Exemple #1
0
 private static void killEnd(AbstractEndNode end) {
   MergeNode merge = end.merge();
   if (merge != null) {
     merge.removeEnd(end);
     StructuredGraph graph = end.graph();
     if (merge instanceof LoopBeginNode && merge.forwardEndCount() == 0) { // dead loop
       for (PhiNode phi : merge.phis().snapshot()) {
         propagateKill(phi);
       }
       LoopBeginNode begin = (LoopBeginNode) merge;
       // disconnect and delete loop ends & loop exits
       for (LoopEndNode loopend : begin.loopEnds().snapshot()) {
         loopend.predecessor().replaceFirstSuccessor(loopend, null);
         loopend.safeDelete();
       }
       begin.removeExits();
       FixedNode loopBody = begin.next();
       if (loopBody != null) { // for small infinite loops, the body may be killed while
         // killing the loop ends
         killCFG(loopBody);
       }
       begin.safeDelete();
     } else if (merge instanceof LoopBeginNode
         && ((LoopBeginNode) merge).loopEnds().isEmpty()) { // not
       // a
       // loop
       // anymore
       graph.reduceDegenerateLoopBegin((LoopBeginNode) merge);
     } else if (merge.phiPredecessorCount() == 1) { // not a merge anymore
       graph.reduceTrivialMerge(merge);
     }
   }
 }
 public void reduceDegenerateLoopBegin(LoopBeginNode begin) {
   assert begin.loopEnds().isEmpty() : "Loop begin still has backedges";
   if (begin.forwardEndCount() == 1) { // bypass merge and remove
     reduceTrivialMerge(begin);
   } else { // convert to merge
     AbstractMergeNode merge = this.add(new MergeNode());
     this.replaceFixedWithFixed(begin, merge);
   }
 }