Check no unreachable blocks in inverted_post_order_compute

2015-10-14  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.

From-SVN: r228789

gcc/ChangeLog

+2015-10-14  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.
+
 2015-10-13  Mikhail Maltsev  <maltsevm@gmail.com>
 
 	* common.opt: Add flag_checking.

gcc/cfganal.c

@@ -194,6 +194,19 @@ 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
    pred and succ that edge represents can be determined, or
@@ -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;

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 *);