Stream: git-wasmtime

Topic: wasmtime / PR #4729 x64: Lower bitcast, fabs, and fneg in...

Wasmtime GitHub notifications bot (Aug 17 2022 at 03:32):

elliottt opened PR #4729 from trevor/x64-bitcast-fabs-fneg to main:

This PR doesn't need to be reviewed until #4722 is merged

---

Migrate the bitcast, fabs, and fneg instructions to ISLE
<!--

Please ensure that the following steps are all taken care of before submitting
the PR.

• [ ] This has been discussed in issue #..., or if not, please tell us why
  here.

• [ ] A short description of what this does, why it is needed; if the
  description becomes long, the matter should probably be discussed in an issue
  first.

• [ ] This PR contains test cases, if meaningful.

• [ ] A reviewer from the core maintainer team has been assigned for this PR.
  If you don't know who could review this, please indicate so. The list of
  suggested reviewers on the right can help you.

Please ensure all communication adheres to the code of conduct.
-->

Wasmtime GitHub notifications bot (Aug 17 2022 at 23:56):

cfallin created PR review comment:

I wonder, would it be better to use a VCodeConstant here to get the appropriate MSBs-only-in-each-lane value?

Wasmtime GitHub notifications bot (Aug 17 2022 at 23:56):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Aug 17 2022 at 23:56):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Aug 18 2022 at 20:05):

elliottt has marked PR #4729 as ready for review.

Wasmtime GitHub notifications bot (Aug 18 2022 at 20:05):

elliottt edited PR #4729 from trevor/x64-bitcast-fabs-fneg to main:

Migrate the bitcast, fabs, and fneg instructions to ISLE
<!--

Please ensure that the following steps are all taken care of before submitting
the PR.

• [ ] This has been discussed in issue #..., or if not, please tell us why
  here.

• [ ] A short description of what this does, why it is needed; if the
  description becomes long, the matter should probably be discussed in an issue
  first.

• [ ] This PR contains test cases, if meaningful.

• [ ] A reviewer from the core maintainer team has been assigned for this PR.
  If you don't know who could review this, please indicate so. The list of
  suggested reviewers on the right can help you.

Please ensure all communication adheres to the code of conduct.
-->

Wasmtime GitHub notifications bot (Aug 18 2022 at 20:07):

elliottt updated PR #4729 from trevor/x64-bitcast-fabs-fneg to main.

Wasmtime GitHub notifications bot (Aug 18 2022 at 20:09):

elliottt updated PR #4729 from trevor/x64-bitcast-fabs-fneg to main.

Wasmtime GitHub notifications bot (Aug 18 2022 at 21:37):

elliottt requested cfallin for a review on PR #4729.

Wasmtime GitHub notifications bot (Aug 18 2022 at 21:38):

elliottt submitted PR review.

Wasmtime GitHub notifications bot (Aug 18 2022 at 21:38):

elliottt created PR review comment:

Would that be a savings over the two instructions?

Wasmtime GitHub notifications bot (Aug 19 2022 at 00:58):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Aug 19 2022 at 00:58):

cfallin created PR review comment:

Possibly, though looking at xorps I see the basic SSE version is not reg, reg/mem but just reg, reg so it would still be a separate load; one load vs. dependent chain of two 1-cycle ops, the latter likely wins. Anyway it's an unimportant enough question that I don't care too much to investigate further :-)

Wasmtime GitHub notifications bot (Aug 19 2022 at 00:59):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Aug 19 2022 at 00:59):

cfallin merged PR #4729.

Last updated: Nov 22 2024 at 17:03 UTC