diff --git a/gcc/cfg.c b/gcc/cfg.c
index cab66c6..ee2e42c 100644
--- a/gcc/cfg.c
+++ b/gcc/cfg.c
@@ -1066,6 +1066,18 @@ initialize_original_copy_tables (void)
   loop_copy = new hash_table<bb_copy_hasher> (10);
 }
 
+/* Reset the data structures to maintain mapping between blocks and
+   its copies.  */
+
+void
+reset_original_copy_tables (void)
+{
+  gcc_assert (original_copy_bb_pool);
+  bb_original->empty ();
+  bb_copy->empty ();
+  loop_copy->empty ();
+}
+
 /* Free the data structures to maintain mapping between blocks and
    its copies.  */
 void
diff --git a/gcc/cfg.h b/gcc/cfg.h
index 6c8ba7e..ad935e3 100644
--- a/gcc/cfg.h
+++ b/gcc/cfg.h
@@ -108,6 +108,7 @@ extern void scale_bbs_frequencies_int (basic_block *, int, int, int);
 extern void scale_bbs_frequencies_gcov_type (basic_block *, int, gcov_type,
 					     gcov_type);
 extern void initialize_original_copy_tables (void);
+extern void reset_original_copy_tables (void);
 extern void free_original_copy_tables (void);
 extern void set_bb_original (basic_block, basic_block);
 extern basic_block get_bb_original (basic_block);