IBM Support

IV53311: MISSING LOAD WITH -O3

Fixes are available

XL C/C++ for AIX Fix Pack 7 (January 2014 PTF) for 12.1
XL C for AIX Fix Pack 8 (March 2014 PTF) for 12.1
XL C/C++ for AIX Fix Pack 8 (March 2014 PTF) for 12.1
XL C/C++ for AIX Fix Pack 11 (February 2015 PTF) for 12.1
XL C for AIX Fix Pack 12 (May 2015 PTF) for 12.1
XL C/C++ for AIX Fix Pack 12 (May 2015 PTF) for 12.1
XL C/C++ for AIX Fix Pack 13 (August 2015 Update) for 12.1
XL C/C++ for AIX Fix Pack 14 (December 2015 Update) for 12.1
XL C for AIX Fix Pack 15 (April 2016 Update) for 12.1
XL C/C++ for AIX Fix Pack 15 (April 2016 Update) for 12.1
XL C for AIX Fix Pack 16 (July 2016 Update) for 12.1
XL C/C++ for AIX Fix Pack 16 (July 2016 Update) for 12.1
XL C/C++ for AIX Fix Pack 17 (November 2016 Update) for 12.1
XL C for AIX Fix Pack 17 (November 2016 Update) for 12.1
XL C for AIX Fix Pack 18 (February 2017 Update) for 12.1
XL C/C++ for AIX Fix Pack 18 (February 2017 Update) for 12.1
XL C for AIX Fix Pack 19 (August 2017 Update) for 12.1
XL C/C++ for AIX Fix Pack 19 (August 2017 Update) for 12.1
XL C for AIX Fix Pack 20 (March 2018 Update) for 12.1
XL C/C++ for AIX Fix Pack 20 (March 2018 Update) for 12.1
XL C for AIX Fix Pack 6 (December 2013 PTF) for 12.1
XL C/C++ for AIX Fix Pack 6 (December 2013 PTF) for 12.1
XL C for AIX Fix Pack 7 (January 2014 PTF) for 12.1
XL C for AIX Fix Pack 9 (July 2014 PTF) for 12.1
XL C/C++ for AIX Fix Pack 9 (July 2014 PTF) for 12.1
XL C for AIX Fix Pack 10 (October 2014 PTF) for 12.1
XL C/C++ for AIX Fix Pack 10 (October 2014 PTF) for 12.1
XL C for AIX Fix Pack 11 (February 2015 PTF) for 12.1
XL C for AIX Fix Pack 13 (August 2015 Update) for 12.1
XL C for AIX Fix Pack 14 (December 2015 Update) for 12.1
XL C/C++ for AIX Fix Pack 21 (January 2019 Update) for 12.1
XL C for AIX Fix Pack 21 (January 2019 Update) for 12.1

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • There are certain scenarios where the compiler might remove a
    necessary load 'after' a sync() instruction before its
    used.
    
    
    An example is the following:
    
    .L1629:
     lwz         r3,96(r31)
     lwz         r6,104(r31)    <---- load of r6
     subf        r4,r6,r3
     addi        r0,r3,-1
     rlwinm.     r3,r4,0,15,31
     beq         .L2014
    
     rlwinm      r4,r0,0,15,31
     stw         r4,96(r31)
     sync                      <---- sync instruction
     ld          r3,144(r31)
     rlwinm      r5,r0,3,12,28
     subf        r0,r6,r0      <---- r6 is being used in subf
    without it being loaded again after the sync instruction
     rlwinm      r0,r0,0,15,31
     cmplw       cr0,r0,r27
     ldx         r3,r3,r5
     std         r3,112(r1)
     beq         .L1655
    
     cmpdi       cr0,r0,0
     bne         .L173
    

Local fix

  • N/A
    

Problem summary

  • USERS AFFECTED:
    Users coding in assembly and those who use the sync instruction
    may be affected by this issue.
    
    PROBLEM DESCRIPTION:
    The compiler forgets to generate a load after the sync
    instruction.
    

Problem conclusion

  • The compiler has been fixed to invalidate all aliasing symbols
    before sync the instruction so that they will be reloaded after
    sync instruction.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV53311

  • Reported component name

    XL C FOR AIX

  • Reported component ID

    5725C7100

  • Reported release

    C10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-12-13

  • Closed date

    2013-12-13

  • Last modified date

    2013-12-13

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

    IV51008

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

Fix information

  • Fixed component name

    XL C FOR AIX

  • Fixed component ID

    5725C7100

Applicable component levels



Document information

More support for: XL C for AIX
Compiler

Software version: 12.1

Reference #: IV53311

Modified date: 13 December 2013