2006-06-07 Andrew MacLeod <amacleod@redhat.com>

	PR middle-end/27793
	* tree-dfa.c (referenced_vars_dup_list): New.  List of duplicate 
	referenced_variables with matching DECL_UID's.
	(find_referenced_vars): Make sure duplicate list is empty to start.
	(referenced_var_p): Remove.
	(referenced_var_check_and_insert): Renamed from referenced_var_insert.  
	Check if var is in the list, and add if needed.  Update the duplicate
	list if a different var is in the list with the same DECL_UID.
	(add_referenced_var): Call routine to check and insert.
	* tree-ssa.c (delete_tree_ssa): Clear var_ann's on duplicates.
	* tree-flow.h (referenced_vars_dup_list): External declaration.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@114480 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 44 insertions, 29 deletions

diff --git a/gcc/tree-dfa.c b/gcc/tree-dfa.c
index 621a0d3d330..b5a01785eac 100644
--- a/gcc/tree-dfa.c
+++ b/gcc/tree-dfa.c
@@ -75,6 +75,8 @@ static tree find_vars_r (tree *, int *, void *);
 
 /* Array of all variables referenced in the function.  */
 htab_t referenced_vars;
+/* List of referenced variables with duplicate UID's.  */
+VEC(tree,gc) *referenced_vars_dup_list;
 
 /* Default definition for this symbols.  If set for symbol, it
    means that the first reference to this variable in the function is a
@@ -100,6 +102,7 @@ find_referenced_vars (void)
   basic_block bb;
   block_stmt_iterator si;
 
+  gcc_assert (VEC_length (tree, referenced_vars_dup_list) == 0);
   FOR_EACH_BB (bb)
     for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
       {
@@ -606,22 +609,6 @@ find_vars_r (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
   return NULL_TREE;
 }
 
-/* Lookup VAR in the referenced_vars hashtable and return true if it is
-   present.  */
-
-static inline bool
-referenced_var_p (tree var)
-{
-  struct int_tree_map *h, in;
-  in.uid = DECL_UID (var);
-  h = (struct int_tree_map *) htab_find_with_hash (referenced_vars, 
-						   &in, 
-						   in.uid);
-  if (h)
-    return h->to != NULL_TREE;
-  return false;
-}
-
 /* Lookup UID in the referenced_vars hashtable and return the associated
    variable.  */
 
@@ -637,22 +624,52 @@ referenced_var_lookup (unsigned int uid)
   return NULL_TREE;
 }
 
-/* Insert the pair UID, TO into the referenced_vars hashtable.  */
+/* Check if TO is in the referenced_vars hash table and insert it if not.  
+   Return true if it required insertion.  */
 
-static void
-referenced_var_insert (unsigned int uid, tree to)
+static bool
+referenced_var_check_and_insert (tree to)
 { 
-  struct int_tree_map *h;
+  struct int_tree_map *h, in;
   void **loc;
+  unsigned int uid = DECL_UID (to);
+
+  in.uid = uid;
+  in.to = to;
+  h = (struct int_tree_map *) htab_find_with_hash (referenced_vars, &in, uid);
+
+  if (h)
+    {
+      unsigned u;
+      tree t = NULL_TREE;
+
+      /* DECL_UID has already been entered in the table.  Verify that it is
+	 the same entry as TO.  */
+      gcc_assert (h->to != NULL);
+      if (h->to == to)
+        return false;
+
+      /* PRs 26757 and 27793.  Maintain a list of duplicate variable pointers
+	 with the same DECL_UID.  There isn't usually very many.
+	 TODO.  Once the C++ front end doesn't create duplicate DECL UID's, this
+	 code can be removed.  */
+      for (u = 0; u < VEC_length (tree, referenced_vars_dup_list); u++)
+	{
+	  t = VEC_index (tree, referenced_vars_dup_list, u);
+	  if (t == to)
+	    break;
+	}
+      if (t != to)
+	VEC_safe_push (tree, gc, referenced_vars_dup_list, to);
+      return false;
+    }
 
   h = GGC_NEW (struct int_tree_map);
   h->uid = uid;
   h->to = to;
   loc = htab_find_slot_with_hash (referenced_vars, h, uid, INSERT);
-  /* This assert can only trigger if a variable with the same UID has been 
-     inserted already.  */
-  gcc_assert ((*(struct int_tree_map **)loc) == NULL);
   *(struct int_tree_map **)  loc = h;
+  return true;
 }
 
 /* Lookup VAR UID in the default_defs hashtable and return the associated
@@ -715,13 +732,11 @@ add_referenced_var (tree var)
   v_ann = get_var_ann (var);
   gcc_assert (DECL_P (var));
   
-  if (!referenced_var_p (var))
+  /* Insert VAR into the referenced_vars has table if it isn't present.  */
+  if (referenced_var_check_and_insert (var))
     {
-      /* This is the first time we find this variable, add it to the
-         REFERENCED_VARS array and annotate it with attributes that are
-	 intrinsic to the variable.  */
-      
-      referenced_var_insert (DECL_UID (var), var);
+      /* This is the first time we found this variable, annotate it with
+	 attributes that are intrinsic to the variable.  */
       
       /* Tag's don't have DECL_INITIAL.  */
       if (MTAG_P (var))