Stream: git-wasmtime

Topic: wasmtime / PR #14141 aarch64: lower `AtomicCAS128` to `ca...

Wasmtime GitHub notifications bot (Aug 15 2026 at 01:28):

V3L0C1T13S opened PR #14141 from microlift:aarch64_atomiccas_128 to bytecodealliance:main:

This PR adds support for lowering AtomicCAS128 by lowering it to caspal, gated behind FEAT_LSE. Lowering to caspal makes it use acquire-release semantics like other atomics do.

This is currently being used in a project I'm working on (privately for now) to emulate the semantics of an x86-64 cmpxchg16b on AArch64 and other backends that may eventually support AtomicCAS128.

Wasmtime GitHub notifications bot (Aug 15 2026 at 01:28):

V3L0C1T13S requested fitzgen for a review on PR #14141.

Wasmtime GitHub notifications bot (Aug 15 2026 at 01:28):

V3L0C1T13S requested wasmtime-compiler-reviewers for a review on PR #14141.

Wasmtime GitHub notifications bot (Aug 15 2026 at 03:00):

github-actions[bot] added the label cranelift on PR #14141.

Wasmtime GitHub notifications bot (Aug 15 2026 at 03:00):

github-actions[bot] added the label cranelift:area:aarch64 on PR #14141.

Wasmtime GitHub notifications bot (Aug 15 2026 at 03:00):

github-actions[bot] added the label isle on PR #14141.

Wasmtime GitHub notifications bot (Aug 15 2026 at 03:00):

github-actions[bot] commented on PR #14141:

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cc @cfallin, @fitzgen

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Wasmtime GitHub notifications bot (Aug 24 2026 at 21:08):

:thumbs_up: fitzgen submitted PR review:

Thanks! Sorry for the delay

Wasmtime GitHub notifications bot (Aug 24 2026 at 21:08):

fitzgen added PR #14141 aarch64: lower AtomicCAS128 to caspal when LSE is supported to the merge queue.

Wasmtime GitHub notifications bot (Aug 24 2026 at 21:33):

github-merge-queue[bot] removed PR #14141 aarch64: lower AtomicCAS128 to caspal when LSE is supported from the merge queue.

Wasmtime GitHub notifications bot (Aug 25 2026 at 18:44):

V3L0C1T13S updated PR #14141.

Wasmtime GitHub notifications bot (Aug 25 2026 at 18:57):

V3L0C1T13S commented on PR #14141:

ISLE verifier failure should be fixed by the newest commit - also reordered the rule for consistency with other rules.

Wasmtime GitHub notifications bot (Aug 25 2026 at 20:03):

:thumbs_up: fitzgen submitted PR review:

Thanks!

Wasmtime GitHub notifications bot (Aug 25 2026 at 20:03):

fitzgen added PR #14141 aarch64: lower AtomicCAS128 to caspal when LSE is supported to the merge queue.

Wasmtime GitHub notifications bot (Aug 25 2026 at 20:28):

github-merge-queue[bot] removed PR #14141 aarch64: lower AtomicCAS128 to caspal when LSE is supported from the merge queue.

Wasmtime GitHub notifications bot (Aug 25 2026 at 20:44):

alexcrichton added PR #14141 aarch64: lower AtomicCAS128 to caspal when LSE is supported to the merge queue.

Wasmtime GitHub notifications bot (Aug 25 2026 at 21:10):

:check: alexcrichton merged PR #14141.

Wasmtime GitHub notifications bot (Aug 25 2026 at 21:10):

alexcrichton removed PR #14141 aarch64: lower AtomicCAS128 to caspal when LSE is supported from the merge queue.

Last updated: Aug 30 2026 at 10:08 UTC