Fix integer overflow in instruction scheduling. This can happen if we have

[oota-llvm.git] / lib / CodeGen / SelectionDAG / ScheduleDAGFast.cpp

diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
index d1930b1a2c75285374bb9a60ab02abd0782f9d88..7eac4d81bb8090eaf547a91bb79ca905293355c5 100644 (file)
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
@@ -134,17 +134,17 @@ void ScheduleDAGFast::Schedule() {
 /// the AvailableQueue if the count reaches zero. Also update its cycle bound.
 void ScheduleDAGFast::ReleasePred(SUnit *SU, SDep *PredEdge) {
   SUnit *PredSU = PredEdge->getSUnit();
-  --PredSU->NumSuccsLeft;
-  
+
 #ifndef NDEBUG
-  if (PredSU->NumSuccsLeft < 0) {
+  if (PredSU->NumSuccsLeft == 0) {
     errs() << "*** Scheduling failed! ***\n";
     PredSU->dump(this);
     errs() << " has been released too many times!\n";
     llvm_unreachable(0);
   }
 #endif
-  
+  --PredSU->NumSuccsLeft;
+
   // If all the node's successors are scheduled, this node is ready
   // to be scheduled. Ignore the special EntrySU node.
   if (PredSU->NumSuccsLeft == 0 && PredSU != &EntrySU) {