avoid special case of a node input being NULL

[libfirm] / ir / ir / irgwalk.c

diff --git a/ir/ir/irgwalk.c b/ir/ir/irgwalk.c
index 440dc61..22feaeb 100644 (file)
--- a/ir/ir/irgwalk.c
+++ b/ir/ir/irgwalk.c
@@ -375,35 +375,26 @@ static void irg_block_walk_2(ir_node *node, irg_walk_func *pre,
 
 /* walks only over Block nodes in the graph.  Has its own visited
    flag, so that it can be interleaved with the other walker.         */
-void irg_block_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
+void irg_block_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post,
+                    void *env)
 {
-       ir_graph *irg = get_irn_irg(node);
-       ir_node *block, *pred;
-       int i;
+       ir_graph *irg   = get_irn_irg(node);
+       ir_node  *block = is_Block(node) ? node : get_nodes_block(node);
 
        hook_irg_block_walk(irg, node, (generic_func *)pre, (generic_func *)post);
 
-       assert(node);
        ir_reserve_resources(irg, IR_RESOURCE_BLOCK_VISITED);
        inc_irg_block_visited(irg);
-       block = is_Block(node) ? node : get_nodes_block(node);
-       assert(is_Block(block));
        irg_block_walk_2(block, pre, post, env);
 
-       /* keepalive: the endless loops ... */
+       /* Some blocks might be only reachable through keep-alive edges */
        if (is_End(node)) {
                int arity = get_irn_arity(node);
+               int i;
                for (i = 0; i < arity; i++) {
-                       pred = get_irn_n(node, i);
-                       if (!is_Block(pred)) {
-                               pred = get_nodes_block(pred);
-                               if (!is_Block(pred)) {
-                                       /* if rare cases a kept node might have a bad block input */
-                                       continue;
-                               }
-                       }
-                       /* Sometimes the blocks died, but are still reachable through kept nodes.
-                        * Make sure the algorithms that try to remove these reach them. */
+                       ir_node *pred = get_irn_n(node, i);
+                       if (!is_Block(pred))
+                               continue;
                        irg_block_walk_2(pred, pre, post, env);
                }
        }
@@ -431,8 +422,10 @@ void irg_walk_anchors(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, vo
        ir_graph * rem = current_ir_graph;
        current_ir_graph = irg;
 
+       ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
        inc_irg_visited(irg);
        irg_walk_2(irg->anchor, pre, post, env);
+       ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
 
        current_ir_graph = rem;
 }