Stream: git-wasmtime

Topic: wasmtime / PR #8673 x64: Improve lowerings for `ctz`/`clz...

Wasmtime GitHub notifications bot (May 21 2024 at 14:28):

afonso360 requested elliottt for a review on PR #8673.

Wasmtime GitHub notifications bot (May 21 2024 at 14:28):

afonso360 requested wasmtime-compiler-reviewers for a review on PR #8673.

Wasmtime GitHub notifications bot (May 21 2024 at 14:28):

afonso360 opened PR #8673 from afonso360:x64-improve-cls-clz to bytecodealliance:main:

:wave: Hey,

This PR slightly improves the lowerings for clz and ctz for small types (i8/i16) by emitting the native {l,t}zcount instructions for these. Previously we would never emit them even if available.

The first commit just expands our compile tests for these new cases, and the second commit contains the actual lowering changes.

Additionally I've also added the use_sse42 flag to the popcnt runtests since it is required to emit the popcnt instruction.

Wasmtime GitHub notifications bot (May 21 2024 at 14:29):

afonso360 edited PR #8673:

:wave: Hey,

This PR slightly improves the lowerings for clz and ctz for some types (i8/i16/i128) by emitting the native {l,t}zcount instructions for these. Previously we would never emit them even if available.

The first commit just expands our compile tests for these new cases, and the second commit contains the actual lowering changes.

Additionally I've also added the use_sse42 flag to the popcnt runtests since it is required to emit the popcnt instruction.

Wasmtime GitHub notifications bot (May 21 2024 at 15:26):

fitzgen submitted PR review:

Nice!

Wasmtime GitHub notifications bot (May 21 2024 at 15:26):

fitzgen has enabled auto merge for PR #8673.

Wasmtime GitHub notifications bot (May 21 2024 at 15:26):

fitzgen has disabled auto merge for PR #8673.

Wasmtime GitHub notifications bot (May 21 2024 at 15:34):

afonso360 updated PR #8673.

Wasmtime GitHub notifications bot (May 21 2024 at 21:24):

fitzgen submitted PR review.

Wasmtime GitHub notifications bot (May 21 2024 at 21:38):

fitzgen merged PR #8673.

Last updated: Dec 13 2025 at 21:03 UTC