benefits of using GCC 3.3

krassykrassy
Posted:
in General Discussion edited January 2014
i wonder if some of you can say something about the performance difference of compiling the code with GCC 3.3 instead of GCC 3.1 ?



is it really worth it?



second, is there is source where i can have a look on the development of GCC and the optimization for PPC in general?



thx

Comments

  • Reply 1 of 9
    thuh freakthuh freak Posts: 2,664member
    well, gcc is made by the fsf and part of the gnu project. checkout their site for full info: link.



    i havent done any tests, and i hadn't noticed any large difference when i was using 3.3 (i've since switched back to 3.1, because fink doesn't like 3.3). i'm sure there is some improvement though.
  • Reply 2 of 9
    scottscott Posts: 7,431member
    Don't mean to take you all off topic but I was having trouble with linking with gcc. It seemed to not be looking in the path is should be looking in for archive files. What up?
  • Reply 3 of 9
    thuh freakthuh freak Posts: 2,664member
    Quote:

    Originally posted by Scott

    Don't mean to take you all off topic but I was having trouble with linking with gcc. It seemed to not be looking in the path is should be looking in for archive files. What up?



    show me the gcc line, i might be able to help.
  • Reply 4 of 9
    davechendavechen Posts: 56member
    gcc 3.3 definitely produces faster code, at least for my stuff. My code is mostly just generic sparse matrix solving in C++, and it seems to run about twice as fast using 3.3 versus 3.1. I haven't looked at the assembly code to figure out why, though.
  • Reply 5 of 9
    amorphamorph Posts: 7,112member
    Apple has their own branch of GCC, which they're good about submitting back to the main code tree, but I'm sure that at this point there are quite a few PPC enhancements in Apple's GCC, but not (yet) in FSF's. In fact, some few might never make the main tree, since FSF approves or disapproves inclusion of code based on their own analysis and interest.
  • Reply 6 of 9
    krassykrassy Posts: 595member
    so far thank you guys very much for the answers. i heard that ibm has its own compiler which is much better optimized for producing high-performance code when comparing it to gcc - is this true? if so, is there a way to use that compiler with apple's developer tools?
  • Reply 7 of 9
    davechendavechen Posts: 56member
    Quote:

    Originally posted by Krassy

    so far thank you guys very much for the answers. i heard that ibm has its own compiler which is much better optimized for producing high-performance code when comparing it to gcc - is this true? if so, is there a way to use that compiler with apple's developer tools?



    I doubt it. Who knows if they've ported it to OS X. Also, companies like IBM, Sun, SGI tend to charge a lot of money fpr their compilers. I think SGI wanted several thousand dollars for it, when we looked into updating.



    I think the best we can hope for is that some IBM compiler people contribute code to GCC, particularly autovectorization stuff.
  • Reply 8 of 9
    krassykrassy Posts: 595member
    since i'm only at the beginning of my project i'll start with 3.3 - i hope that i don't get the same problems scott had run in... thx so far
  • Reply 9 of 9
    krassykrassy Posts: 595member
    today i found an info that ibm will offer its' own x/x++,fortran compiler for linux and mac os x. it is specially optimized for the G5 and beats gcc 3.3 in many tasks



    http://www-3.ibm.com/software/awdtools/ccompilers/
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