Try to fix a rare edges bug:

- if a node was built with edges disabled gets dead, but is revived by CSE when edges are enabled, it had NO edges
- tries to keep track of such dead nodes ...

[r26954]

ir/ir/iredges.c

@@ -479,6 +479,34 @@ static void edges_node_deleted_kind(ir_node *old, ir_edge_kind_t kind, ir_graph
 	}
 }
 
+/**
+ * A node might be revivaled by CSE. Assure its edges.
+ *
+ * @param irn   the node
+ * @param kind  the kind of edges to remove
+ * @param irg   the irg of the old node
+ */
+static void edges_node_revival_kind(ir_node *irn, ir_edge_kind_t kind, ir_graph *irg)
+{
+	irn_edge_info_t *info;
+	int             i, n;
+
+	if (!edges_activated_kind(irg, kind))
+		return;
+
+	info = _get_irn_edge_info(irn, kind);
+	if (info->edges_built)
+		return;
+
+	DBG((dbg, LEVEL_5, "node revivaled (kind: %s): %+F\n", get_kind_str(kind), irn));
+
+	foreach_tgt(irn, i, n, kind) {
+		ir_node *tgt = get_n(irn, i, kind);
+		edges_notify_edge_kind(irn, i, tgt, NULL, kind, irg);
+	}
+	info->edges_built = 1;
+}
+
 struct build_walker {
 	ir_graph       *irg;
 	ir_edge_kind_t kind;
@@ -501,6 +529,7 @@ static void build_edges_walker(ir_node *irn, void *data) {
 		ir_node *pred = get_n(irn, i, kind);
 		edges_notify_edge_kind(irn, i, pred, NULL, kind, irg);
 	}
+	_get_irn_edge_info(irn, kind)->edges_built = 1;
 }
 
 /**
@@ -512,7 +541,8 @@ static void init_lh_walker(ir_node *irn, void *data) {
 	ir_edge_kind_t      kind = w->kind;
 	list_head           *head = _get_irn_outs_head(irn, kind);
 	INIT_LIST_HEAD(head);
-	_get_irn_edge_info(irn, kind)->out_count = 0;
+	_get_irn_edge_info(irn, kind)->edges_built = 0;
+	_get_irn_edge_info(irn, kind)->out_count   = 0;
 }
 
 /**
@@ -533,7 +563,8 @@ static void init_lh_walker_dep(ir_node *irn, void *data) {
 	int                 i;
 
 	INIT_LIST_HEAD(head);
-	_get_irn_edge_info(irn, kind)->out_count = 0;
+	_get_irn_edge_info(irn, kind)->edges_built = 0;
+	_get_irn_edge_info(irn, kind)->out_count   = 0;
 
 	for (i = get_irn_deps(irn) - 1; i >= 0; --i) {
 		ir_node *dep = get_irn_dep(irn, i);
@@ -541,7 +572,8 @@ static void init_lh_walker_dep(ir_node *irn, void *data) {
 		head = _get_irn_outs_head(dep, kind);
 
 		INIT_LIST_HEAD(head);
-		_get_irn_edge_info(dep, kind)->out_count = 0;
+		_get_irn_edge_info(dep, kind)->edges_built = 0;
+		_get_irn_edge_info(dep, kind)->out_count   = 0;
 	}
 }
 
@@ -557,8 +589,7 @@ typedef struct visitor_info_t {
 static void visitor(ir_node *irn, void *data) {
 	visitor_info_t *info = data;
 
-	if (!irn_visited(irn)) {
-		mark_irn_visited(irn);
+	if (!irn_visited_else_mark(irn)) {
 		info->visit(irn, info->data);
 	}
 }
@@ -968,6 +999,10 @@ void edges_node_deleted(ir_node *irn, ir_graph *irg) {
 	edges_node_deleted_kind(irn, EDGE_KIND_BLOCK, irg);
 }
 
+void edges_node_revival(ir_node *irn, ir_graph *irg) {
+	edges_node_revival_kind(irn, EDGE_KIND_NORMAL, irg);
+	edges_node_revival_kind(irn, EDGE_KIND_BLOCK, irg);
+}
 
 const ir_edge_t *(get_irn_out_edge_first_kind)(const ir_node *irn, ir_edge_kind_t kind) {
 	return _get_irn_out_edge_first_kind(irn, kind);

ir/ir/iredges_t.h

@@ -143,6 +143,11 @@ void edges_notify_edge_kind(ir_node *src, int pos, ir_node *tgt, ir_node *old_tg
 */
 void edges_node_deleted(ir_node *old, ir_graph *irg);
 
+/**
+ * A node might be revivaled by CSE.
+ */
+void edges_node_revival(ir_node *node, ir_graph *irg);
+
 void edges_invalidate_kind(ir_node *irn, ir_edge_kind_t kind, ir_graph *irg);
 
 /**

ir/ir/irnode.c

@@ -168,8 +168,12 @@ new_ir_node(dbg_info *db, ir_graph *irg, ir_node *block, ir_op *op, ir_mode *mod
 	res->out     = NULL;
 	res->node_nr = get_irp_new_node_nr();
 
-	for (i = 0; i < EDGE_KIND_LAST; ++i)
+	for (i = 0; i < EDGE_KIND_LAST; ++i) {
 		INIT_LIST_HEAD(&res->edge_info[i].outs_head);
+		/* edges will be build immediately */
+		res->edge_info[i].edges_built = 1;
+		res->edge_info[i].out_count = 0;
+	}
 
 	/* don't put this into the for loop, arity is -1 for some nodes! */
 	edges_notify_edge(res, -1, res->in[0], NULL, irg);

ir/ir/iropt.c

@@ -6368,6 +6368,9 @@ ir_node *identify_remember(pset *value_table, ir_node *n) {
 
 	if (o != n) {
 		update_known_irn(o, n);
+
+		/* n is reachable again */
+		edges_node_revival(n, get_irn_irg(n));
 	}
 
 	return o;

ir/ir/irtypes.h

@@ -340,7 +340,8 @@ typedef union {
  */
 typedef struct _irn_edge_kind_info_t {
 	struct list_head outs_head;  /**< The list of all outs. */
-	int out_count;               /**< Number of outs in the list. */
+	unsigned edges_built : 1;    /**< Set edges where built for this node. */
+	unsigned out_count : 31;     /**< Number of outs in the list. */
 } irn_edge_info_t;
 
 typedef irn_edge_info_t irn_edges_info_t[EDGE_KIND_LAST];