Use x30 register name with LLVM 23+ by malezjaa · Pull Request #163062 · rust-lang/rust

malezjaa · 2026-09-20T09:24:08Z

Closes #148900

Thanks to llvm/llvm-project#167783, LLVM now recognizes the x30/x29 register names.

r? @folkertdev

taiki-e · 2026-09-20T09:32:10Z

IIUC, the fix is available on LLVM 23+ (llvm/llvm-project@47e142b), but our minimum LLVM version is LLVM 21.

rust/src/bootstrap/src/core/build_steps/llvm.rs

Line 811 in feaadee

panic!("\n\nbad LLVM version: {version}, need >=21\n\n")

malezjaa · 2026-09-20T09:36:16Z

Oh yeah... I didn't think about that, sorry!

folkertdev · 2026-09-20T10:21:12Z

We can at least update the comments though (same for llvm/llvm-project#179740). And you can make using the new register name conditional on the LLVM version (plenty of code does that), and use 2 revisions to check both > 22 and <= 22. The advantage of that is that we'll definitely clean it up once we drop support for version 22.

malezjaa · 2026-09-20T12:02:58Z

Updated. I guess this shouldn't close the original issue anymore? (#148900)

folkertdev

Do you want to do the arm one (llvm/llvm-project#179740) too? It's the same idea.

View changes since this review

malezjaa · 2026-09-20T12:11:14Z

Okay, I'll do arm too.

folkertdev

thanks!

@bors r+

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rust-bors · 2026-09-20T17:55:15Z

📌 Commit 3de0624 has been approved by folkertdev

It is now in the queue for this repository.

@folkertdev

…rkaround, r=folkertdev Use x30 register name with LLVM 23+ Closes rust-lang#148900 Thanks to llvm/llvm-project#167783, LLVM now recognizes the `x30`/`x29` register names. r? @folkertdev

Rollup of 15 pull requests Successful merges: - #161051 (When error from local macro, include macro def span) - #162750 (add case mapping fast paths for Latin-1) - #162831 (Do not continue past `rustc_resolve` when encountering duplicated items) - #162835 (rustdoc: account for nested parens and split text events in bare urls lint) - #163044 (Report runtime range endpoints for runtime values) - #163062 (Use x30 register name with LLVM 23+) - #158102 (When compiling without a specified `--edition`, emit a note) - #162984 (Windows: don't error if `access_mode` is set on `OpenOptions`) - #163005 (Avoid unreachable integer underflow check in `CStr::count_bytes()`) - #163019 (Prepare for the introduction of forced keywords (`k#`)) - #163020 (Dir: fix fallback impl for remove_dir) - #163047 (Use verbose suggestion for `mut binding` instead of `&mut binding`) - #163075 (Fix ArgAttributes mismatches in ABI UI tests for LoongArch64 and RiscV64) - #163079 (enable `f128` from `u64`/`i64` test) - #163082 (Remove `TypeChecker::root_cx`)

@folkertdev

…rkaround, r=folkertdev Use x30 register name with LLVM 23+ Closes rust-lang#148900 Thanks to llvm/llvm-project#167783, LLVM now recognizes the `x30`/`x29` register names. r? @folkertdev

…uwer Rollup of 18 pull requests Successful merges: - #161051 (When error from local macro, include macro def span) - #161629 (Streamline `StateDiffCollector`) - #162750 (add case mapping fast paths for Latin-1) - #162831 (Do not continue past `rustc_resolve` when encountering duplicated items) - #162835 (rustdoc: account for nested parens and split text events in bare urls lint) - #162952 (Depend on lockfiles to prevent GC of the current session) - #163044 (Report runtime range endpoints for runtime values) - #163062 (Use x30 register name with LLVM 23+) - #158102 (When compiling without a specified `--edition`, emit a note) - #162939 (Declare multi-kind constants for MacroKinds) - #162984 (Windows: don't error if `access_mode` is set on `OpenOptions`) - #163005 (Avoid unreachable integer underflow check in `CStr::count_bytes()`) - #163019 (Prepare for the introduction of forced keywords (`k#`)) - #163020 (Dir: fix fallback impl for remove_dir) - #163047 (Use verbose suggestion for `mut binding` instead of `&mut binding`) - #163075 (Fix ArgAttributes mismatches in ABI UI tests for LoongArch64 and RiscV64) - #163079 (enable `f128` from `u64`/`i64` test) - #163082 (Remove `TypeChecker::root_cx`)

…uwer Rollup of 19 pull requests Successful merges: - #161051 (When error from local macro, include macro def span) - #161629 (Streamline `StateDiffCollector`) - #162750 (add case mapping fast paths for Latin-1) - #162831 (Do not continue past `rustc_resolve` when encountering duplicated items) - #162835 (rustdoc: account for nested parens and split text events in bare urls lint) - #162952 (Depend on lockfiles to prevent GC of the current session) - #163044 (Report runtime range endpoints for runtime values) - #163062 (Use x30 register name with LLVM 23+) - #163091 (miri subtree update) - #162939 (Declare multi-kind constants for MacroKinds) - #162984 (Windows: don't error if `access_mode` is set on `OpenOptions`) - #163005 (Avoid unreachable integer underflow check in `CStr::count_bytes()`) - #163019 (Prepare for the introduction of forced keywords (`k#`)) - #163020 (Dir: fix fallback impl for remove_dir) - #163041 (Be more explicit on suggestion type without changing how they are rendered) - #163047 (Use verbose suggestion for `mut binding` instead of `&mut binding`) - #163075 (Fix ArgAttributes mismatches in ABI UI tests for LoongArch64 and RiscV64) - #163079 (enable `f128` from `u64`/`i64` test) - #163082 (Remove `TypeChecker::root_cx`)

@folkertdev

Rollup merge of #163062 - malezjaa:remove-aarch64-x30-asm-workaround, r=folkertdev Use x30 register name with LLVM 23+ Closes #148900 Thanks to llvm/llvm-project#167783, LLVM now recognizes the `x30`/`x29` register names. r? @folkertdev

…uwer Rollup of 19 pull requests Successful merges: - rust-lang/rust#161051 (When error from local macro, include macro def span) - rust-lang/rust#161629 (Streamline `StateDiffCollector`) - rust-lang/rust#162750 (add case mapping fast paths for Latin-1) - rust-lang/rust#162831 (Do not continue past `rustc_resolve` when encountering duplicated items) - rust-lang/rust#162835 (rustdoc: account for nested parens and split text events in bare urls lint) - rust-lang/rust#162952 (Depend on lockfiles to prevent GC of the current session) - rust-lang/rust#163044 (Report runtime range endpoints for runtime values) - rust-lang/rust#163062 (Use x30 register name with LLVM 23+) - rust-lang/rust#163091 (miri subtree update) - rust-lang/rust#162939 (Declare multi-kind constants for MacroKinds) - rust-lang/rust#162984 (Windows: don't error if `access_mode` is set on `OpenOptions`) - rust-lang/rust#163005 (Avoid unreachable integer underflow check in `CStr::count_bytes()`) - rust-lang/rust#163019 (Prepare for the introduction of forced keywords (`k#`)) - rust-lang/rust#163020 (Dir: fix fallback impl for remove_dir) - rust-lang/rust#163041 (Be more explicit on suggestion type without changing how they are rendered) - rust-lang/rust#163047 (Use verbose suggestion for `mut binding` instead of `&mut binding`) - rust-lang/rust#163075 (Fix ArgAttributes mismatches in ABI UI tests for LoongArch64 and RiscV64) - rust-lang/rust#163079 (enable `f128` from `u64`/`i64` test) - rust-lang/rust#163082 (Remove `TypeChecker::root_cx`)

rustbot assigned folkertdev Sep 20, 2026

malezjaa closed this Sep 20, 2026

rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Sep 20, 2026

malezjaa reopened this Sep 20, 2026

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Sep 20, 2026

malezjaa force-pushed the remove-aarch64-x30-asm-workaround branch from 744fd28 to bca6e26 Compare September 20, 2026 12:01

malezjaa changed the title ~~remove x30 asm workaround on aarch64~~ Use x30 register name with LLVM 23+ Sep 20, 2026

folkertdev reviewed Sep 20, 2026

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Comment thread tests/codegen-llvm/asm-aarch64-x30.rs Outdated

Comment thread compiler/rustc_codegen_llvm/src/asm.rs Outdated

malezjaa added 2 commits September 20, 2026 14:14

Use x30 register name with LLVM 23+

35ec478

Use r14 register name with LLVM 23+

3de0624

malezjaa force-pushed the remove-aarch64-x30-asm-workaround branch from bca6e26 to 3de0624 Compare September 20, 2026 12:30

folkertdev reviewed Sep 20, 2026

View reviewed changes

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 20, 2026

Zalathar mentioned this pull request Sep 21, 2026

Rollup of 15 pull requests #163086

Closed

JonathanBrouwer mentioned this pull request Sep 21, 2026

Rollup of 18 pull requests #163089

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JonathanBrouwer mentioned this pull request Sep 21, 2026

Rollup of 19 pull requests #163095

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rust-bors Bot merged commit 0e00d84 into rust-lang:main Sep 21, 2026
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rustbot added this to the 1.100.0 milestone Sep 21, 2026

zachs18 mentioned this pull request Sep 23, 2026

thumbv6m-none-eabi inline asm clobber_abi("C") fails with register 'LR' allocated for constraint '{r14}' does not match required type #163173

Closed

github-actions Bot mentioned this pull request Oct 2, 2026

Toolchain upgrade to nightly-2026-09-25 flux-rs/flux#1803

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Use x30 register name with LLVM 23+ - #163062

Use x30 register name with LLVM 23+#163062
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