also do unreachable code elimination during gcse

ir/ir/irgopt.c

@@ -187,16 +187,16 @@ int optimize_graph_df(ir_graph *irg)
 
 	if (get_opt_global_cse()) {
 		set_irg_pinned(irg, op_pin_state_floats);
-	} else {
-		/* 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 */
-		set_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK);
-		if (get_irg_dom_state(irg) == dom_consistent)
-			irg_block_walk_graph(irg, NULL, kill_dead_blocks, NULL);
 	}
 
+	/* 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 */
+	set_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK);
+	if (get_irg_dom_state(irg) == dom_consistent)
+		irg_block_walk_graph(irg, NULL, kill_dead_blocks, NULL);
+
 	/* invalidate info */
 	set_irg_outs_inconsistent(irg);
 	set_irg_doms_inconsistent(irg);

ir/ir/iropt.c

@@ -6274,10 +6274,8 @@ static ir_node *gigo(ir_node *node)
 {
 	ir_op *op = get_irn_op(node);
 
-	/* Nodes in bad blocks are bad.
-	 * Beware: we can only read the block of a non-floating node. */
-	if (op != op_Block && is_irn_pinned_in_irg(node)
-	    && is_Bad(get_nodes_block(node))) {
+	/* Code in "Bad" blocks is unreachable and can be replaced by Bad */
+	if (op != op_Block && is_Bad(get_nodes_block(node))) {
 	    ir_graph *irg = get_irn_irg(node);
 		return get_irg_bad(irg);
 	}
@@ -6304,7 +6302,7 @@ static ir_node *gigo(ir_node *node)
 	}
 
 	return node;
-}  /* gigo */
+}
 
 /**
  * These optimizations deallocate nodes from the obstack.

ir/opt/code_placement.c

@@ -45,14 +45,6 @@ static bool is_block_reachable(ir_node *block)
 	return get_Block_dom_depth(block) >= 0;
 }
 
-/* mark node as not-visited */
-static void clear_irn_visited(ir_node *node)
-{
-	ir_graph    *irg     = get_irn_irg(node);
-	ir_visited_t visited = get_irg_visited(irg);
-	set_irn_visited(node, visited-1);
-}
-
 /**
  * Find the earliest correct block for node n.  --- Place n into the
  * same Block as its dominance-deepest Input.
@@ -112,20 +104,7 @@ static void place_floats_early(ir_node *n, waitq *worklist)
 	arity = get_irn_arity(n);
 	place_floats_early(block, worklist);
 	for (i = 0; i < arity; ++i) {
-		ir_node *pred       = get_irn_n(n, i);
-		ir_node *pred_block = get_nodes_block(pred);
-
-		/* gcse can lead to predecessors of reachable code being unreachable.
-		 * Move them into the current block in this case */
-		if (!is_block_reachable(pred_block)) {
-			ir_node *new_pred_block = block;
-			assert(get_irn_pinned(pred) == op_pin_state_floats);
-			if (is_Phi(n)) {
-				new_pred_block = get_Block_cfgpred_block(block, i);
-			}
-			set_nodes_block(pred, new_pred_block);
-			clear_irn_visited(pred);
-		}
+		ir_node *pred = get_irn_n(n, i);
 		place_floats_early(pred, worklist);
 	}