> Feel free to start creating patches so we can get an idea of what the changes would look like. Hopefully it's not that dramatic.


Okay, will do. I have a few smaller patches to start with. Clang-cl tries to be as compatible as possible with cl, so I don't expect drastic changes. I'm currently trying to figure out an include issue with timeval, but so far the patches have been few and small.


> Be very careful making performance claims without benchmarks to back it up, and ideally against multiple sets of hardware (MSVC is designed and tested to perform well across a range of processors, often by engineers who work for the manufacturer - intuition would suggest that an open source compiler is probably not 30% better all the time). Don't focus on the number right now, but do try to collect the justification before you expect or encourage others to do the work.


I did not mean to say it would make Python 30% faster in all cases, I meant "up to 30% faster". This number is based on benchmarks of CPython with and without computed goto, and my own experiments of benchmarks comparing CPython in the WSL, and native Windows CPython releases on x86_64. But your point is well taken, and I will of course benchmark Python compiled with clang-cl once I have a complete working version.


> Since the ABI is compatible, there should be no problem enabling extensions to be built using this compiler (assuming someone is willing to become a distutils maintainer, as there are currently none). You don't need to ask here to create a third-party library that enables this.


When you say "someone to become a distutils maintainer" you mean for clang-cl specifically? If that is the case, I'm happy to add support and commit to continuing to work on clang-cl support in distutils, as I expect to use it a fair amount.


> I haven't heard any complaints about access to the compilers being an issue recently, so the only reasons to switch the interpreter itself would be source compatibility (essentially, the clang clib is better than our custom Win32 code) or performance. But we need a positive reason to switch support, not just the ability.


I agree there should be a good reason to move away from the MSVC compiler. The decision to move can be re-evaluated when there is a good argument to warrant it.