LI76786: INCORRECT TRAP WITH OPTIMIZATION

June 2012 Update for XL Fortran for Linux, V13.1
October 2012 Update for XL Fortran for Linux, V13.1
XL Fortran for Linux Fix Pack 8 (June 2013 Update) for 13.1

APAR status

• Closed as program error.

Error description

• When compiling with the follwoing option set, the final exe
  (a.out) traps at runtime on line 31:
    MLONE(:) = 0
  
  ===== COMPILE COMMAND:
  $export OBJECT_MODE=64
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648
  $parkind1.F90
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648 pardim.F90
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648 yomcst.F90
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648
  yomfger.F90 xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648
  jstream_mod.F90
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648 jquire.F90
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648 jdummy.F90
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648
  inifger.F90
  $xlf90_r -qnohot -C -c -O3 -q64 -g -qstrict  -NS32648 driver.F90
  $xlf90_r -b64  -o a.out *.o
  
  Below is the output that I see in DBX...
  $ dbx a.out
  Type 'help' for help.
  Core file "core" is not a valid core file (ignored)
  reading symbolic information ...
  (dbx) run
   calling inifger
   INIFGER Start
  
  Trace/BPT trap in inifger at line 31 in file "inifger.F90" ($t1)
     31     MLONE(:) = 0
  (dbx) where
  inifger(), line 31 in "inifger.F90"
  _main(), line 2 in "driver.F90"
  (dbx) x
    $r0:0x000000000000080c  $stkp:0x0ffffffffffd8050
  $toc:0x0000000110000760
    $r3:0x00000001100028a0    $r4:0x0000000000000809
  $r5:0x0ffffffffffd8318
    $r6:0x0000000000000007    $r7:0x000000000000080b
  $r8:0x0000000110000874
    $r9:0x0000000000000806   $r10:0x0000000000000000
  $r11:0x0000000000000000
   $r12:0x000000010000073c   $r13:0x00000001100c8b40
  $r14:0x0000000000000808
   $r15:0x0ffffffffffff758   $r16:0x0ffffffffffff768
  $r17:0x0000000000000000
   $r18:0x0ffffffffffffed0   $r19:0x09fffffff000a798
  $r20:0xbadc0ffee0ddf00d
   $r21:0xbadc0ffee0ddf00d   $r22:0xbadc0ffee0ddf00d
  $r23:0xbadc0ffee0ddf00d
   $r24:0xbadc0ffee0ddf00d   $r25:0xbadc0ffee0ddf00d
  $r26:0x0000000110000880
   $r27:0x0000000000000001   $r28:0x0000000110000870
  $r29:0x0000000100001570
   $r30:0x0ffffffffffe0308   $r31:0x0000000000000000
   $iar:0x00000001000007d0   $msr:0xa00000000002d0b2
  $cr:0x2224422b
  $link:0x00000001000010b0   $ctr:0x0ffffffffffd8116
  $xer:0x2000000f
    $mq:0x79005f5f
  
            Condition status = 0:e 1:e 2:e 3:g 4:g 5:e 6:e 7:leo
          [unset $noflregs to view floating point registers]
          [unset $novregs to view vector registers]
  in inifger at line 31 in file "inifger.F90" ($t1)
  0x1000007d0 (inifger+0x150) 09040808       tdgti   r4,0x808
  (dbx) quit
  $
  
  From the above output and when analysing the listing output, the
  problematic line seems to be
   31| 000164 tdi      09040808   1     TCT8
  gr5=gr4,2056,0x2/gt,2
  

Local fix

• n/a
  

Problem summary

• USERS AFFECTED:
  XL Fortran users using O3 and up may potentially be affected by
  this issue.
  
  PROBLEM DESCRIPTION:
  An internal scheduling algorithm was causing bounds-checking
  traps to occur erroneously.
  

Problem conclusion

• The internal scheduling algorithm has been modified to handle
  the above case.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IV12205

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  XL FORTRAN LINU

• Fixed component ID

  5724X1600

Applicable component levels

• RD10 PSN IV12205

     UP06/09/13