Support `vfp5` target feature
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- Dominant language
- Rust
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- 119k
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Description
ARM Cortex-M7 has vfp5, according to documentation - 1 and 2.
LLVM already has it, see https://github.com/llvm/llvm-project/issues/95053 (FPUVersion::VFPV5).
Seems to rustc doesn't supports it, throwing message
'+vfp5' is not a recognized feature for this target (ignoring feature)
Could be great to support vfp5 in the rustc ❤️🔥
Oh I see that there is vfp4d16sp feature. Am I right? Maybe could be good to create alias for it as vfp5?
https://github.com/rust-lang/rust/blob/35e6e4c5e9d3936df098d30750f28716740ea71b/compiler/rustc_target/src/spec/targets/thumbv7em_none_eabihf.rs#L29-L36
Also I see features
vfp4d16- VFP4 instructions with only 16 d-registersvfp4d16sp- VFP4 instructions with only 16 d-registers and no double precisionvfp4sp- VFP4 instructions with no double precision
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with compiler/rustc_target/src/spec/targets/thumbv7em_none_eabihf.rs and compare its existing VFP feature names with LLVM's FPUVersion::VFPV5 referenced in the issue. Determine whether vfp5 should be supported directly or treated as an alias, then verify that the target feature is accepted instead of being ignored.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100