diff gcc/tree-ssa-operands.c @ 55:77e2b8dfacca gcc-4.4.5

update it from 4.4.3 to 4.5.0
author ryoma <e075725@ie.u-ryukyu.ac.jp>
date Fri, 12 Feb 2010 23:39:51 +0900
parents 58ad6c70ea60
children 326d9e06c2e3 b7f97abdc517
line wrap: on
line diff
--- a/gcc/tree-ssa-operands.c	Sun Feb 07 18:28:00 2010 +0900
+++ b/gcc/tree-ssa-operands.c	Fri Feb 12 23:39:51 2010 +0900
@@ -1,5 +1,5 @@
 /* SSA operands management for trees.
-   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -35,55 +35,50 @@
 #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. 
+/* 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 
+   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.  
+   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 
+   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 4 of these routines, each representing one of the 
+   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 4 of these routines, each representing one of the
    4 types of operands. Defs, Uses, Virtual Uses, and Virtual May Defs.
 
-   The append_* routines check for duplication, and simply keep a list of 
+   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 
+   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 4 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 
+   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'.  */
 
-/* Helper functions from gimple.c.  These are GIMPLE manipulation
-   routines that only the operand scanner should need.  */
-void gimple_set_stored_syms (gimple, bitmap, bitmap_obstack *);
-void gimple_set_loaded_syms (gimple, bitmap, bitmap_obstack *);
-
 /* Structure storing statistics on how many call clobbers we have, and
    how many where avoided.  */
 
-static struct 
+static struct
 {
   /* Number of call-clobbered ops we attempt to add to calls in
      add_call_clobbered_mem_symbols.  */
@@ -95,7 +90,7 @@
 
   /* 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;
@@ -114,7 +109,7 @@
 /* By default, operands are loaded.  */
 #define opf_use		0
 
-/* Operand is the target of an assignment expression or a 
+/* Operand is the target of an assignment expression or a
    call-clobbered variable.  */
 #define opf_def 	(1 << 0)
 
@@ -137,70 +132,21 @@
 /* Array for building all the use operands.  */
 static VEC(tree,heap) *build_uses;
 
-/* Set for building all the VDEF operands.  */
-static VEC(tree,heap) *build_vdefs;
+/* The built VDEF operand.  */
+static tree build_vdef;
 
-/* Set for building all the VUSE operands.  */
-static VEC(tree,heap) *build_vuses;
+/* The built VUSE operand.  */
+static tree build_vuse;
 
-/* Bitmap obstack for our datastructures that needs to survive across	
+/* Bitmap obstack for our datastructures that needs to survive across
    compilations of multiple functions.  */
 static bitmap_obstack operands_bitmap_obstack;
 
-/* Set for building all the loaded symbols.  */
-static bitmap build_loads;
-
-/* Set for building all the stored symbols.  */
-static bitmap build_stores;
-
 static void get_expr_operands (gimple, tree *, int);
 
 /* Number of functions with initialized ssa_operands.  */
 static int n_initialized = 0;
 
-/* Statement change buffer.  Data structure used to record state
-   information for statements.  This is used to determine what needs
-   to be done in order to update the SSA web after a statement is
-   modified by a pass.  If STMT is a statement that has just been
-   created, or needs to be folded via fold_stmt, or anything that
-   changes its physical structure then the pass should:
-
-   1- Call push_stmt_changes (&stmt) to record the current state of
-      STMT before any modifications are made.
-
-   2- Make all appropriate modifications to the statement.
-
-   3- Call pop_stmt_changes (&stmt) to find new symbols that
-      need to be put in SSA form, SSA name mappings for names that
-      have disappeared, recompute invariantness for address
-      expressions, cleanup EH information, etc.
-
-   If it is possible to determine that the statement was not modified,
-   instead of calling pop_stmt_changes it is quicker to call
-   discard_stmt_changes to avoid the expensive and unnecessary operand
-   re-scan and change comparison.  */
-
-struct scb_d
-{
-  /* Pointer to the statement being modified.  */
-  gimple *stmt_p;
-
-  /* If the statement references memory these are the sets of symbols
-     loaded and stored by the statement.  */
-  bitmap loads;
-  bitmap stores;
-};
-
-typedef struct scb_d *scb_t;
-DEF_VEC_P(scb_t);
-DEF_VEC_ALLOC_P(scb_t,heap);
-
-/* Stack of statement change buffers (SCB).  Every call to
-   push_stmt_changes pushes a new buffer onto the stack.  Calls to
-   pop_stmt_changes pop a buffer off of the stack and compute the set
-   of changes for the popped statement.  */
-static VEC(scb_t,heap) *scb_stack;
-
 /* Return the DECL_UID of the base variable of T.  */
 
 static inline unsigned
@@ -213,54 +159,6 @@
 }
 
 
-/* Comparison function for qsort used in operand_build_sort_virtual.  */
-
-int
-operand_build_cmp (const void *p, const void *q)
-{
-  const_tree const e1 = *((const_tree const *)p);
-  const_tree const e2 = *((const_tree const *)q);
-  const unsigned int u1 = get_name_decl (e1);
-  const unsigned int 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
@@ -277,93 +175,44 @@
 }
 
 
-/* VOPs are of variable sized, so the free list maps "free buckets" to the 
-   following table:  
-    bucket   # operands
-    ------   ----------
-	0	1
-	1	2
-	  ...
-	15	16
-	16	17-24
-	17	25-32
-	18	31-40
-	  ...
-	29	121-128
-   Any VOPs larger than this are simply added to the largest bucket when they
-   are freed.  */
+/* Create the VOP variable, an artificial global variable to act as a
+   representative of all of the virtual operands FUD chain.  */
+
+static void
+create_vop_var (void)
+{
+  tree global_var;
+
+  gcc_assert (cfun->gimple_df->vop == NULL_TREE);
 
-
-/* Return the number of operands used in bucket BUCKET.  */
+  global_var = build_decl (BUILTINS_LOCATION, VAR_DECL,
+			   get_identifier (".MEM"),
+			   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;
 
-static inline int
-vop_free_bucket_size (int bucket)
-{
-#ifdef ENABLE_CHECKING
-  gcc_assert (bucket >= 0 && bucket < NUM_VOP_FREE_BUCKETS);
-#endif
-  if (bucket < 16)
-    return bucket + 1;
-  return (bucket - 13) * 8;
+  create_var_ann (global_var);
+  add_referenced_var (global_var);
+  cfun->gimple_df->vop = global_var;
 }
 
-
-/* For a vop of NUM operands, return the bucket NUM belongs to.  If NUM is 
-   beyond the end of the bucket table, return -1.  */
-
-static inline int 
-vop_free_bucket_index (int num)
-{
-  gcc_assert (num > 0 && NUM_VOP_FREE_BUCKETS > 16);
-
-  /* Sizes 1 through 16 use buckets 0-15.  */
-  if (num <= 16)
-    return num - 1;
-  /* Buckets 16 - NUM_VOP_FREE_BUCKETS represent 8 unit chunks.  */
-  num = 14 + (num - 1) / 8;
-  if (num >= NUM_VOP_FREE_BUCKETS)
-    return -1;
-  else
-    return num;
-}
-
-
-/* Initialize the VOP free buckets.  */
-
-static inline void
-init_vop_buckets (void)
-{
-  int x;
+/* These are the sizes of the operand memory buffer in bytes which gets
+   allocated each time more operands space is required.  The final value is
+   the amount that is allocated every time after that.
+   In 1k we can fit 25 use operands (or 63 def operands) on a host with
+   8 byte pointers, that would be 10 statements each with 1 def and 2
+   uses.  */
 
-  for (x = 0; x < NUM_VOP_FREE_BUCKETS; x++)
-    gimple_ssa_operands (cfun)->vop_free_buckets[x] = NULL;
-}
-
-
-/* Add PTR to the appropriate VOP bucket.  */
-
-static inline void
-add_vop_to_freelist (voptype_p ptr)
-{
-  int bucket = vop_free_bucket_index (VUSE_VECT_NUM_ELEM (ptr->usev));
-
-  /* Too large, use the largest bucket so its not a complete throw away.  */
-  if (bucket == -1)
-    bucket = NUM_VOP_FREE_BUCKETS - 1;
-
-  ptr->next = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
-  gimple_ssa_operands (cfun)->vop_free_buckets[bucket] = ptr;
-}
- 
-
-/* These are the sizes of the operand memory  buffer which gets allocated each 
-   time more operands space is required.  The final value is the amount that is
-   allocated every time after that.  */
-  
 #define OP_SIZE_INIT	0
-#define OP_SIZE_1	30
-#define OP_SIZE_2	110
-#define OP_SIZE_3	511
+#define OP_SIZE_1	(1024 - sizeof (void *))
+#define OP_SIZE_2	(1024 * 4 - sizeof (void *))
+#define OP_SIZE_3	(1024 * 16 - sizeof (void *))
 
 /* Initialize the operand cache routines.  */
 
@@ -374,22 +223,18 @@
     {
       build_defs = VEC_alloc (tree, heap, 5);
       build_uses = VEC_alloc (tree, heap, 10);
-      build_vuses = VEC_alloc (tree, heap, 25);
-      build_vdefs = VEC_alloc (tree, heap, 25);
+      build_vuse = NULL_TREE;
+      build_vdef = NULL_TREE;
       bitmap_obstack_initialize (&operands_bitmap_obstack);
-      build_loads = BITMAP_ALLOC (&operands_bitmap_obstack);
-      build_stores = BITMAP_ALLOC (&operands_bitmap_obstack);
-      scb_stack = VEC_alloc (scb_t, heap, 20);
     }
 
   gcc_assert (gimple_ssa_operands (cfun)->operand_memory == NULL);
-  gcc_assert (gimple_ssa_operands (cfun)->mpt_table == NULL);
   gimple_ssa_operands (cfun)->operand_memory_index
      = gimple_ssa_operands (cfun)->ssa_operand_mem_size;
   gimple_ssa_operands (cfun)->ops_active = true;
   memset (&clobber_stats, 0, sizeof (clobber_stats));
-  init_vop_buckets ();
   gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_INIT;
+  create_vop_var ();
 }
 
 
@@ -399,22 +244,13 @@
 fini_ssa_operands (void)
 {
   struct ssa_operand_memory_d *ptr;
-  unsigned ix;
-  tree mpt;
 
   if (!--n_initialized)
     {
       VEC_free (tree, heap, build_defs);
       VEC_free (tree, heap, build_uses);
-      VEC_free (tree, heap, build_vdefs);
-      VEC_free (tree, heap, build_vuses);
-      BITMAP_FREE (build_loads);
-      BITMAP_FREE (build_stores);
-
-      /* The change buffer stack had better be empty.  */
-      gcc_assert (VEC_length (scb_t, scb_stack) == 0);
-      VEC_free (scb_t, heap, scb_stack);
-      scb_stack = NULL;
+      build_vdef = NULL_TREE;
+      build_vuse = NULL_TREE;
     }
 
   gimple_ssa_operands (cfun)->free_defs = NULL;
@@ -427,21 +263,13 @@
       ggc_free (ptr);
     }
 
-  for (ix = 0;
-       VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, ix, mpt);
-       ix++)
-    {
-      if (mpt)
-	BITMAP_FREE (MPT_SYMBOLS (mpt));
-    }
-
-  VEC_free (tree, heap, gimple_ssa_operands (cfun)->mpt_table);
-
   gimple_ssa_operands (cfun)->ops_active = false;
 
   if (!n_initialized)
     bitmap_obstack_release (&operands_bitmap_obstack);
 
+  cfun->gimple_df->vop = NULL_TREE;
+
   if (dump_file && (dump_flags & TDF_STATS))
     {
       fprintf (dump_file, "Original clobbered vars:           %d\n",
@@ -460,47 +288,45 @@
 }
 
 
-/* Return memory for operands of SIZE chunks.  */
-                                                                              
+/* Return memory for an operand of size SIZE.  */
+
 static inline void *
 ssa_operand_alloc (unsigned size)
 {
   char *ptr;
 
+  gcc_assert (size == sizeof (struct use_optype_d)
+	      || size == sizeof (struct def_optype_d));
+
   if (gimple_ssa_operands (cfun)->operand_memory_index + size
       >= gimple_ssa_operands (cfun)->ssa_operand_mem_size)
     {
       struct ssa_operand_memory_d *ptr;
 
-      if (gimple_ssa_operands (cfun)->ssa_operand_mem_size == OP_SIZE_INIT)
-	gimple_ssa_operands (cfun)->ssa_operand_mem_size
-	   = OP_SIZE_1 * sizeof (struct voptype_d);
-      else
-	if (gimple_ssa_operands (cfun)->ssa_operand_mem_size
-	    == OP_SIZE_1 * sizeof (struct voptype_d))
-	  gimple_ssa_operands (cfun)->ssa_operand_mem_size
-	     = OP_SIZE_2 * sizeof (struct voptype_d);
-	else
-	  gimple_ssa_operands (cfun)->ssa_operand_mem_size
-	     = OP_SIZE_3 * sizeof (struct voptype_d);
+      switch (gimple_ssa_operands (cfun)->ssa_operand_mem_size)
+	{
+	case OP_SIZE_INIT:
+	  gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_1;
+	  break;
+	case OP_SIZE_1:
+	  gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_2;
+	  break;
+	case OP_SIZE_2:
+	case OP_SIZE_3:
+	  gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_3;
+	  break;
+	default:
+	  gcc_unreachable ();
+	}
 
-      /* Go right to the maximum size if the request is too large.  */
-      if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
-        gimple_ssa_operands (cfun)->ssa_operand_mem_size
-	  = OP_SIZE_3 * sizeof (struct voptype_d);
-
-      /* We can reliably trigger the case that we need arbitrary many
-	 operands (see PR34093), so allocate a buffer just for this request.  */
-      if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
-	gimple_ssa_operands (cfun)->ssa_operand_mem_size = size;
-
-      ptr = (struct ssa_operand_memory_d *) 
-	      ggc_alloc (sizeof (struct ssa_operand_memory_d) 
-			 + gimple_ssa_operands (cfun)->ssa_operand_mem_size - 1);
+      ptr = (struct ssa_operand_memory_d *)
+	      ggc_alloc (sizeof (void *)
+			 + gimple_ssa_operands (cfun)->ssa_operand_mem_size);
       ptr->next = gimple_ssa_operands (cfun)->operand_memory;
       gimple_ssa_operands (cfun)->operand_memory = ptr;
       gimple_ssa_operands (cfun)->operand_memory_index = 0;
     }
+
   ptr = &(gimple_ssa_operands (cfun)->operand_memory
 	  ->mem[gimple_ssa_operands (cfun)->operand_memory_index]);
   gimple_ssa_operands (cfun)->operand_memory_index += size;
@@ -546,58 +372,9 @@
 }
 
 
-/* Allocate a vop with NUM elements.  */
-
-static inline struct voptype_d *
-alloc_vop (int num)
-{
-  struct voptype_d *ret = NULL;
-  int alloc_size = 0;
-
-  int bucket = vop_free_bucket_index (num);
-  if (bucket != -1)
-    {
-      /* If there is a free operand, use it.  */
-      if (gimple_ssa_operands (cfun)->vop_free_buckets[bucket] != NULL)
-	{
-	  ret = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
-	  gimple_ssa_operands (cfun)->vop_free_buckets[bucket] = 
-		  gimple_ssa_operands (cfun)->vop_free_buckets[bucket]->next;
-	}
-      else
-        alloc_size = vop_free_bucket_size(bucket);
-    }
-  else
-    alloc_size = num;
-
-  if (alloc_size > 0)
-    ret = (struct voptype_d *)ssa_operand_alloc (
-	sizeof (struct voptype_d) + (alloc_size - 1) * sizeof (vuse_element_t));
-
-  VUSE_VECT_NUM_ELEM (ret->usev) = num;
-  return ret;
-}
-
-
-/* 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, gimple stmt)
-{
-  /*  fold_stmt may have changed the stmt pointers.  */
-  if (ptr->loc.stmt != stmt)
-    ptr->loc.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));
-}
-
-
 /* Adds OP to the list of defs after LAST.  */
 
-static inline def_optype_p 
+static inline def_optype_p
 add_def_op (tree *op, def_optype_p last)
 {
   def_optype_p new_def;
@@ -626,56 +403,6 @@
 }
 
 
-/* Return a virtual op pointer with NUM elements which are all
-   initialized to OP and are linked into the immediate uses for STMT.
-   The new vop is appended after PREV.  */
-
-static inline voptype_p
-add_vop (gimple stmt, tree op, int num, voptype_p prev)
-{
-  voptype_p new_vop;
-  int x;
-
-  new_vop = alloc_vop (num);
-  for (x = 0; x < num; x++)
-    {
-      VUSE_OP_PTR (new_vop, x)->prev = NULL;
-      SET_VUSE_OP (new_vop, x, op);
-      VUSE_OP_PTR (new_vop, x)->use = &new_vop->usev.uses[x].use_var;
-      link_imm_use_stmt (VUSE_OP_PTR (new_vop, x),
-			 new_vop->usev.uses[x].use_var, stmt);
-    }
-
-  if (prev)
-    prev->next = new_vop;
-  new_vop->next = NULL;
-  return new_vop;
-}
-
-
-/* Adds OP to the list of vuses of statement STMT after LAST, and moves
-   LAST to the new element.  */
-
-static inline voptype_p
-add_vuse_op (gimple stmt, tree op, int num, voptype_p last)
-{
-  voptype_p new_vop = add_vop (stmt, op, num, last);
-  VDEF_RESULT (new_vop) = NULL_TREE;
-  return new_vop;
-}
-
-
-/* Adds OP to the list of vdefs of statement STMT after LAST, and moves
-   LAST to the new element.  */
-
-static inline voptype_p
-add_vdef_op (gimple stmt, tree op, int num, voptype_p last)
-{
-  voptype_p new_vop = add_vop (stmt, op, num, last);
-  VDEF_RESULT (new_vop) = op;
-  return new_vop;
-}
-  
 
 /* Takes elements from build_defs and turns them into def operands of STMT.
    TODO -- Make build_defs VEC of tree *.  */
@@ -691,6 +418,19 @@
   /* There should only be a single real definition per assignment.  */
   gcc_assert ((stmt && gimple_code (stmt) != GIMPLE_ASSIGN) || num <= 1);
 
+  /* Pre-pend the vdef we may have built.  */
+  if (build_vdef != NULL_TREE)
+    {
+      tree oldvdef = gimple_vdef (stmt);
+      if (oldvdef
+	  && TREE_CODE (oldvdef) == SSA_NAME)
+	oldvdef = SSA_NAME_VAR (oldvdef);
+      if (oldvdef != build_vdef)
+	gimple_set_vdef (stmt, build_vdef);
+      VEC_safe_insert (tree, heap, build_defs, 0, (tree)gimple_vdef_ptr (stmt));
+      ++num;
+    }
+
   new_list.next = NULL;
   last = &new_list;
 
@@ -698,6 +438,23 @@
 
   new_i = 0;
 
+  /* Clear and unlink a no longer necessary VDEF.  */
+  if (build_vdef == NULL_TREE
+      && gimple_vdef (stmt) != NULL_TREE)
+    {
+      if (TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
+	{
+	  unlink_stmt_vdef (stmt);
+	  release_ssa_name (gimple_vdef (stmt));
+	}
+      gimple_set_vdef (stmt, NULL_TREE);
+    }
+
+  /* If we have a non-SSA_NAME VDEF, mark it for renaming.  */
+  if (gimple_vdef (stmt)
+      && TREE_CODE (gimple_vdef (stmt)) != SSA_NAME)
+    mark_sym_for_renaming (gimple_vdef (stmt));
+
   /* Check for the common case of 1 def that hasn't changed.  */
   if (old_ops && old_ops->next == NULL && num == 1
       && (tree *) VEC_index (tree, build_defs, 0) == DEF_OP_PTR (old_ops))
@@ -716,17 +473,6 @@
 
   /* Now set the stmt's operands.  */
   gimple_set_def_ops (stmt, new_list.next);
-
-#ifdef ENABLE_CHECKING
-  {
-    def_optype_p ptr;
-    unsigned x = 0;
-    for (ptr = gimple_def_ops (stmt); ptr; ptr = ptr->next)
-      x++;
-
-    gcc_assert (x == num);
-  }
-#endif
 }
 
 
@@ -740,11 +486,29 @@
   struct use_optype_d new_list;
   use_optype_p old_ops, ptr, last;
 
+  /* Pre-pend the VUSE we may have built.  */
+  if (build_vuse != NULL_TREE)
+    {
+      tree oldvuse = gimple_vuse (stmt);
+      if (oldvuse
+	  && TREE_CODE (oldvuse) == SSA_NAME)
+	oldvuse = SSA_NAME_VAR (oldvuse);
+      if (oldvuse != (build_vuse != NULL_TREE
+		      ? build_vuse : build_vdef))
+	gimple_set_vuse (stmt, NULL_TREE);
+      VEC_safe_insert (tree, heap, build_uses, 0, (tree)gimple_vuse_ptr (stmt));
+    }
+
   new_list.next = NULL;
   last = &new_list;
 
   old_ops = gimple_use_ops (stmt);
 
+  /* Clear a no longer necessary VUSE.  */
+  if (build_vuse == NULL_TREE
+      && gimple_vuse (stmt) != NULL_TREE)
+    gimple_set_vuse (stmt, NULL_TREE);
+
   /* If there is anything in the old list, free it.  */
   if (old_ops)
     {
@@ -754,267 +518,23 @@
       gimple_ssa_operands (cfun)->free_uses = old_ops;
     }
 
+  /* If we added a VUSE, make sure to set the operand if it is not already
+     present and mark it for renaming.  */
+  if (build_vuse != NULL_TREE
+      && gimple_vuse (stmt) == NULL_TREE)
+    {
+      gimple_set_vuse (stmt, gimple_vop (cfun));
+      mark_sym_for_renaming (gimple_vop (cfun));
+    }
+
   /* Now create nodes for all the new nodes.  */
   for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
-    last = add_use_op (stmt, 
-		       (tree *) VEC_index (tree, build_uses, new_i), 
+    last = add_use_op (stmt,
+		       (tree *) VEC_index (tree, build_uses, new_i),
 		       last);
 
   /* Now set the stmt's operands.  */
   gimple_set_use_ops (stmt, new_list.next);
-
-#ifdef ENABLE_CHECKING
-  {
-    unsigned x = 0;
-    for (ptr = gimple_use_ops (stmt); ptr; ptr = ptr->next)
-      x++;
-
-    gcc_assert (x == VEC_length (tree, build_uses));
-  }
-#endif
-}
-
-
-/* Takes elements from BUILD_VDEFS and turns them into vdef operands of
-   STMT.  */
-
-static inline void
-finalize_ssa_vdefs (gimple stmt)
-{
-  unsigned new_i;
-  struct voptype_d new_list;
-  voptype_p old_ops, ptr, last;
-
-  /* Set the symbols referenced by STMT.  */
-  gimple_set_stored_syms (stmt, build_stores, &operands_bitmap_obstack);
-
-  /* If aliases have not been computed, do not instantiate a virtual
-     operator on STMT.  Initially, we only compute the SSA form on
-     GIMPLE registers.  The virtual SSA form is only computed after
-     alias analysis, so virtual operators will remain unrenamed and
-     the verifier will complain.  However, alias analysis needs to
-     access symbol load/store information, so we need to compute
-     those.  */
-  if (!gimple_aliases_computed_p (cfun))
-    return;
-
-  new_list.next = NULL;
-  last = &new_list;
-
-  old_ops = gimple_vdef_ops (stmt);
-  new_i = 0;
-  while (old_ops && new_i < VEC_length (tree, build_vdefs))
-    {
-      tree op = VEC_index (tree, build_vdefs, new_i);
-      unsigned new_uid = get_name_decl (op);
-      unsigned old_uid = get_name_decl (VDEF_RESULT (old_ops));
-
-      /* FIXME, for now each VDEF operator should have at most one
-	 operand in their RHS.  */
-      gcc_assert (VDEF_NUM (old_ops) == 1);
-
-      if (old_uid == new_uid)
-        {
-	  /* If the symbols are the same, reuse the existing operand.  */
-	  last->next = old_ops;
-	  last = old_ops;
-	  old_ops = old_ops->next;
-	  last->next = NULL;
-	  set_virtual_use_link (VDEF_OP_PTR (last, 0), stmt);
-	  new_i++;
-	}
-      else if (old_uid < new_uid)
-	{
-	  /* If old is less than new, old goes to the free list.  */
-	  voptype_p next;
-	  delink_imm_use (VDEF_OP_PTR (old_ops, 0));
-	  next = old_ops->next;
-	  add_vop_to_freelist (old_ops);
-	  old_ops = next;
-	}
-      else
-	{
-	  /* This is a new operand.  */
-	  last = add_vdef_op (stmt, op, 1, last);
-	  new_i++;
-	}
-    }
-
-  /* If there is anything remaining in BUILD_VDEFS, simply emit it.  */
-  for ( ; new_i < VEC_length (tree, build_vdefs); new_i++)
-    last = add_vdef_op (stmt, VEC_index (tree, build_vdefs, new_i), 1, last);
-
-  /* If there is anything in the old list, free it.  */
-  if (old_ops)
-    {
-      for (ptr = old_ops; ptr; ptr = last)
-        {
-	  last = ptr->next;
-	  delink_imm_use (VDEF_OP_PTR (ptr, 0));
-	  add_vop_to_freelist (ptr);
-	}
-    }
-
-  /* Now set STMT's operands.  */
-  gimple_set_vdef_ops (stmt, new_list.next);
-
-#ifdef ENABLE_CHECKING
-  {
-    unsigned x = 0;
-    for (ptr = gimple_vdef_ops (stmt); ptr; ptr = ptr->next)
-      x++;
-
-    gcc_assert (x == VEC_length (tree, build_vdefs));
-  }
-#endif
-}
-
-
-/* Takes elements from BUILD_VUSES and turns them into VUSE operands of
-   STMT.  */
-
-static inline void
-finalize_ssa_vuse_ops (gimple stmt)
-{
-  unsigned new_i, old_i;
-  voptype_p old_ops, last;
-  VEC(tree,heap) *new_ops;
-
-  /* Set the symbols referenced by STMT.  */
-  gimple_set_loaded_syms (stmt, build_loads, &operands_bitmap_obstack);
-
-  /* If aliases have not been computed, do not instantiate a virtual
-     operator on STMT.  Initially, we only compute the SSA form on
-     GIMPLE registers.  The virtual SSA form is only computed after
-     alias analysis, so virtual operators will remain unrenamed and
-     the verifier will complain.  However, alias analysis needs to
-     access symbol load/store information, so we need to compute
-     those.  */
-  if (!gimple_aliases_computed_p (cfun))
-    return;
-
-  /* STMT should have at most one VUSE operator.  */
-  old_ops = gimple_vuse_ops (stmt);
-  gcc_assert (old_ops == NULL || old_ops->next == NULL);
-
-  new_ops = NULL;
-  new_i = old_i = 0;
-  while (old_ops
-         && old_i < VUSE_NUM (old_ops)
-	 && new_i < VEC_length (tree, build_vuses))
-    {
-      tree new_op = VEC_index (tree, build_vuses, new_i);
-      tree old_op = VUSE_OP (old_ops, old_i);
-      unsigned new_uid = get_name_decl (new_op);
-      unsigned old_uid = get_name_decl (old_op);
-
-      if (old_uid == new_uid)
-        {
-	  /* If the symbols are the same, reuse the existing operand.  */
-	  VEC_safe_push (tree, heap, new_ops, old_op);
-	  new_i++;
-	  old_i++;
-	}
-      else if (old_uid < new_uid)
-	{
-	  /* If OLD_UID is less than NEW_UID, the old operand has
-	     disappeared, skip to the next old operand.  */
-	  old_i++;
-	}
-      else
-	{
-	  /* This is a new operand.  */
-	  VEC_safe_push (tree, heap, new_ops, new_op);
-	  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++)
-    VEC_safe_push (tree, heap, new_ops, VEC_index (tree, build_vuses, new_i));
-
-  /* If there is anything in the old list, free it.  */
-  if (old_ops)
-    {
-      for (old_i = 0; old_i < VUSE_NUM (old_ops); old_i++)
-	delink_imm_use (VUSE_OP_PTR (old_ops, old_i));
-      add_vop_to_freelist (old_ops);
-      gimple_set_vuse_ops (stmt, NULL);
-    }
-
-  /* If there are any operands, instantiate a VUSE operator for STMT.  */
-  if (new_ops)
-    {
-      tree op;
-      unsigned i;
-
-      last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
-
-      for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
-	SET_USE (VUSE_OP_PTR (last, (int) i), op);
-
-      gimple_set_vuse_ops (stmt, last);
-      VEC_free (tree, heap, new_ops);
-    }
-
-#ifdef ENABLE_CHECKING
-  {
-    unsigned x;
-    
-    if (gimple_vuse_ops (stmt))
-      {
-	gcc_assert (gimple_vuse_ops (stmt)->next == NULL);
-	x = VUSE_NUM (gimple_vuse_ops (stmt));
-      }
-    else
-      x = 0;
-
-    gcc_assert (x == VEC_length (tree, build_vuses));
-  }
-#endif
-}
-
-/* Return a new VUSE operand vector for STMT.  */
-                                                                              
-static void
-finalize_ssa_vuses (gimple stmt)
-{
-  unsigned num, num_vdefs;
-  unsigned vuse_index;
-
-  /* Remove superfluous VUSE operands.  If the statement already has a
-     VDEF operator for a variable 'a', then a VUSE for 'a' is not
-     needed because VDEFs imply a VUSE of the variable.  For instance,
-     suppose that variable 'a' is pointed-to by p and q:
-
-	      # VUSE <a_2>
-	      # a_3 = VDEF <a_2>
-	      *p = *q;
-
-     The VUSE <a_2> is superfluous because it is implied by the
-     VDEF operator.  */
-  num = VEC_length (tree, build_vuses);
-  num_vdefs = VEC_length (tree, build_vdefs);
-
-  if (num > 0 && num_vdefs > 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_vdef_list)
-	      {
-		VEC_ordered_remove (tree, build_vuses, vuse_index);
-		continue;
-	      }
-	  }
-	vuse_index++;
-      }
-
-  finalize_ssa_vuse_ops (stmt);
 }
 
 
@@ -1024,38 +544,20 @@
 static inline void
 cleanup_build_arrays (void)
 {
-  unsigned i;
-  tree t;
-
-  for (i = 0; VEC_iterate (tree, build_vdefs, i, t); i++)
-    if (TREE_CODE (t) != SSA_NAME)
-      var_ann (t)->in_vdef_list = false;
-
-  for (i = 0; VEC_iterate (tree, build_vuses, i, t); i++)
-    if (TREE_CODE (t) != SSA_NAME)
-      var_ann (t)->in_vuse_list = false;
-
-  VEC_truncate (tree, build_vdefs, 0);
-  VEC_truncate (tree, build_vuses, 0);
+  build_vdef = NULL_TREE;
+  build_vuse = NULL_TREE;
   VEC_truncate (tree, build_defs, 0);
   VEC_truncate (tree, build_uses, 0);
-  bitmap_clear (build_loads);
-  bitmap_clear (build_stores);
 }
 
 
 /* Finalize all the build vectors, fill the new ones into INFO.  */
-                                                                              
+
 static inline void
 finalize_ssa_stmt_operands (gimple stmt)
 {
   finalize_ssa_defs (stmt);
   finalize_ssa_uses (stmt);
-  if (gimple_has_mem_ops (stmt))
-    {
-      finalize_ssa_vdefs (stmt);
-      finalize_ssa_vuses (stmt);
-    }
   cleanup_build_arrays ();
 }
 
@@ -1067,10 +569,8 @@
 {
   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_vdefs) == 0);
-  gcc_assert (bitmap_empty_p (build_loads));
-  gcc_assert (bitmap_empty_p (build_stores));
+  gcc_assert (build_vuse == NULL_TREE);
+  gcc_assert (build_vdef == NULL_TREE);
 }
 
 
@@ -1097,31 +597,16 @@
 static inline void
 append_vdef (tree var)
 {
-  tree sym;
-
-  if (TREE_CODE (var) != SSA_NAME)
-    {
-      tree mpt;
-      var_ann_t ann;
-
-      /* If VAR belongs to a memory partition, use it instead of VAR.  */
-      mpt = memory_partition (var);
-      if (mpt)
-	var = mpt;
+  if (!optimize)
+    return;
 
-      /* Don't allow duplicate entries.  */
-      ann = get_var_ann (var);
-      if (ann->in_vdef_list)
-        return;
+  gcc_assert ((build_vdef == NULL_TREE
+	       || build_vdef == var)
+	      && (build_vuse == NULL_TREE
+		  || build_vuse == var));
 
-      ann->in_vdef_list = true;
-      sym = var;
-    }
-  else
-    sym = SSA_NAME_VAR (var);
-
-  VEC_safe_push (tree, heap, build_vdefs, var);
-  bitmap_set_bit (build_stores, DECL_UID (sym));
+  build_vdef = var;
+  build_vuse = var;
 }
 
 
@@ -1130,303 +615,32 @@
 static inline void
 append_vuse (tree var)
 {
-  tree sym;
-
-  if (TREE_CODE (var) != SSA_NAME)
-    {
-      tree mpt;
-      var_ann_t ann;
-
-      /* If VAR belongs to a memory partition, use it instead of VAR.  */
-      mpt = memory_partition (var);
-      if (mpt)
-	var = mpt;
+  if (!optimize)
+    return;
 
-      /* Don't allow duplicate entries.  */
-      ann = get_var_ann (var);
-      if (ann->in_vuse_list)
-	return;
-      else if (ann->in_vdef_list)
-       {
-         /* We don't want a vuse if we already have a vdef, but we must
-            still put this in build_loads.  */
-         bitmap_set_bit (build_loads, DECL_UID (var));
-         return;
-       }
+  gcc_assert (build_vuse == NULL_TREE
+	      || build_vuse == var);
 
-      ann->in_vuse_list = true;
-      sym = var;
-    }
-  else
-    sym = SSA_NAME_VAR (var);
-
-  VEC_safe_push (tree, heap, build_vuses, var);
-  bitmap_set_bit (build_loads, DECL_UID (sym));
+  build_vuse = 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.
-
-   XXX: We should handle the NO_ALIAS attributes here.  */
-
-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 == gimple_global_var (cfun))
-    return true;
-
-  /* If ref is a TARGET_MEM_REF, just return true, as we can't really
-     disambiguate them right now.  */
-  if (ref && TREE_CODE (ref) == TARGET_MEM_REF)
-    return true;
-  
-  /* 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.
-
-     Another case we have to allow is accessing a variable
-     through an array access at offset zero.  This happens from
-     code generated by the fortran frontend like
-
-     char[1:1] & my_char_ref;
-     char my_char;
-     my_char_ref_1 = (char[1:1] &) &my_char;
-     D.874_2 = (*my_char_ref_1)[1]{lb: 1 sz: 1};
-  */
-  if (ref 
-      && flag_strict_aliasing
-      && TREE_CODE (ref) != INDIRECT_REF
-      && !MTAG_P (alias)
-      && base
-      && (TREE_CODE (base) != INDIRECT_REF
-	  || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
-      && (TREE_CODE (base) != INDIRECT_REF
-	  || TREE_CODE (ref) != ARRAY_REF
-	  || offset != 0
-	  || (DECL_SIZE (alias)
-	      && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
-	      && size != -1
-	      && (unsigned HOST_WIDE_INT)size
-	      != TREE_INT_CST_LOW (DECL_SIZE (alias))))
-      && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
-      && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
-      && !var_ann (alias)->is_heapvar
-      /* 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)
-	   && !var_ann (alias)->is_heapvar
-	   && !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 for STMT.  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.  IS_CALL_SITE is true if the
-   affected statement is a call site.  */
+/* Add virtual operands for STMT.  FLAGS is as in get_expr_operands.  */
 
 static void
-add_virtual_operand (tree var, gimple stmt, int flags,
-		     tree full_ref, HOST_WIDE_INT offset,
-		     HOST_WIDE_INT size, bool is_call_site)
+add_virtual_operand (gimple stmt ATTRIBUTE_UNUSED, int flags)
 {
-  bitmap aliases = NULL;
-  tree sym;
-  var_ann_t v_ann;
-  
-  sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
-  v_ann = var_ann (sym);
-  
-  /* Mark the statement as having memory operands.  */
-  gimple_set_references_memory (stmt, true);
-
-  /* If the variable cannot be modified and this is a VDEF 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 VDEF, 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_implicit) && unmodifiable_var_p (var))
-    flags &= ~opf_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
+  /* Add virtual operands to the stmt, unless the caller has specifically
+     requested not to do that (used when adding operands inside an
      ADDR_EXPR expression).  */
   if (flags & opf_no_vops)
     return;
-  
-  if (MTAG_P (var))
-    aliases = MTAG_ALIASES (var);
 
-  if (aliases == NULL)
-    {
-      if (!gimple_aliases_computed_p (cfun) && (flags & opf_def))
-	gimple_set_has_volatile_ops (stmt, true);
-
-      /* The variable is not aliased or it is an alias tag.  */
-      if (flags & opf_def)
-	append_vdef (var);
-      else
-	append_vuse (var);
-    }
-  else
-    {
-      bitmap_iterator bi;
-      unsigned int i;
-      bool none_added = true;
-      
-      /* The variable is aliased.  Add its aliases to the virtual
-	 operands.  */
-      gcc_assert (!bitmap_empty_p (aliases));
-
-      EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
-	{
-	  tree al = referenced_var (i);
-
-	  /* Call-clobbered tags may have non-call-clobbered
-	     symbols in their alias sets.  Ignore them if we are
-	     adding VOPs for a call site.  */
-	  if (is_call_site && !is_call_clobbered (al))
-	    continue;
+  gcc_assert (!is_gimple_debug (stmt));
 
-	  /* If we do not know the full reference tree or if the access is
-	     unspecified [0, -1], we cannot prune it.  Otherwise try doing
-	     so using access_can_touch_variable.  */
-	  if (full_ref
-	      && !access_can_touch_variable (full_ref, al, offset, size))
-	    continue;
-
-	  if (flags & opf_def)
-	    append_vdef (al);
-	  else
-	    append_vuse (al);
-	  none_added = false;
-	}
-
-      if (flags & opf_def)
-	{
-	  /* 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 (none_added
-	      || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
-		  && is_call_site))
-	    append_vdef (var);
-	}
-      else
-	{
-	  /* Even if no aliases have been added, we still need to
-	     establish def-use and use-def chains, lest
-	     transformations think that this is not a memory
-	     reference.  For an example of this scenario, see
-	     testsuite/g++.dg/opt/cleanup1.C.  */
-	  if (none_added)
-	    append_vuse (var);
-	}
-    }
+  if (flags & opf_def)
+    append_vdef (gimple_vop (cfun));
+  else
+    append_vuse (gimple_vop (cfun));
 }
 
 
@@ -1439,13 +653,11 @@
 add_stmt_operand (tree *var_p, gimple stmt, int flags)
 {
   tree var, sym;
-  var_ann_t v_ann;
 
   gcc_assert (SSA_VAR_P (*var_p));
 
   var = *var_p;
   sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
-  v_ann = var_ann (sym);
 
   /* Mark statements with volatile operands.  */
   if (TREE_THIS_VOLATILE (sym))
@@ -1460,130 +672,44 @@
 	append_use (var_p);
     }
   else
-    add_virtual_operand (var, stmt, flags, NULL_TREE, 0, -1, false);
+    add_virtual_operand (stmt, flags);
 }
 
-/* Subroutine of get_indirect_ref_operands.  ADDR is the address
-   that is dereferenced, the meaning of the rest of the arguments
-   is the same as in get_indirect_ref_operands.  */
+/* Mark the base address of REF as having its address taken.
+   REF may be a single variable whose address has been taken or any
+   other valid GIMPLE memory reference (structure reference, array,
+   etc).  */
 
 static void
-get_addr_dereference_operands (gimple stmt, tree *addr, int flags,
-			       tree full_ref, HOST_WIDE_INT offset,
-			       HOST_WIDE_INT size, bool recurse_on_base)
+mark_address_taken (tree ref)
 {
-  tree ptr = *addr;
-
-  /* Mark the statement as having memory operands.  */
-  gimple_set_references_memory (stmt, true);
-
-  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, stmt, 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;
+  tree var;
 
-	  /* 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 or that a propagation pass forgot to
-	     update the alias information on the pointers.  */
-	  if (dump_file
-	      && TREE_CODE (ptr) == SSA_NAME
-	      && (pi == NULL
-		  || (pi->name_mem_tag == NULL_TREE
-		      && !pi->pt_anything))
-	      && gimple_aliases_computed_p (cfun))
-	    {
-	      fprintf (dump_file,
-		  "NOTE: no flow-sensitive alias info for ");
-	      print_generic_expr (dump_file, ptr, dump_flags);
-	      fprintf (dump_file, " in ");
-	      print_gimple_stmt (dump_file, stmt, 0, 0);
-	    }
-
-	  if (TREE_CODE (ptr) == SSA_NAME)
-	    ptr = SSA_NAME_VAR (ptr);
-	  v_ann = var_ann (ptr);
-
-	  /* If we don't know what this pointer points to then we have
-	     to make sure to not prune virtual operands based on offset
-	     and size.  */
-	  if (v_ann->symbol_mem_tag)
-	    {
-	      add_virtual_operand (v_ann->symbol_mem_tag, stmt, flags,
-				   full_ref, 0, -1, false);
-	      /* Make sure we add the SMT itself.  */
-	      if (!(flags & opf_no_vops))
-		{
-		  if (flags & opf_def)
-		    append_vdef (v_ann->symbol_mem_tag);
-		  else
-		    append_vuse (v_ann->symbol_mem_tag);
-		}
-	    }
-
-	  /* Aliasing information is missing; mark statement as
-	     volatile so we won't optimize it out too actively.  */
-          else if (!gimple_aliases_computed_p (cfun)
-                   && (flags & opf_def))
-	    gimple_set_has_volatile_ops (stmt, true);
-	}
-    }
-  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.  */
-      gimple_set_has_volatile_ops (stmt, 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, addr, opf_use);
+  /* 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 && DECL_P (var))
+    TREE_ADDRESSABLE (var) = 1;
 }
 
 
 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
-   ALIGN_INDIRECT_REF and MISALIGNED_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 (gimple stmt, tree expr, int flags, tree full_ref,
-			   HOST_WIDE_INT offset, HOST_WIDE_INT size,
+get_indirect_ref_operands (gimple stmt, tree expr, int flags,
 			   bool recurse_on_base)
 {
   tree *pptr = &TREE_OPERAND (expr, 0);
@@ -1591,8 +717,13 @@
   if (TREE_THIS_VOLATILE (expr))
     gimple_set_has_volatile_ops (stmt, true);
 
-  get_addr_dereference_operands (stmt, pptr, flags, full_ref, offset, size,
-				 recurse_on_base);
+  /* Add the VOP.  */
+  add_virtual_operand (stmt, flags);
+
+  /* If requested, add a USE operand for the base pointer.  */
+  if (recurse_on_base)
+    get_expr_operands (stmt, pptr,
+		       opf_use | (flags & opf_no_vops));
 }
 
 
@@ -1601,166 +732,14 @@
 static void
 get_tmr_operands (gimple stmt, tree expr, int flags)
 {
-  tree tag;
-
-  /* Mark the statement as having memory operands.  */
-  gimple_set_references_memory (stmt, true);
-
   /* First record the real operands.  */
-  get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
-  get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
+  get_expr_operands (stmt, &TMR_BASE (expr), opf_use | (flags & opf_no_vops));
+  get_expr_operands (stmt, &TMR_INDEX (expr), opf_use | (flags & opf_no_vops));
 
   if (TMR_SYMBOL (expr))
-    gimple_add_to_addresses_taken (stmt, TMR_SYMBOL (expr));
-
-  tag = TMR_TAG (expr);
-  if (!tag)
-    {
-      /* Something weird, so ensure that we will be careful.  */
-      gimple_set_has_volatile_ops (stmt, true);
-      return;
-    }
-  if (!MTAG_P (tag))
-    {
-      get_expr_operands (stmt, &tag, flags);
-      return;
-    }
-
-  add_virtual_operand (tag, stmt, flags, expr, 0, -1, false);
-}
-
-
-/* Add clobbering definitions for .GLOBAL_VAR or for each of the call
-   clobbered variables in the function.  */
-
-static void
-add_call_clobber_ops (gimple stmt, tree callee ATTRIBUTE_UNUSED)
-{
-  unsigned u;
-  bitmap_iterator bi;
-  bitmap not_read_b, not_written_b;
-
-  gcc_assert (!(gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST)));
-
-  /* If we created .GLOBAL_VAR earlier, just use it.  */
-  if (gimple_global_var (cfun))
-    {
-      tree var = gimple_global_var (cfun);
-      add_virtual_operand (var, stmt, opf_def, NULL, 0, -1, true);
-      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 (cgraph_node (callee)) : NULL; 
-  not_written_b = callee ? ipa_reference_get_not_written_global (cgraph_node (callee)) : NULL;
-
-  /* Add a VDEF operand for every call clobbered variable.  */
-  EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
-    {
-      tree var = referenced_var_lookup (u);
-      tree real_var = var;
-      bool not_read;
-      bool not_written;
-
-      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.  */
+    mark_address_taken (TMR_SYMBOL (expr));
 
-      if (not_written)
-	{
-	  clobber_stats.static_write_clobbers_avoided++;
-	  if (!not_read)
-	    add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
-	  else
-	    clobber_stats.static_read_clobbers_avoided++;
-	}
-      else
-	add_virtual_operand (var, stmt, opf_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 (gimple stmt, tree callee ATTRIBUTE_UNUSED)
-{
-  unsigned u;
-  bitmap_iterator bi;
-  bitmap not_read_b;
-
-  /* Const functions do not reference memory.  */
-  if (gimple_call_flags (stmt) & ECF_CONST)
-    return;
-
-  not_read_b = callee ? ipa_reference_get_not_read_global (cgraph_node (callee)) : NULL;
-
-  /* For pure functions we compute non-escaped uses separately.  */
-  if (gimple_call_flags (stmt) & ECF_PURE)
-    EXECUTE_IF_SET_IN_BITMAP (gimple_call_used_vars (cfun), 0, u, bi)
-      {
-	tree var = referenced_var_lookup (u);
-	tree real_var = var;
-	bool not_read;
-
-	if (unmodifiable_var_p (var))
-	  continue;
-
-	not_read = not_read_b
-	    ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
-	    : false;
-
-	clobber_stats.readonly_clobbers++;
-
-	/* See if this variable is really used by this function.  */
-	if (!not_read)
-	  add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
-	else
-	  clobber_stats.static_readonly_clobbers_avoided++;
-      }
-
-  /* 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 (gimple_global_var (cfun))
-    {
-      tree var = gimple_global_var (cfun);
-      add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
-      return;
-    }
-
-  /* Add a VUSE for each call-clobbered variable.  */
-  EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
-    {
-      tree var = referenced_var (u);
-      tree real_var = var;
-      bool not_read;
-      
-      clobber_stats.readonly_clobbers++;
-
-      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_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
-    }
+  add_virtual_operand (stmt, flags);
 }
 
 
@@ -1768,25 +747,22 @@
    escape, add them to the VDEF/VUSE lists for it.  */
 
 static void
-maybe_add_call_clobbered_vops (gimple stmt)
+maybe_add_call_vops (gimple stmt)
 {
   int call_flags = gimple_call_flags (stmt);
 
-  /* Mark the statement as having memory operands.  */
-  gimple_set_references_memory (stmt, true);
-
   /* If aliases have been computed already, add VDEF or VUSE
      operands for all the symbols that have been found to be
      call-clobbered.  */
-  if (gimple_aliases_computed_p (cfun) && !(call_flags & ECF_NOVOPS))
+  if (!(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.  */ 
+      /* 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 (!(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
-	add_call_clobber_ops (stmt, gimple_call_fndecl (stmt));
+	add_virtual_operand (stmt, opf_def);
       else if (!(call_flags & ECF_CONST))
-	add_call_read_ops (stmt, gimple_call_fndecl (stmt));
+	add_virtual_operand (stmt, opf_use);
     }
 }
 
@@ -1822,7 +798,7 @@
 	{
 	  tree t = get_base_address (TREE_VALUE (link));
 	  if (t && DECL_P (t))
-	    gimple_add_to_addresses_taken (stmt, t);
+	    mark_address_taken (t);
 	}
 
       get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
@@ -1842,7 +818,7 @@
 	{
 	  tree t = get_base_address (TREE_VALUE (link));
 	  if (t && DECL_P (t))
-	    gimple_add_to_addresses_taken (stmt, t);
+	    mark_address_taken (t);
 	}
 
       get_expr_operands (stmt, &TREE_VALUE (link), 0);
@@ -1854,23 +830,7 @@
       tree link = gimple_asm_clobber_op (stmt, i);
       if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
 	{
-	  unsigned i;
-	  bitmap_iterator bi;
-
-	  /* Mark the statement as having memory operands.  */
-	  gimple_set_references_memory (stmt, true);
-
-	  EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
-	    {
-	      tree var = referenced_var (i);
-	      add_stmt_operand (&var, stmt, opf_def | opf_implicit);
-	    }
-
-	  EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
-	    {
-	      tree var = referenced_var (i);
-	      add_stmt_operand (&var, stmt, opf_def | opf_implicit);
-	    }
+	  add_virtual_operand (stmt, opf_def);
 	  break;
 	}
     }
@@ -1887,10 +847,14 @@
   enum tree_code code;
   enum tree_code_class codeclass;
   tree expr = *expr_p;
+  int uflags = opf_use;
 
   if (expr == NULL)
     return;
 
+  if (is_gimple_debug (stmt))
+    uflags |= (flags & opf_no_vops);
+
   code = TREE_CODE (expr);
   codeclass = TREE_CODE_CLASS (code);
 
@@ -1901,7 +865,8 @@
 	 reference to it, but the fact that the statement takes its
 	 address will be of interest to some passes (e.g. alias
 	 resolution).  */
-      gimple_add_to_addresses_taken (stmt, TREE_OPERAND (expr, 0));
+      if (!is_gimple_debug (stmt))
+	mark_address_taken (TREE_OPERAND (expr, 0));
 
       /* If the address is invariant, there may be no interesting
 	 variable references inside.  */
@@ -1918,8 +883,6 @@
       return;
 
     case SSA_NAME:
-    case SYMBOL_MEMORY_TAG:
-    case NAME_MEMORY_TAG:
      add_stmt_operand (expr_p, stmt, flags);
      return;
 
@@ -1929,13 +892,17 @@
       add_stmt_operand (expr_p, stmt, flags);
       return;
 
+    case DEBUG_EXPR_DECL:
+      gcc_assert (gimple_debug_bind_p (stmt));
+      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, expr, 0, -1, true);
+      get_indirect_ref_operands (stmt, expr, flags, true);
       return;
 
     case TARGET_MEM_REF:
@@ -1948,33 +915,22 @@
     case REALPART_EXPR:
     case IMAGPART_EXPR:
       {
-	tree ref;
-	HOST_WIDE_INT offset, size, maxsize;
-
 	if (TREE_THIS_VOLATILE (expr))
 	  gimple_set_has_volatile_ops (stmt, true);
 
-	ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
-	if (TREE_CODE (ref) == INDIRECT_REF)
-	  {
-	    get_indirect_ref_operands (stmt, ref, flags, expr, offset,
-		                       maxsize, false);
-	    flags |= opf_no_vops;
-	  }
+	get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
 
-	get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
-	
 	if (code == COMPONENT_REF)
 	  {
 	    if (TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
 	      gimple_set_has_volatile_ops (stmt, true);
-	    get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
+	    get_expr_operands (stmt, &TREE_OPERAND (expr, 2), uflags);
 	  }
 	else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
 	  {
-            get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
-            get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
-            get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
+            get_expr_operands (stmt, &TREE_OPERAND (expr, 1), uflags);
+            get_expr_operands (stmt, &TREE_OPERAND (expr, 2), uflags);
+            get_expr_operands (stmt, &TREE_OPERAND (expr, 3), uflags);
 	  }
 
 	return;
@@ -1983,15 +939,15 @@
     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_use);
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 1), uflags);
       get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
       return;
 
     case COND_EXPR:
     case VEC_COND_EXPR:
-      get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
-      get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
-      get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 0), uflags);
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 1), uflags);
+      get_expr_operands (stmt, &TREE_OPERAND (expr, 2), uflags);
       return;
 
     case CONSTRUCTOR:
@@ -2004,7 +960,7 @@
 	for (idx = 0;
 	     VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
 	     idx++)
-	  get_expr_operands (stmt, &ce->value, opf_use);
+	  get_expr_operands (stmt, &ce->value, uflags);
 
 	return;
       }
@@ -2042,15 +998,10 @@
         return;
       }
 
-    case CHANGE_DYNAMIC_TYPE_EXPR:
-      gcc_unreachable ();
-
     case FUNCTION_DECL:
     case LABEL_DECL:
     case CONST_DECL:
     case CASE_LABEL_EXPR:
-    case FILTER_EXPR:
-    case EXC_PTR_EXPR:
       /* Expressions that make no memory references.  */
       return;
 
@@ -2083,6 +1034,13 @@
 
   if (code == GIMPLE_ASM)
     get_asm_expr_operands (stmt);
+  else if (is_gimple_debug (stmt))
+    {
+      if (gimple_debug_bind_p (stmt)
+	  && gimple_debug_bind_has_value_p (stmt))
+	get_expr_operands (stmt, gimple_debug_bind_get_value_ptr (stmt),
+			   opf_use | opf_no_vops);
+    }
   else
     {
       size_t i, start = 0;
@@ -2098,14 +1056,7 @@
 
       /* Add call-clobbered operands, if needed.  */
       if (code == GIMPLE_CALL)
-	maybe_add_call_clobbered_vops (stmt);
-
-      /* Make sure the return value is addressable in case of NRV.  */
-      if (code == GIMPLE_CALL
-	  && gimple_call_lhs (stmt) != NULL_TREE
-	  && gimple_call_return_slot_opt_p (stmt)
-	  && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
-	gimple_add_to_addresses_taken (stmt, gimple_call_lhs (stmt));
+	maybe_add_call_vops (stmt);
     }
 }
 
@@ -2115,25 +1066,12 @@
 static void
 build_ssa_operands (gimple stmt)
 {
-  /* Initially assume that the statement has no volatile operands and
-     makes no memory references.  */
+  /* Initially assume that the statement has no volatile operands.  */
   gimple_set_has_volatile_ops (stmt, false);
-  gimple_set_references_memory (stmt, false);
-
-  /* Just clear the bitmap so we don't end up reallocating it over and over.  */
-  if (gimple_addresses_taken (stmt))
-    bitmap_clear (gimple_addresses_taken (stmt));
 
   start_ssa_stmt_operands ();
   parse_ssa_operands (stmt);
-  operand_build_sort_virtual (build_vuses);
-  operand_build_sort_virtual (build_vdefs);
   finalize_ssa_stmt_operands (stmt);
-
-  /* For added safety, assume that statements with volatile operands
-     also reference memory.  */
-  if (gimple_has_volatile_ops (stmt))
-    gimple_set_references_memory (stmt, true);
 }
 
 
@@ -2145,9 +1083,6 @@
 {
   def_optype_p defs = gimple_def_ops (stmt), last_def;
   use_optype_p uses = gimple_use_ops (stmt), last_use;
-  voptype_p vuses = gimple_vuse_ops (stmt);
-  voptype_p vdefs = gimple_vdef_ops (stmt), vdef, next_vdef;
-  unsigned i;
 
   if (defs)
     {
@@ -2168,32 +1103,10 @@
       gimple_set_use_ops (stmt, NULL);
     }
 
-  if (vuses)
-    {
-      for (i = 0; i < VUSE_NUM (vuses); i++)
-	delink_imm_use (VUSE_OP_PTR (vuses, i));
-      add_vop_to_freelist (vuses);
-      gimple_set_vuse_ops (stmt, NULL);
-    }
-
-  if (vdefs)
-    {
-      for (vdef = vdefs; vdef; vdef = next_vdef)
-	{
-	  next_vdef = vdef->next;
-	  delink_imm_use (VDEF_OP_PTR (vdef, 0));
-	  add_vop_to_freelist (vdef);
-	}
-      gimple_set_vdef_ops (stmt, NULL);
-    }
-
-  if (gimple_has_ops (stmt))
-    gimple_set_addresses_taken (stmt, NULL);
-
   if (gimple_has_mem_ops (stmt))
     {
-      gimple_set_stored_syms (stmt, NULL, &operands_bitmap_obstack);
-      gimple_set_loaded_syms (stmt, NULL, &operands_bitmap_obstack);
+      gimple_set_vuse (stmt, NULL_TREE);
+      gimple_set_vdef (stmt, NULL_TREE);
     }
 }
 
@@ -2218,113 +1131,6 @@
 }
 
 
-/* Copies virtual operands from SRC to DST.  */
-
-void
-copy_virtual_operands (gimple dest, gimple src)
-{
-  unsigned int i, n;
-  voptype_p src_vuses, dest_vuses;
-  voptype_p src_vdefs, dest_vdefs;
-  struct voptype_d vuse;
-  struct voptype_d vdef;
-
-  if (!gimple_has_mem_ops (src))
-    return;
-
-  gimple_set_vdef_ops (dest, NULL);
-  gimple_set_vuse_ops (dest, NULL);
-
-  gimple_set_stored_syms (dest, gimple_stored_syms (src),
-			  &operands_bitmap_obstack);
-  gimple_set_loaded_syms (dest, gimple_loaded_syms (src),
-			  &operands_bitmap_obstack);
-
-  /* Copy all the VUSE operators and corresponding operands.  */
-  dest_vuses = &vuse;
-  for (src_vuses = gimple_vuse_ops (src);
-       src_vuses;
-       src_vuses = src_vuses->next)
-    {
-      n = VUSE_NUM (src_vuses);
-      dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
-      for (i = 0; i < n; i++)
-	SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
-
-      if (gimple_vuse_ops (dest) == NULL)
-	gimple_set_vuse_ops (dest, vuse.next);
-    }
-
-  /* Copy all the VDEF operators and corresponding operands.  */
-  dest_vdefs = &vdef;
-  for (src_vdefs = gimple_vdef_ops (src);
-       src_vdefs;
-       src_vdefs = src_vdefs->next)
-    {
-      n = VUSE_NUM (src_vdefs);
-      dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
-      VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
-      for (i = 0; i < n; i++)
-	SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
-
-      if (gimple_vdef_ops (dest) == NULL)
-	gimple_set_vdef_ops (dest, vdef.next);
-    }
-}
-
-
-/* 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.  If DELINK_IMM_USES_P is specified, the immediate
-   uses of this stmt will be de-linked.  */
-
-void
-create_ssa_artificial_load_stmt (gimple new_stmt, gimple old_stmt,
-				 bool delink_imm_uses_p)
-{
-  tree op;
-  ssa_op_iter iter;
-  use_operand_p use_p;
-  unsigned i;
-
-  gimple_set_modified (new_stmt, false);
-
-  /* Process NEW_STMT looking for operands.  */
-  start_ssa_stmt_operands ();
-  parse_ssa_operands (new_stmt);
-
-  for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
-    if (TREE_CODE (op) != SSA_NAME)
-      var_ann (op)->in_vuse_list = false;
-   
-  for (i = 0; VEC_iterate (tree, build_vdefs, i, op); i++)
-    if (TREE_CODE (op) != SSA_NAME)
-      var_ann (op)->in_vdef_list = false;
-
-  /* Remove any virtual operands that were found.  */
-  VEC_truncate (tree, build_vdefs, 0);
-  VEC_truncate (tree, build_vuses, 0);
-
-  /* Clear the loads and stores bitmaps.  */
-  bitmap_clear (build_loads);
-  bitmap_clear (build_stores);
-
-  /* For each VDEF on the original statement, we want to create a
-     VUSE of the VDEF result operand on the new statement.  */
-  FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
-    append_vuse (op);
-
-  finalize_ssa_stmt_operands (new_stmt);
-
-  /* All uses in this fake stmt must not be in the immediate use lists.  */
-  if (delink_imm_uses_p)
-    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.  */
 
@@ -2373,43 +1179,6 @@
   *exp1 = op0;
 }
 
-/* Add the base address of REF to SET.  */
-
-void
-add_to_addressable_set (tree ref, bitmap *set)
-{
-  tree var;
-
-  /* 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 (*set == NULL)
-	*set = BITMAP_ALLOC (&operands_bitmap_obstack);
-
-      bitmap_set_bit (*set, DECL_UID (var));
-      TREE_ADDRESSABLE (var) = 1;
-    }
-}
-
-
-/* Add the base address of REF to the set of addresses taken by STMT.
-   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
-gimple_add_to_addresses_taken (gimple stmt, tree ref)
-{
-  gcc_assert (gimple_has_ops (stmt));
-  add_to_addressable_set (ref, gimple_addresses_taken_ptr (stmt));
-}
-
 
 /* 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.  */
@@ -2437,7 +1206,7 @@
     {
       if (prev != ptr->prev)
 	goto error;
-      
+
       if (ptr->use == NULL)
 	goto error; /* 2 roots, or SAFE guard node.  */
       else if (*(ptr->use) != var)
@@ -2475,7 +1244,7 @@
       fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->loc.stmt);
       print_gimple_stmt (f, ptr->loc.stmt, 0, TDF_SLIM);
     }
-  fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr, 
+  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");
@@ -2554,192 +1323,27 @@
 }
 
 
-/* Create a new change buffer for the statement pointed by STMT_P and
-   push the buffer into SCB_STACK.  Each change buffer
-   records state information needed to determine what changed in the
-   statement.  Mainly, this keeps track of symbols that may need to be
-   put into SSA form, SSA name replacements and other information
-   needed to keep the SSA form up to date.  */
+/* Unlink STMTs virtual definition from the IL by propagating its use.  */
 
 void
-push_stmt_changes (gimple *stmt_p)
+unlink_stmt_vdef (gimple stmt)
 {
-  gimple stmt;
-  scb_t buf;
-
-  stmt = *stmt_p;
-
-  /* It makes no sense to keep track of PHI nodes.  */
-  if (gimple_code (stmt) == GIMPLE_PHI)
-    return;
-
-  buf = XNEW (struct scb_d);
-  memset (buf, 0, sizeof *buf);
-
-  buf->stmt_p = stmt_p;
-
-  if (gimple_references_memory_p (stmt))
-    {
-      tree op;
-      ssa_op_iter i;
-
-      FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
-	{
-	  tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
-	  if (buf->loads == NULL)
-	    buf->loads = BITMAP_ALLOC (NULL);
-	  bitmap_set_bit (buf->loads, DECL_UID (sym));
-	}
-
-      FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
-	{
-	  tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
-	  if (buf->stores == NULL)
-	    buf->stores = BITMAP_ALLOC (NULL);
-	  bitmap_set_bit (buf->stores, DECL_UID (sym));
-	}
-    }
-
-  VEC_safe_push (scb_t, heap, scb_stack, buf);
-}
+  use_operand_p use_p;
+  imm_use_iterator iter;
+  gimple use_stmt;
+  tree vdef = gimple_vdef (stmt);
 
-
-/* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
-   for renaming.  The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1).  */
-
-static void
-mark_difference_for_renaming (bitmap s1, bitmap s2)
-{
-  if (s1 == NULL && s2 == NULL)
-    return;
-
-  if (s1 && s2 == NULL)
-    mark_set_for_renaming (s1);
-  else if (s1 == NULL && s2)
-    mark_set_for_renaming (s2);
-  else if (!bitmap_equal_p (s1, s2))
-    {
-      bitmap t1 = BITMAP_ALLOC (NULL);
-      bitmap_xor (t1, s1, s2);
-      mark_set_for_renaming (t1);
-      BITMAP_FREE (t1);
-    }
-}
-
-
-/* Pop the top SCB from SCB_STACK and act on the differences between
-   what was recorded by push_stmt_changes and the current state of
-   the statement.  */
-
-void
-pop_stmt_changes (gimple *stmt_p)
-{
-  tree op;
-  gimple stmt;
-  ssa_op_iter iter;
-  bitmap loads, stores;
-  scb_t buf;
-
-  stmt = *stmt_p;
-
-  /* It makes no sense to keep track of PHI nodes.  */
-  if (gimple_code (stmt) == GIMPLE_PHI)
+  if (!vdef
+      || TREE_CODE (vdef) != SSA_NAME)
     return;
 
-  buf = VEC_pop (scb_t, scb_stack);
-  gcc_assert (stmt_p == buf->stmt_p);
-
-  /* Force an operand re-scan on the statement and mark any newly
-     exposed variables.  */
-  update_stmt (stmt);
-
-  /* Determine whether any memory symbols need to be renamed.  If the
-     sets of loads and stores are different after the statement is
-     modified, then the affected symbols need to be renamed.
-     
-     Note that it may be possible for the statement to not reference
-     memory anymore, but we still need to act on the differences in
-     the sets of symbols.  */
-  loads = stores = NULL;
-  if (gimple_references_memory_p (stmt))
+  FOR_EACH_IMM_USE_STMT (use_stmt, iter, gimple_vdef (stmt))
     {
-      tree op;
-      ssa_op_iter i;
-
-      FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
-	{
-	  tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
-	  if (loads == NULL)
-	    loads = BITMAP_ALLOC (NULL);
-	  bitmap_set_bit (loads, DECL_UID (sym));
-	}
-
-      FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
-	{
-	  tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
-	  if (stores == NULL)
-	    stores = BITMAP_ALLOC (NULL);
-	  bitmap_set_bit (stores, DECL_UID (sym));
-	}
+      FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+	SET_USE (use_p, gimple_vuse (stmt));
     }
 
-  /* If LOADS is different from BUF->LOADS, the affected
-     symbols need to be marked for renaming.  */
-  mark_difference_for_renaming (loads, buf->loads);
-
-  /* Similarly for STORES and BUF->STORES.  */
-  mark_difference_for_renaming (stores, buf->stores);
-
-  /* Mark all the naked GIMPLE register operands for renaming.  */
-  FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
-    if (DECL_P (op))
-      mark_sym_for_renaming (op);
-
-  /* FIXME, need to add more finalizers here.  Cleanup EH info,
-     recompute invariants for address expressions, add
-     SSA replacement mappings, etc.  For instance, given
-     testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
-     the form:
-
-	  # SMT.4_20 = VDEF <SMT.4_16>
-	  D.1576_11 = 1.0e+0;
-
-     So, the VDEF will disappear, but instead of marking SMT.4 for
-     renaming it would be far more efficient to establish a
-     replacement mapping that would replace every reference of
-     SMT.4_20 with SMT.4_16.  */
-
-  /* Free memory used by the buffer.  */
-  BITMAP_FREE (buf->loads);
-  BITMAP_FREE (buf->stores);
-  BITMAP_FREE (loads);
-  BITMAP_FREE (stores);
-  buf->stmt_p = NULL;
-  free (buf);
+  if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt)))
+    SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vuse (stmt)) = 1;
 }
 
-
-/* Discard the topmost change buffer from SCB_STACK.  This is useful
-   when the caller realized that it did not actually modified the
-   statement.  It avoids the expensive operand re-scan.  */
-
-void
-discard_stmt_changes (gimple *stmt_p)
-{
-  scb_t buf;
-  gimple stmt;
-  
-  /* It makes no sense to keep track of PHI nodes.  */
-  stmt = *stmt_p;
-  if (gimple_code (stmt) == GIMPLE_PHI)
-    return;
-
-  buf = VEC_pop (scb_t, scb_stack);
-  gcc_assert (stmt_p == buf->stmt_p);
-
-  /* Free memory used by the buffer.  */
-  BITMAP_FREE (buf->loads);
-  BITMAP_FREE (buf->stores);
-  buf->stmt_p = NULL;
-  free (buf);
-}