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

*** 1,7 ****
  /*
!  * Copyright (c) 2014, 2015, 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, 2017, 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.
*** 26,43 ****
--- 26,46 ----
  
  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.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.ValueNode;
  import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
  
+ import jdk.vm.ci.code.CodeUtil;
+ 
  /**
   * The {@code NarrowNode} converts an integer to a narrower integer.
   */
  @NodeInfo(cycles = CYCLES_1)
  public final class NarrowNode extends IntegerConvertNode<Narrow, SignExtend> {
*** 85,95 ****
              NarrowNode other = (NarrowNode) forValue;
              return new NarrowNode(other.getValue(), other.getInputBits(), getResultBits());
          } else if (forValue instanceof IntegerConvertNode) {
              // SignExtendNode or ZeroExtendNode
              IntegerConvertNode<?, ?> other = (IntegerConvertNode<?, ?>) forValue;
!             if (other.getValue().getUsageCount() == 1 && other.getUsageCount() > 1) {
                  // Do not perform if this will introduce a new live value.
                  // If the original value's usage count is > 1, there is already another user.
                  // If the convert's usage count is <=1, it will be dead code eliminated.
                  return this;
              }
--- 88,98 ----
              NarrowNode other = (NarrowNode) forValue;
              return new NarrowNode(other.getValue(), other.getInputBits(), getResultBits());
          } else if (forValue instanceof IntegerConvertNode) {
              // SignExtendNode or ZeroExtendNode
              IntegerConvertNode<?, ?> other = (IntegerConvertNode<?, ?>) forValue;
!             if (other.getValue().hasExactlyOneUsage() && other.hasMoreThanOneUsage()) {
                  // Do not perform if this will introduce a new live value.
                  // If the original value's usage count is > 1, there is already another user.
                  // If the convert's usage count is <=1, it will be dead code eliminated.
                  return this;
              }
*** 103,123 ****
                  return new NarrowNode(other.getValue(), other.getInputBits(), getResultBits());
              } else {
                  if (other instanceof SignExtendNode) {
                      // sxxx -(sign-extend)-> ssssssss sssssxxx -(narrow)-> sssssxxx
                      // ==> sxxx -(sign-extend)-> sssssxxx
!                     return new SignExtendNode(other.getValue(), other.getInputBits(), getResultBits());
                  } else if (other instanceof ZeroExtendNode) {
                      // xxxx -(zero-extend)-> 00000000 00000xxx -(narrow)-> 0000xxxx
                      // ==> xxxx -(zero-extend)-> 0000xxxx
                      return new ZeroExtendNode(other.getValue(), other.getInputBits(), getResultBits());
                  }
              }
          }
          return this;
      }
  
      @Override
      public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {
          nodeValueMap.setResult(this, gen.emitNarrow(nodeValueMap.operand(getValue()), getResultBits()));
      }
  }
--- 106,142 ----
                  return new NarrowNode(other.getValue(), other.getInputBits(), getResultBits());
              } else {
                  if (other instanceof SignExtendNode) {
                      // sxxx -(sign-extend)-> ssssssss sssssxxx -(narrow)-> sssssxxx
                      // ==> sxxx -(sign-extend)-> sssssxxx
!                     return SignExtendNode.create(other.getValue(), other.getInputBits(), getResultBits());
                  } else if (other instanceof ZeroExtendNode) {
                      // xxxx -(zero-extend)-> 00000000 00000xxx -(narrow)-> 0000xxxx
                      // ==> xxxx -(zero-extend)-> 0000xxxx
                      return new ZeroExtendNode(other.getValue(), other.getInputBits(), getResultBits());
                  }
              }
+         } else if (forValue instanceof AndNode) {
+             AndNode andNode = (AndNode) forValue;
+             IntegerStamp yStamp = (IntegerStamp) andNode.getY().stamp();
+             IntegerStamp xStamp = (IntegerStamp) andNode.getX().stamp();
+             long relevantMask = CodeUtil.mask(this.getResultBits());
+             if ((relevantMask & yStamp.downMask()) == relevantMask) {
+                 return create(andNode.getX(), this.getResultBits());
+             } else if ((relevantMask & xStamp.downMask()) == relevantMask) {
+                 return create(andNode.getY(), this.getResultBits());
+             }
          }
+ 
          return this;
      }
  
      @Override
      public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {
          nodeValueMap.setResult(this, gen.emitNarrow(nodeValueMap.operand(getValue()), getResultBits()));
      }
+ 
+     @Override
+     public boolean mayNullCheckSkipConversion() {
+         return false;
+     }
  }