optimize_graph_df removes all Bads now

diff --git a/ir/ir/irgopt.c b/ir/ir/irgopt.c
index a4c454b..1af16dd 100644 (file)
--- a/ir/ir/irgopt.c
+++ b/ir/ir/irgopt.c
@@ -171,6 +171,107 @@ static void opt_walker(ir_node *n, void *env)
        }
 }
 
+static void clear_block_phis(ir_node *node, void *env) {
+       (void) env;
+       if (is_Block(node)) {
+               set_Block_phis(node, NULL);
+       }
+}
+
+static void collect_block_phis(ir_node *node, void *env) {
+       (void) env;
+       if (is_Phi(node)) {
+               add_Block_phi(get_nodes_block(node), node);
+       }
+}
+
+static int count_non_bads(ir_node *node) {
+       int arity = get_irn_arity(node);
+       int count = 0;
+       int i;
+       for (i=0; i<arity; ++i) {
+               if (!is_Bad(get_irn_n(node, i)))
+                       count++;
+       }
+       return count;
+}
+
+static void block_remove_bads(ir_node *block, int *changed) {
+       int i, j;
+       ir_node **new_in;
+       const int max = get_irn_arity(block);
+       const int new_max = count_non_bads(block);
+       assert (max >= new_max);
+
+       if (is_Bad(block) || max == new_max) return;
+
+       new_in = ALLOCAN(ir_node*, new_max);
+       *changed = 1;
+
+       assert (get_Block_dom_depth(block) >= 0);
+
+       /* 1. Create a new block without Bad inputs */
+       j = 0;
+       for (i = 0; i < max; ++i) {
+               ir_node *block_pred = get_irn_n(block, i);
+               if (!is_Bad(block_pred)) {
+                       new_in[j++] = block_pred;
+               }
+       }
+       assert (j == new_max);
+
+       /* If the end block is unreachable, it might have zero predecessors. */
+       ir_node *end_block = get_irg_end_block(get_irn_irg(block));
+       if (new_max == 0 && block == end_block) {
+               set_irn_in(block, new_max, new_in);
+               return;
+       }
+
+       ir_node *new_block =  new_r_Block(get_irn_irg(block), new_max, new_in);
+
+       /* 2. Remove inputs on Phis, where the block input is Bad. */
+       ir_node *phi = get_Block_phis(block);
+       if (phi != NULL) {
+               do {
+                       ir_node* next = get_Phi_next(phi);
+                       if (get_irn_arity(phi) != new_max) {
+                               j = 0;
+                               for (i = 0; i < max; ++i) {
+                                       ir_node *block_pred = get_irn_n(block, i);
+
+                                       if (!is_Bad(block_pred)) {
+                                               ir_node *pred = get_irn_n(phi, i);
+                                               new_in[j++] = pred;
+                                       }
+                               }
+                               assert (j == new_max);
+
+                               ir_node *new_phi = new_r_Phi(new_block, new_max, new_in, get_irn_mode(phi));
+                               exchange(phi, new_phi);
+                       }
+                       phi = next;
+               } while (phi != NULL);
+       }
+
+       exchange(block, new_block);
+}
+
+/* Remove Bad nodes from Phi and Block inputs.
+ *
+ * Precondition: No unreachable code.
+ * Postcondition: No Bad nodes.
+ */
+static int remove_Bads(ir_graph *irg) {
+       int changed = 0;
+       /* build phi list per block */
+       irg_walk_graph(irg, clear_block_phis, collect_block_phis, NULL);
+
+       /* actually remove Bads */
+       irg_block_walk_graph(irg, NULL, (void (*)(struct ir_node *, void *)) block_remove_bads, &changed);
+
+       return changed;
+}
+
 /* Applies local optimizations to all nodes in the graph until fixpoint. */
 int optimize_graph_df(ir_graph *irg)
 {
@@ -232,6 +333,9 @@ int optimize_graph_df(ir_graph *irg)
        end = get_irg_end(irg);
        remove_End_Bads_and_doublets(end);
 
+       if (remove_Bads(irg))
+               edges_deactivate(irg);
+
        clear_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK);
 
        current_ir_graph = rem;