src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.loop.phases/src/org/graalvm/compiler/loop/phases/LoopSafepointEliminationPhase.java

rev 56282 : [mq]: graal

*** 1,7 ****
  /*
!  * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2011, 2019, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 38,60 ****
  public class LoopSafepointEliminationPhase extends BasePhase<MidTierContext> {
  
      @Override
      protected void run(StructuredGraph graph, MidTierContext context) {
          LoopsData loops = new LoopsData(graph);
-         if (context.getOptimisticOptimizations().useLoopLimitChecks(graph.getOptions()) && graph.getGuardsStage().allowsFloatingGuards()) {
              loops.detectedCountedLoops();
              for (LoopEx loop : loops.countedLoops()) {
                  if (loop.loop().getChildren().isEmpty() && loop.counted().getStamp().getBits() <= 32) {
                      boolean hasSafepoint = false;
                      for (LoopEndNode loopEnd : loop.loopBegin().loopEnds()) {
                          hasSafepoint |= loopEnd.canSafepoint();
                      }
                      if (hasSafepoint) {
                          loop.counted().createOverFlowGuard();
!                         loop.loopBegin().disableSafepoint();
                      }
                  }
              }
          }
          for (LoopEx loop : loops.loops()) {
              for (LoopEndNode loopEnd : loop.loopBegin().loopEnds()) {
                  Block b = loops.getCFG().blockFor(loopEnd);
--- 38,66 ----
  public class LoopSafepointEliminationPhase extends BasePhase<MidTierContext> {
  
      @Override
      protected void run(StructuredGraph graph, MidTierContext context) {
          LoopsData loops = new LoopsData(graph);
          loops.detectedCountedLoops();
          for (LoopEx loop : loops.countedLoops()) {
              if (loop.loop().getChildren().isEmpty() && loop.counted().getStamp().getBits() <= 32) {
                  boolean hasSafepoint = false;
                  for (LoopEndNode loopEnd : loop.loopBegin().loopEnds()) {
                      hasSafepoint |= loopEnd.canSafepoint();
                  }
                  if (hasSafepoint) {
+                     if (!loop.counted().counterNeverOverflows()) {
+                         // Counter can overflow, need to create a guard.
+                         if (context.getOptimisticOptimizations().useLoopLimitChecks(graph.getOptions()) && graph.getGuardsStage().allowsFloatingGuards()) {
                              loop.counted().createOverFlowGuard();
!                         } else {
!                             // Cannot disable this safepoint, because the loop could overflow.
!                             continue;
                          }
                      }
+                     loop.loopBegin().disableSafepoint();
+                 }
              }
          }
          for (LoopEx loop : loops.loops()) {
              for (LoopEndNode loopEnd : loop.loopBegin().loopEnds()) {
                  Block b = loops.getCFG().blockFor(loopEnd);