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LI78224: INLINED MEMSET IMPROVEMENT FOR CONSTANT SIZE

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • For memset() cases where the size/number of characters to write
    is constant, the inlined memset() code that is generated can be
    improved.
    
    
       === TEST CASE ===
    
    void set11(char *start, char c)
    {
      memset(start, c, 19);   // Size value (19) is constant
    }
    

Local fix

Problem summary

  • PROBLEM DESCRIPTION:
    The memset() function uses 2 registers when the compile time
    length is known and it involves more than 1 different sized
    store.  This is a small performance issue.
    
    USERS AFFECTED:
    memset() users
    

Problem conclusion

  • Use the longest value needed to generate for all the stores.
    

Temporary fix

Comments

APAR Information

  • APAR number

    LI78224

  • Reported component name

    XL C/C++ FOR LI

  • Reported component ID

    5725C7300

  • Reported release

    D10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-10-30

  • Closed date

    2014-10-30

  • Last modified date

    2014-10-30

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

    IV61656

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

Fix information

  • Fixed component name

    XL C/C++ FOR LI

  • Fixed component ID

    5725C7300

Applicable component levels



Document information

More support for: XL C/C++ for Linux
Compiler

Software version: 13.1

Reference #: LI78224

Modified date: 30 October 2014