Revert "[PR64164] Drop copyrename, use coalescible partition as base when optimizing."

This reverts commit c66acc7cedd89bfd22124caec44b8427c9082dac.

Conflicts:
	gcc/ChangeLog
	gcc/testsuite/ChangeLog

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@224310 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 96 insertions, 5 deletions

diff --git a/gcc/tree-ssa-live.c b/gcc/tree-ssa-live.c
index 0f32b14a863..204e70b6f44 100644
--- a/gcc/tree-ssa-live.c
+++ b/gcc/tree-ssa-live.c
@@ -89,6 +89,90 @@ static void  verify_live_on_entry (tree_live_info_p);
    ssa_name or variable, and vice versa.  */
 
 
+/* Hashtable helpers.  */
+
+struct tree_int_map_hasher : typed_noop_remove <tree_int_map>
+{
+  typedef tree_int_map *value_type;
+  typedef tree_int_map *compare_type;
+  static inline hashval_t hash (const tree_int_map *);
+  static inline bool equal (const tree_int_map *, const tree_int_map *);
+};
+
+inline hashval_t
+tree_int_map_hasher::hash (const tree_int_map *v)
+{
+  return tree_map_base_hash (v);
+}
+
+inline bool
+tree_int_map_hasher::equal (const tree_int_map *v, const tree_int_map *c)
+{
+  return tree_int_map_eq (v, c);
+}
+
+
+/* This routine will initialize the basevar fields of MAP.  */
+
+static void
+var_map_base_init (var_map map)
+{
+  int x, num_part;
+  tree var;
+  struct tree_int_map *m, *mapstorage;
+
+  num_part = num_var_partitions (map);
+  hash_table<tree_int_map_hasher> tree_to_index (num_part);
+  /* We can have at most num_part entries in the hash tables, so it's
+     enough to allocate so many map elements once, saving some malloc
+     calls.  */
+  mapstorage = m = XNEWVEC (struct tree_int_map, num_part);
+
+  /* If a base table already exists, clear it, otherwise create it.  */
+  free (map->partition_to_base_index);
+  map->partition_to_base_index = (int *) xmalloc (sizeof (int) * num_part);
+
+  /* Build the base variable list, and point partitions at their bases.  */
+  for (x = 0; x < num_part; x++)
+    {
+      struct tree_int_map **slot;
+      unsigned baseindex;
+      var = partition_to_var (map, x);
+      if (SSA_NAME_VAR (var)
+	  && (!VAR_P (SSA_NAME_VAR (var))
+	      || !DECL_IGNORED_P (SSA_NAME_VAR (var))))
+	m->base.from = SSA_NAME_VAR (var);
+      else
+	/* This restricts what anonymous SSA names we can coalesce
+	   as it restricts the sets we compute conflicts for.
+	   Using TREE_TYPE to generate sets is the easies as
+	   type equivalency also holds for SSA names with the same
+	   underlying decl. 
+
+	   Check gimple_can_coalesce_p when changing this code.  */
+	m->base.from = (TYPE_CANONICAL (TREE_TYPE (var))
+			? TYPE_CANONICAL (TREE_TYPE (var))
+			: TREE_TYPE (var));
+      /* If base variable hasn't been seen, set it up.  */
+      slot = tree_to_index.find_slot (m, INSERT);
+      if (!*slot)
+	{
+	  baseindex = m - mapstorage;
+	  m->to = baseindex;
+	  *slot = m;
+	  m++;
+	}
+      else
+	baseindex = (*slot)->to;
+      map->partition_to_base_index[x] = baseindex;
+    }
+
+  map->num_basevars = m - mapstorage;
+
+  free (mapstorage);
+}
+
+
 /* Remove the base table in MAP.  */
 
 static void
@@ -266,17 +350,21 @@ partition_view_fini (var_map map, bitmap selected)
 }
 
 
-/* Create a partition view which includes all the used partitions in MAP.  */
+/* Create a partition view which includes all the used partitions in MAP.  If
+   WANT_BASES is true, create the base variable map as well.  */
 
 void
-partition_view_normal (var_map map)
+partition_view_normal (var_map map, bool want_bases)
 {
   bitmap used;
 
   used = partition_view_init (map);
   partition_view_fini (map, used);
 
-  var_map_base_fini (map);
+  if (want_bases)
+    var_map_base_init (map);
+  else
+    var_map_base_fini (map);
 }
 
 
@@ -285,7 +373,7 @@ partition_view_normal (var_map map)
    as well.  */
 
 void
-partition_view_bitmap (var_map map, bitmap only)
+partition_view_bitmap (var_map map, bitmap only, bool want_bases)
 {
   bitmap used;
   bitmap new_partitions = BITMAP_ALLOC (NULL);
@@ -301,7 +389,10 @@ partition_view_bitmap (var_map map, bitmap only)
     }
   partition_view_fini (map, new_partitions);
 
-  var_map_base_fini (map);
+  if (want_bases)
+    var_map_base_init (map);
+  else
+    var_map_base_fini (map);
 }