4 ms·

> Everything has correctness issues somewhere. This is fallacy of gray. The blog post isn't complaining that there are non-zero bugs, it's complaining that whe

> Everything has correctness issues somewhere. This is fallacy of gray. The blog post isn't complaining that there are non-zero bugs, it's complaining that when you use the language you hit a lot of correctness bugs. More bugs than you'd hit using e.g. python. Also, to the extent that Julia uses LLVM, a correctness bug in LLVM is also a correctness bug in Julia. So arguing "LLVM has lots of correctness bugs" is not helping the case... > because the code is all Julia, it's really easy to dig in there and find potential bugs. The blog post is about bugs hit while running code, not bugs found while reading code. The fact the issue can be understood and pointed at is great, but it's the number of issues being hit that's the problem.

suavesito 4y ago
> So arguing "LLVM has lots of correctness bugs" is not helping the case It does not help the case about the correctness of Julia, but it does help the case about Julia having more bugs than other software (negatively for the other projects). Every library built with LLVM that touches those code paths will have those bugs. Another thing to have in mind is that Julia ships patches for some of these, that are not used upstream yet. So Julia does not suffer from some bugs on LLVM that other projects might.
- ChrisRackauckas 4y ago
  It shows that Julia's tests are systematically finding (and leading to fixes) of numerical bugs that are pervasive throughout the rest of the LLVM ecosystem. And since Julia's LLVM is patched to solve these while other variants of LLVM are not, Julia is more correct in these aspects than other languages which rely on the Base build of LLVM. Of course Julia doesn't solve "all bugs", but some of them (like the correctness of certain math library implementations) really make you question how hard other language tests are hammering those for correctness testing (Julia has a lot of numerical tests checking the precision of such methods against MPFR bigfloats at higher precision to ensure ~X ulp correctness for example). Julia definitely spends a lot of time testing numerical correctness than it does testing something like a web server. It's just a prioritization thing.
  - nickitolas 4y ago
    Do Julia devs not upstream their LLVM patches?
    - adgjlsfhk1 4y ago
      We do, but it takes a while for LLVM to accept and release patches, so by the time any one issue is fixed, there will be a new bug to take it's place.

suavesito 4y ago

> So arguing "LLVM has lots of correctness bugs" is not helping the case It does not help the case about the correctness of Julia, but it does help the case about Julia having more bugs than other software (negatively for the other projects). Every library built with LLVM that touches those code paths will have those bugs. Another thing to have in mind is that Julia ships patches for some of these, that are not used upstream yet. So Julia does not suffer from some bugs on LLVM that other projects might.

ChrisRackauckas 4y ago
It shows that Julia's tests are systematically finding (and leading to fixes) of numerical bugs that are pervasive throughout the rest of the LLVM ecosystem. And since Julia's LLVM is patched to solve these while other variants of LLVM are not, Julia is more correct in these aspects than other languages which rely on the Base build of LLVM. Of course Julia doesn't solve "all bugs", but some of them (like the correctness of certain math library implementations) really make you question how hard other language tests are hammering those for correctness testing (Julia has a lot of numerical tests checking the precision of such methods against MPFR bigfloats at higher precision to ensure ~X ulp correctness for example). Julia definitely spends a lot of time testing numerical correctness than it does testing something like a web server. It's just a prioritization thing.
- nickitolas 4y ago
  Do Julia devs not upstream their LLVM patches?
  - adgjlsfhk1 4y ago
    We do, but it takes a while for LLVM to accept and release patches, so by the time any one issue is fixed, there will be a new bug to take it's place.