src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/calc/NarrowNode.java

rev 56282 : [mq]: graal

*** 1,7 ****
  /*
!  * Copyright (c) 2014, 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) 2014, 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.
*** 24,39 ****
--- 24,41 ----
  
  package org.graalvm.compiler.nodes.calc;
  
  import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1;
  
+ import org.graalvm.compiler.core.common.calc.CanonicalCondition;
  import org.graalvm.compiler.core.common.type.ArithmeticOpTable;
  import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp;
  import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp.Narrow;
  import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp.SignExtend;
  import org.graalvm.compiler.core.common.type.IntegerStamp;
  import org.graalvm.compiler.core.common.type.PrimitiveStamp;
+ import org.graalvm.compiler.core.common.type.Stamp;
  import org.graalvm.compiler.graph.NodeClass;
  import org.graalvm.compiler.graph.spi.CanonicalizerTool;
  import org.graalvm.compiler.lir.gen.ArithmeticLIRGeneratorTool;
  import org.graalvm.compiler.nodeinfo.NodeInfo;
  import org.graalvm.compiler.nodes.NodeView;
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          }
      }
  
      @Override
      public boolean isLossless() {
+         return checkLossless(this.getResultBits());
+     }
+ 
+     private boolean checkLossless(int bits) {
+         Stamp valueStamp = this.getValue().stamp(NodeView.DEFAULT);
+         if (bits > 0 && valueStamp instanceof IntegerStamp) {
+             IntegerStamp integerStamp = (IntegerStamp) valueStamp;
+             long valueUpMask = integerStamp.upMask();
+             if ((valueUpMask & CodeUtil.mask(bits)) == valueUpMask) {
+                 return true;
+             }
+         }
          return false;
      }
  
      @Override
+     public boolean preservesOrder(CanonicalCondition cond) {
+         switch (cond) {
+             case LT:
+                 // Must guarantee that also sign bit does not flip.
+                 return checkLossless(this.getResultBits() - 1);
+             default:
+                 return checkLossless(this.getResultBits());
+         }
+     }
+ 
+     @Override
      public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) {
          NodeView view = NodeView.from(tool);
          ValueNode ret = super.canonical(tool, forValue);
          if (ret != this) {
              return ret;