re PR middle-end/38474 (compile time explosion in dataflow_set_preserve_mem_locs at -O3)

	PR middle-end/38474
	* cfgexpand.c (add_alias_set_conflicts): Remove.
	(expand_used_vars): Don't call it.
	(aggregate_contains_union_type): Remove.
	* function.c (n_temp_slots_in_use): New static data.
	(make_slot_available, assign_stack_temp_for_type): Update it.
	(init_temp_slots): Zero it.
	(remove_unused_temp_slot_addresses): Use it for quicker removal.
	(remove_unused_temp_slot_addresses_1): Use htab_clear_slot.

From-SVN: r188667

gcc/ChangeLog

 2012-06-15  Michael Matz  <matz@suse.de>
 
+	PR middle-end/38474
+	* cfgexpand.c (add_alias_set_conflicts): Remove.
+	(expand_used_vars): Don't call it.
+	(aggregate_contains_union_type): Remove.
+	* function.c (n_temp_slots_in_use): New static data.
+	(make_slot_available, assign_stack_temp_for_type): Update it.
+	(init_temp_slots): Zero it.
+	(remove_unused_temp_slot_addresses): Use it for quicker removal.
+	(remove_unused_temp_slot_addresses_1): Use htab_clear_slot.
+
+2012-06-15  Michael Matz  <matz@suse.de>
+
 	* gimplify.c (gimplify_compound_literal_expr): Take gimple_test_f
 	argument, don't emit assign statement if value is directly usable.
 	(gimplify_expr): Adjust.
@@ -190,9 +202,9 @@
 2012-06-14  Richard Earnshaw  <rearnsha@arm.com>
 
 	* arm.opt (mfp=2, mfp=3, mfpe, mfpe=2, mfpe=3): Delete options.
-        * arm-fpus.def (fpa, fpe2, fpe3, maverick): Delete FPU types.
+	* arm-fpus.def (fpa, fpe2, fpe3, maverick): Delete FPU types.
 	* arm-tables.opt: Regenerated.
-        * doc/invoke.texi: Remove references to deleted options.
+	* doc/invoke.texi: Remove references to deleted options.
 
 2012-06-14  Sandeep Kumar Singh  <Sandeep.Singh2@kpitcummins.com>
 

gcc/cfgexpand.c

@@ -329,70 +329,6 @@ stack_var_conflict_p (size_t x, size_t y)
   return bitmap_bit_p (a->conflicts, y);
 }
 
-/* Returns true if TYPE is or contains a union type.  */
-
-static bool
-aggregate_contains_union_type (tree type)
-{
-  tree field;
-
-  if (TREE_CODE (type) == UNION_TYPE
-      || TREE_CODE (type) == QUAL_UNION_TYPE)
-    return true;
-  if (TREE_CODE (type) == ARRAY_TYPE)
-    return aggregate_contains_union_type (TREE_TYPE (type));
-  if (TREE_CODE (type) != RECORD_TYPE)
-    return false;
-
-  for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
-    if (TREE_CODE (field) == FIELD_DECL)
-      if (aggregate_contains_union_type (TREE_TYPE (field)))
-	return true;
-
-  return false;
-}
-
-/* A subroutine of expand_used_vars.  If two variables X and Y have alias
-   sets that do not conflict, then do add a conflict for these variables
-   in the interference graph.  We also need to make sure to add conflicts
-   for union containing structures.  Else RTL alias analysis comes along
-   and due to type based aliasing rules decides that for two overlapping
-   union temporaries { short s; int i; } accesses to the same mem through
-   different types may not alias and happily reorders stores across
-   life-time boundaries of the temporaries (See PR25654).  */
-
-static void
-add_alias_set_conflicts (void)
-{
-  size_t i, j, n = stack_vars_num;
-
-  for (i = 0; i < n; ++i)
-    {
-      tree type_i = TREE_TYPE (stack_vars[i].decl);
-      bool aggr_i = AGGREGATE_TYPE_P (type_i);
-      bool contains_union;
-
-      contains_union = aggregate_contains_union_type (type_i);
-      for (j = 0; j < i; ++j)
-	{
-	  tree type_j = TREE_TYPE (stack_vars[j].decl);
-	  bool aggr_j = AGGREGATE_TYPE_P (type_j);
-	  if (aggr_i != aggr_j
-	      /* Either the objects conflict by means of type based
-		 aliasing rules, or we need to add a conflict.  */
-	      || !objects_must_conflict_p (type_i, type_j)
-	      /* In case the types do not conflict ensure that access
-		 to elements will conflict.  In case of unions we have
-		 to be careful as type based aliasing rules may say
-		 access to the same memory does not conflict.  So play
-		 safe and add a conflict in this case when
-                 -fstrict-aliasing is used.  */
-              || (contains_union && flag_strict_aliasing))
-	    add_stack_var_conflict (i, j);
-	}
-    }
-}
-
 /* Callback for walk_stmt_ops.  If OP is a decl touched by add_stack_var
    enter its partition number into bitmap DATA.  */
 
@@ -1625,10 +1561,6 @@ expand_used_vars (void)
   if (stack_vars_num > 0)
     {
       add_scope_conflicts ();
-      /* Due to the way alias sets work, no variables with non-conflicting
-	 alias sets may be assigned the same address.  Add conflicts to
-	 reflect this.  */
-      add_alias_set_conflicts ();
 
       /* If stack protection is enabled, we don't share space between
 	 vulnerable data and non-vulnerable data.  */

gcc/function.c

@@ -571,6 +571,7 @@ struct GTY(()) temp_slot {
 /* A table of addresses that represent a stack slot.  The table is a mapping
    from address RTXen to a temp slot.  */
 static GTY((param_is(struct temp_slot_address_entry))) htab_t temp_slot_address_table;
+static size_t n_temp_slots_in_use;
 
 /* Entry for the above hash table.  */
 struct GTY(()) temp_slot_address_entry {
@@ -647,6 +648,7 @@ make_slot_available (struct temp_slot *temp)
   insert_slot_to_list (temp, &avail_temp_slots);
   temp->in_use = 0;
   temp->level = -1;
+  n_temp_slots_in_use--;
 }
 
 /* Compute the hash value for an address -> temp slot mapping.
@@ -699,7 +701,7 @@ remove_unused_temp_slot_addresses_1 (void **slot, void *data ATTRIBUTE_UNUSED)
   const struct temp_slot_address_entry *t;
   t = (const struct temp_slot_address_entry *) *slot;
   if (! t->temp_slot->in_use)
-    *slot = NULL;
+    htab_clear_slot (temp_slot_address_table, slot);
   return 1;
 }
 
@@ -707,9 +709,13 @@ remove_unused_temp_slot_addresses_1 (void **slot, void *data ATTRIBUTE_UNUSED)
 static void
 remove_unused_temp_slot_addresses (void)
 {
-  htab_traverse (temp_slot_address_table,
-		 remove_unused_temp_slot_addresses_1,
-		 NULL);
+  /* Use quicker clearing if there aren't any active temp slots.  */
+  if (n_temp_slots_in_use)
+    htab_traverse (temp_slot_address_table,
+		   remove_unused_temp_slot_addresses_1,
+		   NULL);
+  else
+    htab_empty (temp_slot_address_table);
 }
 
 /* Find the temp slot corresponding to the object at address X.  */
@@ -901,6 +907,7 @@ assign_stack_temp_for_type (enum machine_mode mode, HOST_WIDE_INT size,
   p->in_use = 1;
   p->type = type;
   p->level = temp_slot_level;
+  n_temp_slots_in_use++;
 
   pp = temp_slots_at_level (p->level);
   insert_slot_to_list (p, pp);
@@ -1212,6 +1219,7 @@ init_temp_slots (void)
   avail_temp_slots = 0;
   used_temp_slots = 0;
   temp_slot_level = 0;
+  n_temp_slots_in_use = 0;
 
   /* Set up the table to map addresses to temp slots.  */
   if (! temp_slot_address_table)
@@ -4496,7 +4504,6 @@ allocate_struct_function (tree fndecl, bool abstract_p)
       /* ??? This could be set on a per-function basis by the front-end
          but is this worth the hassle?  */
       cfun->can_throw_non_call_exceptions = flag_non_call_exceptions;
-      cfun->can_delete_dead_exceptions = flag_delete_dead_exceptions;
     }
 }