GCC 4.2.0 release.

1 files changed, 2583 insertions, 0 deletions

diff --git a/contrib/gcc/tree-ssa-operands.c b/contrib/gcc/tree-ssa-operands.c
new file mode 100644
index 0000000..804f821
--- /dev/null
+++ b/contrib/gcc/tree-ssa-operands.c
@@ -0,0 +1,2583 @@
+/* SSA operands management for trees.
+   Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, 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 COPYING.  If not, write to
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "flags.h"
+#include "function.h"
+#include "diagnostic.h"
+#include "tree-flow.h"
+#include "tree-inline.h"
+#include "tree-pass.h"
+#include "ggc.h"
+#include "timevar.h"
+#include "toplev.h"
+#include "langhooks.h"
+#include "ipa-reference.h"
+
+/* This file contains the code required to manage the operands cache of the 
+   SSA optimizer.  For every stmt, we maintain an operand cache in the stmt 
+   annotation.  This cache contains operands that will be of interest to 
+   optimizers and other passes wishing to manipulate the IL. 
+
+   The operand type are broken up into REAL and VIRTUAL operands.  The real 
+   operands are represented as pointers into the stmt's operand tree.  Thus 
+   any manipulation of the real operands will be reflected in the actual tree.
+   Virtual operands are represented solely in the cache, although the base 
+   variable for the SSA_NAME may, or may not occur in the stmt's tree.  
+   Manipulation of the virtual operands will not be reflected in the stmt tree.
+
+   The routines in this file are concerned with creating this operand cache 
+   from a stmt tree.
+
+   The operand tree is the parsed by the various get_* routines which look 
+   through the stmt tree for the occurrence of operands which may be of 
+   interest, and calls are made to the append_* routines whenever one is 
+   found.  There are 5 of these routines, each representing one of the 
+   5 types of operands. Defs, Uses, Virtual Uses, Virtual May Defs, and 
+   Virtual Must Defs.
+
+   The append_* routines check for duplication, and simply keep a list of 
+   unique objects for each operand type in the build_* extendable vectors.
+
+   Once the stmt tree is completely parsed, the finalize_ssa_operands() 
+   routine is called, which proceeds to perform the finalization routine 
+   on each of the 5 operand vectors which have been built up.
+
+   If the stmt had a previous operand cache, the finalization routines 
+   attempt to match up the new operands with the old ones.  If it's a perfect 
+   match, the old vector is simply reused.  If it isn't a perfect match, then 
+   a new vector is created and the new operands are placed there.  For 
+   virtual operands, if the previous cache had SSA_NAME version of a 
+   variable, and that same variable occurs in the same operands cache, then 
+   the new cache vector will also get the same SSA_NAME.
+
+  i.e., if a stmt had a VUSE of 'a_5', and 'a' occurs in the new operand 
+  vector for VUSE, then the new vector will also be modified such that 
+  it contains 'a_5' rather than 'a'.  */
+
+/* Flags to describe operand properties in helpers.  */
+
+/* By default, operands are loaded.  */
+#define opf_none	0
+
+/* Operand is the target of an assignment expression or a 
+   call-clobbered variable.  */
+#define opf_is_def 	(1 << 0)
+
+/* Operand is the target of an assignment expression.  */
+#define opf_kill_def 	(1 << 1)
+
+/* No virtual operands should be created in the expression.  This is used
+   when traversing ADDR_EXPR nodes which have different semantics than
+   other expressions.  Inside an ADDR_EXPR node, the only operands that we
+   need to consider are indices into arrays.  For instance, &a.b[i] should
+   generate a USE of 'i' but it should not generate a VUSE for 'a' nor a
+   VUSE for 'b'.  */
+#define opf_no_vops 	(1 << 2)
+
+/* Operand is a "non-specific" kill for call-clobbers and such.  This
+   is used to distinguish "reset the world" events from explicit
+   MODIFY_EXPRs.  */
+#define opf_non_specific  (1 << 3)
+
+/* Array for building all the def operands.  */
+static VEC(tree,heap) *build_defs;
+
+/* Array for building all the use operands.  */
+static VEC(tree,heap) *build_uses;
+
+/* Array for building all the V_MAY_DEF operands.  */
+static VEC(tree,heap) *build_v_may_defs;
+
+/* Array for building all the VUSE operands.  */
+static VEC(tree,heap) *build_vuses;
+
+/* Array for building all the V_MUST_DEF operands.  */
+static VEC(tree,heap) *build_v_must_defs;
+
+/* These arrays are the cached operand vectors for call clobbered calls.  */
+static bool ops_active = false;
+
+static GTY (()) struct ssa_operand_memory_d *operand_memory = NULL;
+static unsigned operand_memory_index;
+
+static void get_expr_operands (tree, tree *, int);
+
+static def_optype_p free_defs = NULL;
+static use_optype_p free_uses = NULL;
+static vuse_optype_p free_vuses = NULL;
+static maydef_optype_p free_maydefs = NULL;
+static mustdef_optype_p free_mustdefs = NULL;
+
+/* Allocates operand OP of given TYPE from the appropriate free list,
+   or of the new value if the list is empty.  */
+
+#define ALLOC_OPTYPE(OP, TYPE)				\
+  do							\
+    {							\
+      TYPE##_optype_p ret = free_##TYPE##s;		\
+      if (ret)						\
+	free_##TYPE##s = ret->next;			\
+      else						\
+	ret = ssa_operand_alloc (sizeof (*ret));	\
+      (OP) = ret;					\
+    } while (0) 
+
+/* Return the DECL_UID of the base variable of T.  */
+
+static inline unsigned
+get_name_decl (tree t)
+{
+  if (TREE_CODE (t) != SSA_NAME)
+    return DECL_UID (t);
+  else
+    return DECL_UID (SSA_NAME_VAR (t));
+}
+
+
+/* Comparison function for qsort used in operand_build_sort_virtual.  */
+
+static int
+operand_build_cmp (const void *p, const void *q)
+{
+  tree e1 = *((const tree *)p);
+  tree e2 = *((const tree *)q);
+  unsigned int u1,u2;
+
+  u1 = get_name_decl (e1);
+  u2 = get_name_decl (e2);
+
+  /* We want to sort in ascending order.  They can never be equal.  */
+#ifdef ENABLE_CHECKING
+  gcc_assert (u1 != u2);
+#endif
+  return (u1 > u2 ? 1 : -1);
+}
+
+
+/* Sort the virtual operands in LIST from lowest DECL_UID to highest.  */
+
+static inline void
+operand_build_sort_virtual (VEC(tree,heap) *list)
+{
+  int num = VEC_length (tree, list);
+
+  if (num < 2)
+    return;
+
+  if (num == 2)
+    {
+      if (get_name_decl (VEC_index (tree, list, 0)) 
+	  > get_name_decl (VEC_index (tree, list, 1)))
+	{  
+	  /* Swap elements if in the wrong order.  */
+	  tree tmp = VEC_index (tree, list, 0);
+	  VEC_replace (tree, list, 0, VEC_index (tree, list, 1));
+	  VEC_replace (tree, list, 1, tmp);
+	}
+      return;
+    }
+
+  /* There are 3 or more elements, call qsort.  */
+  qsort (VEC_address (tree, list), 
+	 VEC_length (tree, list), 
+	 sizeof (tree),
+	 operand_build_cmp);
+}
+
+
+/*  Return true if the SSA operands cache is active.  */
+
+bool
+ssa_operands_active (void)
+{
+  return ops_active;
+}
+
+
+/* Structure storing statistics on how many call clobbers we have, and
+   how many where avoided.  */
+
+static struct 
+{
+  /* Number of call-clobbered ops we attempt to add to calls in
+     add_call_clobber_ops.  */
+  unsigned int clobbered_vars;
+
+  /* Number of write-clobbers (V_MAY_DEFs) avoided by using
+     not_written information.  */
+  unsigned int static_write_clobbers_avoided;
+
+  /* Number of reads (VUSEs) avoided by using not_read information.  */
+  unsigned int static_read_clobbers_avoided;
+  
+  /* Number of write-clobbers avoided because the variable can't escape to
+     this call.  */
+  unsigned int unescapable_clobbers_avoided;
+
+  /* Number of read-only uses we attempt to add to calls in
+     add_call_read_ops.  */
+  unsigned int readonly_clobbers;
+
+  /* Number of read-only uses we avoid using not_read information.  */
+  unsigned int static_readonly_clobbers_avoided;
+} clobber_stats;
+  
+
+/* Initialize the operand cache routines.  */
+
+void
+init_ssa_operands (void)
+{
+  build_defs = VEC_alloc (tree, heap, 5);
+  build_uses = VEC_alloc (tree, heap, 10);
+  build_vuses = VEC_alloc (tree, heap, 25);
+  build_v_may_defs = VEC_alloc (tree, heap, 25);
+  build_v_must_defs = VEC_alloc (tree, heap, 25);
+
+  gcc_assert (operand_memory == NULL);
+  operand_memory_index = SSA_OPERAND_MEMORY_SIZE;
+  ops_active = true;
+  memset (&clobber_stats, 0, sizeof (clobber_stats));
+}
+
+
+/* Dispose of anything required by the operand routines.  */
+
+void
+fini_ssa_operands (void)
+{
+  struct ssa_operand_memory_d *ptr;
+  VEC_free (tree, heap, build_defs);
+  VEC_free (tree, heap, build_uses);
+  VEC_free (tree, heap, build_v_must_defs);
+  VEC_free (tree, heap, build_v_may_defs);
+  VEC_free (tree, heap, build_vuses);
+  free_defs = NULL;
+  free_uses = NULL;
+  free_vuses = NULL;
+  free_maydefs = NULL;
+  free_mustdefs = NULL;
+  while ((ptr = operand_memory) != NULL)
+    {
+      operand_memory = operand_memory->next;
+      ggc_free (ptr);
+    }
+
+  ops_active = false;
+  
+  if (dump_file && (dump_flags & TDF_STATS))
+    {
+      fprintf (dump_file, "Original clobbered vars:%d\n",
+	       clobber_stats.clobbered_vars);
+      fprintf (dump_file, "Static write clobbers avoided:%d\n",
+	       clobber_stats.static_write_clobbers_avoided);
+      fprintf (dump_file, "Static read clobbers avoided:%d\n",
+	       clobber_stats.static_read_clobbers_avoided);
+      fprintf (dump_file, "Unescapable clobbers avoided:%d\n",
+	       clobber_stats.unescapable_clobbers_avoided);
+      fprintf (dump_file, "Original read-only clobbers:%d\n",
+	       clobber_stats.readonly_clobbers);
+      fprintf (dump_file, "Static read-only clobbers avoided:%d\n",
+	       clobber_stats.static_readonly_clobbers_avoided);
+    }
+}
+
+
+/* Return memory for operands of SIZE chunks.  */
+                                                                              
+static inline void *
+ssa_operand_alloc (unsigned size)
+{
+  char *ptr;
+  if (operand_memory_index + size >= SSA_OPERAND_MEMORY_SIZE)
+    {
+      struct ssa_operand_memory_d *ptr;
+      ptr = GGC_NEW (struct ssa_operand_memory_d);
+      ptr->next = operand_memory;
+      operand_memory = ptr;
+      operand_memory_index = 0;
+    }
+  ptr = &(operand_memory->mem[operand_memory_index]);
+  operand_memory_index += size;
+  return ptr;
+}
+
+
+
+/* This routine makes sure that PTR is in an immediate use list, and makes
+   sure the stmt pointer is set to the current stmt.  */
+
+static inline void
+set_virtual_use_link (use_operand_p ptr, tree stmt)
+{
+  /*  fold_stmt may have changed the stmt pointers.  */
+  if (ptr->stmt != stmt)
+    ptr->stmt = stmt;
+
+  /* If this use isn't in a list, add it to the correct list.  */
+  if (!ptr->prev)
+    link_imm_use (ptr, *(ptr->use));
+}
+
+/* Appends ELT after TO, and moves the TO pointer to ELT.  */
+
+#define APPEND_OP_AFTER(ELT, TO)	\
+  do					\
+    {					\
+      (TO)->next = (ELT);		\
+      (TO) = (ELT);			\
+    } while (0)
+
+/* Appends head of list FROM after TO, and move both pointers
+   to their successors.  */
+
+#define MOVE_HEAD_AFTER(FROM, TO)	\
+  do					\
+    {					\
+      APPEND_OP_AFTER (FROM, TO);	\
+      (FROM) = (FROM)->next;		\
+    } while (0)
+
+/* Moves OP to appropriate freelist.  OP is set to its successor.  */
+
+#define MOVE_HEAD_TO_FREELIST(OP, TYPE)			\
+  do							\
+    {							\
+      TYPE##_optype_p next = (OP)->next;		\
+      (OP)->next = free_##TYPE##s;			\
+      free_##TYPE##s = (OP);				\
+      (OP) = next;					\
+    } while (0)
+
+/* Initializes immediate use at USE_PTR to value VAL, and links it to the list
+   of immediate uses.  STMT is the current statement.  */
+
+#define INITIALIZE_USE(USE_PTR, VAL, STMT)		\
+  do							\
+    {							\
+      (USE_PTR)->use = (VAL);				\
+      link_imm_use_stmt ((USE_PTR), *(VAL), (STMT));	\
+    } while (0)
+
+/* Adds OP to the list of defs after LAST, and moves
+   LAST to the new element.  */
+
+static inline void
+add_def_op (tree *op, def_optype_p *last)
+{
+  def_optype_p new;
+
+  ALLOC_OPTYPE (new, def);
+  DEF_OP_PTR (new) = op;
+  APPEND_OP_AFTER (new, *last);  
+}
+
+/* Adds OP to the list of uses of statement STMT after LAST, and moves
+   LAST to the new element.  */
+
+static inline void
+add_use_op (tree stmt, tree *op, use_optype_p *last)
+{
+  use_optype_p new;
+
+  ALLOC_OPTYPE (new, use);
+  INITIALIZE_USE (USE_OP_PTR (new), op, stmt);
+  APPEND_OP_AFTER (new, *last);  
+}
+
+/* Adds OP to the list of vuses of statement STMT after LAST, and moves
+   LAST to the new element.  */
+
+static inline void
+add_vuse_op (tree stmt, tree op, vuse_optype_p *last)
+{
+  vuse_optype_p new;
+
+  ALLOC_OPTYPE (new, vuse);
+  VUSE_OP (new) = op;
+  INITIALIZE_USE (VUSE_OP_PTR (new), &VUSE_OP (new), stmt);
+  APPEND_OP_AFTER (new, *last);  
+}
+
+/* Adds OP to the list of maydefs of statement STMT after LAST, and moves
+   LAST to the new element.  */
+
+static inline void
+add_maydef_op (tree stmt, tree op, maydef_optype_p *last)
+{
+  maydef_optype_p new;
+
+  ALLOC_OPTYPE (new, maydef);
+  MAYDEF_RESULT (new) = op;
+  MAYDEF_OP (new) = op;
+  INITIALIZE_USE (MAYDEF_OP_PTR (new), &MAYDEF_OP (new), stmt);
+  APPEND_OP_AFTER (new, *last);  
+}
+
+/* Adds OP to the list of mustdefs of statement STMT after LAST, and moves
+   LAST to the new element.  */
+
+static inline void
+add_mustdef_op (tree stmt, tree op, mustdef_optype_p *last)
+{
+  mustdef_optype_p new;
+
+  ALLOC_OPTYPE (new, mustdef);
+  MUSTDEF_RESULT (new) = op;
+  MUSTDEF_KILL (new) = op;
+  INITIALIZE_USE (MUSTDEF_KILL_PTR (new), &MUSTDEF_KILL (new), stmt);
+  APPEND_OP_AFTER (new, *last);
+}
+
+/* Takes elements from build_defs and turns them into def operands of STMT.
+   TODO -- Given that def operands list is not necessarily sorted, merging
+	   the operands this way does not make much sense.
+	-- Make build_defs VEC of tree *.  */
+
+static inline void
+finalize_ssa_def_ops (tree stmt)
+{
+  unsigned new_i;
+  struct def_optype_d new_list;
+  def_optype_p old_ops, last;
+  tree *old_base;
+
+  new_list.next = NULL;
+  last = &new_list;
+
+  old_ops = DEF_OPS (stmt);
+
+  new_i = 0;
+  while (old_ops && new_i < VEC_length (tree, build_defs))
+    {
+      tree *new_base = (tree *) VEC_index (tree, build_defs, new_i);
+      old_base = DEF_OP_PTR (old_ops);
+
+      if (old_base == new_base)
+        {
+	  /* if variables are the same, reuse this node.  */
+	  MOVE_HEAD_AFTER (old_ops, last);
+	  new_i++;
+	}
+      else if (old_base < new_base)
+	{
+	  /* if old is less than new, old goes to the free list.  */
+	  MOVE_HEAD_TO_FREELIST (old_ops, def);
+	}
+      else
+	{
+	  /* This is a new operand.  */
+	  add_def_op (new_base, &last);
+	  new_i++;
+	}
+    }
+
+  /* If there is anything remaining in the build_defs list, simply emit it.  */
+  for ( ; new_i < VEC_length (tree, build_defs); new_i++)
+    add_def_op ((tree *) VEC_index (tree, build_defs, new_i), &last);
+
+  last->next = NULL;
+
+  /* If there is anything in the old list, free it.  */
+  if (old_ops)
+    {
+      old_ops->next = free_defs;
+      free_defs = old_ops;
+    }
+
+  /* Now set the stmt's operands.  */
+  DEF_OPS (stmt) = new_list.next;
+
+#ifdef ENABLE_CHECKING
+  {
+    def_optype_p ptr;
+    unsigned x = 0;
+    for (ptr = DEF_OPS (stmt); ptr; ptr = ptr->next)
+      x++;
+
+    gcc_assert (x == VEC_length (tree, build_defs));
+  }
+#endif
+}
+
+/* This routine will create stmt operands for STMT from the def build list.  */
+
+static void
+finalize_ssa_defs (tree stmt)
+{
+  unsigned int num = VEC_length (tree, build_defs);
+
+  /* There should only be a single real definition per assignment.  */
+  gcc_assert ((stmt && TREE_CODE (stmt) != MODIFY_EXPR) || num <= 1);
+
+  /* If there is an old list, often the new list is identical, or close, so
+     find the elements at the beginning that are the same as the vector.  */
+  finalize_ssa_def_ops (stmt);
+  VEC_truncate (tree, build_defs, 0);
+}
+
+/* Takes elements from build_uses and turns them into use operands of STMT.
+   TODO -- Make build_uses VEC of tree *.  */
+
+static inline void
+finalize_ssa_use_ops (tree stmt)
+{
+  unsigned new_i;
+  struct use_optype_d new_list;
+  use_optype_p old_ops, ptr, last;
+
+  new_list.next = NULL;
+  last = &new_list;
+
+  old_ops = USE_OPS (stmt);
+
+  /* If there is anything in the old list, free it.  */
+  if (old_ops)
+    {
+      for (ptr = old_ops; ptr; ptr = ptr->next)
+	delink_imm_use (USE_OP_PTR (ptr));
+      old_ops->next = free_uses;
+      free_uses = old_ops;
+    }
+
+  /* Now create nodes for all the new nodes.  */
+  for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
+    add_use_op (stmt, (tree *) VEC_index (tree, build_uses, new_i), &last);
+
+  last->next = NULL;
+
+  /* Now set the stmt's operands.  */
+  USE_OPS (stmt) = new_list.next;
+
+#ifdef ENABLE_CHECKING
+  {
+    unsigned x = 0;
+    for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
+      x++;
+
+    gcc_assert (x == VEC_length (tree, build_uses));
+  }
+#endif
+}
+
+/* Return a new use operand vector for STMT, comparing to OLD_OPS_P.  */
+                                                                              
+static void
+finalize_ssa_uses (tree stmt)
+{
+#ifdef ENABLE_CHECKING
+  {
+    unsigned x;
+    unsigned num = VEC_length (tree, build_uses);
+
+    /* If the pointer to the operand is the statement itself, something is
+       wrong.  It means that we are pointing to a local variable (the 
+       initial call to update_stmt_operands does not pass a pointer to a 
+       statement).  */
+    for (x = 0; x < num; x++)
+      gcc_assert (*((tree *)VEC_index (tree, build_uses, x)) != stmt);
+  }
+#endif
+  finalize_ssa_use_ops (stmt);
+  VEC_truncate (tree, build_uses, 0);
+}
+
+
+/* Takes elements from build_v_may_defs and turns them into maydef operands of
+   STMT.  */
+
+static inline void
+finalize_ssa_v_may_def_ops (tree stmt)
+{
+  unsigned new_i;
+  struct maydef_optype_d new_list;
+  maydef_optype_p old_ops, ptr, last;
+  tree act;
+  unsigned old_base, new_base;
+
+  new_list.next = NULL;
+  last = &new_list;
+
+  old_ops = MAYDEF_OPS (stmt);
+
+  new_i = 0;
+  while (old_ops && new_i < VEC_length (tree, build_v_may_defs))
+    {
+      act = VEC_index (tree, build_v_may_defs, new_i);
+      new_base = get_name_decl (act);
+      old_base = get_name_decl (MAYDEF_OP (old_ops));
+
+      if (old_base == new_base)
+        {
+	  /* if variables are the same, reuse this node.  */
+	  MOVE_HEAD_AFTER (old_ops, last);
+	  set_virtual_use_link (MAYDEF_OP_PTR (last), stmt);
+	  new_i++;
+	}
+      else if (old_base < new_base)
+	{
+	  /* if old is less than new, old goes to the free list.  */
+	  delink_imm_use (MAYDEF_OP_PTR (old_ops));
+	  MOVE_HEAD_TO_FREELIST (old_ops, maydef);
+	}
+      else
+	{
+	  /* This is a new operand.  */
+	  add_maydef_op (stmt, act, &last);
+	  new_i++;
+	}
+    }
+
+  /* If there is anything remaining in the build_v_may_defs list, simply emit it.  */
+  for ( ; new_i < VEC_length (tree, build_v_may_defs); new_i++)
+    add_maydef_op (stmt, VEC_index (tree, build_v_may_defs, new_i), &last);
+
+  last->next = NULL;
+
+  /* If there is anything in the old list, free it.  */
+  if (old_ops)
+    {
+      for (ptr = old_ops; ptr; ptr = ptr->next)
+	delink_imm_use (MAYDEF_OP_PTR (ptr));
+      old_ops->next = free_maydefs;
+      free_maydefs = old_ops;
+    }
+
+  /* Now set the stmt's operands.  */
+  MAYDEF_OPS (stmt) = new_list.next;
+
+#ifdef ENABLE_CHECKING
+  {
+    unsigned x = 0;
+    for (ptr = MAYDEF_OPS (stmt); ptr; ptr = ptr->next)
+      x++;
+
+    gcc_assert (x == VEC_length (tree, build_v_may_defs));
+  }
+#endif
+}
+
+static void
+finalize_ssa_v_may_defs (tree stmt)
+{
+  finalize_ssa_v_may_def_ops (stmt);
+}
+                                                                               
+
+/* Clear the in_list bits and empty the build array for V_MAY_DEFs.  */
+
+static inline void
+cleanup_v_may_defs (void)
+{
+  unsigned x, num;
+  num = VEC_length (tree, build_v_may_defs);
+
+  for (x = 0; x < num; x++)
+    {
+      tree t = VEC_index (tree, build_v_may_defs, x);
+      if (TREE_CODE (t) != SSA_NAME)
+	{
+	  var_ann_t ann = var_ann (t);
+	  ann->in_v_may_def_list = 0;
+	}
+    }
+  VEC_truncate (tree, build_v_may_defs, 0);
+}                                                                             
+
+
+/* Takes elements from build_vuses and turns them into vuse operands of
+   STMT.  */
+
+static inline void
+finalize_ssa_vuse_ops (tree stmt)
+{
+  unsigned new_i;
+  struct vuse_optype_d new_list;
+  vuse_optype_p old_ops, ptr, last;
+  tree act;
+  unsigned old_base, new_base;
+
+  new_list.next = NULL;
+  last = &new_list;
+
+  old_ops = VUSE_OPS (stmt);
+
+  new_i = 0;
+  while (old_ops && new_i < VEC_length (tree, build_vuses))
+    {
+      act = VEC_index (tree, build_vuses, new_i);
+      new_base = get_name_decl (act);
+      old_base = get_name_decl (VUSE_OP (old_ops));
+
+      if (old_base == new_base)
+        {
+	  /* if variables are the same, reuse this node.  */
+	  MOVE_HEAD_AFTER (old_ops, last);
+	  set_virtual_use_link (VUSE_OP_PTR (last), stmt);
+	  new_i++;
+	}
+      else if (old_base < new_base)
+	{
+	  /* if old is less than new, old goes to the free list.  */
+	  delink_imm_use (USE_OP_PTR (old_ops));
+	  MOVE_HEAD_TO_FREELIST (old_ops, vuse);
+	}
+      else
+	{
+	  /* This is a new operand.  */
+	  add_vuse_op (stmt, act, &last);
+	  new_i++;
+	}
+    }
+
+  /* If there is anything remaining in the build_vuses list, simply emit it.  */
+  for ( ; new_i < VEC_length (tree, build_vuses); new_i++)
+    add_vuse_op (stmt, VEC_index (tree, build_vuses, new_i), &last);
+
+  last->next = NULL;
+
+  /* If there is anything in the old list, free it.  */
+  if (old_ops)
+    {
+      for (ptr = old_ops; ptr; ptr = ptr->next)
+	delink_imm_use (VUSE_OP_PTR (ptr));
+      old_ops->next = free_vuses;
+      free_vuses = old_ops;
+    }
+
+  /* Now set the stmt's operands.  */
+  VUSE_OPS (stmt) = new_list.next;
+
+#ifdef ENABLE_CHECKING
+  {
+    unsigned x = 0;
+    for (ptr = VUSE_OPS (stmt); ptr; ptr = ptr->next)
+      x++;
+
+    gcc_assert (x == VEC_length (tree, build_vuses));
+  }
+#endif
+}
+                                                                              
+/* Return a new VUSE operand vector, comparing to OLD_OPS_P.  */
+                                                                              
+static void
+finalize_ssa_vuses (tree stmt)
+{
+  unsigned num, num_v_may_defs;
+  unsigned vuse_index;
+
+  /* Remove superfluous VUSE operands.  If the statement already has a
+     V_MAY_DEF operation for a variable 'a', then a VUSE for 'a' is
+     not needed because V_MAY_DEFs imply a VUSE of the variable.  For
+     instance, suppose that variable 'a' is aliased:
+
+	      # VUSE <a_2>
+	      # a_3 = V_MAY_DEF <a_2>
+	      a = a + 1;
+
+     The VUSE <a_2> is superfluous because it is implied by the
+     V_MAY_DEF operation.  */
+  num = VEC_length (tree, build_vuses);
+  num_v_may_defs = VEC_length (tree, build_v_may_defs);
+
+  if (num > 0 && num_v_may_defs > 0)
+    {
+      for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
+        {
+	  tree vuse;
+	  vuse = VEC_index (tree, build_vuses, vuse_index);
+	  if (TREE_CODE (vuse) != SSA_NAME)
+	    {
+	      var_ann_t ann = var_ann (vuse);
+	      ann->in_vuse_list = 0;
+	      if (ann->in_v_may_def_list)
+	        {
+		  VEC_ordered_remove (tree, build_vuses, vuse_index);
+		  continue;
+		}
+	    }
+	  vuse_index++;
+	}
+    }
+  else
+    {
+      /* Clear out the in_list bits.  */
+      for (vuse_index = 0;
+	  vuse_index < VEC_length (tree, build_vuses);
+	  vuse_index++)
+	{
+	  tree t = VEC_index (tree, build_vuses, vuse_index);
+	  if (TREE_CODE (t) != SSA_NAME)
+	    {
+	      var_ann_t ann = var_ann (t);
+	      ann->in_vuse_list = 0;
+	    }
+	}
+    }
+
+  finalize_ssa_vuse_ops (stmt);
+
+  /* The V_MAY_DEF build vector wasn't cleaned up because we needed it.  */
+  cleanup_v_may_defs ();
+                                                                              
+  /* Free the VUSEs build vector.  */
+  VEC_truncate (tree, build_vuses, 0);
+
+}
+
+/* Takes elements from build_v_must_defs and turns them into mustdef operands of
+   STMT.  */
+
+static inline void
+finalize_ssa_v_must_def_ops (tree stmt)
+{
+  unsigned new_i;
+  struct mustdef_optype_d new_list;
+  mustdef_optype_p old_ops, ptr, last;
+  tree act;
+  unsigned old_base, new_base;
+
+  new_list.next = NULL;
+  last = &new_list;
+
+  old_ops = MUSTDEF_OPS (stmt);
+
+  new_i = 0;
+  while (old_ops && new_i < VEC_length (tree, build_v_must_defs))
+    {
+      act = VEC_index (tree, build_v_must_defs, new_i);
+      new_base = get_name_decl (act);
+      old_base = get_name_decl (MUSTDEF_KILL (old_ops));
+
+      if (old_base == new_base)
+        {
+	  /* If variables are the same, reuse this node.  */
+	  MOVE_HEAD_AFTER (old_ops, last);
+	  set_virtual_use_link (MUSTDEF_KILL_PTR (last), stmt);
+	  new_i++;
+	}
+      else if (old_base < new_base)
+	{
+	  /* If old is less than new, old goes to the free list.  */
+	  delink_imm_use (MUSTDEF_KILL_PTR (old_ops));
+	  MOVE_HEAD_TO_FREELIST (old_ops, mustdef);
+	}
+      else
+	{
+	  /* This is a new operand.  */
+	  add_mustdef_op (stmt, act, &last);
+	  new_i++;
+	}
+    }
+
+  /* If there is anything remaining in the build_v_must_defs list, simply emit it.  */
+  for ( ; new_i < VEC_length (tree, build_v_must_defs); new_i++)
+    add_mustdef_op (stmt, VEC_index (tree, build_v_must_defs, new_i), &last);
+
+  last->next = NULL;
+
+  /* If there is anything in the old list, free it.  */
+  if (old_ops)
+    {
+      for (ptr = old_ops; ptr; ptr = ptr->next)
+	delink_imm_use (MUSTDEF_KILL_PTR (ptr));
+      old_ops->next = free_mustdefs;
+      free_mustdefs = old_ops;
+    }
+
+  /* Now set the stmt's operands.  */
+  MUSTDEF_OPS (stmt) = new_list.next;
+
+#ifdef ENABLE_CHECKING
+  {
+    unsigned x = 0;
+    for (ptr = MUSTDEF_OPS (stmt); ptr; ptr = ptr->next)
+      x++;
+
+    gcc_assert (x == VEC_length (tree, build_v_must_defs));
+  }
+#endif
+}
+
+static void
+finalize_ssa_v_must_defs (tree stmt)
+{
+  /* In the presence of subvars, there may be more than one V_MUST_DEF
+     per statement (one for each subvar).  It is a bit expensive to
+     verify that all must-defs in a statement belong to subvars if
+     there is more than one must-def, so we don't do it.  Suffice to
+     say, if you reach here without having subvars, and have num >1,
+     you have hit a bug.  */
+  finalize_ssa_v_must_def_ops (stmt);
+  VEC_truncate (tree, build_v_must_defs, 0);
+}
+
+
+/* Finalize all the build vectors, fill the new ones into INFO.  */
+                                                                              
+static inline void
+finalize_ssa_stmt_operands (tree stmt)
+{
+  finalize_ssa_defs (stmt);
+  finalize_ssa_uses (stmt);
+  finalize_ssa_v_must_defs (stmt);
+  finalize_ssa_v_may_defs (stmt);
+  finalize_ssa_vuses (stmt);
+}
+
+
+/* Start the process of building up operands vectors in INFO.  */
+
+static inline void
+start_ssa_stmt_operands (void)
+{
+  gcc_assert (VEC_length (tree, build_defs) == 0);
+  gcc_assert (VEC_length (tree, build_uses) == 0);
+  gcc_assert (VEC_length (tree, build_vuses) == 0);
+  gcc_assert (VEC_length (tree, build_v_may_defs) == 0);
+  gcc_assert (VEC_length (tree, build_v_must_defs) == 0);
+}
+
+
+/* Add DEF_P to the list of pointers to operands.  */
+
+static inline void
+append_def (tree *def_p)
+{
+  VEC_safe_push (tree, heap, build_defs, (tree)def_p);
+}
+
+
+/* Add USE_P to the list of pointers to operands.  */
+
+static inline void
+append_use (tree *use_p)
+{
+  VEC_safe_push (tree, heap, build_uses, (tree)use_p);
+}
+
+
+/* Add a new virtual may def for variable VAR to the build array.  */
+
+static inline void
+append_v_may_def (tree var)
+{
+  if (TREE_CODE (var) != SSA_NAME)
+    {
+      var_ann_t ann = get_var_ann (var);
+
+      /* Don't allow duplicate entries.  */
+      if (ann->in_v_may_def_list)
+	return;
+      ann->in_v_may_def_list = 1;
+    }
+
+  VEC_safe_push (tree, heap, build_v_may_defs, (tree)var);
+}
+
+
+/* Add VAR to the list of virtual uses.  */
+
+static inline void
+append_vuse (tree var)
+{
+  /* Don't allow duplicate entries.  */
+  if (TREE_CODE (var) != SSA_NAME)
+    {
+      var_ann_t ann = get_var_ann (var);
+
+      if (ann->in_vuse_list || ann->in_v_may_def_list)
+        return;
+      ann->in_vuse_list = 1;
+    }
+
+  VEC_safe_push (tree, heap, build_vuses, (tree)var);
+}
+
+
+/* Add VAR to the list of virtual must definitions for INFO.  */
+
+static inline void
+append_v_must_def (tree var)
+{
+  unsigned i;
+
+  /* Don't allow duplicate entries.  */
+  for (i = 0; i < VEC_length (tree, build_v_must_defs); i++)
+    if (var == VEC_index (tree, build_v_must_defs, i))
+      return;
+
+  VEC_safe_push (tree, heap, build_v_must_defs, (tree)var);
+}
+
+
+/* REF is a tree that contains the entire pointer dereference
+   expression, if available, or NULL otherwise.  ALIAS is the variable
+   we are asking if REF can access.  OFFSET and SIZE come from the
+   memory access expression that generated this virtual operand.  */
+
+static bool
+access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
+			   HOST_WIDE_INT size)
+{  
+  bool offsetgtz = offset > 0;
+  unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
+  tree base = ref ? get_base_address (ref) : NULL;
+
+  /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
+     using a call-clobbered memory tag.  By definition, call-clobbered
+     memory tags can always touch .GLOBAL_VAR.  */
+  if (alias == global_var)
+    return true;
+
+  /* We cannot prune nonlocal aliases because they are not type
+     specific.  */
+  if (alias == nonlocal_all)
+    return true;
+
+  /* If ALIAS is an SFT, it can't be touched if the offset     
+     and size of the access is not overlapping with the SFT offset and
+     size.  This is only true if we are accessing through a pointer
+     to a type that is the same as SFT_PARENT_VAR.  Otherwise, we may
+     be accessing through a pointer to some substruct of the
+     structure, and if we try to prune there, we will have the wrong
+     offset, and get the wrong answer.
+     i.e., we can't prune without more work if we have something like
+
+     struct gcc_target
+     {
+       struct asm_out
+       {
+         const char *byte_op;
+	 struct asm_int_op
+	 {    
+	   const char *hi;
+	 } aligned_op;
+       } asm_out;
+     } targetm;
+     
+     foo = &targetm.asm_out.aligned_op;
+     return foo->hi;
+
+     SFT.1, which represents hi, will have SFT_OFFSET=32 because in
+     terms of SFT_PARENT_VAR, that is where it is.
+     However, the access through the foo pointer will be at offset 0.  */
+  if (size != -1
+      && TREE_CODE (alias) == STRUCT_FIELD_TAG
+      && base
+      && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
+      && !overlap_subvar (offset, size, alias, NULL))
+    {
+#ifdef ACCESS_DEBUGGING
+      fprintf (stderr, "Access to ");
+      print_generic_expr (stderr, ref, 0);
+      fprintf (stderr, " may not touch ");
+      print_generic_expr (stderr, alias, 0);
+      fprintf (stderr, " in function %s\n", get_name (current_function_decl));
+#endif
+      return false;
+    }
+
+  /* Without strict aliasing, it is impossible for a component access
+     through a pointer to touch a random variable, unless that
+     variable *is* a structure or a pointer.
+
+     That is, given p->c, and some random global variable b,
+     there is no legal way that p->c could be an access to b.
+     
+     Without strict aliasing on, we consider it legal to do something
+     like:
+
+     struct foos { int l; };
+     int foo;
+     static struct foos *getfoo(void);
+     int main (void)
+     {
+       struct foos *f = getfoo();
+       f->l = 1;
+       foo = 2;
+       if (f->l == 1)
+         abort();
+       exit(0);
+     }
+     static struct foos *getfoo(void)     
+     { return (struct foos *)&foo; }
+     
+     (taken from 20000623-1.c)
+
+     The docs also say/imply that access through union pointers
+     is legal (but *not* if you take the address of the union member,
+     i.e. the inverse), such that you can do
+
+     typedef union {
+       int d;
+     } U;
+
+     int rv;
+     void breakme()
+     {
+       U *rv0;
+       U *pretmp = (U*)&rv;
+       rv0 = pretmp;
+       rv0->d = 42;    
+     }
+     To implement this, we just punt on accesses through union
+     pointers entirely.
+  */
+  else if (ref 
+	   && flag_strict_aliasing
+	   && TREE_CODE (ref) != INDIRECT_REF
+	   && !MTAG_P (alias)
+	   && (TREE_CODE (base) != INDIRECT_REF
+	       || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
+	   && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
+	   && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
+	   && !POINTER_TYPE_P (TREE_TYPE (alias))
+	   /* When the struct has may_alias attached to it, we need not to
+	      return true.  */
+	   && get_alias_set (base))
+    {
+#ifdef ACCESS_DEBUGGING
+      fprintf (stderr, "Access to ");
+      print_generic_expr (stderr, ref, 0);
+      fprintf (stderr, " may not touch ");
+      print_generic_expr (stderr, alias, 0);
+      fprintf (stderr, " in function %s\n", get_name (current_function_decl));
+#endif
+      return false;
+    }
+
+  /* If the offset of the access is greater than the size of one of
+     the possible aliases, it can't be touching that alias, because it
+     would be past the end of the structure.  */
+  else if (ref
+	   && flag_strict_aliasing
+	   && TREE_CODE (ref) != INDIRECT_REF
+	   && !MTAG_P (alias)
+	   && !POINTER_TYPE_P (TREE_TYPE (alias))
+	   && offsetgtz
+	   && DECL_SIZE (alias)
+	   && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
+	   && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
+    {
+#ifdef ACCESS_DEBUGGING
+      fprintf (stderr, "Access to ");
+      print_generic_expr (stderr, ref, 0);
+      fprintf (stderr, " may not touch ");
+      print_generic_expr (stderr, alias, 0);
+      fprintf (stderr, " in function %s\n", get_name (current_function_decl));
+#endif
+      return false;
+    }	   
+
+  return true;
+}
+
+
+/* Add VAR to the virtual operands array.  FLAGS is as in
+   get_expr_operands.  FULL_REF is a tree that contains the entire
+   pointer dereference expression, if available, or NULL otherwise.
+   OFFSET and SIZE come from the memory access expression that
+   generated this virtual operand.  FOR_CLOBBER is true is this is
+   adding a virtual operand for a call clobber.  */
+
+static void 
+add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
+		     tree full_ref, HOST_WIDE_INT offset,
+		     HOST_WIDE_INT size, bool for_clobber)
+{
+  VEC(tree,gc) *aliases;
+  tree sym;
+  var_ann_t v_ann;
+  
+  sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
+  v_ann = var_ann (sym);
+  
+  /* Mark statements with volatile operands.  Optimizers should back
+     off from statements having volatile operands.  */
+  if (TREE_THIS_VOLATILE (sym) && s_ann)
+    s_ann->has_volatile_ops = true;
+
+  /* If the variable cannot be modified and this is a V_MAY_DEF change
+     it into a VUSE.  This happens when read-only variables are marked
+     call-clobbered and/or aliased to writable variables.  So we only
+     check that this only happens on non-specific stores.
+
+     Note that if this is a specific store, i.e. associated with a
+     modify_expr, then we can't suppress the V_MAY_DEF, lest we run
+     into validation problems.
+
+     This can happen when programs cast away const, leaving us with a
+     store to read-only memory.  If the statement is actually executed
+     at runtime, then the program is ill formed.  If the statement is
+     not executed then all is well.  At the very least, we cannot ICE.  */
+  if ((flags & opf_non_specific) && unmodifiable_var_p (var))
+    flags &= ~(opf_is_def | opf_kill_def);
+  
+  /* The variable is not a GIMPLE register.  Add it (or its aliases) to
+     virtual operands, unless the caller has specifically requested
+     not to add virtual operands (used when adding operands inside an
+     ADDR_EXPR expression).  */
+  if (flags & opf_no_vops)
+    return;
+  
+  aliases = v_ann->may_aliases;
+  if (aliases == NULL)
+    {
+      /* The variable is not aliased or it is an alias tag.  */
+      if (flags & opf_is_def)
+	{
+	  if (flags & opf_kill_def)
+	    {
+	      /* V_MUST_DEF for non-aliased, non-GIMPLE register 
+		 variable definitions.  */
+	      gcc_assert (!MTAG_P (var)
+			  || TREE_CODE (var) == STRUCT_FIELD_TAG);
+	      append_v_must_def (var);
+	    }
+	  else
+	    {
+	      /* Add a V_MAY_DEF for call-clobbered variables and
+		 memory tags.  */
+	      append_v_may_def (var);
+	    }
+	}
+      else
+	append_vuse (var);
+    }
+  else
+    {
+      unsigned i;
+      tree al;
+      
+      /* The variable is aliased.  Add its aliases to the virtual
+	 operands.  */
+      gcc_assert (VEC_length (tree, aliases) != 0);
+      
+      if (flags & opf_is_def)
+	{
+	  
+	  bool none_added = true;
+
+	  for (i = 0; VEC_iterate (tree, aliases, i, al); i++)
+	    {
+	      if (!access_can_touch_variable (full_ref, al, offset, size))
+		continue;
+	      
+	      none_added = false;
+	      append_v_may_def (al);
+	    }
+
+	  /* If the variable is also an alias tag, add a virtual
+	     operand for it, otherwise we will miss representing
+	     references to the members of the variable's alias set.	     
+	     This fixes the bug in gcc.c-torture/execute/20020503-1.c.
+	     
+	     It is also necessary to add bare defs on clobbers for
+	     SMT's, so that bare SMT uses caused by pruning all the
+	     aliases will link up properly with calls.   In order to
+	     keep the number of these bare defs we add down to the
+	     minimum necessary, we keep track of which SMT's were used
+	     alone in statement vdefs or VUSEs.  */
+	  if (v_ann->is_aliased
+	      || none_added
+	      || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
+		  && for_clobber
+		  && SMT_USED_ALONE (var)))
+	    {
+	      /* Every bare SMT def we add should have SMT_USED_ALONE
+		 set on it, or else we will get the wrong answer on
+		 clobbers.  Sadly, this assertion trips on code that
+		 violates strict aliasing rules, because they *do* get
+		 the clobbers wrong, since it is illegal code.  As a
+		 result, we currently only enable it for aliasing
+		 debugging.  Someone might wish to turn this code into
+		 a nice strict-aliasing warning, since we *know* it
+		 will get the wrong answer...  */
+#ifdef ACCESS_DEBUGGING
+	      if (none_added
+		  && !updating_used_alone && aliases_computed_p
+		  && TREE_CODE (var) == SYMBOL_MEMORY_TAG)
+		gcc_assert (SMT_USED_ALONE (var));
+#endif
+	      append_v_may_def (var);
+	    }
+	}
+      else
+	{
+	  bool none_added = true;
+	  for (i = 0; VEC_iterate (tree, aliases, i, al); i++)
+	    {
+	      if (!access_can_touch_variable (full_ref, al, offset, size))
+		continue;
+	      none_added = false;
+	      append_vuse (al);
+	    }
+
+	  /* Similarly, append a virtual uses for VAR itself, when
+	     it is an alias tag.  */
+	  if (v_ann->is_aliased || none_added)
+	    append_vuse (var);
+	}
+    }
+}
+
+
+/* Add *VAR_P to the appropriate operand array for S_ANN.  FLAGS is as in
+   get_expr_operands.  If *VAR_P is a GIMPLE register, it will be added to
+   the statement's real operands, otherwise it is added to virtual
+   operands.  */
+
+static void
+add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
+{
+  bool is_real_op;
+  tree var, sym;
+  var_ann_t v_ann;
+
+  var = *var_p;
+  gcc_assert (SSA_VAR_P (var));
+
+  is_real_op = is_gimple_reg (var);
+
+  /* If this is a real operand, the operand is either an SSA name or a 
+     decl.  Virtual operands may only be decls.  */
+  gcc_assert (is_real_op || DECL_P (var));
+
+  sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
+  v_ann = var_ann (sym);
+
+  /* Mark statements with volatile operands.  Optimizers should back
+     off from statements having volatile operands.  */
+  if (TREE_THIS_VOLATILE (sym) && s_ann)
+    s_ann->has_volatile_ops = true;
+
+  if (is_real_op)
+    {
+      /* The variable is a GIMPLE register.  Add it to real operands.  */
+      if (flags & opf_is_def)
+	append_def (var_p);
+      else
+	append_use (var_p);
+    }
+  else
+    add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
+}
+
+
+/* A subroutine of get_expr_operands to handle INDIRECT_REF,
+   ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.  
+
+   STMT is the statement being processed, EXPR is the INDIRECT_REF
+      that got us here.
+   
+   FLAGS is as in get_expr_operands.
+
+   FULL_REF contains the full pointer dereference expression, if we
+      have it, or NULL otherwise.
+
+   OFFSET and SIZE are the location of the access inside the
+      dereferenced pointer, if known.
+
+   RECURSE_ON_BASE should be set to true if we want to continue
+      calling get_expr_operands on the base pointer, and false if
+      something else will do it for us.  */
+
+static void
+get_indirect_ref_operands (tree stmt, tree expr, int flags,
+			   tree full_ref,
+			   HOST_WIDE_INT offset, HOST_WIDE_INT size,
+			   bool recurse_on_base)
+{
+  tree *pptr = &TREE_OPERAND (expr, 0);
+  tree ptr = *pptr;
+  stmt_ann_t s_ann = stmt_ann (stmt);
+
+  /* Stores into INDIRECT_REF operands are never killing definitions.  */
+  flags &= ~opf_kill_def;
+
+  if (SSA_VAR_P (ptr))
+    {
+      struct ptr_info_def *pi = NULL;
+
+      /* If PTR has flow-sensitive points-to information, use it.  */
+      if (TREE_CODE (ptr) == SSA_NAME
+	  && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
+	  && pi->name_mem_tag)
+	{
+	  /* PTR has its own memory tag.  Use it.  */
+	  add_virtual_operand (pi->name_mem_tag, s_ann, flags,
+			       full_ref, offset, size, false);
+	}
+      else
+	{
+	  /* If PTR is not an SSA_NAME or it doesn't have a name
+	     tag, use its symbol memory tag.  */
+	  var_ann_t v_ann;
+
+	  /* If we are emitting debugging dumps, display a warning if
+	     PTR is an SSA_NAME with no flow-sensitive alias
+	     information.  That means that we may need to compute
+	     aliasing again.  */
+	  if (dump_file
+	      && TREE_CODE (ptr) == SSA_NAME
+	      && pi == NULL)
+	    {
+	      fprintf (dump_file,
+		  "NOTE: no flow-sensitive alias info for ");
+	      print_generic_expr (dump_file, ptr, dump_flags);
+	      fprintf (dump_file, " in ");
+	      print_generic_stmt (dump_file, stmt, dump_flags);
+	    }
+
+	  if (TREE_CODE (ptr) == SSA_NAME)
+	    ptr = SSA_NAME_VAR (ptr);
+	  v_ann = var_ann (ptr);
+
+	  if (v_ann->symbol_mem_tag)
+	    add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
+				 full_ref, offset, size, false);
+	}
+    }
+  else if (TREE_CODE (ptr) == INTEGER_CST)
+    {
+      /* If a constant is used as a pointer, we can't generate a real
+	 operand for it but we mark the statement volatile to prevent
+	 optimizations from messing things up.  */
+      if (s_ann)
+	s_ann->has_volatile_ops = true;
+      return;
+    }
+  else
+    {
+      /* Ok, this isn't even is_gimple_min_invariant.  Something's broke.  */
+      gcc_unreachable ();
+    }
+
+  /* If requested, add a USE operand for the base pointer.  */
+  if (recurse_on_base)
+    get_expr_operands (stmt, pptr, opf_none);
+}
+
+
+/* A subroutine of get_expr_operands to handle TARGET_MEM_REF.  */
+
+static void
+get_tmr_operands (tree stmt, tree expr, int flags)
+{
+  tree tag = TMR_TAG (expr), ref;
+  HOST_WIDE_INT offset, size, maxsize;
+  subvar_t svars, sv;
+  stmt_ann_t s_ann = stmt_ann (stmt);
+
+  /* First record the real operands.  */
+  get_expr_operands (stmt, &TMR_BASE (expr), opf_none);
+  get_expr_operands (stmt, &TMR_INDEX (expr), opf_none);
+
+  /* MEM_REFs should never be killing.  */
+  flags &= ~opf_kill_def;
+
+  if (TMR_SYMBOL (expr))
+    {
+      stmt_ann_t ann = stmt_ann (stmt);
+      add_to_addressable_set (TMR_SYMBOL (expr), &ann->addresses_taken);
+    }
+
+  if (!tag)
+    {
+      /* Something weird, so ensure that we will be careful.  */
+      stmt_ann (stmt)->has_volatile_ops = true;
+      return;
+    }
+
+  if (DECL_P (tag))
+    {
+      get_expr_operands (stmt, &tag, flags);
+      return;
+    }
+
+  ref = get_ref_base_and_extent (tag, &offset, &size, &maxsize);
+  gcc_assert (ref != NULL_TREE);
+  svars = get_subvars_for_var (ref);
+  for (sv = svars; sv; sv = sv->next)
+    {
+      bool exact;		
+      if (overlap_subvar (offset, maxsize, sv->var, &exact))
+	{
+	  int subvar_flags = flags;
+	  if (!exact || size != maxsize)
+	    subvar_flags &= ~opf_kill_def;
+	  add_stmt_operand (&sv->var, s_ann, subvar_flags);
+	}
+    }
+}
+
+
+/* Add clobbering definitions for .GLOBAL_VAR or for each of the call
+   clobbered variables in the function.  */
+
+static void
+add_call_clobber_ops (tree stmt, tree callee)
+{
+  unsigned u;
+  bitmap_iterator bi;
+  stmt_ann_t s_ann = stmt_ann (stmt);
+  bitmap not_read_b, not_written_b;
+  
+  /* Functions that are not const, pure or never return may clobber
+     call-clobbered variables.  */
+  if (s_ann)
+    s_ann->makes_clobbering_call = true;
+
+  /* If we created .GLOBAL_VAR earlier, just use it.  See compute_may_aliases 
+     for the heuristic used to decide whether to create .GLOBAL_VAR or not.  */
+  if (global_var)
+    {
+      add_stmt_operand (&global_var, s_ann, opf_is_def);
+      return;
+    }
+
+  /* Get info for local and module level statics.  There is a bit
+     set for each static if the call being processed does not read
+     or write that variable.  */
+  not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL; 
+  not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL; 
+  /* Add a V_MAY_DEF operand for every call clobbered variable.  */
+  EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, u, bi)
+    {
+      tree var = referenced_var_lookup (u);
+      unsigned int escape_mask = var_ann (var)->escape_mask;
+      tree real_var = var;
+      bool not_read;
+      bool not_written;
+      
+      /* Not read and not written are computed on regular vars, not
+	 subvars, so look at the parent var if this is an SFT. */
+      if (TREE_CODE (var) == STRUCT_FIELD_TAG)
+	real_var = SFT_PARENT_VAR (var);
+
+      not_read = not_read_b ? bitmap_bit_p (not_read_b, 
+					    DECL_UID (real_var)) : false;
+      not_written = not_written_b ? bitmap_bit_p (not_written_b, 
+						  DECL_UID (real_var)) : false;
+      gcc_assert (!unmodifiable_var_p (var));
+      
+      clobber_stats.clobbered_vars++;
+
+      /* See if this variable is really clobbered by this function.  */
+
+      /* Trivial case: Things escaping only to pure/const are not
+	 clobbered by non-pure-const, and only read by pure/const. */
+      if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
+	{
+	  tree call = get_call_expr_in (stmt);
+	  if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
+	    {
+	      add_stmt_operand (&var, s_ann, opf_none);
+	      clobber_stats.unescapable_clobbers_avoided++;
+	      continue;
+	    }
+	  else
+	    {
+	      clobber_stats.unescapable_clobbers_avoided++;
+	      continue;
+	    }
+	}
+            
+      if (not_written)
+	{
+	  clobber_stats.static_write_clobbers_avoided++;
+	  if (!not_read)
+	    add_stmt_operand (&var, s_ann, opf_none);
+	  else
+	    clobber_stats.static_read_clobbers_avoided++;
+	}
+      else
+	add_virtual_operand (var, s_ann, opf_is_def, NULL, 0, -1, true);
+    }
+}
+
+
+/* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
+   function.  */
+
+static void
+add_call_read_ops (tree stmt, tree callee)
+{
+  unsigned u;
+  bitmap_iterator bi;
+  stmt_ann_t s_ann = stmt_ann (stmt);
+  bitmap not_read_b;
+
+  /* if the function is not pure, it may reference memory.  Add
+     a VUSE for .GLOBAL_VAR if it has been created.  See add_referenced_var
+     for the heuristic used to decide whether to create .GLOBAL_VAR.  */
+  if (global_var)
+    {
+      add_stmt_operand (&global_var, s_ann, opf_none);
+      return;
+    }
+  
+  not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL; 
+
+  /* Add a VUSE for each call-clobbered variable.  */
+  EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, u, bi)
+    {
+      tree var = referenced_var (u);
+      tree real_var = var;
+      bool not_read;
+      
+      clobber_stats.readonly_clobbers++;
+
+      /* Not read and not written are computed on regular vars, not
+	 subvars, so look at the parent var if this is an SFT. */
+
+      if (TREE_CODE (var) == STRUCT_FIELD_TAG)
+	real_var = SFT_PARENT_VAR (var);
+
+      not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
+	                    : false;
+      
+      if (not_read)
+	{
+	  clobber_stats.static_readonly_clobbers_avoided++;
+	  continue;
+	}
+            
+      add_stmt_operand (&var, s_ann, opf_none | opf_non_specific);
+    }
+}
+
+
+/* A subroutine of get_expr_operands to handle CALL_EXPR.  */
+
+static void
+get_call_expr_operands (tree stmt, tree expr)
+{
+  tree op;
+  int call_flags = call_expr_flags (expr);
+
+  /* If aliases have been computed already, add V_MAY_DEF or V_USE
+     operands for all the symbols that have been found to be
+     call-clobbered.
+     
+     Note that if aliases have not been computed, the global effects
+     of calls will not be included in the SSA web. This is fine
+     because no optimizer should run before aliases have been
+     computed.  By not bothering with virtual operands for CALL_EXPRs
+     we avoid adding superfluous virtual operands, which can be a
+     significant compile time sink (See PR 15855).  */
+  if (aliases_computed_p
+      && !bitmap_empty_p (call_clobbered_vars)
+      && !(call_flags & ECF_NOVOPS))
+    {
+      /* A 'pure' or a 'const' function never call-clobbers anything. 
+	 A 'noreturn' function might, but since we don't return anyway 
+	 there is no point in recording that.  */ 
+      if (TREE_SIDE_EFFECTS (expr)
+	  && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
+	add_call_clobber_ops (stmt, get_callee_fndecl (expr));
+      else if (!(call_flags & ECF_CONST))
+	add_call_read_ops (stmt, get_callee_fndecl (expr));
+    }
+
+  /* Find uses in the called function.  */
+  get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_none);
+
+  for (op = TREE_OPERAND (expr, 1); op; op = TREE_CHAIN (op))
+    get_expr_operands (stmt, &TREE_VALUE (op), opf_none);
+
+  get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
+}
+
+
+/* Scan operands in the ASM_EXPR stmt referred to in INFO.  */
+
+static void
+get_asm_expr_operands (tree stmt)
+{
+  stmt_ann_t s_ann = stmt_ann (stmt);
+  int noutputs = list_length (ASM_OUTPUTS (stmt));
+  const char **oconstraints
+    = (const char **) alloca ((noutputs) * sizeof (const char *));
+  int i;
+  tree link;
+  const char *constraint;
+  bool allows_mem, allows_reg, is_inout;
+
+  for (i=0, link = ASM_OUTPUTS (stmt); link; ++i, link = TREE_CHAIN (link))
+    {
+      constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
+      oconstraints[i] = constraint;
+      parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
+	                       &allows_reg, &is_inout);
+
+      /* This should have been split in gimplify_asm_expr.  */
+      gcc_assert (!allows_reg || !is_inout);
+
+      /* Memory operands are addressable.  Note that STMT needs the
+	 address of this operand.  */
+      if (!allows_reg && allows_mem)
+	{
+	  tree t = get_base_address (TREE_VALUE (link));
+	  if (t && DECL_P (t) && s_ann)
+	    add_to_addressable_set (t, &s_ann->addresses_taken);
+	}
+
+      get_expr_operands (stmt, &TREE_VALUE (link), opf_is_def);
+    }
+
+  for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
+    {
+      constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
+      parse_input_constraint (&constraint, 0, 0, noutputs, 0,
+			      oconstraints, &allows_mem, &allows_reg);
+
+      /* Memory operands are addressable.  Note that STMT needs the
+	 address of this operand.  */
+      if (!allows_reg && allows_mem)
+	{
+	  tree t = get_base_address (TREE_VALUE (link));
+	  if (t && DECL_P (t) && s_ann)
+	    add_to_addressable_set (t, &s_ann->addresses_taken);
+	}
+
+      get_expr_operands (stmt, &TREE_VALUE (link), 0);
+    }
+
+
+  /* Clobber memory for asm ("" : : : "memory");  */
+  for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
+    if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
+      {
+	unsigned i;
+	bitmap_iterator bi;
+
+	/* Clobber all call-clobbered variables (or .GLOBAL_VAR if we
+	   decided to group them).  */
+	if (global_var)
+	  add_stmt_operand (&global_var, s_ann, opf_is_def);
+	else
+	  EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, bi)
+	    {
+	      tree var = referenced_var (i);
+	      add_stmt_operand (&var, s_ann, opf_is_def | opf_non_specific);
+	    }
+
+	/* Now clobber all addressables.  */
+	EXECUTE_IF_SET_IN_BITMAP (addressable_vars, 0, i, bi)
+	    {
+	      tree var = referenced_var (i);
+
+	      /* Subvars are explicitly represented in this list, so
+		 we don't need the original to be added to the clobber
+		 ops, but the original *will* be in this list because 
+		 we keep the addressability of the original
+		 variable up-to-date so we don't screw up the rest of
+		 the backend.  */
+	      if (var_can_have_subvars (var)
+		  && get_subvars_for_var (var) != NULL)
+		continue;		
+
+	      add_stmt_operand (&var, s_ann, opf_is_def | opf_non_specific);
+	    }
+
+	break;
+      }
+}
+
+
+/* Scan operands for the assignment expression EXPR in statement STMT.  */
+
+static void
+get_modify_expr_operands (tree stmt, tree expr)
+{
+  /* First get operands from the RHS.  */
+  get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
+
+  /* For the LHS, use a regular definition (OPF_IS_DEF) for GIMPLE
+     registers.  If the LHS is a store to memory, we will either need
+     a preserving definition (V_MAY_DEF) or a killing definition
+     (V_MUST_DEF).
+
+     Preserving definitions are those that modify a part of an
+     aggregate object for which no subvars have been computed (or the
+     reference does not correspond exactly to one of them). Stores
+     through a pointer are also represented with V_MAY_DEF operators.
+
+     The determination of whether to use a preserving or a killing
+     definition is done while scanning the LHS of the assignment.  By
+     default, assume that we will emit a V_MUST_DEF.  */
+  get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_is_def|opf_kill_def);
+}
+
+
+/* Recursively scan the expression pointed to by EXPR_P in statement
+   STMT.  FLAGS is one of the OPF_* constants modifying how to
+   interpret the operands found.  */
+
+static void
+get_expr_operands (tree stmt, tree *expr_p, int flags)
+{
+  enum tree_code code;
+  enum tree_code_class class;
+  tree expr = *expr_p;
+  stmt_ann_t s_ann = stmt_ann (stmt);
+
+  if (expr == NULL)
+    return;
+
+  code = TREE_CODE (expr);
+  class = TREE_CODE_CLASS (code);
+
+  switch (code)
+    {
+    case ADDR_EXPR:
+      /* Taking the address of a variable does not represent a
+	 reference to it, but the fact that the statement takes its
+	 address will be of interest to some passes (e.g. alias
+	 resolution).  */
+      add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
+
+      /* If the address is invariant, there may be no interesting
+	 variable references inside.  */
+      if (is_gimple_min_invariant (expr))
+	return;
+
+      /* Otherwise, there may be variables referenced inside but there
+	 should be no VUSEs created, since the referenced objects are
+	 not really accessed.  The only operands that we should find
+	 here are ARRAY_REF indices which will always be real operands
+	 (GIMPLE does not allow non-registers as array indices).  */
+      flags |= opf_no_vops;
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
+      return;
+
+    case SSA_NAME:
+    case STRUCT_FIELD_TAG:
+    case SYMBOL_MEMORY_TAG:
+    case NAME_MEMORY_TAG:
+     add_stmt_operand (expr_p, s_ann, flags);
+     return;
+
+    case VAR_DECL:
+    case PARM_DECL:
+    case RESULT_DECL:
+      {
+	subvar_t svars;
+	
+	/* Add the subvars for a variable, if it has subvars, to DEFS
+	   or USES.  Otherwise, add the variable itself.  Whether it
+	   goes to USES or DEFS depends on the operand flags.  */
+	if (var_can_have_subvars (expr)
+	    && (svars = get_subvars_for_var (expr)))
+	  {
+	    subvar_t sv;
+	    for (sv = svars; sv; sv = sv->next)
+	      add_stmt_operand (&sv->var, s_ann, flags);
+	  }
+	else
+	  add_stmt_operand (expr_p, s_ann, flags);
+
+	return;
+      }
+
+    case MISALIGNED_INDIRECT_REF:
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
+      /* fall through */
+
+    case ALIGN_INDIRECT_REF:
+    case INDIRECT_REF:
+      get_indirect_ref_operands (stmt, expr, flags, NULL_TREE, 0, -1, true);
+      return;
+
+    case TARGET_MEM_REF:
+      get_tmr_operands (stmt, expr, flags);
+      return;
+
+    case ARRAY_REF:
+    case ARRAY_RANGE_REF:
+    case COMPONENT_REF:
+    case REALPART_EXPR:
+    case IMAGPART_EXPR:
+      {
+	tree ref;
+	HOST_WIDE_INT offset, size, maxsize;
+	bool none = true;
+
+	/* This component reference becomes an access to all of the
+	   subvariables it can touch, if we can determine that, but
+	   *NOT* the real one.  If we can't determine which fields we
+	   could touch, the recursion will eventually get to a
+	   variable and add *all* of its subvars, or whatever is the
+	   minimum correct subset.  */
+	ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
+	if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
+	  {
+	    subvar_t sv;
+	    subvar_t svars = get_subvars_for_var (ref);
+
+	    for (sv = svars; sv; sv = sv->next)
+	      {
+		bool exact;		
+
+		if (overlap_subvar (offset, maxsize, sv->var, &exact))
+		  {
+	            int subvar_flags = flags;
+		    none = false;
+		    if (!exact || size != maxsize)
+		      subvar_flags &= ~opf_kill_def;
+		    add_stmt_operand (&sv->var, s_ann, subvar_flags);
+		  }
+	      }
+
+	    if (!none)
+	      flags |= opf_no_vops;
+	  }
+	else if (TREE_CODE (ref) == INDIRECT_REF)
+	  {
+	    get_indirect_ref_operands (stmt, ref, flags, expr, offset,
+		                       maxsize, false);
+	    flags |= opf_no_vops;
+	  }
+
+	/* Even if we found subvars above we need to ensure to see
+	   immediate uses for d in s.a[d].  In case of s.a having
+	   a subvar or we would miss it otherwise.  */
+	get_expr_operands (stmt, &TREE_OPERAND (expr, 0),
+			   flags & ~opf_kill_def);
+	
+	if (code == COMPONENT_REF)
+	  {
+	    if (s_ann && TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
+	      s_ann->has_volatile_ops = true; 
+	    get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
+	  }
+	else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
+	  {
+            get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
+            get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
+            get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_none);
+	  }
+
+	return;
+      }
+
+    case WITH_SIZE_EXPR:
+      /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
+	 and an rvalue reference to its second argument.  */
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
+      return;
+
+    case CALL_EXPR:
+      get_call_expr_operands (stmt, expr);
+      return;
+
+    case COND_EXPR:
+    case VEC_COND_EXPR:
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_none);
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
+      return;
+
+    case MODIFY_EXPR:
+      get_modify_expr_operands (stmt, expr);
+      return;
+
+    case CONSTRUCTOR:
+      {
+	/* General aggregate CONSTRUCTORs have been decomposed, but they
+	   are still in use as the COMPLEX_EXPR equivalent for vectors.  */
+	constructor_elt *ce;
+	unsigned HOST_WIDE_INT idx;
+
+	for (idx = 0;
+	     VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
+	     idx++)
+	  get_expr_operands (stmt, &ce->value, opf_none);
+
+	return;
+      }
+
+    case BIT_FIELD_REF:
+      /* Stores using BIT_FIELD_REF are always preserving definitions.  */
+      flags &= ~opf_kill_def;
+
+      /* Fallthru  */
+
+    case TRUTH_NOT_EXPR:
+    case VIEW_CONVERT_EXPR:
+    do_unary:
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
+      return;
+
+    case TRUTH_AND_EXPR:
+    case TRUTH_OR_EXPR:
+    case TRUTH_XOR_EXPR:
+    case COMPOUND_EXPR:
+    case OBJ_TYPE_REF:
+    case ASSERT_EXPR:
+    do_binary:
+      {
+	get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
+	get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
+	return;
+      }
+
+    case DOT_PROD_EXPR:
+    case REALIGN_LOAD_EXPR:
+      {
+	get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
+        get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
+        get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
+        return;
+      }
+
+    case BLOCK:
+    case FUNCTION_DECL:
+    case EXC_PTR_EXPR:
+    case FILTER_EXPR:
+    case LABEL_DECL:
+    case CONST_DECL:
+    case OMP_PARALLEL:
+    case OMP_SECTIONS:
+    case OMP_FOR:
+    case OMP_SINGLE:
+    case OMP_MASTER:
+    case OMP_ORDERED:
+    case OMP_CRITICAL:
+    case OMP_RETURN:
+    case OMP_CONTINUE:
+      /* Expressions that make no memory references.  */
+      return;
+
+    default:
+      if (class == tcc_unary)
+	goto do_unary;
+      if (class == tcc_binary || class == tcc_comparison)
+	goto do_binary;
+      if (class == tcc_constant || class == tcc_type)
+	return;
+    }
+
+  /* If we get here, something has gone wrong.  */
+#ifdef ENABLE_CHECKING
+  fprintf (stderr, "unhandled expression in get_expr_operands():\n");
+  debug_tree (expr);
+  fputs ("\n", stderr);
+#endif
+  gcc_unreachable ();
+}
+
+
+/* Parse STMT looking for operands.  When finished, the various
+   build_* operand vectors will have potential operands in them.  */
+
+static void
+parse_ssa_operands (tree stmt)
+{
+  enum tree_code code;
+
+  code = TREE_CODE (stmt);
+  switch (code)
+    {
+    case MODIFY_EXPR:
+      get_modify_expr_operands (stmt, stmt);
+      break;
+
+    case COND_EXPR:
+      get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_none);
+      break;
+
+    case SWITCH_EXPR:
+      get_expr_operands (stmt, &SWITCH_COND (stmt), opf_none);
+      break;
+
+    case ASM_EXPR:
+      get_asm_expr_operands (stmt);
+      break;
+
+    case RETURN_EXPR:
+      get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_none);
+      break;
+
+    case GOTO_EXPR:
+      get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_none);
+      break;
+
+    case LABEL_EXPR:
+      get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_none);
+      break;
+
+    case BIND_EXPR:
+    case CASE_LABEL_EXPR:
+    case TRY_CATCH_EXPR:
+    case TRY_FINALLY_EXPR:
+    case EH_FILTER_EXPR:
+    case CATCH_EXPR:
+    case RESX_EXPR:
+      /* These nodes contain no variable references.  */
+      break;
+
+    default:
+      /* Notice that if get_expr_operands tries to use &STMT as the
+	 operand pointer (which may only happen for USE operands), we
+	 will fail in add_stmt_operand.  This default will handle
+	 statements like empty statements, or CALL_EXPRs that may
+	 appear on the RHS of a statement or as statements themselves.  */
+      get_expr_operands (stmt, &stmt, opf_none);
+      break;
+    }
+}
+
+
+/* Create an operands cache for STMT.  */
+
+static void
+build_ssa_operands (tree stmt)
+{
+  stmt_ann_t ann = get_stmt_ann (stmt);
+  
+  /* Initially assume that the statement has no volatile operands.  */
+  if (ann)
+    ann->has_volatile_ops = false;
+
+  start_ssa_stmt_operands ();
+
+  parse_ssa_operands (stmt);
+  operand_build_sort_virtual (build_vuses);
+  operand_build_sort_virtual (build_v_may_defs);
+  operand_build_sort_virtual (build_v_must_defs);
+
+  finalize_ssa_stmt_operands (stmt);
+}
+
+
+/* Free any operands vectors in OPS.  */
+
+void 
+free_ssa_operands (stmt_operands_p ops)
+{
+  ops->def_ops = NULL;
+  ops->use_ops = NULL;
+  ops->maydef_ops = NULL;
+  ops->mustdef_ops = NULL;
+  ops->vuse_ops = NULL;
+}
+
+
+/* Get the operands of statement STMT.  */
+
+void
+update_stmt_operands (tree stmt)
+{
+  stmt_ann_t ann = get_stmt_ann (stmt);
+
+  /* If update_stmt_operands is called before SSA is initialized, do
+     nothing.  */
+  if (!ssa_operands_active ())
+    return;
+
+  /* The optimizers cannot handle statements that are nothing but a
+     _DECL.  This indicates a bug in the gimplifier.  */
+  gcc_assert (!SSA_VAR_P (stmt));
+
+  gcc_assert (ann->modified);
+
+  timevar_push (TV_TREE_OPS);
+
+  build_ssa_operands (stmt);
+
+  /* Clear the modified bit for STMT.  */
+  ann->modified = 0;
+
+  timevar_pop (TV_TREE_OPS);
+}
+
+
+/* Copies virtual operands from SRC to DST.  */
+
+void
+copy_virtual_operands (tree dest, tree src)
+{
+  tree t;
+  ssa_op_iter iter, old_iter;
+  use_operand_p use_p, u2;
+  def_operand_p def_p, d2;
+
+  build_ssa_operands (dest);
+
+  /* Copy all the virtual fields.  */
+  FOR_EACH_SSA_TREE_OPERAND (t, src, iter, SSA_OP_VUSE)
+    append_vuse (t);
+  FOR_EACH_SSA_TREE_OPERAND (t, src, iter, SSA_OP_VMAYDEF)
+    append_v_may_def (t);
+  FOR_EACH_SSA_TREE_OPERAND (t, src, iter, SSA_OP_VMUSTDEF)
+    append_v_must_def (t);
+
+  if (VEC_length (tree, build_vuses) == 0
+      && VEC_length (tree, build_v_may_defs) == 0
+      && VEC_length (tree, build_v_must_defs) == 0)
+    return;
+
+  /* Now commit the virtual operands to this stmt.  */
+  finalize_ssa_v_must_defs (dest);
+  finalize_ssa_v_may_defs (dest);
+  finalize_ssa_vuses (dest);
+
+  /* Finally, set the field to the same values as then originals.  */
+  t = op_iter_init_tree (&old_iter, src, SSA_OP_VUSE);
+  FOR_EACH_SSA_USE_OPERAND (use_p, dest, iter, SSA_OP_VUSE)
+    {
+      gcc_assert (!op_iter_done (&old_iter));
+      SET_USE (use_p, t);
+      t = op_iter_next_tree (&old_iter);
+    }
+  gcc_assert (op_iter_done (&old_iter));
+
+  op_iter_init_maydef (&old_iter, src, &u2, &d2);
+  FOR_EACH_SSA_MAYDEF_OPERAND (def_p, use_p, dest, iter)
+    {
+      gcc_assert (!op_iter_done (&old_iter));
+      SET_USE (use_p, USE_FROM_PTR (u2));
+      SET_DEF (def_p, DEF_FROM_PTR (d2));
+      op_iter_next_maymustdef (&u2, &d2, &old_iter);
+    }
+  gcc_assert (op_iter_done (&old_iter));
+
+  op_iter_init_mustdef (&old_iter, src, &u2, &d2);
+  FOR_EACH_SSA_MUSTDEF_OPERAND (def_p, use_p, dest, iter)
+    {
+      gcc_assert (!op_iter_done (&old_iter));
+      SET_USE (use_p, USE_FROM_PTR (u2));
+      SET_DEF (def_p, DEF_FROM_PTR (d2));
+      op_iter_next_maymustdef (&u2, &d2, &old_iter);
+    }
+  gcc_assert (op_iter_done (&old_iter));
+
+}
+
+
+/* Specifically for use in DOM's expression analysis.  Given a store, we
+   create an artificial stmt which looks like a load from the store, this can
+   be used to eliminate redundant loads.  OLD_OPS are the operands from the 
+   store stmt, and NEW_STMT is the new load which represents a load of the
+   values stored.  */
+
+void
+create_ssa_artficial_load_stmt (tree new_stmt, tree old_stmt)
+{
+  stmt_ann_t ann;
+  tree op;
+  ssa_op_iter iter;
+  use_operand_p use_p;
+  unsigned x;
+
+  ann = get_stmt_ann (new_stmt);
+
+  /* Process the stmt looking for operands.  */
+  start_ssa_stmt_operands ();
+  parse_ssa_operands (new_stmt);
+
+  for (x = 0; x < VEC_length (tree, build_vuses); x++)
+    {
+      tree t = VEC_index (tree, build_vuses, x);
+      if (TREE_CODE (t) != SSA_NAME)
+	{
+	  var_ann_t ann = var_ann (t);
+	  ann->in_vuse_list = 0;
+	}
+    }
+   
+  for (x = 0; x < VEC_length (tree, build_v_may_defs); x++)
+    {
+      tree t = VEC_index (tree, build_v_may_defs, x);
+      if (TREE_CODE (t) != SSA_NAME)
+	{
+	  var_ann_t ann = var_ann (t);
+	  ann->in_v_may_def_list = 0;
+	}
+    }
+
+  /* Remove any virtual operands that were found.  */
+  VEC_truncate (tree, build_v_may_defs, 0);
+  VEC_truncate (tree, build_v_must_defs, 0);
+  VEC_truncate (tree, build_vuses, 0);
+
+  /* For each VDEF on the original statement, we want to create a
+     VUSE of the V_MAY_DEF result or V_MUST_DEF op on the new 
+     statement.  */
+  FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, 
+			     (SSA_OP_VMAYDEF | SSA_OP_VMUSTDEF))
+    append_vuse (op);
+    
+  /* Now build the operands for this new stmt.  */
+  finalize_ssa_stmt_operands (new_stmt);
+
+  /* All uses in this fake stmt must not be in the immediate use lists.  */
+  FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
+    delink_imm_use (use_p);
+}
+
+
+/* Swap operands EXP0 and EXP1 in statement STMT.  No attempt is done
+   to test the validity of the swap operation.  */
+
+void
+swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
+{
+  tree op0, op1;
+  op0 = *exp0;
+  op1 = *exp1;
+
+  /* If the operand cache is active, attempt to preserve the relative
+     positions of these two operands in their respective immediate use
+     lists.  */
+  if (ssa_operands_active () && op0 != op1)
+    {
+      use_optype_p use0, use1, ptr;
+      use0 = use1 = NULL;
+
+      /* Find the 2 operands in the cache, if they are there.  */
+      for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
+	if (USE_OP_PTR (ptr)->use == exp0)
+	  {
+	    use0 = ptr;
+	    break;
+	  }
+
+      for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
+	if (USE_OP_PTR (ptr)->use == exp1)
+	  {
+	    use1 = ptr;
+	    break;
+	  }
+
+      /* If both uses don't have operand entries, there isn't much we can do
+         at this point.  Presumably we don't need to worry about it.  */
+      if (use0 && use1)
+        {
+	  tree *tmp = USE_OP_PTR (use1)->use;
+	  USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
+	  USE_OP_PTR (use0)->use = tmp;
+	}
+    }
+
+  /* Now swap the data.  */
+  *exp0 = op1;
+  *exp1 = op0;
+}
+
+
+/* Add the base address of REF to the set *ADDRESSES_TAKEN.  If
+   *ADDRESSES_TAKEN is NULL, a new set is created.  REF may be
+   a single variable whose address has been taken or any other valid
+   GIMPLE memory reference (structure reference, array, etc).  If the
+   base address of REF is a decl that has sub-variables, also add all
+   of its sub-variables.  */
+
+void
+add_to_addressable_set (tree ref, bitmap *addresses_taken)
+{
+  tree var;
+  subvar_t svars;
+
+  gcc_assert (addresses_taken);
+
+  /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
+     as the only thing we take the address of.  If VAR is a structure,
+     taking the address of a field means that the whole structure may
+     be referenced using pointer arithmetic.  See PR 21407 and the
+     ensuing mailing list discussion.  */
+  var = get_base_address (ref);
+  if (var && SSA_VAR_P (var))
+    {
+      if (*addresses_taken == NULL)
+	*addresses_taken = BITMAP_GGC_ALLOC ();      
+      
+      if (var_can_have_subvars (var)
+	  && (svars = get_subvars_for_var (var)))
+	{
+	  subvar_t sv;
+	  for (sv = svars; sv; sv = sv->next)
+	    {
+	      bitmap_set_bit (*addresses_taken, DECL_UID (sv->var));
+	      TREE_ADDRESSABLE (sv->var) = 1;
+	    }
+	}
+      else
+	{
+	  bitmap_set_bit (*addresses_taken, DECL_UID (var));
+	  TREE_ADDRESSABLE (var) = 1;
+	}
+    }
+}
+
+
+/* Scan the immediate_use list for VAR making sure its linked properly.
+   Return TRUE if there is a problem and emit an error message to F.  */
+
+bool
+verify_imm_links (FILE *f, tree var)
+{
+  use_operand_p ptr, prev, list;
+  int count;
+
+  gcc_assert (TREE_CODE (var) == SSA_NAME);
+
+  list = &(SSA_NAME_IMM_USE_NODE (var));
+  gcc_assert (list->use == NULL);
+
+  if (list->prev == NULL)
+    {
+      gcc_assert (list->next == NULL);
+      return false;
+    }
+
+  prev = list;
+  count = 0;
+  for (ptr = list->next; ptr != list; )
+    {
+      if (prev != ptr->prev)
+	goto error;
+      
+      if (ptr->use == NULL)
+	goto error; /* 2 roots, or SAFE guard node.  */
+      else if (*(ptr->use) != var)
+	goto error;
+
+      prev = ptr;
+      ptr = ptr->next;
+
+      /* Avoid infinite loops.  50,000,000 uses probably indicates a
+	 problem.  */
+      if (count++ > 50000000)
+	goto error;
+    }
+
+  /* Verify list in the other direction.  */
+  prev = list;
+  for (ptr = list->prev; ptr != list; )
+    {
+      if (prev != ptr->next)
+	goto error;
+      prev = ptr;
+      ptr = ptr->prev;
+      if (count-- < 0)
+	goto error;
+    }
+
+  if (count != 0)
+    goto error;
+
+  return false;
+
+ error:
+  if (ptr->stmt && stmt_modified_p (ptr->stmt))
+    {
+      fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
+      print_generic_stmt (f, ptr->stmt, TDF_SLIM);
+    }
+  fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr, 
+	   (void *)ptr->use);
+  print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
+  fprintf(f, "\n");
+  return true;
+}
+
+
+/* Dump all the immediate uses to FILE.  */
+
+void
+dump_immediate_uses_for (FILE *file, tree var)
+{
+  imm_use_iterator iter;
+  use_operand_p use_p;
+
+  gcc_assert (var && TREE_CODE (var) == SSA_NAME);
+
+  print_generic_expr (file, var, TDF_SLIM);
+  fprintf (file, " : -->");
+  if (has_zero_uses (var))
+    fprintf (file, " no uses.\n");
+  else
+    if (has_single_use (var))
+      fprintf (file, " single use.\n");
+    else
+      fprintf (file, "%d uses.\n", num_imm_uses (var));
+
+  FOR_EACH_IMM_USE_FAST (use_p, iter, var)
+    {
+      if (use_p->stmt == NULL && use_p->use == NULL)
+        fprintf (file, "***end of stmt iterator marker***\n");
+      else
+	if (!is_gimple_reg (USE_FROM_PTR (use_p)))
+	  print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS);
+	else
+	  print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
+    }
+  fprintf(file, "\n");
+}
+
+
+/* Dump all the immediate uses to FILE.  */
+
+void
+dump_immediate_uses (FILE *file)
+{
+  tree var;
+  unsigned int x;
+
+  fprintf (file, "Immediate_uses: \n\n");
+  for (x = 1; x < num_ssa_names; x++)
+    {
+      var = ssa_name(x);
+      if (!var)
+        continue;
+      dump_immediate_uses_for (file, var);
+    }
+}
+
+
+/* Dump def-use edges on stderr.  */
+
+void
+debug_immediate_uses (void)
+{
+  dump_immediate_uses (stderr);
+}
+
+
+/* Dump def-use edges on stderr.  */
+
+void
+debug_immediate_uses_for (tree var)
+{
+  dump_immediate_uses_for (stderr, var);
+}
+
+#include "gt-tree-ssa-operands.h"