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  1. JDK
  2. JDK-8129397

hotspot incorrect inline optimization

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    Details

    • Subcomponent:
    • CPU:
      x86_64
    • OS:
      linux

      Description

      FULL PRODUCT VERSION :
      java -version
      openjdk version "1.8.0_60"
      OpenJDK Runtime Environment (build 1.8.0_60-b16)
      OpenJDK 64-Bit Server VM (build 25.60-b16, mixed mode)

      and other JDK

       java -version
      openjdk version "1.8.0_45"
      OpenJDK Runtime Environment (build 1.8.0_45-b14)
      OpenJDK 64-Bit Server VM (build 25.45-b02, mixed mode)


      FULL OS VERSION :
      Fedora Linux x64, different version from F17-to F21

      A DESCRIPTION OF THE PROBLEM :
      At some point hotspot incorrectly inline functions,
      option Option -XX:InlineSmallCode=0 does help.

      See https://bugzilla.redhat.com/show_bug.cgi?id=1233827

      THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: No

      THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: Yes

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      run YY.java code
      at some point you would get
      k= rmoms=[D@4b1d6571 moms=[D@1b835480 r=[D@3549bca9
      k= rmoms=[D@4f25b795 moms=[D@6fb365ed r=[D@6e950bcf
      k= rmoms=null moms=null r=null
      Exception in thread "main" java.lang.NullPointerException
              at YY.mulVV(YY.java:78)
              at YY.mulVV(YY.java:70)
              at YY.getX(YY.java:33)
              at YY.runTests(YY.java:14)
              at YY.main(YY.java:88)


      EXPECTED VERSUS ACTUAL BEHAVIOR :
      java -XX:InlineSmallCode=0 YY
      y=6405.9478662121455


      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      class YY {

          static final java.util.Random R=new java.util.Random(1);

          
          double runTests(final int ntests)
          {
      double yy=0;
      for(int k=0;k<ntests;k++)
      {
      final int d=R.nextInt(23)+3;
      final double [] m=new double [d];
      for(int j=0;j<d;j++) m[j]=R.nextDouble();
      final double [] v=getX(m);
      for(int j=0;j<v.length;j++) yy+=v[j];
      }
      return yy;
          }

          

      public double [] getX(final double [] moms)
      {
          final double [] r=new double [moms.length-1];
          final double [] rmoms=new double [moms.length];
          //System.err.println("INIT:rmoms="+rmoms+" moms="+moms+" r="+r);
          for(int k=0;k<r.length;k++)
          {
      final double [] tmp=new double [k+1];
      tmp[k]=1;
      setxP(rmoms,tmp);
      System.err.println("k="/*+k*/+" rmoms="+rmoms+" moms="+moms+" r="+r);
      r[k]=mulVV(k+2,rmoms,moms); // Line 544 !!! Arguments are null !!!
          }
          return r;
      }

      public void setxP(final double [] r,final double [] x)
      {
          setxP(x.length,r,x);
      }

      static final YY BASIS=new YY();

      public void setxP(final int n,final double [] res,final double [] p)
      {
          BASIS.setaxbP(n-1,res,p,1,0);
      }

      public void setaxbP(final int n,final double [] res,final double [] p,final double a,final double b)
      {
          double r=p[n];
          res[n]=res[n+1]=0;
          for(int k=n;k>=0;k--)
          {
      final double ar=a*r;
      res[k+1]-=(k+1)*(ar);
      res[k]+=(2*k+1)*(ar)+b*r;
      if(k>0)
      {
      final double t=p[k-1];
      res[k-1]=-k*(ar);
      r=t;
      }
          }
      }

      public static double mulVV(final int n,final double [] a,final double [] b)
      {
          return mulVV(n,a,0,b,0);
      }

      public static double mulVV(final int n,final double [] a,final int off_a,final double [] b,final int off_b)
      {
          double s=0;
          for(int i=n;--i>=0;)
          {
      s+=a[i+off_a]*b[i+off_b];
          }
          return s;
      }
          


          public static void main(String [] args)
          {
      final int ntests=10000000;
      final double y=new YY().runTests(ntests);
      System.err.println("y="+y);
          }

      }


      ---------- END SOURCE ----------

        Attachments

        1. 7u80result.txt
          5.26 MB
        2. 8u45result.txt
          6.65 MB
        3. 8u60result.txt
          12.68 MB

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            Assignee:
            vlivanov Vladimir Ivanov
            Reporter:
            webbuggrp Webbug Group
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              Dates

              Created:
              Updated:
              Resolved: