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@a4lg a4lg commented Sep 17, 2025

This PR updates documentation links and fixes minor issues:

  1. Non-existent zb is removed (b exists but not stabilized yet).
  2. Wrong link for the zbkc target feature is fixed.
  3. Implication from the zbc target feature is updated (reflects the behavior of rustc_target: Adjust RISC-V feature implication rust#140139).

Note that this PR itself does not attempt to stabilize any of new extensions (target features) but makes the documentation more solid.

@rustbot rustbot added the S-waiting-on-review Status: The marked PR is awaiting review from a maintainer label Sep 17, 2025
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a4lg commented Sep 17, 2025

Note that, this PR is separated from #1987 (which includes stabilization of new extensions) for early adoption of the non-stabilization part.
The next submission of #1987 will be is now based on this PR.

The `Zb` extension does not exist and we instead have the `B` extension
which is a superset of the three subextensions: `Zba`, `Zbb` and `Zbs`.

For now (since `B` extension is not stabilized on Rust),
this commit just removes `Zb`.
This is the latest ratified ISA Manual version and more importantly,
some individual documents are merged into this.

So, this commit consistently use this Manual (this version) where possible.

Along with this, this commit substitutes link IDs from `rv-zb-*` to `rv-*`
because `rv-zb-*` will look like the different document (bit-manipulation)
is referenced.
rust-lang/rust#140139 changed the target feature implication without
updating the Reference.  That change is came from the fact that the Zbc
extension is a functional superset of the Zbkc extension.

This commit fixes this issue.

Appendix - List of all Zbkc / Zbc instructions:

*   `clmul`  (Zbkc / Zbc)
*   `clmulh` (Zbkc / Zbc)
*   `clmulr` (Zbc only)
@a4lg a4lg force-pushed the riscv-extension-ref-update-2025.1 branch from d1fcd20 to 0752505 Compare September 18, 2025 01:02
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ehuss commented Sep 23, 2025

@Amanieu can you take a look at this?
Also ping @taiki-e since you approved #2005. I'm not sure if you're interested in reviewing these.

We need an appropriate group of people to ping for RISC-V.

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a4lg commented Sep 24, 2025

@ehuss This is a strict subset of #1987 (which contains all of this PR (4 commits) + one stabilization commit) and it seems @Amanieu approved that superset.

So IIUC, @Amanieu effectively approved all of the changes here.

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Thanks!

@ehuss ehuss added this pull request to the merge queue Sep 29, 2025
@ehuss ehuss removed this pull request from the merge queue due to a manual request Sep 29, 2025
@ehuss ehuss enabled auto-merge September 29, 2025 00:02
@ehuss ehuss added this pull request to the merge queue Sep 29, 2025
Merged via the queue into rust-lang:master with commit 4c8f8b7 Sep 29, 2025
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@rustbot rustbot removed the S-waiting-on-review Status: The marked PR is awaiting review from a maintainer label Sep 29, 2025
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5 participants