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

*** 82,113 ****
  
          if (forValue instanceof SignExtendNode) {
              // sxxx -(sign-extend)-> ssss sxxx -(sign-extend)-> ssssssss sssssxxx
              // ==> sxxx -(sign-extend)-> ssssssss sssssxxx
              SignExtendNode other = (SignExtendNode) forValue;
!             return new SignExtendNode(other.getValue(), other.getInputBits(), getResultBits());
          } else if (forValue instanceof ZeroExtendNode) {
              ZeroExtendNode other = (ZeroExtendNode) forValue;
              if (other.getResultBits() > other.getInputBits()) {
                  // sxxx -(zero-extend)-> 0000 sxxx -(sign-extend)-> 00000000 0000sxxx
                  // ==> sxxx -(zero-extend)-> 00000000 0000sxxx
!                 return new ZeroExtendNode(other.getValue(), other.getInputBits(), getResultBits());
              }
          }
  
          if (forValue.stamp() instanceof IntegerStamp) {
              IntegerStamp inputStamp = (IntegerStamp) forValue.stamp();
              if ((inputStamp.upMask() & (1L << (getInputBits() - 1))) == 0L) {
                  // 0xxx -(sign-extend)-> 0000 0xxx
                  // ==> 0xxx -(zero-extend)-> 0000 0xxx
!                 return new ZeroExtendNode(forValue, getInputBits(), getResultBits());
              }
          }
  
          return this;
      }
  
      @Override
      public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {
          nodeValueMap.setResult(this, gen.emitSignExtend(nodeValueMap.operand(getValue()), getInputBits(), getResultBits()));
      }
  }
--- 82,118 ----
  
          if (forValue instanceof SignExtendNode) {
              // sxxx -(sign-extend)-> ssss sxxx -(sign-extend)-> ssssssss sssssxxx
              // ==> sxxx -(sign-extend)-> ssssssss sssssxxx
              SignExtendNode other = (SignExtendNode) forValue;
!             return SignExtendNode.create(other.getValue(), other.getInputBits(), getResultBits());
          } else if (forValue instanceof ZeroExtendNode) {
              ZeroExtendNode other = (ZeroExtendNode) forValue;
              if (other.getResultBits() > other.getInputBits()) {
                  // sxxx -(zero-extend)-> 0000 sxxx -(sign-extend)-> 00000000 0000sxxx
                  // ==> sxxx -(zero-extend)-> 00000000 0000sxxx
!                 return ZeroExtendNode.create(other.getValue(), other.getInputBits(), getResultBits());
              }
          }
  
          if (forValue.stamp() instanceof IntegerStamp) {
              IntegerStamp inputStamp = (IntegerStamp) forValue.stamp();
              if ((inputStamp.upMask() & (1L << (getInputBits() - 1))) == 0L) {
                  // 0xxx -(sign-extend)-> 0000 0xxx
                  // ==> 0xxx -(zero-extend)-> 0000 0xxx
!                 return ZeroExtendNode.create(forValue, getInputBits(), getResultBits());
              }
          }
  
          return this;
      }
  
      @Override
      public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {
          nodeValueMap.setResult(this, gen.emitSignExtend(nodeValueMap.operand(getValue()), getInputBits(), getResultBits()));
      }
+ 
+     @Override
+     public boolean mayNullCheckSkipConversion() {
+         return true;
+     }
  }