From: Matthias Braun <matze@braunis.de>
Date: Thu, 5 May 2011 09:31:58 +0000 (+0200)
Subject: optimize_graph_df: iterate marking of unreachable blocks to guarantee that all unreac... 
X-Git-Url: http://nsz.repo.hu/git/?a=commitdiff_plain;h=ca3c5f449efdd622e037b667fbe88c5011b747d4;p=libfirm

optimize_graph_df: iterate marking of unreachable blocks to guarantee that all unreachable code is killed
---

diff --git a/ir/ir/irdumptxt.c b/ir/ir/irdumptxt.c
index 322da9be4..f8918b814 100644
--- a/ir/ir/irdumptxt.c
+++ b/ir/ir/irdumptxt.c
@@ -135,12 +135,12 @@ void dump_irnode_to_file(FILE *F, ir_node *n)
 			fprintf(F, "  Label: %lu\n", get_entity_label(get_Block_entity(n)));
 		fprintf(F, "  block visited: %ld\n", get_Block_block_visited(n));
 		fprintf(F, "  block marked: %u\n", get_Block_mark(n));
-		if (get_irg_dom_state(get_irn_irg(n)) != dom_none) {
+		if (get_irg_dom_state(get_irn_irg(n)) == dom_consistent) {
 			fprintf(F, "  dom depth %d\n", get_Block_dom_depth(n));
 			fprintf(F, "  domtree pre num %d\n", get_Block_dom_tree_pre_num(n));
 			fprintf(F, "  max subtree pre num %d\n", get_Block_dom_max_subtree_pre_num(n));
 		}
-		if (get_irg_postdom_state(get_irn_irg(n)) != dom_none) {
+		if (get_irg_postdom_state(get_irn_irg(n)) == dom_consistent) {
 			fprintf(F, "  pdom depth %d\n", get_Block_postdom_depth(n));
 			fprintf(F, "  pdomtree pre num %d\n", get_Block_pdom_tree_pre_num(n));
 			fprintf(F, "  max pdomsubtree pre num %d\n", get_Block_pdom_max_subtree_pre_num(n));
diff --git a/ir/ir/irgopt.c b/ir/ir/irgopt.c
index 256296c8b..7a312e6ed 100644
--- a/ir/ir/irgopt.c
+++ b/ir/ir/irgopt.c
@@ -100,12 +100,35 @@ void local_optimize_node(ir_node *n)
 	current_ir_graph = rem;
 }
 
+/**
+ * Enqueue all users of a node to a wait queue.
+ * Handles mode_T nodes.
+ */
+static void enqueue_users(ir_node *n, pdeq *waitq)
+{
+	const ir_edge_t *edge;
+
+	foreach_out_edge(n, edge) {
+		ir_node *succ = get_edge_src_irn(edge);
+
+		if (get_irn_link(succ) != waitq) {
+			pdeq_putr(waitq, succ);
+			set_irn_link(succ, waitq);
+		}
+		if (get_irn_mode(succ) == mode_T) {
+		/* A mode_T node has Proj's. Because most optimizations
+			run on the Proj's we have to enqueue them also. */
+			enqueue_users(succ, waitq);
+		}
+	}
+}
+
 /**
  * Block-Walker: uses dominance depth to mark dead blocks.
  */
 static void kill_dead_blocks(ir_node *block, void *env)
 {
-	(void) env;
+	pdeq *waitq = (pdeq*) env;
 
 	if (get_Block_dom_depth(block) < 0) {
 		/*
@@ -113,6 +136,7 @@ static void kill_dead_blocks(ir_node *block, void *env)
 		 * the End block, i.e. it is always reachable from Start
 		 */
 		ir_graph *irg = get_irn_irg(block);
+		enqueue_users(block, waitq);
 		exchange(block, get_irg_bad(irg));
 	}
 }
@@ -128,29 +152,6 @@ void local_optimize_graph(ir_graph *irg)
 	current_ir_graph = rem;
 }
 
-/**
- * Enqueue all users of a node to a wait queue.
- * Handles mode_T nodes.
- */
-static void enqueue_users(ir_node *n, pdeq *waitq)
-{
-	const ir_edge_t *edge;
-
-	foreach_out_edge(n, edge) {
-		ir_node *succ = get_edge_src_irn(edge);
-
-		if (get_irn_link(succ) != waitq) {
-			pdeq_putr(waitq, succ);
-			set_irn_link(succ, waitq);
-		}
-		if (get_irn_mode(succ) == mode_T) {
-		/* A mode_T node has Proj's. Because most optimizations
-			run on the Proj's we have to enqueue them also. */
-			enqueue_users(succ, waitq);
-		}
-	}
-}
-
 /**
  * Data flow optimization walker.
  * Optimizes all nodes and enqueue its users
@@ -181,7 +182,6 @@ int optimize_graph_df(ir_graph *irg)
 	current_ir_graph = irg;
 
 	state = edges_assure(irg);
-	assure_doms(irg);
 
 	/* Clean the value_table in irg for the CSE. */
 	new_identities(irg);
@@ -191,11 +191,8 @@ int optimize_graph_df(ir_graph *irg)
 	}
 
 	/* The following enables unreachable code elimination (=Blocks may be
-	 * Bad). We cannot enable it in global_cse nodes since we can't
-	 * determine a nodes block there and therefore can't remove all code
-	 * in unreachable blocks */
+	 * Bad). */
 	set_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK);
-	irg_block_walk_graph(irg, NULL, kill_dead_blocks, NULL);
 
 	/* invalidate info */
 	set_irg_outs_inconsistent(irg);
@@ -211,11 +208,17 @@ int optimize_graph_df(ir_graph *irg)
 	 * so if it's not empty, the graph has been changed */
 	changed = !pdeq_empty(waitq);
 
-	/* finish the wait queue */
-	while (! pdeq_empty(waitq)) {
-		ir_node *n = (ir_node*)pdeq_getl(waitq);
-		opt_walker(n, waitq);
-	}
+	do {
+		/* finish the wait queue */
+		while (! pdeq_empty(waitq)) {
+			ir_node *n = (ir_node*)pdeq_getl(waitq);
+			opt_walker(n, waitq);
+		}
+		/* kill newly generated unreachable code */
+		set_irg_outs_inconsistent(irg);
+		compute_doms(irg);
+		irg_block_walk_graph(irg, NULL, kill_dead_blocks, waitq);
+	} while (! pdeq_empty(waitq));
 
 	del_pdeq(waitq);
 
@@ -226,7 +229,7 @@ int optimize_graph_df(ir_graph *irg)
 
 	/* Finally kill BAD and doublets from the keep alives.
 	   Doing this AFTER edges where deactivated saves cycles */
-	end  = get_irg_end(irg);
+	end = get_irg_end(irg);
 	remove_End_Bads_and_doublets(end);
 
 	clear_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK);
diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index 51e885475..6a6dfbae8 100644
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -6284,28 +6284,7 @@ static ir_node *gigo(ir_node *node)
 		return get_irg_bad(irg);
 	}
 
-	/* Blocks, Phis and Tuples may have dead inputs, e.g., if one of the
-	   blocks predecessors is dead. */
-	if (op != op_Block && op != op_Phi && op != op_Tuple && op != op_Anchor
-			&& op != op_Sync && op != op_End) {
-		ir_graph *irg = get_irn_irg(node);
-		int irn_arity = get_irn_arity(node);
-		int i;
-
-		for (i = 0; i < irn_arity; i++) {
-			ir_node *pred = get_irn_n(node, i);
-
-			if (is_Bad(pred)) {
-				/* be careful not to kill cfopts too early or we might violate
-				 * the 1 cfop per block property */
-				if (!is_cfop(node)
-						|| is_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK))
-					return get_irg_bad(irg);
-			}
-		}
-	}
-
-	return node;
+	return false;
 }
 
 /**