[PATCH GCC 2/9]Add interface reseting original copy tables in cfg.c

[Bin Cheng]

Hi,
This simple patch adds interface reseting original copy table in cfg.c.  This 
will be used in rewriting vect_do_peeling_* functions in vectorizer so that we 
don't need to release/allocate tables between prolog and epilog peeling.

Thanks,
bin

2016-09-01  Bin Cheng  <bin.ch...@arm.com>

        * cfg.c (reset_original_copy_tables): New func.
        * cfg.h (reset_original_copy_tables): New decl.
diff --git a/gcc/cfg.c b/gcc/cfg.c
index cab66c6..8e4a044 100644
--- a/gcc/cfg.c
+++ b/gcc/cfg.c
@@ -1066,6 +1066,15 @@ initialize_original_copy_tables (void)
   loop_copy = new hash_table<bb_copy_hasher> (10);
 }
 
+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);