Re: Code quality

>On the other hand: ... I've heard of software companies for which compile
>time is everything, who refuse to add optimizations that will make -O more
>than twice as slow as non-optimizing.


On the third hand: :-)


I've got this large set of modules which are based on a few tree
structures. Now if I change something in those structures, I've got to
recompile >50k lines. Once everything is stable, it doesn't need
recompilation that often. But to emphasize your remark.


  Compiling the largest module with -W0,-opt,0 (Apollo-ees for noptimisation)
  it takes about 15 secs to compile. (CPU time that is, Wall time > 1.30)
  Doing the same with -W0,-opt,3 it takes over 2.5 minutes :{
  (And all this takeing a mere 15 minutes of wallclock time :{{ )


And the fun part with this is:


There's a rather large switch inside, and the compiler manages to mess up
its table, and generate eronous code, or backend failures. Which get fixed
once in a while by using level 3 optimisation. (Hence I knew the time.)
Supposedly GCC has some of the same features, most compilers are not very
often exersized at the nopt. level and have relatively more bugs in that
part.


Once programs are finished and release upon the poor user, I'll start
optimising. (And test before release). Only when a program has run
flawlessly for a long while I'll take out all the asserts to get your last
1%.


>The marketplace takes all kinds.


Which I fully underscribe, as you've guessed.


Willem Jan Withagen


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