Stream: git-wasmtime

Topic: wasmtime / PR #1762 Replace InsertLane format with Ternar...

view this post on Zulip Wasmtime GitHub notifications bot (May 26 2020 at 21:13):

abrown opened PR #1762 from ternary-imm8 to master:

The InsertLane format has an ordering (value().imm().value()) and immediate name ("lane") that make it awkward to use for other instructions. This changes the ordering (value().value().imm()) and uses the default name ("imm") throughout the codebase.

view this post on Zulip Wasmtime GitHub notifications bot (May 26 2020 at 21:14):

abrown requested iximeow for a review on PR #1762.

view this post on Zulip Wasmtime GitHub notifications bot (May 26 2020 at 22:40):

abrown updated PR #1762 from ternary-imm8 to master:

The InsertLane format has an ordering (value().imm().value()) and immediate name ("lane") that make it awkward to use for other instructions. This changes the ordering (value().value().imm()) and uses the default name ("imm") throughout the codebase.

view this post on Zulip Wasmtime GitHub notifications bot (May 29 2020 at 16:09):

iximeow submitted PR Review.

view this post on Zulip Wasmtime GitHub notifications bot (May 29 2020 at 16:09):

iximeow submitted PR Review.

view this post on Zulip Wasmtime GitHub notifications bot (May 29 2020 at 16:09):

iximeow created PR Review Comment:

I'm surprised to see we don't use 0x6b/0x69-encoded IMUL, where TernaryImm8 would be a better-fitting format in fact (it's a three-operand encoding in the form imul rrr, r/m, imm8, or imm32 for the 32/64-bit forms). Do you know what other instructions are referenced here? A read through the legalizer seems to suggest this isn't actually true.

view this post on Zulip Wasmtime GitHub notifications bot (May 29 2020 at 21:46):

iximeow submitted PR Review.

view this post on Zulip Wasmtime GitHub notifications bot (May 29 2020 at 21:46):

iximeow created PR Review Comment:

answer: x86_pshufd where the immediate is not a lane selector, it's a mask of how to shuffle (where there is no encoding for a type-invalid mask that we would want to check in this arm)

and this comment will become more true in the future with additional instructions taking mask immediates.

view this post on Zulip Wasmtime GitHub notifications bot (May 29 2020 at 22:08):

abrown closed without merge PR #1762.

Last updated: Nov 22 2024 at 16:03 UTC