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This is exactly why I've been concerned about LLVM's use of a non-copyleft license: unlike with GCC, vendors can create their own proprietary extensions and opt

This is exactly why I've been concerned about LLVM's use of a non-copyleft license: unlike with GCC, vendors can create their own proprietary extensions and optimizations without contributing them back to the community. (In the past, people have dismissed such concerns, saying that it would be impractical for anyone to actually do such a thing. But this project by Intel shows that it isn't just possible--in fact, it's almost inevitable.)

josefx 5y ago
> In the past, people have dismissed such concerns The problem is GCC made these concerns completely irrelevant. You wanted refactoring support for C or C++? Either build it on clang or get screamed at by RMS for leaking GCC internals when text base search and replace was enough for him in the early 80s. The simple fact is that there is no GNU based alternative to clang/llvm.
- arthur2e5 5y ago
  The “good” news on this front is that RMS has been allegedly removed from GCC’s steering committee as a side-effect of the flames of April. Emphasis on “alleged”, since some heavyweights say he was never there to begin with. https://lwn.net/Articles/853230 https://lwn.net/Articles/853230 Somewhere down the thread there are questions about AST, I think.
atty 5y ago
I think it is relevant to point out that Intel’s compiler team would almost certainly never have chosen LLVM in the first place, if it forced them to release whatever secret sauce is giving them the performance increases we see in those performance plots. So it’s not so much a “look at how much LLVM is missing out on by not using copyleft”, it’s more of a “LLVM has gotten some benefit from Intel adopting their tech and putting some of their work back into the open source project”. Sure, I’d love for Intel to upstream every optimization they make, but I don’t see that as necessary or even good business sense for either Intel or LLVM.
ip26 5y ago
Why is this worse than totally proprietary & closed source icc?
- pjmlp 5y ago
  Leeching on the work that Johnny/Jane dev might have contributed to LLVM as part of their PhD thesis in compiler optimisations.
  - Thiez 5y ago
    If Johnny/Jane didn't want their contributions to be used like that they could have licensed them differently though, or contributed to gcc instead. Of course llvm wouldn't accept their contributions if they were licensed under, say, the AGPL. But presumably getting their changes upstreamed is not a condition for completing their thesis, so it's their choice. As a PHD student they are hopefully capable of reading and understanding these licenses (to the degree that someone who hasn't studied law can understand such things).
    - pjmlp 5y ago
      True, except in this fictional story maybe the condition was set by the professor, university department and not a free option of the respective student that now sees his work being abused by a mega corp too cheap to contribute back.
      - Thiez 5y ago
        Sure, in that very specific and somewhat unlikely scenario. Maybe the professor demanded a handjob as well. Or perhaps the university claims ownership over all intellectual property produced by the PhD student as part of their thesis, and they're unable to upstream their source to any project under any license. In any case, it sounds like you want to blame the llvm license for the bad feelings the student might have, but that blame is misdirected: the student should aim their anger (if any) at their professor or university for introducing unreasonable requirements. Or maybe they should suck it up because without llvm they would have had to pick another subject for their thesis. I suspect that llvm wouldn't have grown to where it is now (for better or for worse) with a copyleft license. And then our student would have been "forced" to contribute to gcc instead, and sign over their copyright to the fsf instead. Finally I think the academic world is a lot like permissive licenses already. Anyone can read papers, use that information in any way, and there is no obligation to contribute back. Only when writing new papers are you expected to acknowledge your sources.
phendrenad2 5y ago
Yes, this is a good reason for people to think twice about using non-copyleft. However, if they choose non-copyleft anyway, it's a bit presumptuous to then say the authors are stupid or misled to choose it.

josefx 5y ago

> In the past, people have dismissed such concerns The problem is GCC made these concerns completely irrelevant. You wanted refactoring support for C or C++? Either build it on clang or get screamed at by RMS for leaking GCC internals when text base search and replace was enough for him in the early 80s. The simple fact is that there is no GNU based alternative to clang/llvm.

arthur2e5 5y ago
The “good” news on this front is that RMS has been allegedly removed from GCC’s steering committee as a side-effect of the flames of April. Emphasis on “alleged”, since some heavyweights say he was never there to begin with. https://lwn.net/Articles/853230 https://lwn.net/Articles/853230 Somewhere down the thread there are questions about AST, I think.

atty 5y ago

I think it is relevant to point out that Intel’s compiler team would almost certainly never have chosen LLVM in the first place, if it forced them to release whatever secret sauce is giving them the performance increases we see in those performance plots. So it’s not so much a “look at how much LLVM is missing out on by not using copyleft”, it’s more of a “LLVM has gotten some benefit from Intel adopting their tech and putting some of their work back into the open source project”. Sure, I’d love for Intel to upstream every optimization they make, but I don’t see that as necessary or even good business sense for either Intel or LLVM.

ip26 5y ago

Why is this worse than totally proprietary & closed source icc?

pjmlp 5y ago
Leeching on the work that Johnny/Jane dev might have contributed to LLVM as part of their PhD thesis in compiler optimisations.
- Thiez 5y ago
  If Johnny/Jane didn't want their contributions to be used like that they could have licensed them differently though, or contributed to gcc instead. Of course llvm wouldn't accept their contributions if they were licensed under, say, the AGPL. But presumably getting their changes upstreamed is not a condition for completing their thesis, so it's their choice. As a PHD student they are hopefully capable of reading and understanding these licenses (to the degree that someone who hasn't studied law can understand such things).
  - pjmlp 5y ago
    True, except in this fictional story maybe the condition was set by the professor, university department and not a free option of the respective student that now sees his work being abused by a mega corp too cheap to contribute back.
    - Thiez 5y ago
      Sure, in that very specific and somewhat unlikely scenario. Maybe the professor demanded a handjob as well. Or perhaps the university claims ownership over all intellectual property produced by the PhD student as part of their thesis, and they're unable to upstream their source to any project under any license. In any case, it sounds like you want to blame the llvm license for the bad feelings the student might have, but that blame is misdirected: the student should aim their anger (if any) at their professor or university for introducing unreasonable requirements. Or maybe they should suck it up because without llvm they would have had to pick another subject for their thesis. I suspect that llvm wouldn't have grown to where it is now (for better or for worse) with a copyleft license. And then our student would have been "forced" to contribute to gcc instead, and sign over their copyright to the fsf instead. Finally I think the academic world is a lot like permissive licenses already. Anyone can read papers, use that information in any way, and there is no obligation to contribute back. Only when writing new papers are you expected to acknowledge your sources.

phendrenad2 5y ago

Yes, this is a good reason for people to think twice about using non-copyleft. However, if they choose non-copyleft anyway, it's a bit presumptuous to then say the authors are stupid or misled to choose it.