LLVM ist a mess

Posted Mar 23, 2024 23:08 UTC (Sat) by donio (guest, #94)
In reply to: LLVM ist a mess by Curan
Parent article: Cranelift code generation comes to Rust

I think there might be a very slowly growing momentum of projects moving away from LLVM. Mesa's ACO shader compiler is the first example that comes to mind, I believe this was motivated primarily by compilation performance. Zig is also working a new backend that won't require LLVM.

Go has famously sidestepped this by doing its own thing (but that was relatively early days for LLVM too). They were criticized for it at the time but on the long run I think it was a wise decision.

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LLVM ist a mess

Posted Mar 25, 2024 7:34 UTC (Mon) by Curan (subscriber, #66186) [Link] (2 responses)

Yeah, it certainly looks that way. Though ACO was, AFAIR a decision driven purely by performance. ACO is just faster than the LLVM path.

LLVM ist a mess

Posted Apr 11, 2024 7:24 UTC (Thu) by daenzer (subscriber, #7050) [Link] (1 responses)

Also, radeonsi hasn't switched the default from LLVM to ACO yet, and it'll probably keep the LLVM backend for some time after that. E.g. AFAIK the radeonsi ACO backend doesn't work with the rusticl frontend yet.

And that's just one driver, Mesa uses LLVM in many other places, the elephant in the room being llvmpipe.

LLVM ist a mess

Posted Apr 11, 2024 7:39 UTC (Thu) by Curan (subscriber, #66186) [Link]

Yeah, the full switch to ACO is not yet there for radeonsi. And, given corporate constraints, might never really happen.

llvmpipe I do not mind. That is a very distinct driver and allows testing for extensions. That would be easy not to build in a production environment with hardware acceleration around. llvmpipe was also very important for virtual machines (these days less). But the core Khronos and/or hardware driver stuff with LLVM dependencies I really wish I could avoid.