[PATCH] Consider also negative edges in cycle detection.

[Martin Liška]

Hi.

The patch is enhancement of r271117 where I started detecting zero
cycles. We also need consider negative edges.

Patch survives gcov.exp and I'll install it after proper testing
next week.

Thanks,
Martin

gcc/ChangeLog:

2019-08-30  Martin Liska  <mli...@suse.cz>

        * gcov.c (path_contains_zero_cycle_arc): Rename to ...
        (path_contains_zero_or_negative_cycle_arc): ... this and handle
        also negative edges.
        (circuit): Handle also negative edges as they can happen
        in some situations.
---
 gcc/gcov.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)



diff --git a/gcc/gcov.c b/gcc/gcov.c
index c65b7153765..f4e65ee46da 100644
--- a/gcc/gcov.c
+++ b/gcc/gcov.c
@@ -730,10 +730,10 @@ unblock (const block_info *u, block_vector_t &blocked,
 /* Return true when PATH contains a zero cycle arc count.  */
 
 static bool
-path_contains_zero_cycle_arc (arc_vector_t &path)
+path_contains_zero_or_negative_cycle_arc (arc_vector_t &path)
 {
   for (unsigned i = 0; i < path.size (); i++)
-    if (path[i]->cs_count == 0)
+    if (path[i]->cs_count <= 0)
       return true;
   return false;
 }
@@ -759,7 +759,7 @@ circuit (block_info *v, arc_vector_t &path, block_info *start,
     {
       block_info *w = arc->dst;
       if (w < start
-	  || arc->cs_count == 0
+	  || arc->cs_count <= 0
 	  || !linfo.has_block (w))
 	continue;
 
@@ -770,7 +770,7 @@ circuit (block_info *v, arc_vector_t &path, block_info *start,
 	  handle_cycle (path, count);
 	  loop_found = true;
 	}
-      else if (!path_contains_zero_cycle_arc (path)
+      else if (!path_contains_zero_or_negative_cycle_arc (path)
 	       &&  find (blocked.begin (), blocked.end (), w) == blocked.end ())
 	loop_found |= circuit (w, path, start, blocked, block_lists, linfo,
 			       count);
@@ -785,7 +785,7 @@ circuit (block_info *v, arc_vector_t &path, block_info *start,
       {
 	block_info *w = arc->dst;
 	if (w < start
-	    || arc->cs_count == 0
+	    || arc->cs_count <= 0
 	    || !linfo.has_block (w))
 	  continue;