Q: List of supported vector extensions / adding new extensions

[mslijepc]

Hi,
Where do you have a list of currently supported vector extensions? Are they all listed in llvm/lib/Target/RISCV/RISCVFeatures.td ?

[arrv-sc]

Hi! Sorry for the late reply.
Unfortunately, our documentation doesn’t currently include a list of supported RISC-V extensions (something we definitely should fix).

In general, Snippy can work with any extension available in LLVM’s backend.
The vector extensions we’ve confirmed to work are:

• V
• Zvbb
• Zvbc
• Zvfbfmin
• Zvfbfwma
• Zvfhmin
• Zvfh

[mslijepc]

Thanks. I will try to compile and run snippy and may come with some more questions.
Do you have plan to add support for other extensions, like zvfbfa or zvma?

[kv-sc]

Support for zvfbfa and zvma isn’t planned in the near future, but we’d really appreciate a merge request adding it — we’d be happy to review and merge it promptly.

[mslijepc]

Thanks. FYI LLVM has a support for zvfbfa

[arrv-sc]

@mslijepc thanks for the info. Cherry-picking this commit right now turned-out to be problematic as it builds upon a lot of llvm-21 features (And this repo currently uses llvm-20). After we sync with llvm-21 this should be much easier, so let's wait with zvfbfa until then.