Stream: git-wasmtime

Topic: wasmtime / PR #13702 Fix deterministic behavior of `i32x4...

Wasmtime GitHub notifications bot (Jun 22 2026 at 04:44):

alexcrichton opened PR #13702 from alexcrichton:fix-aarch64-sdot to bytecodealliance:main:

This commit fixes a number of minor issues derivative of #13640. The issues here are:

• Wasmtime's previous lowering of i32x4.relaxed_dot_i8x16_i7x16_add_s was incorrect in the deterministic profile, notably performing an intermediate truncation. This is spec-allowed behavior for the instruction in general, but deterministic semantics don't do this. This meant that the CLIF generated for this instruction needed updating.

• The CLIF matcher for the sdot instruction added in #13640 was incorrect. While it correctly matched the CLIF lowering for i32x4.relaxed_dot_i8x16_i7x16_add_s and was a correct lowering for that instruction, it wasn't actually a correct implementation for the CLIF subexpression. The ISLE matcher here is adjusted to match the new CLIF emitted for the deterministic semantics of i32x4.relaxed_dot_i8x16_i7x16_add_s which sdot matches.

Some various tests are adjusted to have more edge cases to test, and some auditing work is done on the i16x8.relaxed_dot_i8x16_i7x16_s instruction as well, but these are the two main issues fixed.

Note that the adjustements visible in golden output tests are for deterministic relaxed simd semantics on x64 and aarch64 without sdot. This is expected as the CLIF has been adjusted to match the spec's deterministic implementation semantics.

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Wasmtime GitHub notifications bot (Jun 22 2026 at 04:44):

alexcrichton requested wasmtime-compiler-reviewers for a review on PR #13702.

Wasmtime GitHub notifications bot (Jun 22 2026 at 04:44):

alexcrichton requested wasmtime-core-reviewers for a review on PR #13702.

Wasmtime GitHub notifications bot (Jun 22 2026 at 04:44):

alexcrichton requested cfallin for a review on PR #13702.

Wasmtime GitHub notifications bot (Jun 22 2026 at 04:56):

alexcrichton updated PR #13702.

Wasmtime GitHub notifications bot (Jun 22 2026 at 08:42):

github-actions[bot] added the label cranelift on PR #13702.

Wasmtime GitHub notifications bot (Jun 22 2026 at 08:42):

github-actions[bot] added the label cranelift:area:aarch64 on PR #13702.

Wasmtime GitHub notifications bot (Jun 22 2026 at 21:31):

:thumbs_up: cfallin submitted PR review.

Wasmtime GitHub notifications bot (Jun 22 2026 at 21:31):

cfallin added PR #13702 Fix deterministic behavior of i32x4.relaxed_dot_i8x16_i7x16_add_s to the merge queue

Wasmtime GitHub notifications bot (Jun 22 2026 at 21:55):

:check: cfallin merged PR #13702.

Wasmtime GitHub notifications bot (Jun 22 2026 at 21:55):

cfallin removed PR #13702 Fix deterministic behavior of i32x4.relaxed_dot_i8x16_i7x16_add_s from the merge queue

Last updated: Jul 29 2026 at 05:03 UTC