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 8e59be0..7dd7717 100644 (file)
--- 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 9236531..67131c9 100644 (file)
--- 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 7ccb66b..95f1215 100644 (file)
--- 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 (file)
index 0000000..b60a0a0
--- /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;
+}