316a79f432
This commit stabilizes RISC-V target features with following constraints:
* Describes a ratified extension.
* Implemented on Rust 1.88.0 or before.
Waiting for four+ version cycles seems sufficient.
* Does not disrupt current rustc's target feature + ABI handling.
It excludes "E" and all floating point-arithmetic extensions.
"Zfinx" family does not involve floating point registers but
not stabilizing for now to avoid possible confusion between
the "F" extension family.
* Not vector-related (floating point and integer).
While integer vector subsets should not cause any ABI issues
(as they don't use ABI-dependent floating point registers),
we need to discuss before stabilizing them.
* Supported by the lowest LLVM version supported by rustc (LLVM 20).
List of target features to be stabilized:
1. "b"
2. "za64rs" (no-RT)
3. "za128rs" (no-RT)
4. "zaamo"
5. "zabha"
6. "zacas"
7. "zalrsc"
8. "zama16b" (no-RT)
9. "zawrs"
10. "zca"
11. "zcb"
12. "zcmop"
13. "zic64b" (no-RT)
14. "zicbom"
15. "zicbop" (no-RT)
16. "zicboz"
17. "ziccamoa" (no-RT)
18. "ziccif" (no-RT)
19. "zicclsm" (no-RT)
20. "ziccrse" (no-RT)
21. "zicntr"
22. "zicond"
23. "zicsr"
24. "zifencei"
25. "zihintntl"
26. "zihintpause"
27. "zihpm"
28. "zimop"
29. "ztso"
Of which, 20 of them (29 minus 9 "no-RT" target features) support
runtime detection through `std::arch::is_riscv_feature_detected!()`.
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| .. | ||
| src | ||
| Cargo.toml | ||
| README.md | ||
rustc_target contains some very low-level details that are
specific to different compilation targets and so forth.
For more information about how rustc works, see the rustc dev guide.