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LI76216: COMPILER WARNING WHEN INLINING WITH -Q64

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APAR status

  • Closed as program error.

Error description

  • When inlining with -q64, a compiler warning is generated
    indicating that inlining has failed. In most cases, this warning
    will not appear if compiling with -q32.
    
    ===== Test Case:
    test.c:
    struct fred {
            int jjj;
    } freddy;
    
    static inline long bar(struct fred fff, int kkk) {
            return fff.jjj+kkk;
    }
    
    main()
    {
            long bbb;
            freddy.jjj = 3;
            bbb = bar(freddy,2);
            printf("bbb = %d (should be 5)\n",bbb);
    }
    ======================
    
    ===== Observed Output:
    $ xlc -q64 -O2 -c test.c
    1500-029: (W) WARNING: subprogram bar could not be inlined into
    main.
    
    $ xlc -q32 -O2 -c test.c
    $
    

Local fix

  • In most cases, compiling with -q32 will hide the problem.
    

Problem summary

  • PROBLEM DESCRIPTION:
    Failure to inline.  If you pass a structure by value and the
    size of the structure is not a multiple of the size of a
    register, then the compiler refuses to inline because it thinks
    there is a type mismatch.  This is more likely to happen with
    -q64 but it can happen with -q32.
    
    USERS AFFECTED:
    Users who depend on inlining.
    

Problem conclusion

  • The fix is to compare the size of the rounded up parameter with
    the size of the argument before issuing a diagnostic and
    refusing to do the inlining.
    

Temporary fix

Comments

APAR Information

  • APAR number

    LI76216

  • Reported component name

    XL C/C++ RHEL52

  • Reported component ID

    5724U8310

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-06-10

  • Closed date

    2011-06-10

  • Last modified date

    2011-06-10

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

    IZ92004

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

Fix information

  • Fixed component name

    XL C/C++ RHEL52

  • Fixed component ID

    5724U8310

Applicable component levels



Document information

More support for: XL C/C++

Software version: A.1

Reference #: LI76216

Modified date: 10 June 2011