add an assertion

diff --git a/rts/parallel/WSDeque.c b/rts/parallel/WSDeque.c
index 8c403c3..ec34a8c 100644 (file)
--- a/rts/parallel/WSDeque.c
+++ b/rts/parallel/WSDeque.c
@@ -151,6 +151,7 @@ popWSDeque (WSDeque *q)
     q->topBound = t+1; /* ...and cached top value as well */
     
     ASSERT_WSDEQUE_INVARIANTS(q); 
+    ASSERT(q->bottom >= q->top);
     
     return removed;
 }