tree-ssanames.c (make_ssa_name): No longer need to clear, then initialize key elements here.

	* tree-ssanames.c (make_ssa_name): No longer need to clear, then
	initialize key elements here.
	(release_ssa_name): Zero the released SSA_NAME here.
	* tree.h (SSA_NAME_EQUIV, SET_SSA_NAME_EQUIV): New macros.
	(struct tree_ssa_name): Add new "equiv" field.
	* tree-ssa-dom.c (const_and_copies): Kill the global varray.
	(tree_ssa_dominator_optimize): No longer allocate, resize or
	clear CONST_AND_COPIES.
	(get_value_for, set_value_for): Kill.
	(thread_across_edge): Get/set the equivalency using
	SSA_NAME_EQUIV and SET_SSA_NAME_EQUIV.
	(restore_vars_to_original_value): Likewise.
	(record_equivalences_from_phis): Likewise.
	(record_dominating_conditions): Likewise.
	(record_const_or_copy, record_equality): Likewise.
	(lookup_avail_expr): Likewise.
	(record_equivalences_from_stmt, cprop_operand): Likewise.
	(cprop_into_successor_phis): No longer need to pass around
	CONST_AND_COPIES.  Callers updated. Get equivalences via
	SSA_NAME_EQUIV.
	(cprop_into_phis): Likewise.

Co-Authored-By: Jan Hubicka <jh@suse.cz>

From-SVN: r87787

gcc/ChangeLog

+2004-09-20 Jeff Law  <law@redhat.com>
+           Jan Hubicka  <jh@suse.cz>
+
+	* tree-ssanames.c (make_ssa_name): No longer need to clear, then
+	initialize key elements here.
+	(release_ssa_name): Zero the released SSA_NAME here.
+	* tree.h (SSA_NAME_EQUIV, SET_SSA_NAME_EQUIV): New macros.
+	(struct tree_ssa_name): Add new "equiv" field.
+	* tree-ssa-dom.c (const_and_copies): Kill the global varray.
+	(tree_ssa_dominator_optimize): No longer allocate, resize or
+	clear CONST_AND_COPIES.
+	(get_value_for, set_value_for): Kill.
+	(thread_across_edge): Get/set the equivalency using
+	SSA_NAME_EQUIV and SET_SSA_NAME_EQUIV.
+	(restore_vars_to_original_value): Likewise.
+	(record_equivalences_from_phis): Likewise.
+	(record_dominating_conditions): Likewise.
+	(record_const_or_copy, record_equality): Likewise.
+	(lookup_avail_expr): Likewise.
+	(record_equivalences_from_stmt, cprop_operand): Likewise.
+	(cprop_into_successor_phis): No longer need to pass around
+	CONST_AND_COPIES.  Callers updated. Get equivalences via
+	SSA_NAME_EQUIV.
+	(cprop_into_phis): Likewise.
+
 2004-09-20  Matt Austern <austern@apple.com>
 	    Zack Weinberg  <zack@codesourcery.com>
 

gcc/tree-ssa-dom.c

@@ -109,16 +109,6 @@ struct expr_hash_elt
   hashval_t hash;
 };
 
-/* Table of constant values and copies indexed by SSA name.  When the
-   renaming pass finds an assignment of a constant (X_i = C) or a copy
-   assignment from another SSA variable (X_i = Y_j), it creates a mapping
-   between X_i and the RHS in this table.  This mapping is used later on,
-   when renaming uses of X_i.  If an assignment to X_i is found in this
-   table, instead of using X_i, we use the RHS of the statement stored in
-   this table (thus performing very simplistic copy and constant
-   propagation).  */
-static varray_type const_and_copies;
-
 /* Stack of dest,src pairs that need to be restored during finalization.
 
    A NULL entry is used to mark the end of pairs which need to be
@@ -229,8 +219,6 @@ struct eq_expr_value
 static void optimize_stmt (struct dom_walk_data *, 
 			   basic_block bb,
 			   block_stmt_iterator);
-static inline tree get_value_for (tree, varray_type table);
-static inline void set_value_for (tree, tree, varray_type table);
 static tree lookup_avail_expr (tree, bool);
 static struct eq_expr_value get_eq_expr_value (tree, int, basic_block);
 static hashval_t avail_expr_hash (const void *);
@@ -281,22 +269,6 @@ local_fold (tree t)
   return t;
 }
 
-/* Return the value associated with variable VAR in TABLE.  */
-
-static inline tree
-get_value_for (tree var, varray_type table)
-{
-  return VARRAY_TREE (table, SSA_NAME_VERSION (var));
-}
-
-/* Associate VALUE to variable VAR in TABLE.  */
-
-static inline void
-set_value_for (tree var, tree value, varray_type table)
-{
-  VARRAY_TREE (table, SSA_NAME_VERSION (var)) = value;
-}
-
 /* Jump threading, redundancy elimination and const/copy propagation. 
 
    This pass may expose new symbols that need to be renamed into SSA.  For
@@ -321,7 +293,6 @@ tree_ssa_dominator_optimize (void)
   avail_exprs = htab_create (1024, real_avail_expr_hash, avail_expr_eq, free);
   VARRAY_TREE_INIT (avail_exprs_stack, 20, "Available expression stack");
   VARRAY_TREE_INIT (block_defs_stack, 20, "Block DEFS stack");
-  VARRAY_TREE_INIT (const_and_copies, num_ssa_names, "const_and_copies");
   VARRAY_TREE_INIT (const_and_copies_stack, 20, "Block const_and_copies stack");
   VARRAY_TREE_INIT (nonzero_vars_stack, 20, "Block nonzero_vars stack");
   VARRAY_TREE_INIT (vrp_variables_stack, 20, "Block vrp_variables stack");
@@ -392,16 +363,12 @@ tree_ssa_dominator_optimize (void)
 
       rewrite_ssa_into_ssa ();
 
-      if (VARRAY_ACTIVE_SIZE (const_and_copies) <= num_ssa_names)
-	{
-	  VARRAY_GROW (const_and_copies, num_ssa_names);
-	  VARRAY_GROW (vrp_data, num_ssa_names);
-	}
+      if (VARRAY_ACTIVE_SIZE (vrp_data) <= num_ssa_names)
+	VARRAY_GROW (vrp_data, num_ssa_names);
 
       /* Reinitialize the various tables.  */
       bitmap_clear (nonzero_vars);
       htab_empty (avail_exprs);
-      VARRAY_CLEAR (const_and_copies);
       VARRAY_CLEAR (vrp_data);
 
       for (i = 0; i < num_referenced_vars; i++)
@@ -525,7 +492,7 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
 
 	      uses_copy[i] = USE_OP (uses, i);
 	      if (TREE_CODE (USE_OP (uses, i)) == SSA_NAME)
-		tmp = get_value_for (USE_OP (uses, i), const_and_copies);
+		tmp = SSA_NAME_EQUIV (USE_OP (uses, i));
 	      if (tmp)
 		SET_USE_OP (uses, i, tmp);
 	    }
@@ -537,7 +504,7 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
 
 	      vuses_copy[i] = VUSE_OP (vuses, i);
 	      if (TREE_CODE (VUSE_OP (vuses, i)) == SSA_NAME)
-		tmp = get_value_for (VUSE_OP (vuses, i), const_and_copies);
+		tmp = SSA_NAME_EQUIV (VUSE_OP (vuses, i));
 	      if (tmp)
 		SET_VUSE_OP (vuses, i, tmp);
 	    }
@@ -629,14 +596,14 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
 	  /* Get the current value of both operands.  */
 	  if (TREE_CODE (op0) == SSA_NAME)
 	    {
-	      tree tmp = get_value_for (op0, const_and_copies);
+	      tree tmp = SSA_NAME_EQUIV (op0);
 	      if (tmp)
 		op0 = tmp;
 	    }
 
 	  if (TREE_CODE (op1) == SSA_NAME)
 	    {
-	      tree tmp = get_value_for (op1, const_and_copies);
+	      tree tmp = SSA_NAME_EQUIV (op1);
 	      if (tmp)
 		op1 = tmp;
 	    }
@@ -676,7 +643,7 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
       else if (TREE_CODE (cond) == SSA_NAME)
 	{
 	  cached_lhs = cond;
-	  cached_lhs = get_value_for (cached_lhs, const_and_copies);
+	  cached_lhs = SSA_NAME_EQUIV (cached_lhs);
 	  if (cached_lhs && ! is_gimple_min_invariant (cached_lhs))
 	    cached_lhs = 0;
 	}
@@ -831,7 +798,7 @@ restore_vars_to_original_value (void)
       prev_value = VARRAY_TOP_TREE (const_and_copies_stack);
       VARRAY_POP (const_and_copies_stack);
 
-      set_value_for (dest, prev_value, const_and_copies);
+      SET_SSA_NAME_EQUIV (dest, prev_value);
     }
 }
 
@@ -1083,7 +1050,7 @@ record_equivalences_from_phis (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
 	 by this assignment, so unwinding just costs time and space.  */
       if (i == PHI_NUM_ARGS (phi)
 	  && may_propagate_copy (lhs, rhs))
-	set_value_for (lhs, rhs, const_and_copies);
+	SET_SSA_NAME_EQUIV (lhs, rhs);
 
       /* Now see if we know anything about the nonzero property for the
 	 result of this PHI.  */
@@ -1479,7 +1446,7 @@ record_dominating_conditions (tree cond)
 static void
 record_const_or_copy_1 (tree x, tree y, tree prev_x)
 {
-  set_value_for (x, y, const_and_copies);
+  SET_SSA_NAME_EQUIV (x, y);
 
   VARRAY_PUSH_TREE (const_and_copies_stack, prev_x);
   VARRAY_PUSH_TREE (const_and_copies_stack, x);
@@ -1491,11 +1458,11 @@ record_const_or_copy_1 (tree x, tree y, tree prev_x)
 static void
 record_const_or_copy (tree x, tree y)
 {
-  tree prev_x = get_value_for (x, const_and_copies);
+  tree prev_x = SSA_NAME_EQUIV (x);
 
   if (TREE_CODE (y) == SSA_NAME)
     {
-      tree tmp = get_value_for (y, const_and_copies);
+      tree tmp = SSA_NAME_EQUIV (y);
       if (tmp)
 	y = tmp;
     }
@@ -1512,9 +1479,9 @@ record_equality (tree x, tree y)
   tree prev_x = NULL, prev_y = NULL;
 
   if (TREE_CODE (x) == SSA_NAME)
-    prev_x = get_value_for (x, const_and_copies);
+    prev_x = SSA_NAME_EQUIV (x);
   if (TREE_CODE (y) == SSA_NAME)
-    prev_y = get_value_for (y, const_and_copies);
+    prev_y = SSA_NAME_EQUIV (y);
 
   /* If one of the previous values is invariant, then use that.
      Otherwise it doesn't matter which value we choose, just so
@@ -2169,9 +2136,7 @@ simplify_switch_and_lookup_avail_expr (tree stmt, int insert)
    nodes of the successors of BB.  */
 
 static void
-cprop_into_successor_phis (basic_block bb,
-			   varray_type const_and_copies,
-			   bitmap nonzero_vars)
+cprop_into_successor_phis (basic_block bb, bitmap nonzero_vars)
 {
   edge e;
 
@@ -2243,7 +2208,7 @@ cprop_into_successor_phis (basic_block bb,
 
 	  /* If we have *ORIG_P in our constant/copy table, then replace
 	     ORIG_P with its value in our constant/copy table.  */
-	  new = VARRAY_TREE (const_and_copies, SSA_NAME_VERSION (orig));
+	  new = SSA_NAME_EQUIV (orig);
 	  if (new
 	      && (TREE_CODE (new) == SSA_NAME
 		  || is_gimple_min_invariant (new))
@@ -2263,7 +2228,7 @@ static void
 cprop_into_phis (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
 		 basic_block bb)
 {
-  cprop_into_successor_phis (bb, const_and_copies, nonzero_vars);
+  cprop_into_successor_phis (bb, nonzero_vars);
 }
 
 /* Search for redundant computations in STMT.  If any are found, then
@@ -2388,7 +2353,7 @@ record_equivalences_from_stmt (tree stmt,
       if (may_optimize_p
 	  && (TREE_CODE (rhs) == SSA_NAME
 	      || is_gimple_min_invariant (rhs)))
-	set_value_for (lhs, rhs, const_and_copies);
+	SET_SSA_NAME_EQUIV (lhs, rhs);
 
       /* alloca never returns zero and the address of a non-weak symbol
 	 is never zero.  NOP_EXPRs and CONVERT_EXPRs can be completely
@@ -2499,7 +2464,7 @@ record_equivalences_from_stmt (tree stmt,
    CONST_AND_COPIES.  */
 
 static bool
-cprop_operand (tree stmt, use_operand_p op_p, varray_type const_and_copies)
+cprop_operand (tree stmt, use_operand_p op_p)
 {
   bool may_have_exposed_new_symbols = false;
   tree val;
@@ -2508,7 +2473,7 @@ cprop_operand (tree stmt, use_operand_p op_p, varray_type const_and_copies)
   /* If the operand has a known constant value or it is known to be a
      copy of some other variable, use the value or copy stored in
      CONST_AND_COPIES.  */
-  val = VARRAY_TREE (const_and_copies, SSA_NAME_VERSION (op));
+  val = SSA_NAME_EQUIV (op);
   if (val)
     {
       tree op_type, val_type;
@@ -2590,7 +2555,7 @@ cprop_operand (tree stmt, use_operand_p op_p, varray_type const_and_copies)
    v_may_def_ops of STMT.  */
 
 static bool
-cprop_into_stmt (tree stmt, varray_type const_and_copies)
+cprop_into_stmt (tree stmt)
 {
   bool may_have_exposed_new_symbols = false;
   use_operand_p op_p;
@@ -2600,8 +2565,7 @@ cprop_into_stmt (tree stmt, varray_type const_and_copies)
   FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_ALL_USES)
     {
       if (TREE_CODE (USE_FROM_PTR (op_p)) == SSA_NAME)
-	may_have_exposed_new_symbols
-	  |= cprop_operand (stmt, op_p, const_and_copies);
+	may_have_exposed_new_symbols |= cprop_operand (stmt, op_p);
     }
 
   if (may_have_exposed_new_symbols)
@@ -2653,7 +2617,7 @@ optimize_stmt (struct dom_walk_data *walk_data, basic_block bb,
     }
 
   /* Const/copy propagate into USES, VUSES and the RHS of V_MAY_DEFs.  */
-  may_have_exposed_new_symbols = cprop_into_stmt (stmt, const_and_copies);
+  may_have_exposed_new_symbols = cprop_into_stmt (stmt);
 
   /* If the statement has been modified with constant replacements,
      fold its RHS before checking for redundant computations.  */
@@ -2895,7 +2859,7 @@ lookup_avail_expr (tree stmt, bool insert)
      use the value from the const_and_copies table.  */
   if (TREE_CODE (lhs) == SSA_NAME)
     {
-      temp = get_value_for (lhs, const_and_copies);
+      temp = SSA_NAME_EQUIV (lhs);
       if (temp)
 	lhs = temp;
     }

gcc/tree-ssanames.c

@@ -186,27 +186,19 @@ make_ssa_name (tree var, tree stmt)
 
   gcc_assert (!stmt || EXPR_P (stmt) || TREE_CODE (stmt) == PHI_NODE);
 
-  /* If our free list has an element, then use it.  Also reuse the
-     SSA version number of the element on the free list which helps
-     keep sbitmaps and arrays sized HIGHEST_SSA_VERSION smaller.  */
+  /* If our free list has an element, then use it.  */
   if (free_ssanames)
     {
-      unsigned int save_version;
-
       t = free_ssanames;
       free_ssanames = TREE_CHAIN (free_ssanames);
 #ifdef GATHER_STATISTICS
       ssa_name_nodes_reused++;
 #endif
 
-      /* Clear the node so that it looks just like one we would have
-	 received from make_node.  */
-      save_version = SSA_NAME_VERSION (t);
-      memset (t, 0, tree_size (t));
-      TREE_SET_CODE (t, SSA_NAME);
-      SSA_NAME_VERSION (t) = save_version;
-      gcc_assert (ssa_name (save_version) == NULL);
-      VARRAY_TREE (ssa_names, save_version) = t;
+      /* The node was cleared out when we put it on the free list, so
+	 there is no need to do so again here.  */
+      gcc_assert (ssa_name (SSA_NAME_VERSION (t)) == NULL);
+      VARRAY_TREE (ssa_names, SSA_NAME_VERSION (t)) = t;
     }
   else
     {
@@ -262,8 +254,27 @@ release_ssa_name (tree var)
      defining statement.  */
   if (! SSA_NAME_IN_FREE_LIST (var))
     {
+      tree saved_ssa_name_var = SSA_NAME_VAR (var);
+      int saved_ssa_name_version = SSA_NAME_VERSION (var);
+
       VARRAY_TREE (ssa_names, SSA_NAME_VERSION (var)) = NULL;
+      memset (var, 0, tree_size (var));
+
+      /* First put back the right tree node so that the tree checking
+	 macros do not complain.  */
+      TREE_SET_CODE (var, SSA_NAME);
+
+      /* Restore the version number.  */
+      SSA_NAME_VERSION (var) = saved_ssa_name_version;
+
+      /* Hopefully this can go away once we have the new incremental
+         SSA updating code installed.  */
+      SSA_NAME_VAR (var) = saved_ssa_name_var;
+
+      /* Note this SSA_NAME is now in the first list.  */
       SSA_NAME_IN_FREE_LIST (var) = 1;
+
+      /* And finally link it into the free list.  */
       TREE_CHAIN (var) = free_ssanames;
       free_ssanames = var;
     }

gcc/tree.h

@@ -1304,12 +1304,23 @@ struct tree_exp GTY(())
 #define SSA_NAME_OCCURS_IN_ABNORMAL_PHI(NODE) \
     SSA_NAME_CHECK (NODE)->common.asm_written_flag
 
+
 /* Nonzero if this SSA_NAME expression is currently on the free list of
    SSA_NAMES.  Using NOTHROW_FLAG seems reasonably safe since throwing
    has no meaning for an SSA_NAME.  */
 #define SSA_NAME_IN_FREE_LIST(NODE) \
     SSA_NAME_CHECK (NODE)->common.nothrow_flag
 
+#define SSA_NAME_EQUIV(NAME) __extension__ \
+  ({  tree equiv = SSA_NAME_CHECK (NAME)->ssa_name.equiv; \
+      if (equiv && TREE_CODE (equiv) == SSA_NAME) \
+	equiv = ssa_name (SSA_NAME_VERSION (equiv)); \
+      equiv; \
+   })
+
+#define SET_SSA_NAME_EQUIV(NAME, EQUIV)\
+   SSA_NAME_CHECK (NAME)->ssa_name.equiv = (EQUIV);
+
 /* Attributes for SSA_NAMEs for pointer-type variables.  */
 #define SSA_NAME_PTR_INFO(N) \
     SSA_NAME_CHECK (N)->ssa_name.ptr_info
@@ -1333,6 +1344,8 @@ struct tree_ssa_name GTY(())
   /* _DECL wrapped by this SSA name.  */
   tree var;
 
+  tree equiv;
+
   /* SSA version number.  */
   unsigned int version;