We might expect some performance improvements with 10.9.2 due to LLVM 3.4

Discussion in 'OS X Mavericks (10.9)' started by iBug2, Jan 8, 2014.

  1. iBug2 macrumors 68040

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    #1
    It seems like LLVM 3.4 has improved a lot on the performance of compiled binaries compared to 3.3. And Apple will be releasing XCode 5.1 soon, which will include LLVM 3.4 and they will be compiling 10.9.2 using 3.4. The same goes for iOS 7.1 as well. It seems like after 4 years, LLVM finally caught up with GCC and actually is performing even better than GCC on many compiles now.
     
  2. Mr. Wonderful macrumors 6502a

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    Feb 19, 2009
    #2
    I'm slightly confused. If LLVM 3.4 requires being compiled on Xcode 5.1, wouldn't Apple have to already be compiling on 5.1 for 10.9.2 and 7.1 to have LLVM 3.4? My point being, I feel like it would be weird for Apple to start compiling 10.9.2 and 7.1 on a different version of Xcode halfway through development?
     
  3. maflynn Moderator

    maflynn

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    #3
    I think 10.9.2 is to far in the pipeline to use a different compiler.
     
  4. iBug2 thread starter macrumors 68040

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    #4
    Well, Apple could have been compiling all the pre-release builds using the svn builds of LLVM 3.4 which have been available for some time. But the final 3.4 release came December 27th. And I don't think it makes much difference to switch compilers in the middle of a beta testing period.
     
  5. Bear macrumors G3

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    #5
    Actually it does. What if the new compiler introduces a behavior difference in the generated code? This could cause additional delays while Apple tracks down issues with code that wasn't modified.

    Apple could start using the new compiler for say 10.9.3 but expect a slightly longer time between 10.9.2 and 10.9.3 if they do to allow for extended testing.
     
  6. iBug2 thread starter macrumors 68040

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    #6
    As far as I know, whatever Apple compiles, they do that with the "current" XCode. So if XCode 5.1 is released before 10.9.2, I can be almost sure that 10.9.2 will be compiled with LLVM 3.4.
     
  7. Bear macrumors G3

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    #7
    In that case expect that there may be a delay in 10.9.2 caused by changing the compiler.
     
  8. mal359 macrumors newbie

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    Oct 11, 2013
    #8
    I hope LLVM 3.4 is a huge improvement. I tried the Intel compiler and was unimpressed.
     
  9. iBug2 thread starter macrumors 68040

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    #9
    According to

    http://www.phoronix.com/scan.php?page=article&item=llvm34_gcc49_compilers&num=1

    3.4 is a huge improvement over 3.3.

    ----------

    We'll never know since 10.9.2 is at the beginning of testing stage anyway.
     
  10. Mr. Retrofire macrumors 601

    Mr. Retrofire

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    #10
    This is an upgrade, not a new compiler. Apple used newer compiler versions for system parts like kernel extensions in the past.
     
  11. Mr. Retrofire macrumors 601

    Mr. Retrofire

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    #11
    Try the PGO and the built-in data prefetch instructions!
     
  12. mal359 macrumors newbie

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    Oct 11, 2013
    #12
    Those are nice, but so many OSX programs are built with Objective-C, which the Intel compilers do not support. Also, Clang/LLVM is faster at building programs and isn't as picky (ICC crashed for me when I was using it to build Emacs and some X libraries).

    It does give Motif programs nice performance, though. The Fortran compiler is also top-notch.
     

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