From 27177e293d914d15fdef3798c1ce1628f83d55ef Mon Sep 17 00:00:00 2001
From: Matthias Braun <matze@braunis.de>
Date: Thu, 5 May 2011 15:31:58 +0200
Subject: [PATCH] verify that all blocks can be found by walk_block_graph

This also ensures the invariant that at least 1 block in an endless
loop is kept.
---
 ir/ir/irgwalk.c  |  7 +------
 ir/ir/irverify.c | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/ir/ir/irgwalk.c b/ir/ir/irgwalk.c
index df0af385d..5ed8c0153 100644
--- a/ir/ir/irgwalk.c
+++ b/ir/ir/irgwalk.c
@@ -393,12 +393,7 @@ void irg_block_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post,
 		int i;
 		for (i = 0; i < arity; i++) {
 			ir_node *pred = get_irn_n(node, i);
-			if (!is_Block(pred)) {
-				pred = get_nodes_block(pred);
-			}
-			/* this walker is also used during optimize_graph_df where we can
-			 * temporarily have Bad as block inputs */
-			if (is_Bad(pred))
+			if (!is_Block(pred))
 				continue;
 			irg_block_walk_2(pred, pre, post, env);
 		}
diff --git a/ir/ir/irverify.c b/ir/ir/irverify.c
index 51d6c3a93..761f56cb1 100644
--- a/ir/ir/irverify.c
+++ b/ir/ir/irverify.c
@@ -1825,6 +1825,7 @@ typedef struct check_cfg_env_t {
 	pmap *branch_nodes; /**< map blocks to their branching nodes,
 	                         map mode_X nodes to the blocks they branch to */
 	int   res;
+	ir_nodeset_t reachable_blocks;
 	ir_nodeset_t kept_nodes;
 	ir_nodeset_t true_projs;
 	ir_nodeset_t false_projs;
@@ -1836,6 +1837,10 @@ static int check_block_cfg(ir_node *block, check_cfg_env_t *env)
 	int   n_cfgpreds;
 	int   i;
 
+	ASSERT_AND_RET_DBG(ir_nodeset_contains(&env->reachable_blocks, block),
+	                   "Block is not reachable by blockwalker (endless loop with no kept block?)", 0,
+	                   ir_printf("block %+F\n", block));
+
 	n_cfgpreds   = get_Block_n_cfgpreds(block);
 	branch_nodes = env->branch_nodes;
 	for (i = 0; i < n_cfgpreds; ++i) {
@@ -1933,6 +1938,12 @@ static void assert_branch(ir_node *node, void *data)
 	}
 }
 
+static void collect_reachable_blocks(ir_node *block, void *data)
+{
+	ir_nodeset_t *reachable_blocks = (ir_nodeset_t*) data;
+	ir_nodeset_insert(reachable_blocks, block);
+}
+
 /**
  * Checks CFG well-formedness
  */
@@ -1941,9 +1952,13 @@ static int check_cfg(ir_graph *irg)
 	check_cfg_env_t env;
 	env.branch_nodes = pmap_create(); /**< map blocks to branch nodes */
 	env.res          = 1;
+	ir_nodeset_init(&env.reachable_blocks);
 	ir_nodeset_init(&env.true_projs);
 	ir_nodeset_init(&env.false_projs);
 
+	irg_block_walk_graph(irg, collect_reachable_blocks, NULL,
+	                     &env.reachable_blocks);
+
 	/* note that we do not use irg_walk_block because it will miss these
 	 * invalid blocks without a jump instruction which we want to detect
 	 * here */
@@ -1964,6 +1979,7 @@ static int check_cfg(ir_graph *irg)
 	ir_nodeset_destroy(&env.false_projs);
 	ir_nodeset_destroy(&env.true_projs);
 	ir_nodeset_destroy(&env.kept_nodes);
+	ir_nodeset_destroy(&env.reachable_blocks);
 	pmap_destroy(env.branch_nodes);
 	return env.res;
 }
-- 
2.20.1