From: hubicka <hubicka@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 10 Feb 2012 12:21:16 +0000 (+0000)
Subject: 	PR middle-end/48600
X-Git-Url: http://git.sourceforge.jp/view?a=commitdiff_plain;h=d34430114a1c24c97fdcc37f005576a981ad7d94;p=pf3gnuchains%2Fgcc-fork.git

	PR middle-end/48600
	* predict.c (predict_paths_for_bb): Prevent looping.
	(predict_paths_leading_to_edge, predict_paths_leading_to): Update.
	* g++.dg/torture/pr48600.C: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@184089 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8e59be03f92..7dd7717fdea 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-02-10  Jan Hubicka  <jh@suse.cz>
+
+	PR middle-end/48600
+	* predict.c (predict_paths_for_bb): Prevent looping.
+	(predict_paths_leading_to_edge, predict_paths_leading_to): Update.
+
 2012-02-10  Roman Zhuykov  <zhroma@ispras.ru>
 
 	* config/arm/arm.c (output_move_double): In one case properly
diff --git a/gcc/predict.c b/gcc/predict.c
index 92365317905..67131c9e759 100644
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -1827,7 +1827,8 @@ tree_estimate_probability_driver (void)
 static void
 predict_paths_for_bb (basic_block cur, basic_block bb,
 		      enum br_predictor pred,
-		      enum prediction taken)
+		      enum prediction taken,
+		      bitmap visited)
 {
   edge e;
   edge_iterator ei;
@@ -1848,7 +1849,7 @@ predict_paths_for_bb (basic_block cur, basic_block bb,
 	continue;
       gcc_assert (bb == cur || dominated_by_p (CDI_POST_DOMINATORS, cur, bb));
 
-      /* See if there is how many edge from e->src that is not abnormal
+      /* See if there is an edge from e->src that is not abnormal
 	 and does not lead to BB.  */
       FOR_EACH_EDGE (e2, ei2, e->src->succs)
 	if (e2 != e
@@ -1861,16 +1862,20 @@ predict_paths_for_bb (basic_block cur, basic_block bb,
 
       /* If there is non-abnormal path leaving e->src, predict edge
 	 using predictor.  Otherwise we need to look for paths
-	 leading to e->src.  */
+	 leading to e->src.
+
+	 The second may lead to infinite loop in the case we are predicitng
+	 regions that are only reachable by abnormal edges.  We simply
+	 prevent visiting given BB twice.  */
       if (found)
         predict_edge_def (e, pred, taken);
-      else
-	predict_paths_for_bb (e->src, e->src, pred, taken);
+      else if (!bitmap_set_bit (visited, e->src->index))
+	predict_paths_for_bb (e->src, e->src, pred, taken, visited);
     }
   for (son = first_dom_son (CDI_POST_DOMINATORS, cur);
        son;
        son = next_dom_son (CDI_POST_DOMINATORS, son))
-    predict_paths_for_bb (son, bb, pred, taken);
+    predict_paths_for_bb (son, bb, pred, taken, visited);
 }
 
 /* Sets branch probabilities according to PREDiction and
@@ -1880,7 +1885,9 @@ static void
 predict_paths_leading_to (basic_block bb, enum br_predictor pred,
 			  enum prediction taken)
 {
-  predict_paths_for_bb (bb, bb, pred, taken);
+  bitmap visited = BITMAP_ALLOC (NULL);
+  predict_paths_for_bb (bb, bb, pred, taken, visited);
+  BITMAP_FREE (visited);
 }
 
 /* Like predict_paths_leading_to but take edge instead of basic block.  */
@@ -1903,7 +1910,11 @@ predict_paths_leading_to_edge (edge e, enum br_predictor pred,
 	break;
       }
   if (!has_nonloop_edge)
-    predict_paths_for_bb (bb, bb, pred, taken);
+    {
+      bitmap visited = BITMAP_ALLOC (NULL);
+      predict_paths_for_bb (bb, bb, pred, taken, visited);
+      BITMAP_FREE (visited);
+    }
   else
     predict_edge_def (e, pred, taken);
 }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7ccb66b1262..95f1215f67b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-02-10  Jan Hubicka  <jh@suse.cz>
+
+	PR middle-end/48600
+	* g++.dg/torture/pr48600.C: New testcase.
+
 2012-02-09  Peter Bergner  <bergner@vnet.ibm.com>
 
 	PR middle-end/52140
diff --git a/gcc/testsuite/g++.dg/torture/pr48600.C b/gcc/testsuite/g++.dg/torture/pr48600.C
new file mode 100644
index 00000000000..b60a0a011ec
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr48600.C
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+
+class mx {
+public:
+    mx();
+};
+
+int main()
+{
+  while (true) {
+      mx *bar = new mx;
+      mx *baz = new mx;
+      continue;
+  }
+  return 0;
+}