Stream: git-wasmtime

Topic: wasmtime / PR #14521 aarch64: widen f16 comparisons when ...

view this post on Zulip Wasmtime GitHub notifications bot (Oct 04 2026 at 09:08):

dotcom07 opened PR #14521 from dotcom07:fix/aarch64-f16-fcmp to bytecodealliance:main:

Fixes #14510.

When an f16 comparison is folded into a branch or select, AArch64 can emit fcmp hN, hM even with has_fp16 disabled. This instruction requires Arm's half-precision floating-point arithmetic extension (FEAT_FP16), so these comparisons can trap on CPUs without that feature.

This widens both operands to f32 in the shared comparison helper when FP16 is unavailable. The scalar f16-to-f32 fcvt conversion does not require FEAT_FP16. This also allows standalone f16 comparisons and zero-extended comparison results to use the same fallback.

Adds precise-output tests for the generated comparisons, an encoding test for the conversion, and runtime tests covering NaNs, signed zeros, infinities, and subnormals. The runtime tests were run on Apple Silicon with has_fp16 enabled and disabled.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 04 2026 at 09:08):

dotcom07 requested cfallin for a review on PR #14521.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 04 2026 at 09:08):

dotcom07 requested wasmtime-compiler-reviewers for a review on PR #14521.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 04 2026 at 15:12):

dotcom07 updated PR #14521.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 04 2026 at 18:14):

github-actions[bot] added the label cranelift on PR #14521.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 04 2026 at 18:14):

github-actions[bot] added the label cranelift:area:aarch64 on PR #14521.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 06 2026 at 17:36):

cfallin commented on PR #14521:

@dotcom07 thanks for this PR -- as with the other one of yours, I plan to get to this early next week.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 09 2026 at 18:28):

:thumbs_up: cfallin submitted PR review.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 09 2026 at 18:29):

cfallin added PR #14521 aarch64: widen f16 comparisons when FP16 is unavailable to the merge queue.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 09 2026 at 18:51):

:check: cfallin merged PR #14521.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 09 2026 at 18:51):

cfallin removed PR #14521 aarch64: widen f16 comparisons when FP16 is unavailable from the merge queue.

Last updated: Oct 11 2026 at 04:10 UTC