[multiple changes]

2006-12-11  Diego Novillo  <dnovillo@redhat.com>

	* doc/tree-ssa.texi: Update documentation for virtual operands
	and the use of push_stmt_changes/pop_stmt_changes.
	* doc/invoke.texi: Remove documentation for params
	global-var-threshold.
	Update documentation on max-aliased-vops.

	* tree-into-ssa.c: Cleanup comments, variables and
	spacing in various functions.
	(regs_to_rename): Declare.
	(mem_syms_to_rename): Declare.
	(dump_update_ssa): Declare.
	(debug_update_ssa): Declare.
	(dump_names_replaced_by): Declare.
	(debug_names_replaced_by): Declare.
	(dump_def_blocks): Declare.
	(debug_def_blocks): Declare.
	(dump_defs_stack): Declare.
	(debug_defs_stack): Declare.
	(dump_currdefs): Declare.
	(debug_currdefs): Declare.
	(mark_def_sites): Do not handle virtual operands.
	(compute_idf): Rename from find_idf.  Update users.
	(register_new_def): Make local.  Convert second argument
	to 'tree'.
	Use BLOCK_DEFS_STACK directly.
	If pushing a non-register, also push the underlying
	symbol.
	(rewrite_stmt): Do not handle virtual operands.
	(dump_tree_ssa): Call dump_def_blocks, dump_defs_stack,
	dump_currdefs and dump_tree_ssa_stats.
	(dump_tree_ssa_stats): Also dump REPL_TBL.
	(replace_use): Remove.  Update all users to call SET_USE
	instead.
	(rewrite_blocks): Move code to free memory to
	fini_ssa_renamer.
	(mark_def_site_blocks): Move initialization code to
	init_ssa_renamer.
	(init_ssa_renamer): New.
	(fini_ssa_renamer): New.
	(rewrite_into_ssa): Call them.
	(prepare_block_for_update): Process SSA_OP_ALL_USES first
	and SSA_OP_ALL_DEFS later.  Do not process virtual
	operands separately.
	(dump_update_ssa): Call dump_decl_set.
	(init_update_ssa): Initialize regs_to_rename and
	mem_syms_to_rename.
	Call init_ssa_renamer.
	(delete_update_ssa): Call fini_ssa_renamer.
	Free blocks_with_phis_to_rewrite.
	(mark_sym_for_renaming): If the variable has
	sub-variables, also mark them.
	If the variable belongs to a partition, also mark it.
	(mark_set_for_renaming): Call mark_sym_for_renaming on
	every symbol in the set.
	(switch_virtuals_to_full_rewrite): Call
	mark_set_for_renaming.
	(update_ssa): Separate syms_to_rename into regs_to_rename
	and mem_syms_to_rename.

	* tree-dump.c (dump_options): Add TDF_MEMSYMS.
	* tree-pretty-print.c (debug_generic_expr): Add TDF_MEMSYMS.
	(debug_generic_stmt): Likewise.
	(debug_tree_chain): Likewise.
	(dump_symbols): New.
	(dump_generic_node): Check for TDF_MEMSYMS.
	Handle MEMORY_PARTITION_TAG.
	If the statement references memory and TDF_MEMSYMS is
	given, call dump_symbols.
	Indicate default names with (D).
	(dump_vops): Update for new virtual operator format.

	* tree.c (init_ttree): Add MEMORY_PARTITION_TAG to
	tree_contains_struct.
	(tree_code_size): Handle MEMORY_PARTITION_TAG.
	(tree_node_structure): Likewise.
	(needs_to_live_in_memory): Handle SSA names.
	* tree.h (MTAG_P): Likewise.
	(struct tree_memory_partition_tag): Declare.
	(MPT_SYMBOLS): Define.
	(union tree_node): Add field 'mpt'.
	* treestruct.def (TS_MEMORY_PARTITION_TAG): Define.
	* tree.def (MEMORY_PARTITION_TAG): Define.

	* tree-pass.h (TDF_MEMSYMS): Define.

	* params.h (GLOBAL_VAR_THRESHOLD): Remove.

	* tree-ssa-alias.c: Include pointer-set.h
	(struct alias_map_d): Remove fields total_alias_vops,
	grouped_p and may_aliases.  Update all users.
	(struct mp_info_def): Declare.
	(mp_info_t): New type.
	(get_smt_for): Rename from get_tmt_for.  Update all
	users.
	(add_may_alias): Add argument ALREADY_ADDED.  If given,
	use it to avoid adding duplicate entries to alias sets.
	(replace_may_alias): Remove.  Update all users.
	(total_alias_vops_cmp): Remove.  Update all users.
	(group_aliases_into): Remove.  Update all users.
	(tree_pointer_compare): Remove.  Update all users.
	(compact_name_tags): Remove.  Update all users.
	(group_aliases): Remove.  Update all users.
	(mark_non_addressable): Move from tree-flow-inline.h.
	Remove the symbol from the partition holding it, if
	needed.
	(dump_mp_info): New.
	(debug_mp_info): New.
	(sort_mp_info): New.
	(create_partition_for): New.
	(rewrite_alias_set_for): New.
	(compute_memory_partitions): New.
	(compute_may_aliases): Call it.
	(init_alias_info): If computing aliases for the first
	time, mark every memory symbol for renaming.
	(have_common_aliases_p): New.
	(compute_flow_insensitive_aliasing): Call it.
	(setup_pointers_and_addressables): Do not cache
	num_referenced_vars.
	For register promoted symbols, mark their former
	partition for renaming.
	(maybe_create_global_var): Only create .GLOBAL_VAR if
	there are no call-clobbered variables and a mix of pure
	and non-pure functions were found.
	(may_alias_p): Tidy comments.
	(create_tag_raw): Remove unused variable new_type.
	(dump_alias_info): call dump_memory_partitions.
	(dump_points_to_info_for): Call dump_decl_set.
	(may_be_aliased): Tidy comments and formatting.

	* timevar.def (TV_MEMORY_PARTITIONING): Define.
	* tree-vectorizer.c (vect_memsyms_to_rename): Rename from
	vect_vnames_to_rename.  Set DECL_UIDs instead of SSA name
	versions in it.
	(slpeel_update_phi_nodes_for_guard1): Ignore memory PHIs.
	* tree-vect-transform.c (vect_transform_loop): Call
	mark_set_for_renaming with vect_memsyms_to_rename.
	* tree-flow-inline.h (zero_imm_uses_p): New.
	(memory_partition): New.
	(set_memory_partition): New.
	(factoring_name_p): New.
	(symbol_mem_tag): New.  Update every function that used
	to access the annotation directly.
	(set_symbol_mem_tag): Likewise.

	* tree-ssa-copy.c (may_propagate_copy): Allow copies
	between a partition and a symbol as long as the symbol
	belongs to the partition.
	(merge_alias_info): Ignore merge requests when memory
	partitions are involved.

	* tree-ssa.c (verify_ssa_name): Check that default
	definitions have empty defining statements.
	(verify_use): Remove argument IS_VIRTUAL.
	Don't call verify_ssa_name.
	(verify_phi_args): Call verify_ssa_name.
	(verify_flow_insensitive_alias_info): Handle MPTs.
	(verify_flow_sensitive_alias_info): Likewise.
	(verify_name_tags): Likewise.
	(verify_call_clobbering): Likewise.
	(verify_ssa): Check for VOPs only after aliasing
	information is available.
	Check virtuals and real operands separately.
	Call verify_ssa_name on every operand.
	(stmt_references_memory_p): Move to tree-ssa-operands.c.
	(walk_use_def_chains_1): Guard against NULL PHI
	arguments.

	* tree-ssa-operands.c (stmt_references_memory_p): Move from
	tree-ssa.c.
	(get_mpt_for): New.
	(dump_memory_partitions): New.
	(debug_memory_partitions): New.

	* tree-flow.h (struct var_ann_d): Add field mpt.
	(struct stmt_ann_d): Add bitfield references_memory.
	* Makefile.in (tree-ssa-structalias.o): Include
	pointer-set.h
	(tree-ssa-alias.o): Likewise.
	* tree-ssa-structalias.c: (update_alias_info): Use
	STORED_SYMS to determine which variables are being
	written to by the store operation.
	* tree-ssa-structalias.h (struct alias_info)
	<total_alias_vops>: Remove.  Update all users.
	<written_vars>: Change to a pointer set.  Update all
	users.
	<dereferenced_ptrs_store>: Likewise.
	<dereferenced_ptrs_load>: Likewise.
	(NUM_REFERENCES): Remove.  Update all users.
	(NUM_REFERENCES_CLEAR): Remove.  Update all users.
	(NUM_REFERENCES_INC): Remove.  Update all users.
	(NUM_REFERENCES_SET): Remove.  Update all users.

	* params.def (PARAM_GLOBAL_VAR_THRESHOLD): Remove.
	Update all users.
	(PARAM_MAX_ALIASED_VOPS): Set to 10.
	* tree-ssanames.c (make_ssa_name): Initialize
	SSA_NAME_IS_DEFAULT_DEF to 0.

2006-12-11  Aldy Hernandez  <aldyh@redhat.com>

	* tree-ssa-dse.c (aggregate_vardecl_d): New.
	(dse_global_data): Add aggregate_vardecl field.
	(dse_possible_dead_store_p): New.
	Add prev_defvar variable.
	Allow immediate uses and previous immediate uses to differ
	if they are setting different parts of the whole.
	(get_aggregate_vardecl): New.
	(dse_record_partial_aggregate_store): New.
	(dse_whole_aggregate_clobbered_p): New.
	(dse_partial_kill_p): New.
	(dse_optimize_stmt): Abstract code checking a possible dead store
	into new function dse_possible_dead_store_p().
	Call dse_maybe_record_aggregate_store().
	When checking whether a STMT and its USE_STMT refer to the
	same memory address, check also for partial kills that clobber
	the whole.
	Move some variable definitions to the block where they are used.
	(aggregate_vardecl_hash): New.
	(aggregate_vardecl_eq): New.
	(aggregate_vardecl_free): New.
	(aggregate_whole_store_p): New.
	(tree_ssa_dse): Initialize and free aggregate_vardecl.
	Mark which aggregate stores we care about.

2006-12-11  Andrew Macleod  <amacleod@redhat.com>

	* tree-ssa-operands.h (struct vuse_element_d): Declare.
	(vuse_element_t): Declare.
	(struct vuse_vec_d): Declare.
	(vuse_vec_p): Declare.
	(VUSE_VECT_NUM_ELEM): Define.
	(VUSE_VECT_ELEMENT_NC): Define.
	(VUSE_ELEMENT_PTR_NC): Define.
	(VUSE_ELEMENT_VAR_NC): Define.
	(VUSE_VECT_ELEMENT): Define.
	(VUSE_ELEMENT_PTR): Define.
	(VUSE_ELEMENT_VAR): Define.
	(struct maydef_optype_d) <use_var>: Remove.
	<use_ptr>: Remove.
	<usev>: Add.
	(struct vuse_optype_d) <kill_var>: Remove.
	<use_ptr>: Remove.
	<usev>: Add.
	(struct mustdef_optype_d) <kill_var>: Remove.
	<use_ptr>: Remove.
	<usev>: Add.
	(VUSE_OP_PTR): Add argument.  Use VUSE_ELEMENT_PTR.
	(VUSE_OP): Add argument.  Use VUSE_ELEMENT_PTR.
	(VUSE_NUM): Define.
	(VUSE_VECT): Define.
	(MAYDEF_OP_PTR): Add argument.  Use VUSE_OP_PTR.
	(MAYDEF_OP): Add argument.  Use VUSE_OP.
	(MAYDEF_NUM): Define.
	(MAYDEF_VECT): Define.
	(MUSTDEF_KILL_PTR): Use VUSE_OP_PTR.
	(MUSTDEF_KILL): Use VUSE_OP.
	(MUSTDEF_NUM): Define.
	(MUSTDEF_VECT): Define.
	(realloc_maydef): Declare.
	(realloc_vuse): Declare.
	(struct ssa_operand_iterator_d) <vuse_index>: Add.
	<mayuse_index>: Add.
	(LOADED_SYMS): Define.
	(STORED_SYMS): Define.
	(FOR_EACH_SSA_MUSTDEF_OPERAND): Call op_iter_next_mustdef.
	* tree-into-ssa.c: Adapt for multi-operand V_MAY_DEF and VUSE
	operators.
	* tree-pretty-print.c: Likewise.
	* tree-ssa-dse.c: Likewise.
	* tree-flow-inline.h: Likewise.
	(op_iter_next_mustdef): New.
	* tree-ssa-operands.c: Likewise.
	(ALLOC_OPTYPE): Remove.
	Update all users.
	(alloc_def): New.
	(alloc_use): New.
	(alloc_maydef): New.
	(alloc_vuse): New.
	(alloc_mustdef): New.
	(realloc_maydef): New.
	(realloc_vuse): New.

2006-12-11  Aldy Hernandez  <aldyh@redhat.com>

	* tree-ssa-operands.c: Remove build_v_must_defs.
	(init_ssa_operands): Delete build_v_must_defs.
	(finalize_ssa_v_must_def_ops): Remove.
	(finalize_ssa_v_must_defs): Remove.
	(finalize_ssa_stmt_operands): Do not call
	finalize_ssa_v_must_defs.
	(start_ssa_stmt_operands): Do not check build_v_must_defs.
	(append_v_must_def): Delete.
	(copy_virtual_operands): Do not copy V_MUST_DEFs.
	(get_modify_expr_operands): Remove reference to V_MUST_DEF from
	comment.  Remove opf_kill_def.
	(build_ssa_operands): Remove references to v_must_defs.
	(copy_virtual_operands): Same.
	(copy_virtual_operands): Same.
	(fini_ssa_operands): Same.
	(free_ssa_operands): Same.
	(add_mustdef_op): Remove.
	Remove mustdef_optype_p.
	(alloc_mustdef): Remove.
	Remove references to V_MUST_DEFs in comment at top of file.
	(get_expr_operands): Remove opf_kill_def.
	(opf_kill_def): Remove.
	(add_virtual_operand): Remove opf_kill_def.
	(get_indirect_ref_operands): Same.
	(get_tmr_operands): Same.

	* tree-vectorizer.c (rename_variables_in_bb): Remove
	SSA_OP_ALL_KILLS.

	* tree-ssa-loop-manip.c (find_uses_to_rename_stmt): Remove
	SSA_OP_ALL_KILLS.
	(check_loop_closed_ssa_stmt): Same.

	* tree-ssa.c (verify_def): Remove V_MUST_DEF from comment.
	(verify_use): Same.
	(verify_ssa): Remove V_MUST_DEFs traces.
	(verify_ssa): Remove SSA_OP_ALL_KILLS.

	* tree-into-ssa.c (mark_def_sites): Change SSA_OP_VMUSTDEF to
	SSA_OP_VMAYDEF.
	(rewrite_update_stmt): Remove SSA_OP_VIRTUAL_KILLS.
	(rewrite_stmt): Remove SSA_OP_ALL_KILLS.

	* tree-ssa-operands.h (struct stmt_operands_d): Remove V_MUST_DEF
	references.
	(MUSTDEF_OPS): Remove.
	(SSA_OP_VMUSTDEF): Remove.
	(FOR_EACH_SSA_MUSTDEF_OPERAND): Remove.
	(struct mustdef_optype_d): Remove.
	Remove mustdef_optype_p.
	(struct stmt_operands_d): Remove mustdef_ops.
	(ssa_operand_iterator_d): Remove mustdefs and mustkills.
	(SSA_OP_VIRTUAL_DEFS): Remove SSA_OP_VMUSTDEF.
	(MUSTDEF_RESULT_PTR): Remove.
	(MUSTDEF_RESULT): Remove.
	(MUSTDEF_KILL_PTR): Remove.
	(MUSTDEF_KILL): Remove.
	(MUSTDEF_NUM): Remove.
	(MUSTDEF_VECT): Remove.
	(SSA_OP_VIRTUAL_KILLS): Remove.
	(SSA_OP_ALL_VIRTUALS): Remove SSA_OP_VIRTUAL_KILLS.
	(SSA_OP_VMUSTKILL): Remove.
	(SSA_OP_ALL_KILLS): Remove.
	(SSA_OP_ALL_OPERANDS): Remove SSA_OP_ALL_KILLS.

	* tree-flow-inline.h (op_iter_init_def): Remove
	SSA_OP_VIRTUAL_KILLS.
	(delink_stmt_imm_use): Remove SSA_OP_ALL_KILLS.

	* tree-ssa-pre.c (compute_rvuse_and_antic_safe): Remove
	SSA_OP_VIRTUAL_KILLS.

	* tree-ssa-loop-im.c (determine_max_movement): Remove
	SSA_OP_VIRTUAL_KILLS.
	(gather_mem_refs_stmt): Same.
	(gather_mem_refs_stmt): Same.

	* tree-ssa-dce.c (mark_really_necessary_kill_operand_phis): Delete.
	(perform_tree_ssa_dce): Remove call to
	mark_really_necessary_kill_operand_phis.

	* tree-flow-inline.h (op_iter_init): Remove setting of mustdefs
	and mustkills.
	(op_iter_next_use): Do not check mustkills.
	(op_iter_next_def): Do not check mustdefs.
	(op_iter_next_tree): Do not check mustkills or mustdefs.
	(clear_and_done_ssa_iter): Do not set mustdefs or mustkills.
	(op_iter_next_maymustdef): Do not check mustkills.
	(op_iter_init_must_and_may_def): Remove SSA_OP_VMUSTKILL.
	(op_iter_init_mustdef): Remove.

	* tree-ssa-live.c (create_ssa_var_map): Change SSA_OP_VMUSTDEF to
	SSA_OP_VMAYDEF.

	* tree-ssa-dse.c (dse_optimize_stmt): Remove SSA_OP_VMUSTDEF.

	* tree-ssa-ccp.c: Remove V_MUST_DEF traces from comments.
	(visit_assignment): Same.

	* tree-ssa-copy.c (copy_prop_visit_assignment): Same.

	* tree-sra.c (mark_all_v_defs_1): Remove V_MUST_DEF from comment.

	* tree-outof-ssa.c (check_replaceable): Remove SSA_OP_VMUSTDEF.

	* tree-pretty-print.c (dump_vops): Remove printing of V_MUST_DEF.
	Remove kill_p variable.

	* tree-dfa.c (struct dfa_stats_d): Remove num_v_must_defs.
	(dump_dfa_stats): Remove code related to V_MUST_DEFs.
	(collect_dfa_stats_r): Do not set num_v_must_defs.
	(mark_new_vars_to_rename): Remove v_must_defs_{before,after}
	code.

	* tree-into-ssa.c (mark_def_sites): Change SSA_OP_VMUSTKILL to
	SSA_OP_VMAYUSE.

	* tree-ssa-pre.c (compute_rvuse_and_antic_safe): Remove
	SSA_OP_VMUSTDEF and SSA_OP_VMUSTKILL.

	* tree-ssa-propagate.c (stmt_makes_single_store): Remove
	SSA_OP_VMUSTDEF.

From-SVN: r119760

1 files changed, 623 insertions, 628 deletions

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 3d4fe56..05cc516 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -47,33 +47,31 @@ Boston, MA 02110-1301, USA.  */
 #include "vec.h"
 #include "bitmap.h"
 #include "vecprim.h"
+#include "pointer-set.h"
 
-/* Obstack used to hold grouping bitmaps and other temporary bitmaps used by
-   aliasing  */
-static bitmap_obstack alias_obstack;
-
-/* Structure to map a variable to its alias set and keep track of the
-   virtual operands that will be needed to represent it.  */
+/* Structure to map a variable to its alias set.  */
 struct alias_map_d
 {
   /* Variable and its alias set.  */
   tree var;
   HOST_WIDE_INT set;
+};
 
-  /* Total number of virtual operands that will be needed to represent
-     all the aliases of VAR.  */
-  long total_alias_vops;
 
-  /* Nonzero if the aliases for this memory tag have been grouped
-     already.  Used in group_aliases.  */
-  unsigned int grouped_p : 1;
+/* Data structures used for computing memory partitions.  */
 
-  /* Set of variables aliased with VAR.  This is the exact same
-     information contained in VAR_ANN (VAR)->MAY_ALIASES, but in
-     bitmap form to speed up alias grouping.  */
-  bitmap may_aliases;
+struct mp_info_def
+{
+  /* Symbol or memory tag.  */
+  tree var;
+
+  /* Number of virtual operators needed to represent references to VAR.  */
+  long num_vops;
 };
 
+typedef struct mp_info_def *mp_info_t;
+DEF_VEC_P(mp_info_t);
+DEF_VEC_ALLOC_P(mp_info_t, heap);
 
 /* Counters used to display statistics on alias analysis.  */
 struct alias_stats_d
@@ -99,21 +97,48 @@ static void finalize_ref_all_pointers (struct alias_info *);
 static void dump_alias_stats (FILE *);
 static bool may_alias_p (tree, HOST_WIDE_INT, tree, HOST_WIDE_INT, bool);
 static tree create_memory_tag (tree type, bool is_type_tag);
-static tree get_tmt_for (tree, struct alias_info *);
+static tree get_smt_for (tree, struct alias_info *);
 static tree get_nmt_for (tree);
-static void add_may_alias (tree, tree);
-static void replace_may_alias (tree, size_t, tree);
+static void add_may_alias (tree, tree, struct pointer_set_t *);
 static struct alias_info *init_alias_info (void);
 static void delete_alias_info (struct alias_info *);
 static void compute_flow_sensitive_aliasing (struct alias_info *);
 static void setup_pointers_and_addressables (struct alias_info *);
 static void create_global_var (void);
 static void maybe_create_global_var (struct alias_info *ai);
-static void group_aliases (struct alias_info *);
 static void set_pt_anything (tree ptr);
 
+void dump_mp_info (FILE *, VEC(mp_info_t,heap) *mp_info_t);
+void debug_mp_info (VEC(mp_info_t,heap) *mp_info_t);
+
 /* Global declarations.  */
 
+/* Mark variable VAR as being non-addressable.  */
+
+static void
+mark_non_addressable (tree var)
+{
+  tree mpt;
+
+  if (!TREE_ADDRESSABLE (var))
+    return;
+
+  mpt = memory_partition (var);
+
+  if (!MTAG_P (var))
+    DECL_CALL_CLOBBERED (var) = false;
+
+  bitmap_clear_bit (gimple_call_clobbered_vars (cfun), DECL_UID (var));
+  TREE_ADDRESSABLE (var) = 0;
+
+  if (mpt)
+    {
+      bitmap_clear_bit (MPT_SYMBOLS (mpt), DECL_UID (var));
+      set_memory_partition (var, NULL_TREE);
+    }
+}
+
+
 /* qsort comparison function to sort type/name tags by DECL_UID.  */
 
 static int
@@ -316,7 +341,7 @@ set_initial_properties (struct alias_info *ai)
   for (i = 0; VEC_iterate (tree, ai->processed_ptrs, i, ptr); i++)
     {
       struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
-      var_ann_t v_ann = var_ann (SSA_NAME_VAR (ptr));
+      tree tag = symbol_mem_tag (SSA_NAME_VAR (ptr));
       
       if (pi->value_escapes_p)
 	{
@@ -325,8 +350,8 @@ set_initial_properties (struct alias_info *ai)
 	  if (pi->name_mem_tag)
 	    mark_call_clobbered (pi->name_mem_tag, pi->escape_mask);
 
-	  if (v_ann->symbol_mem_tag)
-	    mark_call_clobbered (v_ann->symbol_mem_tag, pi->escape_mask);
+	  if (tag)
+	    mark_call_clobbered (tag, pi->escape_mask);
 
 	  if (pi->pt_vars)
 	    {
@@ -341,9 +366,9 @@ set_initial_properties (struct alias_info *ai)
       /* If the name tag is call clobbered, so is the symbol tag
 	 associated with the base VAR_DECL.  */
       if (pi->name_mem_tag
-	  && v_ann->symbol_mem_tag
+	  && tag
 	  && is_call_clobbered (pi->name_mem_tag))
-	mark_call_clobbered (v_ann->symbol_mem_tag, pi->escape_mask);
+	mark_call_clobbered (tag, pi->escape_mask);
 
       /* Name tags and symbol tags that we don't know where they point
 	 to, might point to global memory, and thus, are clobbered.
@@ -362,10 +387,10 @@ set_initial_properties (struct alias_info *ai)
       
       if ((pi->pt_global_mem || pi->pt_anything) 
 	  && pi->is_dereferenced
-	  && v_ann->symbol_mem_tag)
+	  && tag)
 	{
-	  mark_call_clobbered (v_ann->symbol_mem_tag, ESCAPE_IS_GLOBAL);
-	  MTAG_GLOBAL (v_ann->symbol_mem_tag) = true;
+	  mark_call_clobbered (tag, ESCAPE_IS_GLOBAL);
+	  MTAG_GLOBAL (tag) = true;
 	}
     }
 }
@@ -395,6 +420,356 @@ compute_call_clobbered (struct alias_info *ai)
   compute_tag_properties ();
 }
 
+/* Dump the MP_INFO array to FILE.  */
+
+void
+dump_mp_info (FILE *file, VEC(mp_info_t,heap) *mp_info)
+{
+  unsigned i;
+  mp_info_t mp_p;
+
+  for (i = 0; VEC_iterate (mp_info_t, mp_info, i, mp_p); i++)
+    {
+      fprintf (file, "%6lu\t", mp_p->num_vops);
+      if (mp_p->var == NULL_TREE)
+	{
+	  fprintf (file, "CALL-CLOBBERED SYMBOLS: ");
+	  dump_decl_set (file, gimple_call_clobbered_vars (cfun));
+	}
+      else
+	dump_variable (file, mp_p->var);
+    }
+}
+
+
+/* Dump the MP_INFO array to stderr.  */
+
+void
+debug_mp_info (VEC(mp_info_t,heap) *mp_info)
+{
+  dump_mp_info (stderr, mp_info);
+}
+
+
+/* Comparison function for qsort used in sort_mp_info.  */
+
+static int
+mp_info_cmp (const void *p, const void *q)
+{
+  mp_info_t e1 = *((const mp_info_t *) p);
+  mp_info_t e2 = *((const mp_info_t *) q);
+
+  /* We want to sort in decreasing order.  */
+  if (e1->num_vops < e2->num_vops)
+    return 1;
+  else if (e1->num_vops > e2->num_vops)
+    return -1;
+  else
+    return 0;
+}
+
+
+/* Sort the array of reference counts used to compute memory partitions.
+   Elements are sorted in descending order of virtual operators needed.  */
+
+static inline void
+sort_mp_info (VEC(mp_info_t,heap) *list)
+{
+  unsigned num = VEC_length (mp_info_t, list);
+
+  if (num < 2)
+    return;
+
+  if (num == 2)
+    {
+      if (VEC_index (mp_info_t, list, 0)->num_vops
+	  < VEC_index (mp_info_t, list, 1)->num_vops)
+	{  
+	  /* Swap elements if they are in the wrong order.  */
+	  mp_info_t tmp = VEC_index (mp_info_t, list, 0);
+	  VEC_replace (mp_info_t, list, 0, VEC_index (mp_info_t, list, 1));
+	  VEC_replace (mp_info_t, list, 1, tmp);
+	}
+
+      return;
+    }
+
+  /* There are 3 or more elements, call qsort.  */
+  qsort (VEC_address (mp_info_t, list), VEC_length (mp_info_t, list), 
+	 sizeof (mp_info_t), mp_info_cmp);
+}
+
+
+/* Create a new partition to hold all the symbols aliased with
+   MP_P->VAR.  If MP_P->VAR is NULL, it partitions the call-clobbered
+   variables. Only symbols that are not already in another partition
+   are added to the new partition created for MP_P->VAR.  */
+
+static void
+create_partition_for (mp_info_t mp_p)
+{
+  tree mpt, sym;
+  VEC(tree,gc) *aliases;
+  unsigned i;
+
+  if (mp_p->num_vops <= (long) MAX_ALIASED_VOPS)
+    return;
+
+  if (mp_p->var == NULL_TREE)
+    {
+      bitmap_iterator bi;
+      bitmap tmp;
+
+      /* Since the partitions we create for call-clobbered variables
+	 will also be marked call-clobbered, make a copy of the
+	 original set to avoid confusing the iterator.  */
+      tmp = BITMAP_ALLOC (NULL);
+      bitmap_copy (tmp, gimple_call_clobbered_vars (cfun));
+
+      /* Process call-clobbered symbols when no MP_P->VAR is given.  */
+      mpt = NULL_TREE;
+      EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
+	{
+	  tree sym = referenced_var (i);
+	  if (memory_partition (sym) == NULL_TREE)
+	    {
+	      if (mpt == NULL_TREE)
+		{
+		  mpt = get_mpt_for (sym);
+		  mp_p->num_vops++;
+		}
+
+	      mark_sym_for_renaming (mpt);
+	      mark_sym_for_renaming (sym);
+	      set_memory_partition (sym, mpt);
+	    }
+
+	  mp_p->num_vops--;
+
+	  /* If we have already grouped enough, stop.  */
+	  if (mp_p->num_vops <= (long) MAX_ALIASED_VOPS)
+	    break;
+	}
+
+      BITMAP_FREE (tmp);
+    }
+  else
+    {
+      aliases = may_aliases (mp_p->var);
+      gcc_assert (VEC_length (tree, aliases) > 1);
+
+      mpt = NULL_TREE;
+      for (i = 0; VEC_iterate (tree, aliases, i, sym); i++)
+	{
+	  /* Only set the memory partition for aliased symbol SYM if
+	     SYM does not belong to another partition.  */
+	  if (memory_partition (sym) == NULL_TREE)
+	    {
+	      if (mpt == NULL_TREE)
+		{
+		  mpt = get_mpt_for (mp_p->var);
+		  mp_p->num_vops++;
+		}
+
+	      mark_sym_for_renaming (mpt);
+	      mark_sym_for_renaming (sym);
+	      set_memory_partition (sym, mpt);
+	    }
+
+	  mp_p->num_vops--;
+
+	  /* If we have already grouped enough, stop.  */
+	  if (mp_p->num_vops <= (long) MAX_ALIASED_VOPS)
+	    break;
+	}
+
+      if (mpt)
+	mark_call_clobbered (mpt, ESCAPE_UNKNOWN);
+    }
+}
+
+
+/* Rewrite the alias set for TAG to use the newly created partitions.
+   If TAG is NULL, rewrite the set of call-clobbered variables.
+   NEW_ALIASES is a scratch bitmap to build the new set of aliases for
+   TAG.  */
+
+static void
+rewrite_alias_set_for (tree tag, bitmap new_aliases)
+{
+  bitmap_iterator bi;
+  unsigned i;
+  tree mpt, sym;
+
+  if (tag == NULL_TREE)
+    {
+      /* Do not rewrite CALL_CLOBBERED_VARS.  If a symbol S is taken
+	 out of this set, the optimizers will no longer consider S as
+	 call-clobbered, and that may lead to wrong transformations
+	 (e.g., pass_tail_calls explicitly examines all the symbols in
+	 the function to determine if it should enable tail-call
+	 marking).  */
+      return;
+    }
+  else
+    {
+      /* Create a new alias set for TAG with the new partitions.  */
+      var_ann_t ann;
+
+      ann = var_ann (tag);
+      for (i = 0; VEC_iterate (tree, ann->may_aliases, i, sym); i++)
+	{
+	  mpt = memory_partition (sym);
+	  if (mpt)
+	    bitmap_set_bit (new_aliases, DECL_UID (mpt));
+	  else
+	    bitmap_set_bit (new_aliases, DECL_UID (sym));
+	}
+
+      /* Rebuild the may-alias array for TAG.  */
+      VEC_free (tree, gc, ann->may_aliases);
+      EXECUTE_IF_SET_IN_BITMAP (new_aliases, 0, i, bi)
+	VEC_safe_push (tree, gc, ann->may_aliases, referenced_var (i));
+    }
+}
+
+
+/* Compute memory partitions.
+
+   The partitioning is straightforward:
+   
+   1- All the memory tags and call-clobbered that cause virtual
+      operators are collected into the MP_INFO table together with the
+      number of virtual operands that would be needed to represent all
+      the members in the alias set.
+
+   2- MP_INFO is sorted in decreasing order of virtual operators.
+
+   3- For every memory tag T in MP_INFO, a new partition MP is created.  
+
+   4- All the symbols S in T's alias set are examined.  If S is not
+      already in another partition then S is added to partition MP.
+
+   6- The estimate of VOPS is updated, if it falls below
+      MAX_ALIASED_VOPS, we stop.  */
+
+static void
+compute_memory_partitions (void)
+{
+  referenced_var_iterator rvi;
+  tree var;
+  unsigned i;
+  struct mp_info_def mp;
+  mp_info_t mp_p;
+  VEC(mp_info_t,heap) *mp_info;
+  long max_num_vops = 0;
+  bitmap new_aliases;
+
+  timevar_push (TV_MEMORY_PARTITIONING);
+
+  mp_info = NULL;
+  max_num_vops = 0;
+
+  /* Add reference counts for all the call-clobbered variables.  */
+  if (!bitmap_empty_p (gimple_call_clobbered_vars (cfun)))
+    {
+      mp.var = NULL_TREE;
+      mp.num_vops = bitmap_count_bits (gimple_call_clobbered_vars (cfun));
+      max_num_vops = mp.num_vops;
+      mp_p = xcalloc (1, sizeof (*mp_p));
+      *mp_p = mp;
+      VEC_safe_push (mp_info_t, heap, mp_info, mp_p);
+    }
+
+  /* Add reference counts for all the symbol tags.  */
+  FOR_EACH_REFERENCED_VAR (var, rvi)
+    {
+      if (TREE_CODE (var) != SYMBOL_MEMORY_TAG
+	  && TREE_CODE (var) != NAME_MEMORY_TAG)
+	continue;
+
+      /* Each reference to VAR will produce as many VOPs as elements
+	 exist in its alias set.  */
+      mp.var = var;
+      mp.num_vops = VEC_length (tree, may_aliases (var));
+
+      /* No point grouping singleton alias sets.  */
+      if (mp.num_vops <= 1)
+	continue;
+
+      mp_p = xcalloc (1, sizeof (*mp_p));
+      *mp_p = mp;
+      VEC_safe_push (mp_info_t, heap, mp_info, mp_p);
+
+      if (mp.num_vops > max_num_vops)
+	max_num_vops = mp.num_vops;
+    }
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "\n%s: Maximum number of VOPS needed per statement: "
+	       "%ld\n", get_name (current_function_decl), max_num_vops);
+    }
+
+  /* No partitions required if we are below the threshold.  */
+  if (max_num_vops <= (long) MAX_ALIASED_VOPS)
+    goto done;
+
+  /* Sort the MP_INFO array in order of decreasing number of
+     virtual operands.  */
+  sort_mp_info (mp_info);
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "\nVOPS generated by pointer dereferences "
+			  "before partitioning:\n");
+      dump_mp_info (dump_file, mp_info);
+    }
+
+  /* Now that we have all the VOP generating tags in the MP_INFO array
+     sorted by decreasing number of VOPS, create memory partitions and
+     group aliased symbols into those partitions.  */
+  for (i = 0; VEC_iterate (mp_info_t, mp_info, i, mp_p); i++)
+    {
+      /* Stop processing if we are already below the threshold.  */
+      if (mp_p->num_vops <= (long) MAX_ALIASED_VOPS)
+	break;
+
+      create_partition_for (mp_p);
+    }
+
+  /* After partitions have been created, rewrite alias sets to use
+     them instead of the original symbols.  This way, if the alias set
+     was computed as { a b c d e f }, and the subset { b e f } was
+     grouped into partition MPT.3, then the new alias set for the tag
+     will be  { a c d MPT.3 }.  */
+  new_aliases = BITMAP_ALLOC (NULL);
+
+  for (i = 0; VEC_iterate (mp_info_t, mp_info, i, mp_p); i++)
+    {
+      rewrite_alias_set_for (mp_p->var, new_aliases);
+      bitmap_clear (new_aliases);
+    }
+
+  BITMAP_FREE (new_aliases);
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "\nVOPS generated by pointer dereferences "
+			  "after partitioning:\n");
+      dump_mp_info (dump_file, mp_info);
+    }
+
+done:
+  /* Free allocated memory.  */
+  for (i = 0; VEC_iterate (mp_info_t, mp_info, i, mp_p); i++)
+    free (mp_p);
+  VEC_free (mp_info_t, heap, mp_info);
+
+  timevar_pop (TV_MEMORY_PARTITIONING);
+}
+
+
 /* Compute may-alias information for every variable referenced in function
    FNDECL.
 
@@ -481,11 +856,11 @@ compute_call_clobbered (struct alias_info *ai)
 		p_6 = &b;
 	      # p_1 = PHI <p_4(1), p_6(2)>;
 
-	      # a_7 = V_MAY_DEF <a_3>;
-	      # b_8 = V_MAY_DEF <b_5>;
+	      # a_7 = VDEF <a_3>;
+	      # b_8 = VDEF <b_5>;
 	      *p_1 = 3;
 
-	      # a_9 = V_MAY_DEF <a_7>
+	      # a_9 = VDEF <a_7>
 	      # VUSE <b_8>
 	      a_9 = b_8 + 2;
 
@@ -537,15 +912,10 @@ compute_may_aliases (void)
   /* Compute call clobbering information.  */
   compute_call_clobbered (ai);
 
-  /* Determine if we need to enable alias grouping.  */
-  if (ai->total_alias_vops >= MAX_ALIASED_VOPS)
-    group_aliases (ai);
-
-  /* If the program has too many call-clobbered variables and/or function
-     calls, create .GLOBAL_VAR and use it to model call-clobbering
-     semantics at call sites.  This reduces the number of virtual operands
-     considerably, improving compile times at the expense of lost
-     aliasing precision.  */
+  /* If the program makes no reference to global variables, but it
+     contains a mixture of pure and non-pure functions, then we need
+     to create use-def and def-def links between these functions to
+     avoid invalid transformations on them.  */
   maybe_create_global_var (ai);
 
   /* If the program contains ref-all pointers, finalize may-alias information
@@ -554,6 +924,9 @@ compute_may_aliases (void)
   if (ai->ref_all_symbol_mem_tag)
     finalize_ref_all_pointers (ai);
 
+  /* Compute memory partitions for every memory variable.  */
+  compute_memory_partitions ();
+
   /* Debugging dumps.  */
   if (dump_file)
     {
@@ -727,14 +1100,13 @@ init_alias_info (void)
   referenced_var_iterator rvi;
   tree var;
 
-  bitmap_obstack_initialize (&alias_obstack);
   ai = XCNEW (struct alias_info);
   ai->ssa_names_visited = sbitmap_alloc (num_ssa_names);
   sbitmap_zero (ai->ssa_names_visited);
   ai->processed_ptrs = VEC_alloc (tree, heap, 50);
-  ai->written_vars = BITMAP_ALLOC (&alias_obstack);
-  ai->dereferenced_ptrs_store = BITMAP_ALLOC (&alias_obstack);
-  ai->dereferenced_ptrs_load = BITMAP_ALLOC (&alias_obstack);
+  ai->written_vars = pointer_set_create ();
+  ai->dereferenced_ptrs_store = pointer_set_create ();
+  ai->dereferenced_ptrs_load = pointer_set_create ();
 
   /* If aliases have been computed before, clear existing information.  */
   if (gimple_aliases_computed_p (cfun))
@@ -753,7 +1125,6 @@ init_alias_info (void)
 	  
 	  ann->is_aliased = 0;
 	  ann->may_aliases = NULL;
-	  NUM_REFERENCES_CLEAR (ann);
 
 	  /* Since we are about to re-discover call-clobbered
 	     variables, clear the call-clobbered flag.  Variables that
@@ -797,6 +1168,15 @@ init_alias_info (void)
 	    }
 	}
     }
+  else
+    {
+      /* If this is the first time we compute aliasing information,
+	 every non-register symbol will need to be put into SSA form
+	 (the initial SSA form only operates on GIMPLE registers).  */
+      FOR_EACH_REFERENCED_VAR (var, rvi)
+	if (!is_gimple_reg (var))
+	  mark_sym_for_renaming (var);
+    }
 
   /* Next time, we will need to reset alias information.  */
   cfun->gimple_df->aliases_computed_p = true;
@@ -811,31 +1191,22 @@ static void
 delete_alias_info (struct alias_info *ai)
 {
   size_t i;
-  referenced_var_iterator rvi;
-  tree var;
 
   sbitmap_free (ai->ssa_names_visited);
+
   VEC_free (tree, heap, ai->processed_ptrs);
 
   for (i = 0; i < ai->num_addressable_vars; i++)
     free (ai->addressable_vars[i]);
-  
-  FOR_EACH_REFERENCED_VAR(var, rvi)
-    {
-      var_ann_t ann = var_ann (var);
-      NUM_REFERENCES_CLEAR (ann);
-    }
-
   free (ai->addressable_vars);
-
+  
   for (i = 0; i < ai->num_pointers; i++)
     free (ai->pointers[i]);
   free (ai->pointers);
 
-  BITMAP_FREE (ai->written_vars);
-  BITMAP_FREE (ai->dereferenced_ptrs_store);
-  BITMAP_FREE (ai->dereferenced_ptrs_load);
-  bitmap_obstack_release (&alias_obstack);
+  pointer_set_destroy (ai->written_vars);
+  pointer_set_destroy (ai->dereferenced_ptrs_store);
+  pointer_set_destroy (ai->dereferenced_ptrs_load);
   free (ai);
 
   delete_points_to_sets ();
@@ -989,31 +1360,51 @@ compute_flow_sensitive_aliasing (struct alias_info *ai)
     {
       unsigned j;
       struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
-      var_ann_t v_ann = var_ann (SSA_NAME_VAR (ptr));
+      tree tag = symbol_mem_tag (SSA_NAME_VAR (ptr));
       bitmap_iterator bi;
 
-
       /* Set up aliasing information for PTR's name memory tag (if it has
 	 one).  Note that only pointers that have been dereferenced will
 	 have a name memory tag.  */
       if (pi->name_mem_tag && pi->pt_vars)
 	EXECUTE_IF_SET_IN_BITMAP (pi->pt_vars, 0, j, bi)
 	  {
-	    add_may_alias (pi->name_mem_tag, referenced_var (j));
-	    if (j != DECL_UID (v_ann->symbol_mem_tag))
-	      add_may_alias (v_ann->symbol_mem_tag, referenced_var (j));
+	    add_may_alias (pi->name_mem_tag, referenced_var (j), NULL);
+	    if (j != DECL_UID (tag))
+	      add_may_alias (tag, referenced_var (j), NULL);
 	  }
     }
 }
 
 
+/* Return TRUE if at least one symbol in TAG's alias set is also
+   present in SET1.  */
+
+static bool
+have_common_aliases_p (struct pointer_set_t *set1, tree tag2)
+{
+  unsigned i;
+  VEC(tree,gc) *aliases2;
+
+  if (set1 == NULL)
+    return false;
+
+  aliases2 = may_aliases (tag2);
+  for (i = 0; i < VEC_length (tree, aliases2); i++)
+    if (pointer_set_contains (set1, VEC_index (tree, aliases2, i)))
+      return true;
+
+  return false;
+}
+
+
 /* Compute type-based alias sets.  Traverse all the pointers and
    addressable variables found in setup_pointers_and_addressables.
    
    For every pointer P in AI->POINTERS and addressable variable V in
    AI->ADDRESSABLE_VARS, add V to the may-alias sets of P's symbol
    memory tag (SMT) if their alias sets conflict.  V is then marked as
-   an alias tag so that the operand scanner knows that statements
+   an aliased symbol so that the operand scanner knows that statements
    containing V have aliased operands.  */
 
 static void
@@ -1021,33 +1412,34 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
 {
   size_t i;
 
-  /* Initialize counter for the total number of virtual operands that
-     aliasing will introduce.  When AI->TOTAL_ALIAS_VOPS goes beyond the
-     threshold set by --params max-alias-vops, we enable alias
-     grouping.  */
-  ai->total_alias_vops = 0;
+  /* Initialize pointer sets to keep track of duplicates in alias
+     sets.  */
+  for (i = 0; i < ai->num_pointers; i++)
+    {
+      tree tag = symbol_mem_tag (ai->pointers[i]->var);
+      var_ann (tag)->common.aux = NULL;
+    }
 
   /* For every pointer P, determine which addressable variables may alias
      with P's symbol memory tag.  */
   for (i = 0; i < ai->num_pointers; i++)
     {
       size_t j;
+      struct pointer_set_t *already_added;
       struct alias_map_d *p_map = ai->pointers[i];
-      tree tag = var_ann (p_map->var)->symbol_mem_tag;
-      var_ann_t tag_ann = var_ann (tag);
+      tree tag = symbol_mem_tag (p_map->var);
       tree var;
 
       /* Call-clobbering information is not finalized yet at this point.  */
       if (PTR_IS_REF_ALL (p_map->var))
 	continue;
 
-      p_map->total_alias_vops = 0;
-      p_map->may_aliases = BITMAP_ALLOC (&alias_obstack);
+      /* Retrieve or create the set of symbols that have already been
+	 added to TAG's alias set.  */
+      if (var_ann (tag)->common.aux == NULL)
+	var_ann (tag)->common.aux = (void *) pointer_set_create ();
 
-      /* Add any pre-existing may_aliases to the bitmap used to represent
-	 TAG's alias set in case we need to group aliases.  */
-      for (j = 0; VEC_iterate (tree, tag_ann->may_aliases, j, var); ++j)
-	bitmap_set_bit (p_map->may_aliases, DECL_UID (var));
+      already_added = (struct pointer_set_t *) var_ann (tag)->common.aux;
 
       for (j = 0; j < ai->num_addressable_vars; j++)
 	{
@@ -1062,48 +1454,23 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
 	  /* Skip memory tags and variables that have never been
 	     written to.  We also need to check if the variables are
 	     call-clobbered because they may be overwritten by
-	     function calls.
-
-	     Note this is effectively random accessing elements in
-	     the sparse bitset, which can be highly inefficient.
-	     So we first check the call_clobbered status of the
-	     tag and variable before querying the bitmap.  */
-	  tag_stored_p = is_call_clobbered (tag)
-	                 || bitmap_bit_p (ai->written_vars, DECL_UID (tag));
-	  var_stored_p = is_call_clobbered (var)
-	                 || bitmap_bit_p (ai->written_vars, DECL_UID (var));
+	     function calls.  */
+	  tag_stored_p = pointer_set_contains (ai->written_vars, tag)
+	                 || is_call_clobbered (tag);
+	  var_stored_p = pointer_set_contains (ai->written_vars, var)
+	                 || is_call_clobbered (var);
 	  if (!tag_stored_p && !var_stored_p)
 	    continue;
 	     
 	  if (may_alias_p (p_map->var, p_map->set, var, v_map->set, false))
 	    {
-	      size_t num_tag_refs, num_var_refs;
-
-	      num_tag_refs = NUM_REFERENCES (tag_ann);
-	      num_var_refs = NUM_REFERENCES (v_ann);
-
-	      /* Add VAR to TAG's may-aliases set.  */
-
 	      /* We should never have a var with subvars here, because
 	         they shouldn't get into the set of addressable vars */
 	      gcc_assert (!var_can_have_subvars (var)
 			  || get_subvars_for_var (var) == NULL);
 
-	      add_may_alias (tag, var);
-	      /* Update the bitmap used to represent TAG's alias set
-		 in case we need to group aliases.  */
-	      bitmap_set_bit (p_map->may_aliases, DECL_UID (var));
-
-	      /* Update the total number of virtual operands due to
-		 aliasing.  Since we are adding one more alias to TAG's
-		 may-aliases set, the total number of virtual operands due
-		 to aliasing will be increased by the number of references
-		 made to VAR and TAG (every reference to TAG will also
-		 count as a reference to VAR).  */
-	      ai->total_alias_vops += (num_var_refs + num_tag_refs);
-	      p_map->total_alias_vops += (num_var_refs + num_tag_refs);
-
-
+	      /* Add VAR to TAG's may-aliases set.  */
+	      add_may_alias (tag, var, already_added);
 	    }
 	}
     }
@@ -1131,18 +1498,20 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
   for (i = 0; i < ai->num_pointers; i++)
     {
       size_t j;
+      struct pointer_set_t *set1;
       struct alias_map_d *p_map1 = ai->pointers[i];
-      tree tag1 = var_ann (p_map1->var)->symbol_mem_tag;
-      bitmap may_aliases1 = p_map1->may_aliases;
+      tree tag1 = symbol_mem_tag (p_map1->var);
 
       if (PTR_IS_REF_ALL (p_map1->var))
 	continue;
 
+      set1 = (struct pointer_set_t *) var_ann (tag1)->common.aux;
+
       for (j = i + 1; j < ai->num_pointers; j++)
 	{
 	  struct alias_map_d *p_map2 = ai->pointers[j];
-	  tree tag2 = var_ann (p_map2->var)->symbol_mem_tag;
-	  bitmap may_aliases2 = p_map2->may_aliases;
+	  tree tag2 = symbol_mem_tag (p_map2->var);
+	  VEC(tree,gc) *may_aliases2 = may_aliases (tag2);
 
 	  if (PTR_IS_REF_ALL (p_map2->var))
 	    continue;
@@ -1153,34 +1522,38 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
 
 	  /* The two pointers may alias each other.  If they already have
 	     symbols in common, do nothing.  */
-	  if (bitmap_intersect_p (may_aliases1, may_aliases2))
+	  if (have_common_aliases_p (set1, tag2))
 	    continue;
 
-	  if (!bitmap_empty_p (may_aliases2))
+	  if (set1 == NULL)
 	    {
-	      unsigned int k;
-	      bitmap_iterator bi;
+	      set1 = pointer_set_create ();
+	      var_ann (tag1)->common.aux = (void *) set1;
+	    }
+
+	  if (VEC_length (tree, may_aliases2) > 0)
+	    {
+	      unsigned k;
+	      tree sym;
 
-	      /* Add all the aliases for TAG2 into TAG1's alias set.
-		 FIXME, update grouping heuristic counters.  */
-	      EXECUTE_IF_SET_IN_BITMAP (may_aliases2, 0, k, bi)
-		add_may_alias (tag1, referenced_var (k));
-	      bitmap_ior_into (may_aliases1, may_aliases2);
+	      /* Add all the aliases for TAG2 into TAG1's alias set.  */
+	      for (k = 0; VEC_iterate (tree, may_aliases2, k, sym); k++)
+		add_may_alias (tag1, sym, set1);
 	    }
 	  else
 	    {
 	      /* Since TAG2 does not have any aliases of its own, add
 		 TAG2 itself to the alias set of TAG1.  */
-	      add_may_alias (tag1, tag2);
-	      bitmap_set_bit (may_aliases1, DECL_UID (tag2));
+	      add_may_alias (tag1, tag2, set1);
 	    }
 	}
+
+      if (set1)
+	{
+	  pointer_set_destroy (set1);
+	  var_ann (tag1)->common.aux = NULL;
+	}
     }
-  
-  if (dump_file)
-    fprintf (dump_file, "\n%s: Total number of aliased vops: %ld\n",
-	     get_name (current_function_decl),
-	     ai->total_alias_vops);
 }
 
 
@@ -1197,326 +1570,29 @@ static void
 finalize_ref_all_pointers (struct alias_info *ai)
 {
   size_t i;
+  struct pointer_set_t *already_added = pointer_set_create ();
 
-  if (gimple_global_var (cfun))
-    add_may_alias (ai->ref_all_symbol_mem_tag, gimple_global_var (cfun));
-  else
-    {
-      /* First add the real call-clobbered variables.  */
-      for (i = 0; i < ai->num_addressable_vars; i++)
-	{
-	  tree var = ai->addressable_vars[i]->var;
-	  if (is_call_clobbered (var))
-	    add_may_alias (ai->ref_all_symbol_mem_tag, var);
-        }
-
-      /* Then add the call-clobbered pointer memory tags.  See
-	 compute_flow_insensitive_aliasing for the rationale.  */
-      for (i = 0; i < ai->num_pointers; i++)
-	{
-	  tree ptr = ai->pointers[i]->var, tag;
-	  if (PTR_IS_REF_ALL (ptr))
-	    continue;
-	  tag = var_ann (ptr)->symbol_mem_tag;
-	  if (is_call_clobbered (tag))
-	    add_may_alias (ai->ref_all_symbol_mem_tag, tag);
-	}
-    }
-}
-
-
-/* Comparison function for qsort used in group_aliases.  */
-
-static int
-total_alias_vops_cmp (const void *p, const void *q)
-{
-  const struct alias_map_d **p1 = (const struct alias_map_d **)p;
-  const struct alias_map_d **p2 = (const struct alias_map_d **)q;
-  long n1 = (*p1)->total_alias_vops;
-  long n2 = (*p2)->total_alias_vops;
-
-  /* We want to sort in descending order.  */
-  return (n1 > n2 ? -1 : (n1 == n2) ? 0 : 1);
-}
-
-/* Group all the aliases for TAG to make TAG represent all the
-   variables in its alias set.  Update the total number
-   of virtual operands due to aliasing (AI->TOTAL_ALIAS_VOPS).  This
-   function will make TAG be the unique alias tag for all the
-   variables in its may-aliases.  So, given:
-
-   	may-aliases(TAG) = { V1, V2, V3 }
-
-   This function will group the variables into:
-
-   	may-aliases(V1) = { TAG }
-	may-aliases(V2) = { TAG }
-	may-aliases(V2) = { TAG }  */
-
-static void
-group_aliases_into (tree tag, bitmap tag_aliases, struct alias_info *ai)
-{
-  unsigned int i;
-  var_ann_t tag_ann = var_ann (tag);
-  size_t num_tag_refs = NUM_REFERENCES (tag_ann);
-  bitmap_iterator bi;
-
-  EXECUTE_IF_SET_IN_BITMAP (tag_aliases, 0, i, bi)
-    {
-      tree var = referenced_var (i);
-      var_ann_t ann = var_ann (var);
-
-      /* Make TAG the unique alias of VAR.  */
-      ann->is_aliased = 0;
-      ann->may_aliases = NULL;
-
-      /* Note that VAR and TAG may be the same if the function has no
-	 addressable variables (see the discussion at the end of
-	 setup_pointers_and_addressables).  */
-      if (var != tag)
-	add_may_alias (var, tag);
-
-      /* Reduce total number of virtual operands contributed
-	 by TAG on behalf of VAR.  Notice that the references to VAR
-	 itself won't be removed.  We will merely replace them with
-	 references to TAG.  */
-      ai->total_alias_vops -= num_tag_refs;
-    }
-
-  /* We have reduced the number of virtual operands that TAG makes on
-     behalf of all the variables formerly aliased with it.  However,
-     we have also "removed" all the virtual operands for TAG itself,
-     so we add them back.  */
-  ai->total_alias_vops += num_tag_refs;
-
-  /* TAG no longer has any aliases.  */
-  tag_ann->may_aliases = NULL;
-}
-
-/* Replacing may aliases in name tags during grouping can up with the
-   same SMT multiple times in the may_alias list.  It's quicker to
-   just remove them post-hoc than it is to avoid them during
-   replacement.  Thus, this routine sorts the may-alias list and
-   removes duplicates.  */
-
-static void
-compact_name_tags (void)
-{
-  referenced_var_iterator rvi;
-  tree var;
-
-  FOR_EACH_REFERENCED_VAR (var, rvi)
+  /* First add the real call-clobbered variables.  */
+  for (i = 0; i < ai->num_addressable_vars; i++)
     {
-      if (TREE_CODE (var) == NAME_MEMORY_TAG)
-	{
-	  VEC(tree, gc) *aliases, *new_aliases;
-	  tree alias, last_alias;
-	  int i;
-	  
-	  last_alias = NULL;
-	  aliases = var_ann (var)->may_aliases;
-	  new_aliases = NULL;
-	  
-	  if (VEC_length (tree, aliases) > 1)
-	    {
-	      bool changed = false;
-	      qsort (VEC_address (tree, aliases), 
-		     VEC_length (tree, aliases),
-		     sizeof (tree), sort_tags_by_id);
-	      
-	      for (i = 0; VEC_iterate (tree, aliases, i, alias); i++)
-		{
-		  if (alias == last_alias)
-		    {
-		      changed = true;
-		      continue;
-		    }
-		  
-		  VEC_safe_push (tree, gc, new_aliases, alias);
-		  last_alias = alias;
-		}
-
-	      /* Only replace the array if something has changed.  */
-	      if (changed)
-		{
-		  VEC_free (tree, gc, aliases);
-		  var_ann (var)->may_aliases = new_aliases;
-		}
-	      else
-		VEC_free (tree, gc, new_aliases);
-	    }
-	}
+      tree var = ai->addressable_vars[i]->var;
+      if (is_call_clobbered (var))
+	add_may_alias (ai->ref_all_symbol_mem_tag, var, already_added);
     }
-}
-
-/* Group may-aliases sets to reduce the number of virtual operands due
-   to aliasing.
-
-     1- Sort the list of pointers in decreasing number of contributed
-	virtual operands.
-
-     2- Take the first entry in AI->POINTERS and revert the role of
-	the memory tag and its aliases.  Usually, whenever an aliased
-	variable Vi is found to alias with a memory tag T, we add Vi
-	to the may-aliases set for T.  Meaning that after alias
-	analysis, we will have:
-
-		may-aliases(T) = { V1, V2, V3, ..., Vn }
-
-	This means that every statement that references T, will get 'n'
-	virtual operands for each of the Vi tags.  But, when alias
-	grouping is enabled, we make T an alias tag and add it to the
-	alias set of all the Vi variables:
-
-		may-aliases(V1) = { T }
-		may-aliases(V2) = { T }
-		...
-		may-aliases(Vn) = { T }
-
-	This has two effects: (a) statements referencing T will only get
-	a single virtual operand, and, (b) all the variables Vi will now
-	appear to alias each other.  So, we lose alias precision to
-	improve compile time.  But, in theory, a program with such a high
-	level of aliasing should not be very optimizable in the first
-	place.
-
-     3- Since variables may be in the alias set of more than one
-	memory tag, the grouping done in step (2) needs to be extended
-	to all the memory tags that have a non-empty intersection with
-	the may-aliases set of tag T.  For instance, if we originally
-	had these may-aliases sets:
-
-		may-aliases(T) = { V1, V2, V3 }
-		may-aliases(R) = { V2, V4 }
-
-	In step (2) we would have reverted the aliases for T as:
-
-		may-aliases(V1) = { T }
-		may-aliases(V2) = { T }
-		may-aliases(V3) = { T }
-
-	But note that now V2 is no longer aliased with R.  We could
-	add R to may-aliases(V2), but we are in the process of
-	grouping aliases to reduce virtual operands so what we do is
-	add V4 to the grouping to obtain:
-
-		may-aliases(V1) = { T }
-		may-aliases(V2) = { T }
-		may-aliases(V3) = { T }
-		may-aliases(V4) = { T }
-
-     4- If the total number of virtual operands due to aliasing is
-	still above the threshold set by max-alias-vops, go back to (2).  */
-
-static void
-group_aliases (struct alias_info *ai)
-{
-  size_t i;
-  tree ptr;
 
-  /* Sort the POINTERS array in descending order of contributed
-     virtual operands.  */
-  qsort (ai->pointers, ai->num_pointers, sizeof (struct alias_map_d *),
-         total_alias_vops_cmp);
-
-  /* For every pointer in AI->POINTERS, reverse the roles of its tag
-     and the tag's may-aliases set.  */
+  /* Then add the call-clobbered pointer memory tags.  See
+     compute_flow_insensitive_aliasing for the rationale.  */
   for (i = 0; i < ai->num_pointers; i++)
     {
-      size_t j;
-      tree tag1 = var_ann (ai->pointers[i]->var)->symbol_mem_tag;
-      bitmap tag1_aliases = ai->pointers[i]->may_aliases;
-
-      /* Skip tags that have been grouped already.  */
-      if (ai->pointers[i]->grouped_p)
-	continue;
-
-      /* See if TAG1 had any aliases in common with other symbol tags.
-	 If we find a TAG2 with common aliases with TAG1, add TAG2's
-	 aliases into TAG1.  */
-      for (j = i + 1; j < ai->num_pointers; j++)
-	{
-	  bitmap tag2_aliases = ai->pointers[j]->may_aliases;
-
-          if (bitmap_intersect_p (tag1_aliases, tag2_aliases))
-	    {
-	      tree tag2 = var_ann (ai->pointers[j]->var)->symbol_mem_tag;
-
-	      bitmap_ior_into (tag1_aliases, tag2_aliases);
-
-	      /* TAG2 does not need its aliases anymore.  */
-	      bitmap_clear (tag2_aliases);
-	      var_ann (tag2)->may_aliases = NULL;
-
-	      /* TAG1 is the unique alias of TAG2.  */
-	      add_may_alias (tag2, tag1);
-
-	      ai->pointers[j]->grouped_p = true;
-	    }
-	}
-
-      /* Now group all the aliases we collected into TAG1.  */
-      group_aliases_into (tag1, tag1_aliases, ai);
-
-      /* If we've reduced total number of virtual operands below the
-	 threshold, stop.  */
-      if (ai->total_alias_vops < MAX_ALIASED_VOPS)
-	break;
-    }
-
-  /* Finally, all the variables that have been grouped cannot be in
-     the may-alias set of name memory tags.  Suppose that we have
-     grouped the aliases in this code so that may-aliases(a) = SMT.20
-
-     	p_5 = &a;
-	...
-	# a_9 = V_MAY_DEF <a_8>
-	p_5->field = 0
-	... Several modifications to SMT.20 ... 
-	# VUSE <a_9>
-	x_30 = p_5->field
-
-     Since p_5 points to 'a', the optimizers will try to propagate 0
-     into p_5->field, but that is wrong because there have been
-     modifications to 'SMT.20' in between.  To prevent this we have to
-     replace 'a' with 'SMT.20' in the name tag of p_5.  */
-  for (i = 0; VEC_iterate (tree, ai->processed_ptrs, i, ptr); i++)
-    {
-      size_t j;
-      tree name_tag = SSA_NAME_PTR_INFO (ptr)->name_mem_tag;
-      VEC(tree,gc) *aliases;
-      tree alias;
-      
-      if (name_tag == NULL_TREE)
+      tree ptr = ai->pointers[i]->var, tag;
+      if (PTR_IS_REF_ALL (ptr))
 	continue;
-
-      aliases = var_ann (name_tag)->may_aliases;
-      for (j = 0; VEC_iterate (tree, aliases, j, alias); j++)
-	{
-	  var_ann_t ann = var_ann (alias);
-
-	  if ((!MTAG_P (alias)
-	       || TREE_CODE (alias) == STRUCT_FIELD_TAG)
-	      && ann->may_aliases)
-	    {
-	      tree new_alias;
-
-	      gcc_assert (VEC_length (tree, ann->may_aliases) == 1);
-
-	      new_alias = VEC_index (tree, ann->may_aliases, 0);
-	      replace_may_alias (name_tag, j, new_alias);
-	    }
-	}
+      tag = symbol_mem_tag (ptr);
+      if (is_call_clobbered (tag))
+	add_may_alias (ai->ref_all_symbol_mem_tag, tag, already_added);
     }
 
-  compact_name_tags ();
-
-  if (dump_file)
-    fprintf (dump_file,
-	     "%s: Total number of aliased vops after grouping: %ld%s\n",
-	     get_name (current_function_decl),
-	     ai->total_alias_vops,
-	     (ai->total_alias_vops < 0) ? " (negative values are OK)" : "");
+  pointer_set_destroy (already_added);
 }
 
 
@@ -1542,7 +1618,7 @@ create_alias_map_for (tree var, struct alias_info *ai)
 static void
 setup_pointers_and_addressables (struct alias_info *ai)
 {
-  size_t n_vars, num_addressable_vars, num_pointers;
+  size_t num_addressable_vars, num_pointers;
   referenced_var_iterator rvi;
   tree var;
   VEC (tree, heap) *varvec = NULL;
@@ -1561,7 +1637,7 @@ setup_pointers_and_addressables (struct alias_info *ai)
 	  /* Since we don't keep track of volatile variables, assume that
 	     these pointers are used in indirect store operations.  */
 	  if (TREE_THIS_VOLATILE (var))
-	    bitmap_set_bit (ai->dereferenced_ptrs_store, DECL_UID (var));
+	    pointer_set_insert (ai->dereferenced_ptrs_store, var);
 
 	  num_pointers++;
 	}
@@ -1577,14 +1653,8 @@ setup_pointers_and_addressables (struct alias_info *ai)
   ai->num_addressable_vars = 0;
   ai->num_pointers = 0;
 
-  /* Since we will be creating symbol memory tags within this loop,
-     cache the value of NUM_REFERENCED_VARS to avoid processing the
-     additional tags unnecessarily.  */
-  n_vars = num_referenced_vars;
-
   FOR_EACH_REFERENCED_VAR_SAFE (var, varvec, srvi)
     {
-      var_ann_t v_ann = var_ann (var);
       subvar_t svars;
 
       /* Name memory tags already have flow-sensitive aliasing
@@ -1637,17 +1707,26 @@ setup_pointers_and_addressables (struct alias_info *ai)
 		 addressable bit, so that it can be optimized as a
 		 regular variable.  */
 	      if (okay_to_mark)
-		mark_non_addressable (var);
+		{
+		  /* The memory partition holding VAR will no longer
+		     contain VAR, and statements referencing it will need
+		     to be udpated.  */
+		  if (memory_partition (var))
+		    mark_sym_for_renaming (memory_partition (var));
+
+		  mark_non_addressable (var);
+		}
 	    }
 	}
 
       /* Global variables and addressable locals may be aliased.  Create an
          entry in ADDRESSABLE_VARS for VAR.  */
-      if (may_be_aliased (var)	  
-	  && (!var_can_have_subvars (var) 
-	      || get_subvars_for_var (var) == NULL))
+      if (may_be_aliased (var))
 	{
-	  create_alias_map_for (var, ai);
+	  if (!var_can_have_subvars (var)
+	      || get_subvars_for_var (var) == NULL)
+	    create_alias_map_for (var, ai);
+
 	  mark_sym_for_renaming (var);
 	}
 
@@ -1655,113 +1734,71 @@ setup_pointers_and_addressables (struct alias_info *ai)
          array and create a symbol memory tag for them.  */
       if (POINTER_TYPE_P (TREE_TYPE (var)))
 	{
-	  if ((bitmap_bit_p (ai->dereferenced_ptrs_store, DECL_UID (var))
-	       || bitmap_bit_p (ai->dereferenced_ptrs_load, DECL_UID (var))))
+	  if ((pointer_set_contains (ai->dereferenced_ptrs_store, var)
+	       || pointer_set_contains (ai->dereferenced_ptrs_load, var)))
 	    {
-	      tree tag;
+	      tree tag, old_tag;
 	      var_ann_t t_ann;
 
 	      /* If pointer VAR still doesn't have a memory tag
 		 associated with it, create it now or re-use an
 		 existing one.  */
-	      tag = get_tmt_for (var, ai);
+	      tag = get_smt_for (var, ai);
 	      t_ann = var_ann (tag);
 
 	      /* The symbol tag will need to be renamed into SSA
 		 afterwards. Note that we cannot do this inside
-		 get_tmt_for because aliasing may run multiple times
+		 get_smt_for because aliasing may run multiple times
 		 and we only create symbol tags the first time.  */
 	      mark_sym_for_renaming (tag);
 
 	      /* Similarly, if pointer VAR used to have another type
 		 tag, we will need to process it in the renamer to
 		 remove the stale virtual operands.  */
-	      if (v_ann->symbol_mem_tag)
-		mark_sym_for_renaming (v_ann->symbol_mem_tag);
+	      old_tag = symbol_mem_tag (var);
+	      if (old_tag)
+		mark_sym_for_renaming (old_tag);
 
 	      /* Associate the tag with pointer VAR.  */
-	      v_ann->symbol_mem_tag = tag;
+	      set_symbol_mem_tag (var, tag);
 
 	      /* If pointer VAR has been used in a store operation,
 		 then its memory tag must be marked as written-to.  */
-	      if (bitmap_bit_p (ai->dereferenced_ptrs_store, DECL_UID (var)))
-		bitmap_set_bit (ai->written_vars, DECL_UID (tag));
-
-	      /* All the dereferences of pointer VAR count as
-		 references of TAG.  Since TAG can be associated with
-		 several pointers, add the dereferences of VAR to the
-		 TAG.  */
-	      NUM_REFERENCES_SET (t_ann, 
-				  NUM_REFERENCES (t_ann)
-				  + NUM_REFERENCES (v_ann));
+	      if (pointer_set_contains (ai->dereferenced_ptrs_store, var))
+		pointer_set_insert (ai->written_vars, tag);
 	    }
 	  else
 	    {
 	      /* The pointer has not been dereferenced.  If it had a
 		 symbol memory tag, remove it and mark the old tag for
 		 renaming to remove it out of the IL.  */
-	      var_ann_t ann = var_ann (var);
-	      tree tag = ann->symbol_mem_tag;
+	      tree tag = symbol_mem_tag (var);
 	      if (tag)
 		{
 		  mark_sym_for_renaming (tag);
-		  ann->symbol_mem_tag = NULL_TREE;
+		  set_symbol_mem_tag (var, NULL_TREE);
 		}
 	    }
 	}
     }
+
   VEC_free (tree, heap, varvec);
 }
 
 
-/* Determine whether to use .GLOBAL_VAR to model call clobbering semantics. At
-   every call site, we need to emit V_MAY_DEF expressions to represent the
-   clobbering effects of the call for variables whose address escapes the
-   current function.
-
-   One approach is to group all call-clobbered variables into a single
-   representative that is used as an alias of every call-clobbered variable
-   (.GLOBAL_VAR).  This works well, but it ties the optimizer hands because
-   references to any call clobbered variable is a reference to .GLOBAL_VAR.
-
-   The second approach is to emit a clobbering V_MAY_DEF for every 
-   call-clobbered variable at call sites.  This is the preferred way in terms 
-   of optimization opportunities but it may create too many V_MAY_DEF operands
-   if there are many call clobbered variables and function calls in the 
-   function.
-
-   To decide whether or not to use .GLOBAL_VAR we multiply the number of
-   function calls found by the number of call-clobbered variables.  If that
-   product is beyond a certain threshold, as determined by the parameterized
-   values shown below, we use .GLOBAL_VAR.
-
-   FIXME.  This heuristic should be improved.  One idea is to use several
-   .GLOBAL_VARs of different types instead of a single one.  The thresholds
-   have been derived from a typical bootstrap cycle, including all target
-   libraries. Compile times were found increase by ~1% compared to using
-   .GLOBAL_VAR.  */
+/* Determine whether to use .GLOBAL_VAR to model call clobbering
+   semantics.  If the function makes no references to global
+   variables and contains at least one call to a non-pure function,
+   then we need to mark the side-effects of the call using .GLOBAL_VAR
+   to represent all possible global memory referenced by the callee.  */
 
 static void
 maybe_create_global_var (struct alias_info *ai)
 {
-  unsigned i, n_clobbered;
-  bitmap_iterator bi;
-  
   /* No need to create it, if we have one already.  */
   if (gimple_global_var (cfun) == NULL_TREE)
     {
-      /* Count all the call-clobbered variables.  */
-      n_clobbered = 0;
-      EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
-	{
-	  n_clobbered++;
-	}
-
-      /* If the number of virtual operands that would be needed to
-	 model all the call-clobbered variables is larger than
-	 GLOBAL_VAR_THRESHOLD, create .GLOBAL_VAR.
-
-	 Also create .GLOBAL_VAR if there are no call-clobbered
+      /* Create .GLOBAL_VAR if there are no call-clobbered
 	 variables and the program contains a mixture of pure/const
 	 and regular function calls.  This is to avoid the problem
 	 described in PR 20115:
@@ -1784,32 +1821,12 @@ maybe_create_global_var (struct alias_info *ai)
 	 So, if we have some pure/const and some regular calls in the
 	 program we create .GLOBAL_VAR to avoid missing these
 	 relations.  */
-      if (ai->num_calls_found * n_clobbered >= (size_t) GLOBAL_VAR_THRESHOLD
-	  || (n_clobbered == 0
-	      && ai->num_calls_found > 0
-	      && ai->num_pure_const_calls_found > 0
-	      && ai->num_calls_found > ai->num_pure_const_calls_found))
+      if (bitmap_count_bits (gimple_call_clobbered_vars (cfun)) == 0
+	  && ai->num_calls_found > 0
+	  && ai->num_pure_const_calls_found > 0
+	  && ai->num_calls_found > ai->num_pure_const_calls_found)
 	create_global_var ();
     }
-
-  /* Mark all call-clobbered symbols for renaming.  Since the initial
-     rewrite into SSA ignored all call sites, we may need to rename
-     .GLOBAL_VAR and the call-clobbered variables.   */
-  EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
-    {
-      tree var = referenced_var (i);
-
-      /* If the function has calls to clobbering functions and
-	 .GLOBAL_VAR has been created, make it an alias for all
-	 call-clobbered variables.  */
-      if (gimple_global_var (cfun) && var != gimple_global_var (cfun))
-	{
-	  add_may_alias (var, gimple_global_var (cfun));
-	  gcc_assert (!get_subvars_for_var (var));
-	}
-      
-      mark_sym_for_renaming (var);
-    }
 }
 
 
@@ -1833,7 +1850,7 @@ may_alias_p (tree ptr, HOST_WIDE_INT mem_alias_set,
   alias_stats.simple_queries++;
 
   /* By convention, a variable cannot alias itself.  */
-  mem = var_ann (ptr)->symbol_mem_tag;
+  mem = symbol_mem_tag (ptr);
   if (mem == var)
     {
       alias_stats.alias_noalias++;
@@ -1882,15 +1899,14 @@ may_alias_p (tree ptr, HOST_WIDE_INT mem_alias_set,
       return false;
     }
 
-  /* If var is a record or union type, ptr cannot point into var
-     unless there is some operation explicit address operation in the
-     program that can reference a field of the ptr's dereferenced
-     type.  This also assumes that the types of both var and ptr are
+  /* If VAR is a record or union type, PTR cannot point into VAR
+     unless there is some explicit address operation in the
+     program that can reference a field of the type pointed-to by PTR.
+     This also assumes that the types of both VAR and PTR are
      contained within the compilation unit, and that there is no fancy
      addressing arithmetic associated with any of the types
      involved.  */
-
-  if ((mem_alias_set != 0) && (var_alias_set != 0))
+  if (mem_alias_set != 0 && var_alias_set != 0)
     {
       tree ptr_type = TREE_TYPE (ptr);
       tree var_type = TREE_TYPE (var);
@@ -1902,13 +1918,13 @@ may_alias_p (tree ptr, HOST_WIDE_INT mem_alias_set,
 	{
 	  int ptr_star_count = 0;
 	  
-	  /* Ipa_type_escape_star_count_of_interesting_type is a little to
-	     restrictive for the pointer type, need to allow pointers to
-	     primitive types as long as those types cannot be pointers
-	     to everything.  */
+	  /* ipa_type_escape_star_count_of_interesting_type is a
+	     little too restrictive for the pointer type, need to
+	     allow pointers to primitive types as long as those types
+	     cannot be pointers to everything.  */
 	  while (POINTER_TYPE_P (ptr_type))
-	    /* Strip the *'s off.  */ 
 	    {
+	      /* Strip the *s off.  */ 
 	      ptr_type = TREE_TYPE (ptr_type);
 	      ptr_star_count++;
 	    }
@@ -1916,7 +1932,6 @@ may_alias_p (tree ptr, HOST_WIDE_INT mem_alias_set,
 	  /* There does not appear to be a better test to see if the 
 	     pointer type was one of the pointer to everything 
 	     types.  */
-	  
 	  if (ptr_star_count > 0)
 	    {
 	      alias_stats.structnoaddress_queries++;
@@ -1930,7 +1945,7 @@ may_alias_p (tree ptr, HOST_WIDE_INT mem_alias_set,
 	    }
 	  else if (ptr_star_count == 0)
 	    {
-	      /* If ptr_type was not really a pointer to type, it cannot 
+	      /* If PTR_TYPE was not really a pointer to type, it cannot 
 		 alias.  */ 
 	      alias_stats.structnoaddress_queries++;
 	      alias_stats.structnoaddress_resolved++;
@@ -1945,15 +1960,15 @@ may_alias_p (tree ptr, HOST_WIDE_INT mem_alias_set,
 }
 
 
-/* Add ALIAS to the set of variables that may alias VAR.  */
+/* Add ALIAS to the set of variables that may alias VAR.  If
+   ALREADY_ADDED is given, it is used to avoid adding the same alias
+   more than once to VAR's alias set.  */
 
 static void
-add_may_alias (tree var, tree alias)
+add_may_alias (tree var, tree alias, struct pointer_set_t *already_added)
 {
-  size_t i;
   var_ann_t v_ann = get_var_ann (var);
   var_ann_t a_ann = get_var_ann (alias);
-  tree al;
 
   /* Don't allow self-referential aliases.  */
   gcc_assert (var != alias);
@@ -1965,29 +1980,22 @@ add_may_alias (tree var, tree alias)
   gcc_assert (may_be_aliased (alias));
 #endif
 
+  /* VAR must be a symbol or a name tag.  */
+  gcc_assert (TREE_CODE (var) == SYMBOL_MEMORY_TAG
+              || TREE_CODE (var) == NAME_MEMORY_TAG);
+
   if (v_ann->may_aliases == NULL)
     v_ann->may_aliases = VEC_alloc (tree, gc, 2);
 
   /* Avoid adding duplicates.  */
-  for (i = 0; VEC_iterate (tree, v_ann->may_aliases, i, al); i++)
-    if (alias == al)
-      return;
+  if (already_added && pointer_set_insert (already_added, alias))
+    return;
 
   VEC_safe_push (tree, gc, v_ann->may_aliases, alias);
   a_ann->is_aliased = 1;
 }
 
 
-/* Replace alias I in the alias sets of VAR with NEW_ALIAS.  */
-
-static void
-replace_may_alias (tree var, size_t i, tree new_alias)
-{
-  var_ann_t v_ann = var_ann (var);
-  VEC_replace (tree, v_ann->may_aliases, i, new_alias);
-}
-
-
 /* Mark pointer PTR as pointing to an arbitrary memory location.  */
 
 static void
@@ -2092,18 +2100,13 @@ is_escape_site (tree stmt)
 /* Create a new memory tag of type TYPE.
    Does NOT push it into the current binding.  */
 
-static tree
+tree
 create_tag_raw (enum tree_code code, tree type, const char *prefix)
 {
   tree tmp_var;
-  tree new_type;
 
-  /* Make the type of the variable writable.  */
-  new_type = build_type_variant (type, 0, 0);
-  TYPE_ATTRIBUTES (new_type) = TYPE_ATTRIBUTES (type);
+  tmp_var = build_decl (code, create_tmp_var_name (prefix), type);
 
-  tmp_var = build_decl (code, create_tmp_var_name (prefix),
-			type);
   /* Make the variable writable.  */
   TREE_READONLY (tmp_var) = 0;
 
@@ -2123,7 +2126,6 @@ create_tag_raw (enum tree_code code, tree type, const char *prefix)
 static tree
 create_memory_tag (tree type, bool is_type_tag)
 {
-  var_ann_t ann;
   tree tag = create_tag_raw (is_type_tag ? SYMBOL_MEMORY_TAG : NAME_MEMORY_TAG,
 			     type, (is_type_tag) ? "SMT" : "NMT");
 
@@ -2134,8 +2136,7 @@ create_memory_tag (tree type, bool is_type_tag)
   /* Memory tags are by definition addressable.  */
   TREE_ADDRESSABLE (tag) = 1;
 
-  ann = get_var_ann (tag);
-  ann->symbol_mem_tag = NULL_TREE;
+  set_symbol_mem_tag (tag, NULL_TREE);
 
   /* Add the tag to the symbol table.  */
   add_referenced_var (tag);
@@ -2170,7 +2171,7 @@ get_nmt_for (tree ptr)
    function populates the array AI->POINTERS.  */
 
 static tree
-get_tmt_for (tree ptr, struct alias_info *ai)
+get_smt_for (tree ptr, struct alias_info *ai)
 {
   size_t i;
   tree tag;
@@ -2196,7 +2197,7 @@ get_tmt_for (tree ptr, struct alias_info *ai)
   for (i = 0, tag = NULL_TREE; i < ai->num_pointers; i++)
     {
       struct alias_map_d *curr = ai->pointers[i];
-      tree curr_tag = var_ann (curr->var)->symbol_mem_tag;
+      tree curr_tag = symbol_mem_tag (curr->var);
       if (tag_set == curr->set)
 	{
 	  tag = curr_tag;
@@ -2213,10 +2214,9 @@ get_tmt_for (tree ptr, struct alias_info *ai)
       /* If PTR did not have a symbol tag already, create a new SMT.*
 	 artificial variable representing the memory location
 	 pointed-to by PTR.  */
-      if (var_ann (ptr)->symbol_mem_tag == NULL_TREE)
+      tag = symbol_mem_tag (ptr);
+      if (tag == NULL_TREE)
 	tag = create_memory_tag (tag_type, true);
-      else
-	tag = var_ann (ptr)->symbol_mem_tag;
 
       /* Add PTR to the POINTERS array.  Note that we are not interested in
 	 PTR's alias set.  Instead, we cache the alias set for the memory that
@@ -2316,11 +2316,8 @@ dump_alias_info (FILE *file)
   fprintf (file, "\nDereferenced pointers\n\n");
 
   FOR_EACH_REFERENCED_VAR (var, rvi)
-    {
-      var_ann_t ann = var_ann (var);
-      if (ann->symbol_mem_tag)
-	dump_variable (file, var);
-    }
+    if (symbol_mem_tag (var))
+      dump_variable (file, var);
 
   fprintf (file, "\nSymbol memory tags\n\n");
   
@@ -2356,6 +2353,8 @@ dump_alias_info (FILE *file)
 	dump_variable (file, var);
     }
 
+  dump_memory_partitions (file);
+
   fprintf (file, "\n");
 }
 
@@ -2421,16 +2420,8 @@ dump_points_to_info_for (FILE *file, tree ptr)
 
       if (pi->pt_vars)
 	{
-	  unsigned ix;
-	  bitmap_iterator bi;
-
-	  fprintf (file, ", points-to vars: { ");
-	  EXECUTE_IF_SET_IN_BITMAP (pi->pt_vars, 0, ix, bi)
-	    {
-	      print_generic_expr (file, referenced_var (ix), dump_flags);
-	      fprintf (file, " ");
-	    }
-	  fprintf (file, "}");
+	  fprintf (file, ", points-to vars: ");
+	  dump_decl_set (file, pi->pt_vars);
 	}
     }
 
@@ -2544,6 +2535,7 @@ debug_may_aliases_for (tree var)
   dump_may_aliases_for (stderr, var);
 }
 
+
 /* Return true if VAR may be aliased.  */
 
 bool
@@ -2555,26 +2547,26 @@ may_be_aliased (tree var)
 
   /* Globally visible variables can have their addresses taken by other
      translation units.  */
-
   if (MTAG_P (var)
       && (MTAG_GLOBAL (var) || TREE_PUBLIC (var)))
     return true;
   else if (!MTAG_P (var)
-      && (DECL_EXTERNAL (var) || TREE_PUBLIC (var)))
+           && (DECL_EXTERNAL (var) || TREE_PUBLIC (var)))
     return true;
 
-  /* Automatic variables can't have their addresses escape any other way.
-     This must be after the check for global variables, as extern declarations
-     do not have TREE_STATIC set.  */
+  /* Automatic variables can't have their addresses escape any other
+     way.  This must be after the check for global variables, as
+     extern declarations do not have TREE_STATIC set.  */
   if (!TREE_STATIC (var))
     return false;
 
-  /* If we're in unit-at-a-time mode, then we must have seen all occurrences
-     of address-of operators, and so we can trust TREE_ADDRESSABLE.  Otherwise
-     we can only be sure the variable isn't addressable if it's local to the
-     current function.  */
+  /* If we're in unit-at-a-time mode, then we must have seen all
+     occurrences of address-of operators, and so we can trust
+     TREE_ADDRESSABLE.  Otherwise we can only be sure the variable
+     isn't addressable if it's local to the current function.  */
   if (flag_unit_at_a_time)
     return false;
+
   if (decl_function_context (var) == current_function_decl)
     return false;
 
@@ -2583,6 +2575,7 @@ may_be_aliased (tree var)
 
 
 /* Given two symbols return TRUE if one is in the alias set of the other.  */
+
 bool
 is_aliased_with (tree tag, tree sym)
 {
@@ -2626,32 +2619,37 @@ is_aliased_with (tree tag, tree sym)
 static tree
 add_may_alias_for_new_tag (tree tag, tree var)
 {
-  var_ann_t v_ann = var_ann (var);
-  VEC(tree, gc) *aliases = v_ann->may_aliases;
+  VEC(tree,gc) *aliases;
+  struct pointer_set_t *already_added;
+  unsigned i;
+  tree al;
+
+  aliases = may_aliases (var);
 
   /* Case 1: |aliases| == 1  */
-  if ((aliases != NULL)
-      && (VEC_length (tree, aliases) == 1))
+  if (VEC_length (tree, aliases) == 1)
     {
       tree ali = VEC_index (tree, aliases, 0);
-
       if (TREE_CODE (ali) == SYMBOL_MEMORY_TAG)
         return ali;
     }
 
+  already_added = pointer_set_create ();
+  for (i = 0; VEC_iterate (tree, may_aliases (tag), i, al); i++)
+    pointer_set_insert (already_added, al);
+
   /* Case 2: |aliases| == 0  */
   if (aliases == NULL)
-    add_may_alias (tag, var);
+    add_may_alias (tag, var, already_added);
   else
     {
       /* Case 3: |aliases| > 1  */
-      unsigned i;
-      tree al;
-
       for (i = 0; VEC_iterate (tree, aliases, i, al); i++)
-        add_may_alias (tag, al);
+        add_may_alias (tag, al, already_added);
     }
 
+  pointer_set_destroy (already_added);
+
   return tag;
 }
 
@@ -2665,7 +2663,6 @@ add_may_alias_for_new_tag (tree tag, tree var)
 void
 new_type_alias (tree ptr, tree var, tree expr)
 {
-  var_ann_t p_ann = var_ann (ptr);
   tree tag_type = TREE_TYPE (TREE_TYPE (ptr));
   tree tag;
   subvar_t svars;
@@ -2676,14 +2673,14 @@ new_type_alias (tree ptr, tree var, tree expr)
   subvar_t sv;
   unsigned int len;
 
-  gcc_assert (p_ann->symbol_mem_tag == NULL_TREE);
+  gcc_assert (symbol_mem_tag (ptr) == NULL_TREE);
   gcc_assert (!MTAG_P (var));
 
   ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
   gcc_assert (ref);
 
   tag = create_memory_tag (tag_type, true);
-  p_ann->symbol_mem_tag = tag;
+  set_symbol_mem_tag (ptr, tag);
 
   /* Add VAR to the may-alias set of PTR's new symbol tag.  If VAR has
      subvars, add the subvars to the tag instead of the actual var.  */
@@ -2739,7 +2736,7 @@ new_type_alias (tree ptr, tree var, tree expr)
 		  /* Can happen only if 'Case 1' of add_may_alias_for_new_tag
 		     took place.  Since more than one svar was found, we add 
 		     'ali' as one of the may_aliases of the new tag.  */ 
-		  add_may_alias (tag, ali);
+		  add_may_alias (tag, ali, NULL);
 		  ali = tag;
 		}
 	    }
@@ -2747,7 +2744,7 @@ new_type_alias (tree ptr, tree var, tree expr)
       VEC_free (tree, heap, overlaps);
     }
 
-  p_ann->symbol_mem_tag = ali;
+  set_symbol_mem_tag (ptr, ali);
   TREE_READONLY (tag) = TREE_READONLY (var);
   MTAG_GLOBAL (tag) = is_global_var (var);
 }
@@ -2866,7 +2863,6 @@ static tree
 create_sft (tree var, tree field, unsigned HOST_WIDE_INT offset,
 	    unsigned HOST_WIDE_INT size)
 {
-  var_ann_t ann;
   tree subvar = create_tag_raw (STRUCT_FIELD_TAG, field, "SFT");
 
   /* We need to copy the various flags from VAR to SUBVAR, so that
@@ -2879,8 +2875,7 @@ create_sft (tree var, tree field, unsigned HOST_WIDE_INT offset,
   TREE_ADDRESSABLE (subvar) = TREE_ADDRESSABLE (var);
 
   /* Add the new variable to REFERENCED_VARS.  */
-  ann = get_var_ann (subvar);
-  ann->symbol_mem_tag = NULL;  	
+  set_symbol_mem_tag (subvar, NULL);
   add_referenced_var (subvar);
   SFT_PARENT_VAR (subvar) = var;
   SFT_OFFSET (subvar) = offset;