA name must be a GIMPLE register, and thus
+	 it cannot be aliased.  */
+      gcc_assert (!may_be_aliased (var));
+
+      /* We are only interested in pointers.  */
+      if (!POINTER_TYPE_P (TREE_TYPE (op)))
+	continue;
+
+      pi = get_ptr_info (op);
+
+      /* Add OP to AI->PROCESSED_PTRS, if it's not there already.  */
+      if (!TEST_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op)))
+	{
+	  SET_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op));
+	  VEC_safe_push (tree, heap, ai->processed_ptrs, op);
+	}
+
+      /* If STMT is a PHI node, then it will not have pointer
+	 dereferences and it will not be an escape point.  */
+      if (gimple_code (stmt) == GIMPLE_PHI)
+	continue;
+
+      /* Determine whether OP is a dereferenced pointer, and if STMT
+	 is an escape point, whether OP escapes.  */
+      count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
+
+      /* For directly dereferenced pointers we can apply
+	 TBAA-pruning to their points-to set.  We may not count the
+	 implicit dereferences &PTR->FLD here.  */
+      if (num_loads + num_stores > 0)
+	pi->is_dereferenced = 1;
+
+      /* Handle a corner case involving address expressions of the
+	 form '&PTR->FLD'.  The problem with these expressions is that
+	 they do not represent a dereference of PTR.  However, if some
+	 other transformation propagates them into an INDIRECT_REF
+	 expression, we end up with '*(&PTR->FLD)' which is folded
+	 into 'PTR->FLD'.
+
+	 So, if the original code had no other dereferences of PTR,
+	 the aliaser will not create memory tags for it, and when
+	 &PTR->FLD gets propagated to INDIRECT_REF expressions, the
+	 memory operations will receive no VDEF/VUSE operands.
+
+	 One solution would be to have count_uses_and_derefs consider
+	 &PTR->FLD a dereference of PTR.  But that is wrong, since it
+	 is not really a dereference but an offset calculation.
+
+	 What we do here is to recognize these special ADDR_EXPR
+	 nodes.  Since these expressions are never GIMPLE values (they
+	 are not GIMPLE invariants), they can only appear on the RHS
+	 of an assignment and their base address is always an
+	 INDIRECT_REF expression.  */
+      if (is_gimple_assign (stmt)
+	  && gimple_assign_rhs_code (stmt) == ADDR_EXPR
+	  && !is_gimple_val (gimple_assign_rhs1 (stmt)))
+	{
+	  /* If the RHS if of the form &PTR->FLD and PTR == OP, then
+	     this represents a potential dereference of PTR.  */
+	  tree rhs = gimple_assign_rhs1 (stmt);
+	  tree base = get_base_address (TREE_OPERAND (rhs, 0));
+	  if (TREE_CODE (base) == INDIRECT_REF
+	      && TREE_OPERAND (base, 0) == op)
+	    num_loads++;
+	}
+
+      if (num_loads + num_stores > 0)
+	{
+	  /* Mark OP as dereferenced.  In a subsequent pass,
+	     dereferenced pointers that point to a set of
+	     variables will be assigned a name tag to alias
+	     all the variables OP points to.  */
+	  pi->memory_tag_needed = 1;
+
+	  /* ???  For always executed direct dereferences we can
+	     apply TBAA-pruning to their escape set.  */
+
+	  /* Mark OP as being dereferenced.  */
+	  pointer_set_insert (ai->dereferenced_ptrs, var);
+
+	  /* Update the frequency estimate for all the dereferences of
+	     pointer OP.  */
+	  update_mem_sym_stats_from_stmt (op, stmt, num_loads, num_stores);
+
+	  /* Indicate that STMT contains pointer dereferences.  */
+	  stmt_dereferences_ptr_p = true;
+	}
+
+      if (stmt_escape_type != NO_ESCAPE && num_loads + num_stores < num_uses)
+	{
+	  /* If STMT is an escape point and STMT contains at
+	     least one direct use of OP, then the value of OP
+	     escapes and so the pointed-to variables need to
+	     be marked call-clobbered.  */
+	  pi->value_escapes_p = 1;
+	  pi->escape_mask |= stmt_escape_type;
+
+	  /* If the statement makes a function call, assume
+	     that pointer OP will be dereferenced in a store
+	     operation inside the called function.  */
+	  if (is_gimple_call (stmt)
+	      || stmt_escape_type == ESCAPE_STORED_IN_GLOBAL)
+	    {
+	      pointer_set_insert (ai->dereferenced_ptrs, var);
+	      pi->memory_tag_needed = 1;
+	    }
+	}
+    }
+
+  if (gimple_code (stmt) == GIMPLE_PHI)
+    return;
+
+  /* Mark stored variables in STMT as being written to and update the
+     memory reference stats for all memory symbols referenced by STMT.  */
+  if (gimple_references_memory_p (stmt))
+    {
+      unsigned i;
+      bitmap_iterator bi;
+
+      mem_ref_stats->num_mem_stmts++;
+
+      /* Notice that we only update memory reference stats for symbols
+	 loaded and stored by the statement if the statement does not
+	 contain pointer dereferences and it is not a call/asm site.
+	 This is to avoid double accounting problems when creating
+	 memory partitions.  After computing points-to information,
+	 pointer dereference statistics are used to update the
+	 reference stats of the pointed-to variables, so here we
+	 should only update direct references to symbols.
+
+	 Indirect references are not updated here for two reasons: (1)
+	 The first time we compute alias information, the sets
+	 LOADED/STORED are empty for pointer dereferences, (2) After
+	 partitioning, LOADED/STORED may have references to
+	 partitions, not the original pointed-to variables.  So, if we
+	 always counted LOADED/STORED here and during partitioning, we
+	 would count many symbols more than once.
+
+	 This does cause some imprecision when a statement has a
+	 combination of direct symbol references and pointer
+	 dereferences (e.g., MEMORY_VAR = *PTR) or if a call site has
+	 memory symbols in its argument list, but these cases do not
+	 occur so frequently as to constitute a serious problem.  */
+      if (!stmt_dereferences_ptr_p
+	  && stmt_escape_type != ESCAPE_TO_CALL
+	  && stmt_escape_type != ESCAPE_TO_PURE_CONST
+	  && stmt_escape_type != ESCAPE_TO_ASM)
+	{
+	  if (gimple_stored_syms (stmt))
+	    EXECUTE_IF_SET_IN_BITMAP (gimple_stored_syms (stmt), 0, i, bi)
+	      update_mem_sym_stats_from_stmt (referenced_var (i), stmt, 0, 1);
+
+	  if (gimple_loaded_syms (stmt))
+	    EXECUTE_IF_SET_IN_BITMAP (gimple_loaded_syms (stmt), 0, i, bi)
+	      update_mem_sym_stats_from_stmt (referenced_var (i), stmt, 1, 0);
+	}
+    }
+}
+
+/* Update various related attributes like escaped addresses,
+   pointer dereferences for loads and stores.  This is used
+   when creating name tags and alias sets.  */
+
+static void
+update_alias_info (struct alias_info *ai)
+{
+  basic_block bb;
+
+  FOR_EACH_BB (bb)
+    {
+      gimple_stmt_iterator gsi;
+      gimple phi;
+
+      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  phi = gsi_stmt (gsi);
+	  if (is_gimple_reg (PHI_RESULT (phi)))
+	    update_alias_info_1 (phi, ai);
+	}
+
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	update_alias_info_1 (gsi_stmt (gsi), ai);
+    }
+}
+
+/* Create memory tags for all the dereferenced pointers and build the
+   ADDRESSABLE_VARS and POINTERS arrays used for building the may-alias
+   sets.  Based on the address escape and points-to information collected
+   earlier, this pass will also clear the TREE_ADDRESSABLE flag from those
+   variables whose address is not needed anymore.  */
+
+static void
+setup_pointers_and_addressables (struct alias_info *ai)
+{
+  size_t num_addressable_vars, num_pointers;
+  referenced_var_iterator rvi;
+  tree var;
+  VEC (tree, heap) *varvec = NULL;
+  safe_referenced_var_iterator srvi;
+
+  /* Size up the arrays ADDRESSABLE_VARS and POINTERS.  */
+  num_addressable_vars = num_pointers = 0;
+  
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (may_be_aliased (var))
+	num_addressable_vars++;
+
+      if (POINTER_TYPE_P (TREE_TYPE (var)))
+	{
+	  /* Since we don't keep track of volatile variables, assume that
+	     these pointers are used in indirect store operations.  */
+	  if (TREE_THIS_VOLATILE (var))
+	    pointer_set_insert (ai->dereferenced_ptrs, var);
+
+	  num_pointers++;
+	}
+    }
+
+  /* Create ADDRESSABLE_VARS and POINTERS.  Note that these arrays are
+     always going to be slightly bigger than we actually need them
+     because some TREE_ADDRESSABLE variables will be marked
+     non-addressable below and only pointers with unique symbol tags are
+     going to be added to POINTERS.  */
+  ai->addressable_vars = XCNEWVEC (struct alias_map_d *, num_addressable_vars);
+  ai->pointers = XCNEWVEC (struct alias_map_d *, num_pointers);
+  ai->num_addressable_vars = 0;
+  ai->num_pointers = 0;
+
+  FOR_EACH_REFERENCED_VAR_SAFE (var, varvec, srvi)
+    {
+      /* Name memory tags already have flow-sensitive aliasing
+	 information, so they need not be processed by
+	 compute_flow_insensitive_aliasing.  Similarly, symbol memory
+	 tags are already accounted for when we process their
+	 associated pointer. 
+      
+         Structure fields, on the other hand, have to have some of this
+         information processed for them, but it's pointless to mark them
+         non-addressable (since they are fake variables anyway).  */
+      if (MTAG_P (var))
+	continue;
+
+      /* Remove the ADDRESSABLE flag from every addressable variable whose
+         address is not needed anymore.  This is caused by the propagation
+         of ADDR_EXPR constants into INDIRECT_REF expressions and the
+         removal of dead pointer assignments done by the early scalar
+         cleanup passes.  */
+      if (TREE_ADDRESSABLE (var))
+	{
+	  if (!bitmap_bit_p (gimple_addressable_vars (cfun), DECL_UID (var))
+	      && TREE_CODE (var) != RESULT_DECL
+	      && !is_global_var (var))
+	    {
+	      bool okay_to_mark = true;
+
+	      /* Since VAR is now a regular GIMPLE register, we will need
+		 to rename VAR into SSA afterwards.  */
+	      mark_sym_for_renaming (var);
+
+	      /* The address of VAR is not needed, remove the
+		 addressable bit, so that it can be optimized as a
+		 regular variable.  */
+	      if (okay_to_mark)
+		{
+		  /* The memory partition holding VAR will no longer
+		     contain VAR, and statements referencing it will need
+		     to be updated.  */
+		  if (memory_partition (var))
+		    mark_sym_for_renaming (memory_partition (var));
+
+		  mark_non_addressable (var);
+		}
+	    }
+	}
+
+      /* Global variables and addressable locals may be aliased.  Create an
+         entry in ADDRESSABLE_VARS for VAR.  */
+      if (may_be_aliased (var))
+	{
+	  create_alias_map_for (var, ai);
+	  mark_sym_for_renaming (var);
+	}
+
+      /* Add pointer variables that have been dereferenced to the POINTERS
+         array and create a symbol memory tag for them.  */
+      if (POINTER_TYPE_P (TREE_TYPE (var)))
+	{
+	  if (pointer_set_contains (ai->dereferenced_ptrs, var))
+	    {
+	      tree tag, old_tag;
+	      var_ann_t t_ann;
+
+	      /* If pointer VAR still doesn't have a memory tag
+		 associated with it, create it now or re-use an
+		 existing one.  */
+	      tag = get_smt_for (var, ai);
+	      t_ann = var_ann (tag);
+
+	      /* The symbol tag will need to be renamed into SSA
+		 afterwards. Note that we cannot do this inside
+		 get_smt_for because aliasing may run multiple times
+		 and we only create symbol tags the first time.  */
+	      mark_sym_for_renaming (tag);
+
+	      /* Similarly, if pointer VAR used to have another type
+		 tag, we will need to process it in the renamer to
+		 remove the stale virtual operands.  */
+	      old_tag = symbol_mem_tag (var);
+	      if (old_tag)
+		mark_sym_for_renaming (old_tag);
+
+	      /* Associate the tag with pointer VAR.  */
+	      set_symbol_mem_tag (var, tag);
+	    }
+	  else
+	    {
+	      /* The pointer has not been dereferenced.  If it had a
+		 symbol memory tag, remove it and mark the old tag for
+		 renaming to remove it out of the IL.  */
+	      tree tag = symbol_mem_tag (var);
+	      if (tag)
+		{
+		  mark_sym_for_renaming (tag);
+		  set_symbol_mem_tag (var, NULL_TREE);
+		}
+	    }
+	}
+    }
+
+  VEC_free (tree, heap, varvec);
+}
+
+
+/* Determine whether to use .GLOBAL_VAR to model call clobbering
+   semantics.  If the function makes no references to global
+   variables and contains at least one call to a non-pure function,
+   then we need to mark the side-effects of the call using .GLOBAL_VAR
+   to represent all possible global memory referenced by the callee.  */
+
+static void
+maybe_create_global_var (void)
+{
+  /* No need to create it, if we have one already.  */
+  if (gimple_global_var (cfun) == NULL_TREE)
+    {
+      struct mem_ref_stats_d *stats = gimple_mem_ref_stats (cfun);
+
+      /* Create .GLOBAL_VAR if there are no call-clobbered
+	 variables and the program contains a mixture of pure/const
+	 and regular function calls.  This is to avoid the problem
+	 described in PR 20115:
+
+	      int X;
+	      int func_pure (void) { return X; }
+	      int func_non_pure (int a) { X += a; }
+	      int foo ()
+	      {
+	 	int a = func_pure ();
+		func_non_pure (a);
+		a = func_pure ();
+		return a;
+	      }
+
+	 Since foo() has no call-clobbered variables, there is
+	 no relationship between the calls to func_pure and
+	 func_non_pure.  Since func_pure has no side-effects, value
+	 numbering optimizations elide the second call to func_pure.
+	 So, if we have some pure/const and some regular calls in the
+	 program we create .GLOBAL_VAR to avoid missing these
+	 relations.  */
+      if (bitmap_empty_p (gimple_call_clobbered_vars (cfun))
+	  && stats->num_call_sites > 0
+	  && stats->num_pure_const_call_sites > 0
+	  && stats->num_call_sites > stats->num_pure_const_call_sites)
+	create_global_var ();
+    }
+}
+
+
+/* Return TRUE if pointer PTR may point to variable VAR.
+   
+   MEM_ALIAS_SET is the alias set for the memory location pointed-to by PTR
+	This is needed because when checking for type conflicts we are
+	interested in the alias set of the memory location pointed-to by
+	PTR.  The alias set of PTR itself is irrelevant.
+   
+   VAR_ALIAS_SET is the alias set for VAR.  */
+
+bool
+may_alias_p (tree ptr, alias_set_type mem_alias_set,
+	     tree var, alias_set_type var_alias_set,
+	     bool alias_set_only)
+{
+  tree mem;
+
+  alias_stats.alias_queries++;
+  alias_stats.simple_queries++;
+
+  /* By convention, a variable cannot alias itself.  */
+  mem = symbol_mem_tag (ptr);
+  if (mem == var)
+    {
+      alias_stats.alias_noalias++;
+      alias_stats.simple_resolved++;
+      return false;
+    }
+
+  /* If -fargument-noalias-global is > 2, pointer arguments may
+     not point to anything else.  */
+  if (flag_argument_noalias > 2 && TREE_CODE (ptr) == PARM_DECL)
+    {
+      alias_stats.alias_noalias++;
+      alias_stats.simple_resolved++;
+      return false;
+    }
+
+  /* If -fargument-noalias-global is > 1, pointer arguments may
+     not point to global variables.  */
+  if (flag_argument_noalias > 1 && is_global_var (var)
+      && TREE_CODE (ptr) == PARM_DECL)
+    {
+      alias_stats.alias_noalias++;
+      alias_stats.simple_resolved++;
+      return false;
+    }
+
+  /* If the pointed to memory has alias set zero, or the pointer
+     is ref-all, or the pointer decl is marked that no TBAA is to
+     be applied, the MEM can alias VAR.  */
+  if (mem_alias_set == 0
+      || DECL_POINTER_ALIAS_SET (ptr) == 0
+      || TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (ptr))
+      || DECL_NO_TBAA_P (ptr))
+    {
+      alias_stats.alias_mayalias++;
+      alias_stats.simple_resolved++;
+      return true;
+    }
+
+  gcc_assert (TREE_CODE (mem) == SYMBOL_MEMORY_TAG);
+
+  alias_stats.tbaa_queries++;
+
+  /* If the alias sets don't conflict then MEM cannot alias VAR.  */
+  if (mem_alias_set != var_alias_set
+      && !alias_set_subset_of (mem_alias_set, var_alias_set))
+    {
+      alias_stats.alias_noalias++;
+      alias_stats.tbaa_resolved++;
+      return false;
+    }
+
+  /* If VAR is a record or union type, PTR cannot point into VAR
+     unless there is some explicit address operation in the
+     program that can reference a field of the type pointed-to by
+     PTR.  This also assumes that the types of both VAR and PTR
+     are contained within the compilation unit, and that there is
+     no fancy addressing arithmetic associated with any of the
+     types involved.  */
+  if (mem_alias_set != 0 && var_alias_set != 0)
+    {
+      tree ptr_type = TREE_TYPE (ptr);
+      tree var_type = TREE_TYPE (var);
+      
+      /* The star count is -1 if the type at the end of the
+	 pointer_to chain is not a record or union type. */ 
+      if (!alias_set_only && 
+	  0 /* FIXME tuples ipa_type_escape_star_count_of_interesting_type (var_type) >= 0*/)
+	{
+	  int ptr_star_count = 0;
+
+	  /* ipa_type_escape_star_count_of_interesting_type is a
+	     little too restrictive for the pointer type, need to
+	     allow pointers to primitive types as long as those
+	     types cannot be pointers to everything.  */
+	  while (POINTER_TYPE_P (ptr_type))
+	    {
+	      /* Strip the *s off.  */ 
+	      ptr_type = TREE_TYPE (ptr_type);
+	      ptr_star_count++;
+	    }
+	  
+	  /* There does not appear to be a better test to see if
+	     the pointer type was one of the pointer to everything
+	     types.  */
+	  if (ptr_star_count > 0)
+	    {
+	      alias_stats.structnoaddress_queries++;
+	      if (ipa_type_escape_field_does_not_clobber_p (var_type, 
+							    TREE_TYPE (ptr)))
+		{
+		  alias_stats.structnoaddress_resolved++;
+		  alias_stats.alias_noalias++;
+		  return false;
+		}
+	    }
+	  else if (ptr_star_count == 0)
+	    {
+	      /* If PTR_TYPE was not really a pointer to type, it cannot 
+		 alias.  */ 
+	      alias_stats.structnoaddress_queries++;
+	      alias_stats.structnoaddress_resolved++;
+	      alias_stats.alias_noalias++;
+	      return false;
+	    }
+	}
+    }
+
+  alias_stats.alias_mayalias++;
+  return true;
+}
+
+/* Return true, if PTR may point to a global variable.  */
+
+bool
+may_point_to_global_var (tree ptr)
+{
+  struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
+
+  /* If we do not have points-to information for this variable,
+     we have to punt.  */
+  if (!pi
+      || !pi->name_mem_tag)
+    return true;
+
+  /* The name memory tag is marked as global variable if the points-to
+     set contains a global variable.  */
+  return is_global_var (pi->name_mem_tag);
+}
+
+/* Add ALIAS to the set of variables that may alias VAR.  */
+
+static void
+add_may_alias (tree var, tree alias)
+{
+  /* Don't allow self-referential aliases.  */
+  gcc_assert (var != alias);
+
+  /* ALIAS must be addressable if it's being added to an alias set.  */
+#if 1
+  TREE_ADDRESSABLE (alias) = 1;
+#else
+  gcc_assert (may_be_aliased (alias));
+#endif
+
+  /* VAR must be a symbol or a name tag.  */
+  gcc_assert (TREE_CODE (var) == SYMBOL_MEMORY_TAG
+              || TREE_CODE (var) == NAME_MEMORY_TAG);
+
+  if (MTAG_ALIASES (var) == NULL)
+    MTAG_ALIASES (var) = BITMAP_ALLOC (&alias_bitmap_obstack);
+  
+  bitmap_set_bit (MTAG_ALIASES (var), DECL_UID (alias));
+}
+
+
+/* Mark pointer PTR as pointing to an arbitrary memory location.  */
+
+static void
+set_pt_anything (tree ptr)
+{
+  struct ptr_info_def *pi = get_ptr_info (ptr);
+
+  pi->pt_anything = 1;
+  /* Anything includes global memory.  */
+  pi->pt_global_mem = 1;
+  pi->pt_vars = NULL;
+
+  /* The pointer used to have a name tag, but we now found it pointing
+     to an arbitrary location.  The name tag needs to be renamed and
+     disassociated from PTR.  */
+  if (pi->name_mem_tag)
+    {
+      mark_sym_for_renaming (pi->name_mem_tag);
+      pi->name_mem_tag = NULL_TREE;
+    }
+}
+
+
+/* Return true if STMT is an "escape" site from the current function.  Escape
+   sites those statements which might expose the address of a variable
+   outside the current function.  STMT is an escape site iff:
+
+   	1- STMT is a function call, or
+	2- STMT is an __asm__ expression, or
+	3- STMT is an assignment to a non-local variable, or
+	4- STMT is a return statement.
+
+   Return the type of escape site found, if we found one, or NO_ESCAPE
+   if none.  */
+
+enum escape_type
+is_escape_site (gimple stmt)
+{
+  if (is_gimple_call (stmt))
+    {
+      if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
+	return ESCAPE_TO_PURE_CONST;
+
+      return ESCAPE_TO_CALL;
+    }
+  else if (gimple_code (stmt) == GIMPLE_ASM)
+    return ESCAPE_TO_ASM;
+  else if (is_gimple_assign (stmt))
+    {
+      tree lhs = gimple_assign_lhs (stmt);
+
+      /* Get to the base of _REF nodes.  */
+      if (TREE_CODE (lhs) != SSA_NAME)
+	lhs = get_base_address (lhs);
+
+      /* If we couldn't recognize the LHS of the assignment, assume that it
+	 is a non-local store.  */
+      if (lhs == NULL_TREE)
+	return ESCAPE_UNKNOWN;
+
+      if (gimple_assign_cast_p (stmt))
+	{
+	  tree from = TREE_TYPE (gimple_assign_rhs1 (stmt));
+	  tree to = TREE_TYPE (lhs);
+
+	  /* If the RHS is a conversion between a pointer and an integer, the
+	     pointer escapes since we can't track the integer.  */
+	  if (POINTER_TYPE_P (from) && !POINTER_TYPE_P (to))
+	    return ESCAPE_BAD_CAST;
+	}
+
+      /* If the LHS is an SSA name, it can't possibly represent a non-local
+	 memory store.  */
+      if (TREE_CODE (lhs) == SSA_NAME)
+	return NO_ESCAPE;
+
+      /* If the LHS is a non-global decl, it isn't a non-local memory store.
+	 If the LHS escapes, the RHS escape is dealt with in the PTA solver.  */
+      if (DECL_P (lhs)
+	  && !is_global_var (lhs))
+	return NO_ESCAPE;
+
+      /* FIXME: LHS is not an SSA_NAME.  Even if it's an assignment to a
+	 local variables we cannot be sure if it will escape, because we
+	 don't have information about objects not in SSA form.  Need to
+	 implement something along the lines of
+
+	 J.-D. Choi, M. Gupta, M. J. Serrano, V. C. Sreedhar, and S. P.
+	 Midkiff, ``Escape analysis for java,'' in Proceedings of the
+	 Conference on Object-Oriented Programming Systems, Languages, and
+	 Applications (OOPSLA), pp. 1-19, 1999.  */
+      return ESCAPE_STORED_IN_GLOBAL;
+    }
+  else if (gimple_code (stmt) == GIMPLE_RETURN)
+    return ESCAPE_TO_RETURN;
+
+  return NO_ESCAPE;
+}
+
+/* Create a new memory tag of type TYPE.
+   Does NOT push it into the current binding.  */
+
+tree
+create_tag_raw (enum tree_code code, tree type, const char *prefix)
+{
+  tree tmp_var;
+
+  tmp_var = build_decl (code, create_tmp_var_name (prefix), type);
+
+  /* Memory tags are always writable and non-static.  */
+  TREE_READONLY (tmp_var) = 0;
+  TREE_STATIC (tmp_var) = 0;
+
+  /* It doesn't start out global.  */
+  MTAG_GLOBAL (tmp_var) = 0;
+  TREE_USED (tmp_var) = 1;
+
+  return tmp_var;
+}
+
+/* Create a new memory tag of type TYPE.  If IS_TYPE_TAG is true, the tag
+   is considered to represent all the pointers whose pointed-to types are
+   in the same alias set class.  Otherwise, the tag represents a single
+   SSA_NAME pointer variable.  */
+
+static tree
+create_memory_tag (tree type, bool is_type_tag)
+{
+  tree tag = create_tag_raw (is_type_tag ? SYMBOL_MEMORY_TAG : NAME_MEMORY_TAG,
+			     type, (is_type_tag) ? "SMT" : "NMT");
+
+  /* By default, memory tags are local variables.  Alias analysis will
+     determine whether they should be considered globals.  */
+  DECL_CONTEXT (tag) = current_function_decl;
+
+  /* Memory tags are by definition addressable.  */
+  TREE_ADDRESSABLE (tag) = 1;
+
+  set_symbol_mem_tag (tag, NULL_TREE);
+
+  /* Add the tag to the symbol table.  */
+  add_referenced_var (tag);
+
+  return tag;
+}
+
+
+/* Create a name memory tag to represent a specific SSA_NAME pointer P_i.
+   This is used if P_i has been found to point to a specific set of
+   variables or to a non-aliased memory location like the address returned
+   by malloc functions.  */
+
+static tree
+get_nmt_for (tree ptr)
+{
+  struct ptr_info_def *pi = get_ptr_info (ptr);
+  tree tag = pi->name_mem_tag;
+
+  if (tag == NULL_TREE)
+    tag = create_memory_tag (TREE_TYPE (TREE_TYPE (ptr)), false);
+  return tag;
+}
+
+
+/* Return the symbol memory tag associated to pointer PTR.  A memory
+   tag is an artificial variable that represents the memory location
+   pointed-to by PTR.  It is used to model the effects of pointer
+   de-references on addressable variables.
+   
+   AI points to the data gathered during alias analysis.  This
+   function populates the array AI->POINTERS.  */
+
+static tree
+get_smt_for (tree ptr, struct alias_info *ai)
+{
+  size_t i;
+  tree tag;
+  tree tag_type = TREE_TYPE (TREE_TYPE (ptr));
+  alias_set_type tag_set;
+
+  /* Get the alias set to be used for the pointed-to memory.  If that
+     differs from what we would get from looking at the type adjust
+     the tag_type to void to make sure we get a proper alias set from
+     just looking at the SMT we create.  */
+  tag_set = get_alias_set (tag_type);
+  if (TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (ptr))
+      /* This is overly conservative but we do not want to assign
+         restrict alias sets here (which if they are not assigned
+         are -2 but still "known").  */
+      || DECL_POINTER_ALIAS_SET_KNOWN_P (ptr))
+    {
+      tag_set = 0;
+      tag_type = void_type_node;
+    }
+
+  /* To avoid creating unnecessary memory tags, only create one memory tag
+     per alias set class.  Note that it may be tempting to group
+     memory tags based on conflicting alias sets instead of
+     equivalence.  That would be wrong because alias sets are not
+     necessarily transitive (as demonstrated by the libstdc++ test
+     23_containers/vector/cons/4.cc).  Given three alias sets A, B, C
+     such that conflicts (A, B) == true and conflicts (A, C) == true,
+     it does not necessarily follow that conflicts (B, C) == true.  */
+  for (i = 0, tag = NULL_TREE; i < ai->num_pointers; i++)
+    {
+      struct alias_map_d *curr = ai->pointers[i];
+      tree curr_tag = symbol_mem_tag (curr->var);
+      if (tag_set == curr->set)
+	{
+	  tag = curr_tag;
+	  break;
+	}
+    }
+
+  /* If VAR cannot alias with any of the existing memory tags, create a new
+     tag for PTR and add it to the POINTERS array.  */
+  if (tag == NULL_TREE)
+    {
+      struct alias_map_d *alias_map;
+
+      /* If PTR did not have a symbol tag already, create a new SMT.*
+	 artificial variable representing the memory location
+	 pointed-to by PTR.  */
+      tag = symbol_mem_tag (ptr);
+      if (tag == NULL_TREE
+	  || tag_set != get_alias_set (tag))
+	tag = create_memory_tag (tag_type, true);
+
+      /* Add PTR to the POINTERS array.  Note that we are not interested in
+	 PTR's alias set.  Instead, we cache the alias set for the memory that
+	 PTR points to.  */
+      alias_map = XCNEW (struct alias_map_d);
+      alias_map->var = ptr;
+      alias_map->set = tag_set;
+      ai->pointers[ai->num_pointers++] = alias_map;
+    }
+
+  /* If the pointed-to type is volatile, so is the tag.  */
+  TREE_THIS_VOLATILE (tag) |= TREE_THIS_VOLATILE (tag_type);
+
+  /* Make sure that the symbol tag has the same alias set as the
+     pointed-to type or at least accesses through the pointer will
+     alias that set.  The latter can happen after the vectorizer
+     created pointers of vector type.  */
+  gcc_assert (tag_set == get_alias_set (tag)
+	      || alias_set_subset_of (tag_set, get_alias_set (tag)));
+
+  return tag;
+}
+
+
+/* Create GLOBAL_VAR, an artificial global variable to act as a
+   representative of all the variables that may be clobbered by function
+   calls.  */
+
+static void
+create_global_var (void)
+{
+  tree global_var = build_decl (VAR_DECL, get_identifier (".GLOBAL_VAR"),
+                                void_type_node);
+  DECL_ARTIFICIAL (global_var) = 1;
+  TREE_READONLY (global_var) = 0;
+  DECL_EXTERNAL (global_var) = 1;
+  TREE_STATIC (global_var) = 1;
+  TREE_USED (global_var) = 1;
+  DECL_CONTEXT (global_var) = NULL_TREE;
+  TREE_THIS_VOLATILE (global_var) = 0;
+  TREE_ADDRESSABLE (global_var) = 0;
+
+  create_var_ann (global_var);
+  mark_call_clobbered (global_var, ESCAPE_UNKNOWN);
+  add_referenced_var (global_var);
+  mark_sym_for_renaming (global_var);
+  cfun->gimple_df->global_var = global_var;
+}
+
+
+/* Dump alias statistics on FILE.  */
+
+static void 
+dump_alias_stats (FILE *file)
+{
+  const char *funcname
+    = lang_hooks.decl_printable_name (current_function_decl, 2);
+  fprintf (file, "\nAlias statistics for %s\n\n", funcname);
+  fprintf (file, "Total alias queries:\t%u\n", alias_stats.alias_queries);
+  fprintf (file, "Total alias mayalias results:\t%u\n", 
+	   alias_stats.alias_mayalias);
+  fprintf (file, "Total alias noalias results:\t%u\n",
+	   alias_stats.alias_noalias);
+  fprintf (file, "Total simple queries:\t%u\n",
+	   alias_stats.simple_queries);
+  fprintf (file, "Total simple resolved:\t%u\n",
+	   alias_stats.simple_resolved);
+  fprintf (file, "Total TBAA queries:\t%u\n",
+	   alias_stats.tbaa_queries);
+  fprintf (file, "Total TBAA resolved:\t%u\n",
+	   alias_stats.tbaa_resolved);
+  fprintf (file, "Total non-addressable structure type queries:\t%u\n",
+	   alias_stats.structnoaddress_queries);
+  fprintf (file, "Total non-addressable structure type resolved:\t%u\n",
+	   alias_stats.structnoaddress_resolved);
+}
+  
+
+/* Dump alias information on FILE.  */
+
+void
+dump_alias_info (FILE *file)
+{
+  size_t i;
+  const char *funcname
+    = lang_hooks.decl_printable_name (current_function_decl, 2);
+  referenced_var_iterator rvi;
+  tree var;
+
+  fprintf (file, "\nAlias information for %s\n\n", funcname);
+
+  dump_memory_partitions (file);
+
+  fprintf (file, "\nFlow-insensitive alias information for %s\n\n", funcname);
+
+  fprintf (file, "Aliased symbols\n\n");
+  
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (may_be_aliased (var))
+	dump_variable (file, var);
+    }
+
+  fprintf (file, "\nDereferenced pointers\n\n");
+
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    if (symbol_mem_tag (var))
+      dump_variable (file, var);
+
+  fprintf (file, "\nSymbol memory tags\n\n");
+  
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (TREE_CODE (var) == SYMBOL_MEMORY_TAG)
+	dump_variable (file, var);
+    }
+
+  fprintf (file, "\n\nFlow-sensitive alias information for %s\n\n", funcname);
+
+  fprintf (file, "SSA_NAME pointers\n\n");
+  for (i = 1; i < num_ssa_names; i++)
+    {
+      tree ptr = ssa_name (i);
+      struct ptr_info_def *pi;
+      
+      if (ptr == NULL_TREE)
+	continue;
+
+      pi = SSA_NAME_PTR_INFO (ptr);
+      if (!SSA_NAME_IN_FREE_LIST (ptr)
+	  && pi
+	  && pi->name_mem_tag)
+	dump_points_to_info_for (file, ptr);
+    }
+
+  fprintf (file, "\nName memory tags\n\n");
+  
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (TREE_CODE (var) == NAME_MEMORY_TAG)
+	dump_variable (file, var);
+    }
+
+  fprintf (file, "\n");
+}
+
+
+/* Dump alias information on stderr.  */
+
+void
+debug_alias_info (void)
+{
+  dump_alias_info (stderr);
+}
+
+
+/* Return the alias information associated with pointer T.  It creates a
+   new instance if none existed.  */
+
+struct ptr_info_def *
+get_ptr_info (tree t)
+{
+  struct ptr_info_def *pi;
+
+  gcc_assert (POINTER_TYPE_P (TREE_TYPE (t)));
+
+  pi = SSA_NAME_PTR_INFO (t);
+  if (pi == NULL)
+    {
+      pi = GGC_CNEW (struct ptr_info_def);
+      SSA_NAME_PTR_INFO (t) = pi;
+    }
+
+  return pi;
+}
+
+/* Dump points-to information for SSA_NAME PTR into FILE.  */
+
+void
+dump_points_to_info_for (FILE *file, tree ptr)
+{
+  struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
+
+  print_generic_expr (file, ptr, dump_flags);
+
+  if (pi)
+    {
+      if (pi->name_mem_tag)
+	{
+	  fprintf (file, ", name memory tag: ");
+	  print_generic_expr (file, pi->name_mem_tag, dump_flags);
+	}
+
+      if (pi->is_dereferenced)
+	fprintf (file, ", is dereferenced");
+      else if (pi->memory_tag_needed)
+	fprintf (file, ", is dereferenced in call");
+
+      if (pi->value_escapes_p)
+	fprintf (file, ", its value escapes");
+
+      if (pi->pt_anything)
+	fprintf (file, ", points-to anything");
+
+      if (pi->pt_null)
+	fprintf (file, ", points-to NULL");
+
+      if (pi->pt_vars)
+	{
+	  fprintf (file, ", points-to vars: ");
+	  dump_decl_set (file, pi->pt_vars);
+	}
+    }
+
+  fprintf (file, "\n");
+}
+
+
+/* Dump points-to information for VAR into stderr.  */
+
+void
+debug_points_to_info_for (tree var)
+{
+  dump_points_to_info_for (stderr, var);
+}
+
+
+/* Dump points-to information into FILE.  NOTE: This function is slow, as
+   it needs to traverse the whole CFG looking for pointer SSA_NAMEs.  */
+
+void
+dump_points_to_info (FILE *file ATTRIBUTE_UNUSED)
+{
+  basic_block bb;
+  gimple_stmt_iterator si;
+  ssa_op_iter iter;
+  const char *fname =
+    lang_hooks.decl_printable_name (current_function_decl, 2);
+  referenced_var_iterator rvi;
+  tree var;
+
+  fprintf (file, "\n\nPointed-to sets for pointers in %s\n\n", fname);
+
+  /* First dump points-to information for the default definitions of
+     pointer variables.  This is necessary because default definitions are
+     not part of the code.  */
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (POINTER_TYPE_P (TREE_TYPE (var)))
+	{
+	  tree def = gimple_default_def (cfun, var);
+	  if (def)
+	    dump_points_to_info_for (file, def);
+	}
+    }
+
+  /* Dump points-to information for every pointer defined in the program.  */
+  FOR_EACH_BB (bb)
+    {
+      for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
+	{
+	  gimple phi = gsi_stmt (si);
+	  tree ptr = PHI_RESULT (phi);
+	  if (POINTER_TYPE_P (TREE_TYPE (ptr)))
+	    dump_points_to_info_for (file, ptr);
+	}
+
+	for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
+	  {
+	    gimple stmt = gsi_stmt (si);
+	    tree def;
+	    FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
+	      if (TREE_CODE (def) == SSA_NAME
+		  && POINTER_TYPE_P (TREE_TYPE (def)))
+		dump_points_to_info_for (file, def);
+	  }
+    }
+
+  fprintf (file, "\n");
+}
+
+
+/* Dump points-to info pointed to by PTO into STDERR.  */
+
+void
+debug_points_to_info (void)
+{
+  dump_points_to_info (stderr);
+}
+
+/* Dump to FILE the list of variables that may be aliasing VAR.  */
+
+void
+dump_may_aliases_for (FILE *file, tree var)
+{
+  bitmap aliases;
+  
+  aliases = MTAG_ALIASES (var);
+  if (aliases)
+    {
+      bitmap_iterator bi;
+      unsigned int i;
+      tree al;
+
+      fprintf (file, "{ ");
+      EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
+	{
+	  al = referenced_var (i);
+	  print_generic_expr (file, al, dump_flags);
+	  fprintf (file, " ");
+	}
+      fprintf (file, "}");
+    }
+}
+
+
+/* Dump to stderr the list of variables that may be aliasing VAR.  */
+
+void
+debug_may_aliases_for (tree var)
+{
+  dump_may_aliases_for (stderr, var);
+}
+
+/* Return true if VAR may be aliased.  */
+
+bool
+may_be_aliased (tree var)
+{
+  /* Obviously.  */
+  if (TREE_ADDRESSABLE (var))
+    return true;
+
+  /* Globally visible variables can have their addresses taken by other
+     translation units.  */
+  if (MTAG_P (var)
+      && MTAG_GLOBAL (var))
+    return true;
+  else if (!MTAG_P (var)
+           && (DECL_EXTERNAL (var) || TREE_PUBLIC (var)))
+    return true;
+
+  /* Automatic variables can't have their addresses escape any other
+     way.  This must be after the check for global variables, as
+     extern declarations do not have TREE_STATIC set.  */
+  if (!TREE_STATIC (var))
+    return false;
+
+  return false;
+}
+
+/* The following is based on code in add_stmt_operand to ensure that the
+   same defs/uses/vdefs/vuses will be found after replacing a reference
+   to var (or ARRAY_REF to var) with an INDIRECT_REF to ptr whose value
+   is the address of var.  Return a memtag for the ptr, after adding the 
+   proper may_aliases to it (which are the aliases of var, if it has any,
+   or var itself).  */
+
+static tree
+add_may_alias_for_new_tag (tree tag, tree var)
+{
+  bitmap aliases = NULL;
+  
+  if (MTAG_P (var))
+    aliases = may_aliases (var);
+
+  /* Case 1: |aliases| == 1  */
+  if (aliases
+      && bitmap_single_bit_set_p (aliases))
+    {
+      tree ali = referenced_var (bitmap_first_set_bit (aliases));
+      if (TREE_CODE (ali) == SYMBOL_MEMORY_TAG)
+        return ali;
+    }
+
+  /* Case 2: |aliases| == 0  */
+  if (aliases == NULL)
+    add_may_alias (tag, var);
+  else
+    {
+      /* Case 3: |aliases| > 1  */
+      union_alias_set_into (tag, aliases);
+    }
+  return tag;
+}
+
+/* Create a new symbol tag for PTR.  Construct the may-alias list of
+   this type tag so that it has the aliasing of VAR according to the
+   location accessed by EXPR.
+
+   Note, the set of aliases represented by the new symbol tag are not
+   marked for renaming.  */
+
+void
+new_type_alias (tree ptr, tree var, tree expr)
+{
+  tree tag_type = TREE_TYPE (TREE_TYPE (ptr));
+  tree tag;
+  tree ali = NULL_TREE;
+  HOST_WIDE_INT offset, size, maxsize;
+  tree ref;
+
+  gcc_assert (symbol_mem_tag (ptr) == NULL_TREE);
+  gcc_assert (!MTAG_P (var));
+
+  ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
+  gcc_assert (ref);
+
+  tag = create_memory_tag (tag_type, true);
+  set_symbol_mem_tag (ptr, tag);
+
+  ali = add_may_alias_for_new_tag (tag, var);
+
+  set_symbol_mem_tag (ptr, ali);
+  MTAG_GLOBAL (tag) = is_global_var (var);
+}
+
+
+/* Reset the call_clobbered flags on our referenced vars.  In
+   theory, this only needs to be done for globals.  */
+
+static unsigned int
+reset_cc_flags (void)
+{
+  tree var;
+  referenced_var_iterator rvi;
+
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    var_ann (var)->call_clobbered = false;
+  return 0;
+}
+
+struct gimple_opt_pass pass_reset_cc_flags =
+{
+ {
+  GIMPLE_PASS,
+  NULL,		 /* name */
+  NULL,  	 /* gate */
+  reset_cc_flags, /* execute */
+  NULL,			 /* sub */
+  NULL,			 /* next */
+  0,			 /* static_pass_number */
+  0,			 /* tv_id */
+  PROP_referenced_vars |PROP_cfg, /* properties_required */
+  0,			 /* properties_provided */
+  0,			 /* properties_destroyed */
+  0,			 /* todo_flags_start */
+  0         	         /* todo_flags_finish */
+ }
+};
+
+
+/* A dummy pass to cause aliases to be computed via TODO_rebuild_alias.  */
+
+struct gimple_opt_pass pass_build_alias =
+{
+ {
+  GIMPLE_PASS,
+  "alias",		    /* name */
+  NULL,			    /* gate */
+  NULL,                     /* execute */
+  NULL,                     /* sub */
+  NULL,                     /* next */
+  0,                        /* static_pass_number */
+  0,                        /* tv_id */
+  PROP_cfg | PROP_ssa,      /* properties_required */
+  PROP_alias,               /* properties_provided */
+  0,                        /* properties_destroyed */
+  0,                        /* todo_flags_start */
+  TODO_rebuild_alias | TODO_dump_func  /* todo_flags_finish */
+ }
+};