tree-ssa-alias.c (compute_may_aliases): Compute flow sensitive before flow insensitive.

2006-12-04  Daniel Berlin  <dberlin@dberlin.org>
	
	* tree-ssa-alias.c (compute_may_aliases):
	Compute flow sensitive before flow insensitive.
	(compute_flow_sensitive_aliasing): Don't try to add
	a symbol memory tag to itself.
	
	* alias.h (alias_set_subset_of): New prototype.

	* alias.c (alias_set_subset_of): New function.

	* tree-ssa-structalias.c: Update comments.
	(struct variable_info): Add finished_solution.
	(new_varinfo): Set finished solution to NULL.
	(var_escaped_vars): Remove.
	(escaped_vars_tree): Remove.
	(escaped_vars_id): Remove.
	(nonlocal_vars_id): Remove.
	(constraint_expr_type): Add INCLUDES.
	(graph_size): Removed.
	(dump_constraint): Support INCLUDES.
	(build_constraint_graph): Ditto.
	(collapse_nodes): Add merge_solutions argument.
	Don't merge attributes.
	(process_unification_queue): Just use collapse_nodes.
	(perform_var_substitution): Update call to collapse_nodes.
	(get_constraint_exp_from_ssa_var): Use INCLUDES.
	(process_constraint): Fix non-field sensitive handling
	Handle includes.
	(get_constraint_for): Use INCLUDES.
	(make_constraint_from_anything): Renamed from
	make_constraint_from_escaped.
	(make_constraint_to_escaped): Removed.
	(find_global_initializers): Removed.
	(create_variable_info_for): Do not make constraints to escaped
	vars anymore.
	(dump_solution_for_var): Don't print out the equivalent points-to
	sets, just use the name of the variable it shares it with.
	(intra_create_variable_infos): Use INCLUDES.
	Change nonlocal variable sets to anything sets.
	(init_base_vars): Remove escaped_vars and nonlocal_var
	initialization. 
	(find_escape_constraints): Removed.
	(delete_points_to_sets): Remove dead code.
	(used_smt_calculated): New variable.
	(set_used_smts): New function.
	(merge_smts_into): New function.
	(find_what_p_points_to): Modify to use SMTs.
	(create_nonlocal_var): Remove.
	
	* tree-ssa-operands.c (access_can_touch_variable): Remove
	reference to nonlocal_all. 

	* tree-ssa.c (verify_name_tags): Remove.

From-SVN: r119502

gcc/ChangeLog

@@ -1,3 +1,50 @@
+2006-12-04  Daniel Berlin  <dberlin@dberlin.org>
+	
+	* tree-ssa-alias.c (compute_may_aliases):
+	Compute flow sensitive before flow insensitive.
+	(compute_flow_sensitive_aliasing): Don't try to add
+	a symbol memory tag to itself.
+	* alias.h (alias_set_subset_of): New prototype.
+	* alias.c (alias_set_subset_of): New function.
+	* tree-ssa-structalias.c: Update comments.
+	(struct variable_info): Add finished_solution.
+	(new_varinfo): Set finished solution to NULL.
+	(var_escaped_vars): Remove.
+	(escaped_vars_tree): Remove.
+	(escaped_vars_id): Remove.
+	(constraint_expr_type): Add INCLUDES.
+	(graph_size): Removed.
+	(dump_constraint): Support INCLUDES.
+	(build_constraint_graph): Ditto.
+	(collapse_nodes): Add merge_solutions argument.
+	Don't merge attributes.
+	(process_unification_queue): Just use collapse_nodes.
+	(perform_var_substitution): Update call to collapse_nodes.
+	(get_constraint_exp_from_ssa_var): Use INCLUDES.
+	(process_constraint): Fix non-field sensitive handling
+	Handle includes.
+	(get_constraint_for): Use INCLUDES.
+	(make_constraint_from_escaped): Use nonlocal_vars_id.
+	(make_constraint_to_escaped): Removed.
+	(find_global_initializers): Removed.
+	(create_variable_info_for): Do not make constraints to escaped
+	vars anymore.
+	(dump_solution_for_var): Don't print out the equivalent points-to
+	sets, just use the name of the variable it shares it with.
+	(intra_create_variable_infos): Use INCLUDES.
+	Move initialization of nonlocal variable to init_base_vars.
+	(init_base_vars): Init nonlocal variable here.
+	Remove escaped_vars initialization.
+	(find_escape_constraints): Removed.
+	(delete_points_to_sets): Remove dead code.
+	(used_smt_calculated): New variable.
+	(set_used_smts): New function.
+	(merge_smts_into): New function.
+	(find_what_p_points_to): Modify to use SMTs.
+	* tree-ssa-operands.c (access_can_touch_variable): Remove
+	reference to nonlocal_all. 
+	* tree-ssa.c (verify_name_tags): Remove.
+	
 2006-12-04  Carlos O'Donell  <carlos@codesourcery.com>
 
 	* config/arm/unwind-arm.c: Adjust __cxa_type_match declaration.

gcc/Makefile.in

@@ -1837,7 +1837,7 @@ stor-layout.o : stor-layout.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
 tree-ssa-structalias.o: tree-ssa-structalias.c tree-ssa-structalias.h \
    $(SYSTEM_H) $(CONFIG_H) $(GGC_H) $(TREE_H) $(TREE_FLOW_H) \
    $(TM_H) coretypes.h $(CGRAPH_H) tree-pass.h $(TIMEVAR_H) \
-   gt-tree-ssa-structalias.h $(PARAMS_H)
+   gt-tree-ssa-structalias.h $(PARAMS_H) $(ALIAS_H)
 tree-ssa.o : tree-ssa.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \
    $(RTL_H) $(TREE_H) $(TM_P_H) $(EXPR_H) output.h $(DIAGNOSTIC_H) \
    toplev.h $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \

gcc/alias.c

@@ -293,6 +293,26 @@ insert_subset_children (splay_tree_node node, void *data)
   return 0;
 }
 
+/* Return true if the first alias set is a subset of the second.  */
+
+bool
+alias_set_subset_of (HOST_WIDE_INT set1, HOST_WIDE_INT set2)
+{
+  alias_set_entry ase;
+
+  /* Everything is a subset of the "aliases everything" set.  */
+  if (set2 == 0)
+    return true;
+
+  /* Otherwise, check if set1 is a subset of set2.  */
+  ase = get_alias_set_entry (set2);
+  if (ase != 0
+      && (splay_tree_lookup (ase->children,
+			     (splay_tree_key) set1)))
+    return true;
+  return false;
+}
+
 /* Return 1 if the two specified alias sets may conflict.  */
 
 int

gcc/alias.h

@@ -25,6 +25,7 @@ extern HOST_WIDE_INT new_alias_set (void);
 extern HOST_WIDE_INT get_varargs_alias_set (void);
 extern HOST_WIDE_INT get_frame_alias_set (void);
 extern bool component_uses_parent_alias_set (tree);
+extern bool alias_set_subset_of (HOST_WIDE_INT, HOST_WIDE_INT);
 
 /* This alias set can be used to force a memory to conflict with all
    other memories, creating a barrier across which no memory reference

gcc/testsuite/gcc.dg/tree-ssa/20031015-1.c

@@ -14,5 +14,5 @@ main(void)
 }
 
 /* The V_*_DEF comes from the initial assignment and the asm.  */
-/* { dg-final { scan-tree-dump-times "_DEF" 3 "alias1" } } */
+/* { dg-final { scan-tree-dump-times "_DEF" 2 "alias1" } } */
 /* { dg-final { cleanup-tree-dump "alias1" } } */

gcc/testsuite/gcc.dg/tree-ssa/20040517-1.c

@@ -17,5 +17,6 @@ void bar (void)
    malloc functions may clobber global memory.  Only the function result
    does not alias any other pointer.
    Hence, we must have a VDEF for a before and after the call to foo().  */
-/* { dg-final { scan-tree-dump-times "V_MAY_DEF" 2 "alias1"} } */
+/* { dg-final { scan-tree-dump-times "V_MAY_DEF" 1 "alias1"} } */
+/* { dg-final { scan-tree-dump-times "V_MUST_DEF" 1 "alias1"} } */
 /* { dg-final { cleanup-tree-dump "alias1" } } */

gcc/testsuite/gcc.dg/tree-ssa/pr26421.c

@@ -16,5 +16,6 @@ int foo(void)
   return a.i;
 }
 
-/* { dg-final { scan-tree-dump-times "V_MAY_DEF" 2 "alias1" } } */
+/* { dg-final { scan-tree-dump-times "V_MAY_DEF" 1 "alias1" } } */
+/* { dg-final { scan-tree-dump-times "V_MUST_DEF" 1 "alias1" } } */
 /* { dg-final { cleanup-tree-dump "alias1" } } */

gcc/tree-ssa-alias.c

@@ -646,15 +646,13 @@ compute_may_aliases (void)
      not needed anymore.  */
   setup_pointers_and_addressables (ai);
 
-  /* Compute flow-sensitive, points-to based aliasing for all the name
-     memory tags.  Note that this pass needs to be done before flow
-     insensitive analysis because it uses the points-to information
-     gathered before to mark call-clobbered symbol tags.  */
-  compute_flow_sensitive_aliasing (ai);
-
   /* Compute type-based flow-insensitive aliasing for all the type
      memory tags.  */
   compute_flow_insensitive_aliasing (ai);
+
+  /* Compute flow-sensitive, points-to based aliasing for all the name
+     memory tags.  */
+  compute_flow_sensitive_aliasing (ai);
   
   /* Compute call clobbering information.  */
   compute_call_clobbered (ai);
@@ -1121,7 +1119,8 @@ compute_flow_sensitive_aliasing (struct alias_info *ai)
 	EXECUTE_IF_SET_IN_BITMAP (pi->pt_vars, 0, j, bi)
 	  {
 	    add_may_alias (pi->name_mem_tag, referenced_var (j));
-	    add_may_alias (v_ann->symbol_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));
 	  }
     }
 }

gcc/tree-ssa-operands.c

@@ -1056,11 +1056,6 @@ access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
   if (alias == gimple_global_var (cfun))
     return true;
 
-  /* We cannot prune nonlocal aliases because they are not type
-     specific.  */
-  if (alias == gimple_nonlocal_all (cfun))
-    return true;
-
   /* If ALIAS is an SFT, it can't be touched if the offset     
      and size of the access is not overlapping with the SFT offset and
      size.  This is only true if we are accessing through a pointer

gcc/tree-ssa.c

@@ -488,131 +488,6 @@ err:
   internal_error ("verify_flow_sensitive_alias_info failed");
 }
 
-DEF_VEC_P (bitmap);
-DEF_VEC_ALLOC_P (bitmap,heap);
-
-/* Verify that all name tags have different points to sets.
-   This algorithm takes advantage of the fact that every variable with the
-   same name tag must have the same points-to set. 
-   So we check a single variable for each name tag, and verify that its
-   points-to set is different from every other points-to set for other name
-   tags.
-
-   Additionally, given a pointer P_i with name tag NMT and symbol tag
-   SMT, this function verified the alias set of SMT is a superset of
-   the alias set of NMT.  */
-
-static void
-verify_name_tags (void)
-{
-  size_t i;  
-  size_t j;
-  bitmap first, second;  
-  VEC(tree,heap) *name_tag_reps = NULL;
-  VEC(bitmap,heap) *pt_vars_for_reps = NULL;
-  bitmap type_aliases = BITMAP_ALLOC (NULL);
-
-  /* First we compute the name tag representatives and their points-to sets.  */
-  for (i = 0; i < num_ssa_names; i++)
-    {
-      struct ptr_info_def *pi;
-      tree smt, ptr = ssa_name (i);
-
-      if (ptr == NULL_TREE)
-	continue;
-      
-      pi = SSA_NAME_PTR_INFO (ptr);
-
-      if (!TREE_VISITED (ptr) 
-	  || !POINTER_TYPE_P (TREE_TYPE (ptr)) 
-	  || !pi
-	  || !pi->name_mem_tag 
-	  || TREE_VISITED (pi->name_mem_tag))
-	continue;
-
-      TREE_VISITED (pi->name_mem_tag) = 1;
-
-      if (pi->pt_vars == NULL)
-	continue;
-
-      VEC_safe_push (tree, heap, name_tag_reps, ptr);
-      VEC_safe_push (bitmap, heap, pt_vars_for_reps, pi->pt_vars);
-
-      /* Verify that alias set of PTR's symbol tag is a superset of the
-	 alias set of PTR's name tag.  */
-      smt = var_ann (SSA_NAME_VAR (ptr))->symbol_mem_tag;
-      if (smt)
-	{
-	  size_t i;
-	  VEC(tree,gc) *aliases = var_ann (smt)->may_aliases;
-	  tree alias;
-
-	  bitmap_clear (type_aliases);
-	  for (i = 0; VEC_iterate (tree, aliases, i, alias); i++)
-	    bitmap_set_bit (type_aliases, DECL_UID (alias));
-
-	  /* When grouping, we may have added PTR's symbol tag into the
-	     alias set of PTR's name tag.  To prevent a false
-	     positive, pretend that SMT is in its own alias set.  */
-	  bitmap_set_bit (type_aliases, DECL_UID (smt));
-
-	  if (bitmap_equal_p (type_aliases, pi->pt_vars))
-	    continue;
-
-	  if (!bitmap_intersect_compl_p (type_aliases, pi->pt_vars))
-	    {
-	      error ("alias set of a pointer's symbol tag should be a superset of the corresponding name tag");
-	      debug_variable (smt);
-	      debug_variable (pi->name_mem_tag);
-	      goto err;
-	    }
-	}
-    }
-  
-  /* Now compare all the representative bitmaps with all other representative
-     bitmaps, to verify that they are all different.  */
-  for (i = 0; VEC_iterate (bitmap, pt_vars_for_reps, i, first); i++)
-    {
-       for (j = i + 1; VEC_iterate (bitmap, pt_vars_for_reps, j, second); j++)
-	 { 
-	   if (bitmap_equal_p (first, second))
-	     {
-	       error ("two different pointers with identical points-to sets but different name tags");
-	       debug_variable (VEC_index (tree, name_tag_reps, j));
-	       goto err;
-	     }
-	 }
-    }
-
-  /* Lastly, clear out the visited flags.  */
-  for (i = 0; i < num_ssa_names; i++)
-    {
-      if (ssa_name (i))
-	{
-	  tree ptr = ssa_name (i);
-	  struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
-	  if (!TREE_VISITED (ptr) 
-	      || !POINTER_TYPE_P (TREE_TYPE (ptr)) 
-	      || !pi
-	      || !pi->name_mem_tag)
-	    continue;
-	  TREE_VISITED (pi->name_mem_tag) = 0;
-	}
-    } 
-
-  /* We do not have to free the bitmaps or trees in the vectors, as
-     they are not owned by us.  */
-  VEC_free (bitmap, heap, pt_vars_for_reps);
-  VEC_free (tree, heap, name_tag_reps);
-  BITMAP_FREE (type_aliases);
-  return;
-  
-err:
-  debug_variable (VEC_index (tree, name_tag_reps, i));
-  internal_error ("verify_name_tags failed");
-}
-
-
 /* Verify the consistency of call clobbering information.  */
 static void
 verify_call_clobbering (void)
@@ -659,7 +534,6 @@ static void
 verify_alias_info (void)
 {
   verify_flow_sensitive_alias_info ();
-  verify_name_tags ();
   verify_call_clobbering ();
   verify_flow_insensitive_alias_info ();
 }