Remove useless backedge marking

I didn't find anything using EDGE_DFS_BACK in RTL infrastructure
used by var-tracking or var-tracking itself, the following removes
this computation.

2020-07-24  Richard Biener  <rguenther@suse.de>

	* var-tracking.c (variable_tracking_main_1): Remove call
	to mark_dfs_back_edges.

diff --git a/gcc/var-tracking.c b/gcc/var-tracking.c
index cca7506..a345fb4 100644 (file)
--- a/gcc/var-tracking.c
+++ b/gcc/var-tracking.c
@@ -10481,7 +10481,6 @@ variable_tracking_main_1 (void)
       return 0;
     }
 
-  mark_dfs_back_edges ();
   if (!vt_initialize ())
     {
       vt_finalize ();