Check no unreachable blocks in inverted_post_order_compute

2015-10-12  Tom de Vries  <tom@codesourcery.com>

	* cfganal.c (verify_no_unreachable_blocks): New function.
	(inverted_post_order_compute) [ENABLE_CHECKING]: Call
	verify_no_unreachable_blocks.
	cfganal.h (verify_no_unreachable_blocks): Declare.
---
 gcc/cfganal.c | 17 +++++++++++++++++
 gcc/cfganal.h |  1 +
 2 files changed, 18 insertions(+)

diff --git a/gcc/cfganal.c b/gcc/cfganal.c
index 279c3b5..1f935eb 100644
--- a/gcc/cfganal.c
+++ b/gcc/cfganal.c
@@ -193,6 +193,19 @@ find_unreachable_blocks (void)
 
   free (worklist);
 }
+
+/* Verify that there are no unreachable blocks in the current function.  */
+
+void
+verify_no_unreachable_blocks (void)
+{
+  find_unreachable_blocks ();
+
+  basic_block bb;
+  FOR_EACH_BB_FN (bb, cfun)
+    gcc_assert ((bb->flags & BB_REACHABLE) != 0);
+}
+
 
 /* Functions to access an edge list with a vector representation.
    Enough data is kept such that given an index number, the
@@ -772,6 +785,10 @@ inverted_post_order_compute (int *post_order)
   int post_order_num = 0;
   sbitmap visited;
 
+#if ENABLE_CHECKING
+  verify_no_unreachable_blocks ();
+#endif
+
   /* Allocate stack for back-tracking up CFG.  */
   stack = XNEWVEC (edge_iterator, n_basic_blocks_for_fn (cfun) + 1);
   sp = 0;
diff --git a/gcc/cfganal.h b/gcc/cfganal.h
index 3eb4764..2ad00c0 100644
--- a/gcc/cfganal.h
+++ b/gcc/cfganal.h
@@ -49,6 +49,7 @@ private:
 
 extern bool mark_dfs_back_edges (void);
 extern void find_unreachable_blocks (void);
+extern void verify_no_unreachable_blocks (void);
 struct edge_list * create_edge_list (void);
 void free_edge_list (struct edge_list *);
 void print_edge_list (FILE *, struct edge_list *);
-- 
1.9.1