backport: copy-prop, incremental SSA updating of FUD chains and newly exposed symbols.

	Merge from tree-cleanup-branch: VRP, store CCP, store
	    copy-prop, incremental SSA updating of FUD chains and
	    newly exposed symbols.

	* Makefile.in (tree-ssa-copy.o): Depend on tree-ssa-propagate.h.
	(OBJS-common): Add tree-vrp.o.
	(tree-vrp.o): New rule.
	* basic-block.h (nearest_common_dominator_for_set): Declare.
	* common.opt (ftree-store-ccp): New flag.
	(ftree-copy-prop): New flag.
	(ftree-vrp): New flag.
	(ftree-store-copy-prop): New flag.
	* dominance.c (nearest_common_dominator_for_set): New.
	* domwalk.c (walk_dominator_tree): Only traverse
	statements in blocks marked in walk_data->interesting_blocks.
	* domwalk.h (struct dom_walk_data): Add field interesting_blocks.
	* fold-const.c (fold): Handle ASSERT_EXPR.
	* opts.c (decode_options): Set flag_tree_copy_prop at -O1.
	Set flag_tree_store_ccp, flag_tree_store_copy_prop and
	flag_tree_vrp at -O2.
	* timevar.def (TV_TREE_VRP): Define.
	(TV_TREE_COPY_PROP): Define.
	(TV_TREE_STORE_COPY_PROP): Define.
	(TV_TREE_SSA_INCREMENTAL): Define.
	(TV_TREE_STORE_CCP): Define.
	* tree-cfg.c (tree_can_merge_blocks_p): Remove reference
	to kill_redundant_phi_nodes from comment.
	(verify_expr): Handle ASSERT_EXPR.
	* tree-dfa.c (mark_new_vars_to_rename): Remove second
	argument.  Update all users.
	(mark_call_clobbered_vars_to_rename): Remove.  Update all
	users.
	* tree-flow-inline.h (unmodifiable_var_p): New.
	* tree-flow.h (enum value_range_type): Declare.
	(struct value_range_def): Declare.
	(value_range): Declare.
	(remove_all_phi_nodes_for): Remove.  Update all users.
	(find_phi_node_for): Declare.
	(add_type_alias): Declare.
	(count_uses_and_derefs): Declare.
	(kill_redundant_phi_nodes): Remove.
	(rewrite_into_ssa): Remove.
	(rewrite_def_def_chains): Remove.
	(update_ssa, register_new_name_mapping, create_new_def_for,
	need_ssa_update_p, name_registered_for_update_p,
	release_ssa_name_after_update_ssa, dump_repl_tbl,
	debug_repl_tbl, dump_names_replaced_by,
	debug_names_replaced_by, mark_sym_for_renaming,
	mark_set_for_renaming, get_current_def, set_current_def,
	get_value_range, dump_value_range, debug_value_range,
	dump_all_value_ranges, debug_all_value_ranges,
	expr_computes_nonzero, loop_depth_of_name,
	unmodifiable_var_p): Declare.
	* tree-gimple.c (is_gimple_formal_tmp_rhs): Handle
	ASSERT_EXPR.
	* tree-into-ssa.c (block_defs_stack): Update comment.
	(old_ssa_names, new_ssa_names, old_virtual_ssa_names,
	syms_to_rename, names_to_release, repl_tbl,
	need_to_initialize_update_ssa_p, need_to_update_vops_p,
	need_to_replace_names_p): New locals.
	(NAME_SETS_GROWTH_FACTOR): Define.
	(struct repl_map_d): Declare.
	(struct mark_def_sites_global_data): Add field
	interesting_blocks.
	(enum rewrite_mode): Declare.
	(REGISTER_DEFS_IN_THIS_STMT): Define.
	(compute_global_livein): Use last_basic_block instead of
	n_basic_blocks.
	(set_def_block): Remove last argument.  Update all callers.
	(prepare_use_operand_for_rename): Remove.  Update all callers.
	(prepare_def_operand_for_rename): Remove.  Update all callers.
	(symbol_marked_for_renaming): New.
	(is_old_name): New.
	(is_new_name): New.
	(repl_map_hash): New.
	(repl_map_eq): New.
	(repl_map_free): New.
	(names_replaced_by): New.
	(add_to_repl_tbl): New.
	(add_new_name_mapping): New.
	(mark_def_sites): Assume that all the operands in the
	statement are in normal form.
	(find_idf): Assert that the block in the stack is valid.
	(get_default_def_for): New.
	(insert_phi_nodes_for): Add new argument 'update_p'.
	Add documentation.
	If update_p is true, add a new mapping between the LHS of
	each new PHI and the name that it replaces.
	(insert_phi_nodes_1): Only call find_idf if needed.
	(get_reaching_def): Call get_default_def_for.
	(rewrite_operand): Remove.
	(rewrite_stmt): Do nothing if REGISTER_DEFS_IN_THIS_STMT
	and REWRITE_THIS_STMT are false.
	Assume that all the operands in the statement are in
	normal form.
	(rewrite_add_phi_arguments): Don't use PHI_REWRITTEN.
	(rewrite_virtual_phi_arguments): Remove.
	(invalidate_name_tags): Remove.
	(register_new_update_single, register_new_update_set,
	rewrite_update_init_block, replace_use,
	rewrite_update_fini_block, rewrite_update_stmt,
	rewrite_update_phi_arguments): New.
	rewrite_blocks): Remove argument 'fix_virtual_phis'.
	Add arguments 'entry', 'what' and 'blocks'.
	Initialize the dominator walker according to 'what' and
	'blocks'.
	Start the dominator walk at 'entry'.
	(mark_def_site_blocks): Add argument 'interesting_blocks'.
	Use it to configure the dominator walker.
	(rewrite_into_ssa): Remove argument 'all'.
	Make internal.
	(rewrite_all_into_ssa): Remove.
	(rewrite_def_def_chains): Remove.
	(mark_def_interesting, mark_use_interesting,
	prepare_phi_args_for_update, prepare_block_for_update,
	prepare_def_site_for, prepare_def_sites,
	dump_names_replaced_by, debug_names_replaced_by,
	dump_repl_tbl, debug_repl_tbl, init_update_ssa,
	delete_update_ssa, create_new_def_for,
	register_new_name_mapping, mark_sym_for_renaming,
	mark_set_for_renaming, need_ssa_update_p,
	name_registered_for_update_p, ssa_names_to_replace,
	release_ssa_name_after_update_ssa,
	insert_updated_phi_nodes_for, update_ssa): New.
	* tree-loop-linear.c (linear_transform_loops): Call
	update_ssa instead of rewrite_into_ssa.
	* tree-optimize.c (vars_to_rename): Remove.
	Update all users.
	(init_tree_optimization_passes): Replace
	pass_redundant_phi with pass_copy_prop.
	Add pass_vrp.
	Replace pass_ccp with pass_store_ccp.
	Add pass_store_copy_prop after pass_store_ccp.
	(execute_todo): If the TODO_ flags don't include updating
	the SSA form, assert that it does not need to be updated.
	Call update_ssa instead of rewrite_into_ssa and
	rewrite_def_def_chains.
	If TODO_verify_loops is set, call verify_loop_closed_ssa.
	(tree_rest_of_compilation):
	* tree-pass.h (TODO_dump_func, TODO_ggc_collect,
	TODO_verify_ssa, TODO_verify_flow, TODO_verify_stmts,
	TODO_cleanup_cfg): Renumber.
	(TODO_verify_loops, TODO_update_ssa,
	TODO_update_ssa_no_phi, TODO_update_ssa_full_phi,
	TODO_update_ssa_only_virtuals): Define.
	(pass_copy_prop, pass_store_ccp, pass_store_copy_prop, pass_vrp):
	Declare.
	* tree-phinodes.c (make_phi_node): Update documentation.
	(remove_all_phi_nodes_for): Remove.
	(find_phi_node_for): New.
	* tree-pretty-print.c (dump_generic_node): Handle ASSERT_EXPR.
	* tree-scalar-evolution.c (follow_ssa_edge_in_rhs): Likewise.
	(interpret_rhs_modify_expr): Likewise.
	* tree-sra.c (decide_instantiations): Mark all symbols in
	SRA_CANDIDATES for renaming.
	(mark_all_v_defs_1): Rename from mark_all_v_defs.
	(mark_all_v_defs): New function.  Update all users to call it
	with the whole list of scalarized statements, not just the
	first one.
	* tree-ssa-alias.c (count_ptr_derefs): Make extern.
	(compute_flow_insensitive_aliasing): If the tag is
	unmodifiable and the variable isn't or vice-versa, don't
	make them alias of each other.
	(setup_pointers_and_addressables): If the type tag for
	VAR is about to change, mark the old one for renaming.
	(add_type_alias): New.
	* tree-ssa-ccp.c: Document SSA-CCP and STORE-CCP.
	(ccp_lattice_t): Rename from latticevalue.
	(value): Remove.  Update all users.
	(const_val): New local variable.
	(do_store_ccp): New local variable.
	(dump_lattice_value): Handle UNINITIALIZED.
	(debug_lattice_value): New.
	(get_default_value): Re-write.
	(set_lattice_value): Re-write.
	(def_to_varying): Remove.  Update all users.
	(likely_value): Return VARYING for statements that make
	stores when STORE_CCP is false.
	Return VARYING for any statement other than MODIFY_EXPR,
	COND_EXPR and SWITCH_EXPR.
	(ccp_initialize): Re-write.
	(replace_uses_in, replace_vuse_in, substitute_and_fold):
	Move to tree-ssa-propagate.c.
	(ccp_lattice_meet): Handle memory stores when
	DO_STORE_CCP is true.
	(ccp_visit_phi_node): Likewise.
	(ccp_fold): Likewise.
	(evaluate_stmt): Likewise.
	(visit_assignment): Likewise.
	(ccp_visit_stmt): Likewise.
	(execute_ssa_ccp): Add argument 'store_ccp'.  Copy it
	into DO_STORE_CCP.
	(do_ssa_ccp): New.
	(pass_ccp): Use it.
	(do_ssa_store_ccp): New.
	(gate_store_ccp): New.
	(pass_store_ccp): Declare.
	* tree-ssa-copy.c: Include tree-ssa-propagate.h.
	(may_propagate_copy): Reformat.
	Don't abort if ORIG is a virtual and DEST isn't.
	If NEW does not have alias information but DEST does,
	copy it.
	(copy_of, cached_last_copy_of, do_store_copy_prop, enum
	copy_prop_kind, which_copy_prop): Declare.
	(stmt_may_generate_copy, get_copy_of_val,
	get_last_copy_of, set_copy_of_val, dump_copy_of,
	copy_prop_visit_assignment, copy_prop_visit_cond_stmt,
	copy_prop_visit_stmt, copy_prop_visit_phi_node,
	init_copy_prop, fini_copy_prop, execute_copy_prop,
	gate_copy_prop, do_copy_prop, gate_store_copy_prop,
	store_copy_prop): New.
	(pass_copy_prop, pass_store_copy_prop): Declare.
	* tree-ssa-dom.c (struct opt_stats_d): Add fields
	'num_const_prop' and 'num_copy_prop'.
	(cprop_operand): Update them.
	(dump_dominator_optimization_stats): Dump them.
	(tree_ssa_dominator_optimize): Call update_ssa instead of
	rewrite_into_ssa.
	(loop_depth_of_name): Declare extern.
	(simplify_cond_and_lookup_avail_expr): Guard against NULL
	values for LOW or HIGH.
	(cprop_into_successor_phis): Only propagate if NEW != ORIG.
	(record_equivalences_from_stmt): Call expr_computes_nonzero.
	(cprop_operand): Only propagate if VAL != OP.
	* tree-ssa-dse.c (dse_optimize_stmt): Mark symbols in removed
	statement for renaming.
	* tree-ssa-loop-im.c (move_computations): Call update_ssa.
	* tree-ssa-loop-ivopts.c (rewrite_address_base): Call
	add_type_alias if necessary.
	Call mark_new_vars_to_rename.
	(tree_ssa_iv_optimize): If new symbols need to be renamed,
	mark every statement updated, call update_ssa and
	rewrite_into_loop_closed_ssa.
	* tree-ssa-loop-manip.c (add_exit_phis): Do not remove DEF_BB
	from LIVEIN if VAR is a virtual.
	* tree-ssa-loop.c (tree_loop_optimizer_init): Call update_ssa.
	* tree-ssa-operands.c (get_expr_operands): Handle ASSERT_EXPR.
	(get_call_expr_operands): Reformat statement.
	(add_stmt_operand): Don't create V_MAY_DEFs for read-only
	symbols.
	* tree-ssa-propagate.c (ssa_prop_init): Initialize
	SSA_NAME_VALUE for every name.
	(first_vdef, stmt_makes_single_load, stmt_makes_single_store,
	get_value_loaded_by): New.
	(replace_uses_in, replace_vuses_in, replace_phi_args_in,
	substitute_and_fold): Move from tree-ssa-ccp.c.
	* tree-ssa-propagate.h (struct prop_value_d, prop_value_t,
	first_vdef, stmt_makes_single_load, stmt_makes_single_store,
	get_value_loaded_by, replace_uses_in, substitute_and_fold):
	Declare.
	* tree-ssa.c (verify_use): Fix error message.
	(propagate_into_addr, replace_immediate_uses, get_eq_name,
	check_phi_redundancy, kill_redundant_phi_nodes,
	pass_redundant_phi): Remove.  Update all users.
	* tree-vect-transform.c (vect_create_data_ref_ptr): Call
	add_type_alias, if necessary.
	* tree-vectorizer.h (struct _stmt_vect_info): Update
	documentation for field 'memtag'.
	* tree-vrp.c: New file.
	* tree.def (ASSERT_EXPR): Define.
	* tree.h (ASSERT_EXPR_VAR): Define.
	(ASSERT_EXPR_COND): Define.
	(SSA_NAME_VALUE_RANGE): Define.
	(struct tree_ssa_name): Add field 'value_range'.
	(PHI_REWRITTEN): Remove.
	(struct tree_phi_node): Remove field 'rewritten'.
	* doc/invoke.texi (-fdump-tree-storeccp, -ftree-copy-prop,
	-ftree-store-copy-prop): Document.
	* doc/tree-ssa.texi: Remove broken link to McCAT's compiler.
	Document usage of update_ssa.

testsuite/ChangeLog

	* g++.dg/tree-ssa/pr18178.C: New test.
	* gcc.c-torture/execute/20030216-1.x: Ignore at -O1.
	* gcc.c-torture/execute/20041019-1.c: New test.
	* gcc.dg/tree-ssa/20041008-1.c: New test.
	* gcc.dg/tree-ssa/ssa-ccp-12.c: New test.
	* gcc.dg/tree-ssa/20030731-2.c: Update to use -fdump-tree-store_ccp.
	* gcc.dg/tree-ssa/20030917-1.c: Likewise.
	* gcc.dg/tree-ssa/20030917-3.c: Likewise.
	* gcc.dg/tree-ssa/20040721-1.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ccp-1.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ccp-2.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ccp-3.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ccp-7.c: Likewise.
	* gcc.dg/tree-ssa/ssa-ccp-9.c: Likewise.

From-SVN: r97884

1 files changed, 1 insertions, 314 deletions

diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c
index e23e665..93b5480 100644
--- a/gcc/tree-ssa.c
+++ b/gcc/tree-ssa.c
@@ -285,7 +285,7 @@ verify_use (basic_block bb, basic_block def_bb, use_operand_p use_p,
     {
       fprintf (stderr, "for SSA_NAME: ");
       print_generic_expr (stderr, ssa_name, TDF_VOPS);
-      fprintf (stderr, "in statement:\n");
+      fprintf (stderr, " in statement:\n");
       print_generic_stmt (stderr, stmt, TDF_VOPS);
     }
 
@@ -1028,319 +1028,6 @@ walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data,
     }
 }
 
-
-/* Replaces VAR with REPL in memory reference expression *X in
-   statement STMT at use location USE_P.  Return TRUE if Anything was done.  */
-
-static bool
-propagate_into_addr (tree stmt, use_operand_p use_p, tree *x, tree repl)
-{
-  tree new_var, ass_stmt, addr_var;
-  basic_block bb;
-  block_stmt_iterator bsi;
-
-  /* There is nothing special to handle in the other cases.  */
-  if (TREE_CODE (repl) != ADDR_EXPR)
-    return false;
-  addr_var = TREE_OPERAND (repl, 0);
-
-  while (handled_component_p (*x)
-	 || TREE_CODE (*x) == REALPART_EXPR
-	 || TREE_CODE (*x) == IMAGPART_EXPR)
-    x = &TREE_OPERAND (*x, 0);
-
-  /* Heres a hack but since KRPhinodes is going away soon, Im not going to 
-     sweat it.  */
-  if (TREE_CODE (*x) != INDIRECT_REF
-      || &(TREE_OPERAND (*x, 0)) != use_p->use)  /* HACK ALERT. */
-    return false;
-
-  if (TREE_TYPE (*x) == TREE_TYPE (addr_var))
-    {
-      *x = addr_var;
-      mark_new_vars_to_rename (stmt, vars_to_rename);
-      return true;
-    }
-
-
-  /* Frontends sometimes produce expressions like *&a instead of a[0].
-     Create a temporary variable to handle this case.  */
-  ass_stmt = build2 (MODIFY_EXPR, void_type_node, NULL_TREE, repl);
-  new_var = duplicate_ssa_name (USE_FROM_PTR (use_p), ass_stmt);
-  TREE_OPERAND (*x, 0) = new_var;
-  TREE_OPERAND (ass_stmt, 0) = new_var;
-
-  bb = bb_for_stmt (stmt);
-  tree_block_label (bb);
-  bsi = bsi_after_labels (bb);
-  bsi_insert_after (&bsi, ass_stmt, BSI_NEW_STMT);
-
-  mark_new_vars_to_rename (stmt, vars_to_rename);
-  return true;
-}
-
-/* Replaces immediate uses of VAR by REPL.  */
-
-static void
-replace_immediate_uses (tree var, tree repl)
-{
-  tree stmt;
-  bool mark_new_vars;
-  use_operand_p imm_use;
-  imm_use_iterator imm_iter;
-
-  FOR_EACH_IMM_USE_SAFE (imm_use, imm_iter, var)
-    {
-      stmt = USE_STMT (imm_use);
-
-      if (TREE_CODE (stmt) == PHI_NODE)
-	{
-	  int index = PHI_ARG_INDEX_FROM_USE (imm_use);
-#ifdef ENABLE_CHECKING
-	  gcc_assert (&(PHI_ARG_IMM_USE_NODE (stmt, index)) == imm_use);
-#endif
-	    SET_USE (imm_use, repl);
-	  if (TREE_CODE (repl) == SSA_NAME
-	      && PHI_ARG_EDGE (stmt, index)->flags & EDGE_ABNORMAL)
-	    SSA_NAME_OCCURS_IN_ABNORMAL_PHI (repl) = 1;
-	  continue;
-	}
-
-      gcc_assert (!stmt_modified_p (stmt));
-
-      mark_new_vars = false;
-      if (is_gimple_reg (SSA_NAME_VAR (var)))
-	{
-	  bool propagated = false;
-	  if (TREE_CODE (stmt) == MODIFY_EXPR)
-	    {
-	      if (TREE_CODE (repl) == ADDR_EXPR)
-		{
-		  propagated =
-		    propagate_into_addr (stmt, imm_use, &TREE_OPERAND (stmt, 0),
-					 repl);
-		  if (!propagated)
-		    propagated =
-		      propagate_into_addr (stmt, imm_use,
-					   &TREE_OPERAND (stmt, 1), repl);
-		}
-	    }
-	  if (!propagated)
-	    propagate_value (imm_use, repl);
-	  mark_new_vars = POINTER_TYPE_P (TREE_TYPE (repl));
-	}
-      else
-        propagate_value (imm_use, repl);
-
-      /* FIXME.  If REPL is a constant, we need to fold STMT.
-	 However, fold_stmt wants a pointer to the statement, because
-	 it may happen that it needs to replace the whole statement
-	 with a new expression.  Since the current def-use machinery
-	 does not return pointers to statements, we call fold_stmt
-	 with the address of a local temporary, if that call changes
-	 the temporary then we fallback on looking for a proper
-	 pointer to STMT by scanning STMT's basic block.
-
-	 Note that all this will become unnecessary soon.  This
-	 pass is being replaced with a proper copy propagation pass
-	 for 4.1 (dnovillo, 2004-09-17).  */
-      if (TREE_CODE (repl) != SSA_NAME)
-	{
-	  tree tmp = stmt;
-	  fold_stmt (&tmp);
-          mark_new_vars = true;
-	  if (tmp != stmt)
-	    {
-	      block_stmt_iterator si = bsi_for_stmt (stmt);
-	      mark_new_vars_to_rename (tmp, vars_to_rename);
-	      bsi_replace (&si, tmp, true);
-	      stmt = bsi_stmt (si);
-	    }
-	}
-
-      /* If REPL is a pointer, it may have different memory tags associated
-	 with it.  For instance, VAR may have had a name tag while REPL
-	 only had a type tag.  In these cases, the virtual operands (if
-	 any) in the statement will refer to different symbols which need
-	 to be renamed.  */
-      if (mark_new_vars)
-	mark_new_vars_to_rename (stmt, vars_to_rename);
-      else
-	update_stmt (stmt);
-    }
-
-}
-
-/* Gets the value VAR is equivalent to according to EQ_TO.  */
-
-static tree
-get_eq_name (tree *eq_to, tree var)
-{
-  unsigned ver;
-  tree val = var;
-
-  while (TREE_CODE (val) == SSA_NAME)
-    {
-      ver = SSA_NAME_VERSION (val);
-      if (!eq_to[ver])
-	break;
-
-      val = eq_to[ver];
-    }
-
-  while (TREE_CODE (var) == SSA_NAME)
-    {
-      ver = SSA_NAME_VERSION (var);
-      if (!eq_to[ver])
-	break;
-
-      var = eq_to[ver];
-      eq_to[ver] = val;
-    }
-
-  return val;
-}
-
-/* Checks whether phi node PHI is redundant and if it is, records the ssa name
-   its result is redundant to to EQ_TO array.  */
-
-static void
-check_phi_redundancy (tree phi, tree *eq_to)
-{
-  tree val = NULL_TREE, def, res = PHI_RESULT (phi), stmt;
-  unsigned i, ver = SSA_NAME_VERSION (res);
-  imm_use_iterator imm_iter;
-  use_operand_p use_p;
-
-  /* It is unlikely that such large phi node would be redundant.  */
-  if (PHI_NUM_ARGS (phi) > 16)
-    return;
-
-  for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++)
-    {
-      def = PHI_ARG_DEF (phi, i);
-
-      if (TREE_CODE (def) == SSA_NAME)
-	{
-	  def = get_eq_name (eq_to, def);
-	  if (def == res)
-	    continue;
-	}
-
-      if (val
-	  && !operand_equal_for_phi_arg_p (val, def))
-	return;
-
-      val = def;
-    }
-
-  /* At least one of the arguments should not be equal to the result, or
-     something strange is happening.  */
-  gcc_assert (val);
-
-  if (get_eq_name (eq_to, res) == val)
-    return;
-
-  if (!may_propagate_copy (res, val))
-    return;
-
-  eq_to[ver] = val;
-
-  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, res)
-    {
-      stmt = USE_STMT (use_p);
-      if (TREE_CODE (stmt) == PHI_NODE)
-	check_phi_redundancy (stmt, eq_to);
-    }
-}
-
-/* Removes redundant phi nodes.
-
-   A redundant PHI node is a PHI node where all of its PHI arguments
-   are the same value, excluding any PHI arguments which are the same
-   as the PHI result.
-
-   A redundant PHI node is effectively a copy, so we forward copy propagate
-   which removes all uses of the destination of the PHI node then
-   finally we delete the redundant PHI node.
-
-   Note that if we can not copy propagate the PHI node, then the PHI
-   will not be removed.  Thus we do not have to worry about dependencies
-   between PHIs and the problems serializing PHIs into copies creates. 
-   
-   The most important effect of this pass is to remove degenerate PHI
-   nodes created by removing unreachable code.  */
-
-void
-kill_redundant_phi_nodes (void)
-{
-  tree *eq_to;
-  unsigned i, old_num_ssa_names;
-  basic_block bb;
-  tree phi, repl, stmt;
-
-  /* The EQ_TO[VER] holds the value by that the ssa name VER should be
-     replaced.  If EQ_TO[VER] is ssa name and it is decided to replace it by
-     other value, it may be necessary to follow the chain till the final value.
-     We perform path shortening (replacing the entries of the EQ_TO array with
-     heads of these chains) whenever we access the field to prevent quadratic
-     complexity (probably would not occur in practice anyway, but let us play
-     it safe).  */
-  eq_to = xcalloc (num_ssa_names, sizeof (tree));
-
-  old_num_ssa_names = num_ssa_names;
-
-  FOR_EACH_BB (bb)
-    {
-      for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
-	check_phi_redundancy (phi, eq_to);
-    }
-
-  /* Now propagate the values.  */
-  for (i = 0; i < old_num_ssa_names; i++)
-    {
-      if (!ssa_name (i))
-	continue;
-
-      repl = get_eq_name (eq_to, ssa_name (i));
-      if (repl != ssa_name (i))
-	replace_immediate_uses (ssa_name (i), repl);
-    }
-
-  /* And remove the dead phis.  */
-  for (i = 0; i < old_num_ssa_names; i++)
-    {
-      if (!ssa_name (i))
-	continue;
-
-      repl = get_eq_name (eq_to, ssa_name (i));
-      if (repl != ssa_name (i))
-	{
-	  stmt = SSA_NAME_DEF_STMT (ssa_name (i));
-	  remove_phi_node (stmt, NULL_TREE);
-	}
-    }
-
-  free (eq_to);
-}
-
-struct tree_opt_pass pass_redundant_phi =
-{
-  "redphi",				/* name */
-  NULL,					/* gate */
-  kill_redundant_phi_nodes,		/* execute */
-  NULL,					/* sub */
-  NULL,					/* next */
-  0,					/* static_pass_number */
-  TV_TREE_REDPHI,			/* tv_id */
-  PROP_cfg | PROP_ssa | PROP_alias,	/* properties_required */
-  0,					/* properties_provided */
-  0,					/* properties_destroyed */
-  0,					/* todo_flags_start */
-  TODO_dump_func | TODO_rename_vars 
-    | TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
-  0					/* letter */
-};
 
 /* Emit warnings for uninitialized variables.  This is done in two passes.