Stream: git-wasmtime

Topic: wasmtime / PR #2699 [x64] Add i64x2.abs

Wasmtime GitHub notifications bot (Mar 02 2021 at 18:10):

abrown opened PR #2699 from i64x2-abs to main:

This instruction has a single instruction lowering in AVX512F/VL and a three instruction lowering in AVX but neither is currently supported in the x64 backend. To implement this, we instead subtract the vector from 0 and use a blending instruction to pick the lanes containing the absolute value.

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Wasmtime GitHub notifications bot (Mar 02 2021 at 18:11):

abrown submitted PR Review.

Wasmtime GitHub notifications bot (Mar 02 2021 at 18:11):

abrown created PR Review Comment:

@cfallin, I am suspicious about the src.clone() above as well as the Writable::from_reg(regs::xmm0())... am I breaking anything?

Wasmtime GitHub notifications bot (Mar 02 2021 at 18:11):

abrown requested cfallin for a review on PR #2699.

Wasmtime GitHub notifications bot (Mar 02 2021 at 18:29):

abrown updated PR #2699 from i64x2-abs to main.

Wasmtime GitHub notifications bot (Mar 02 2021 at 18:42):

cfallin submitted PR Review.

Wasmtime GitHub notifications bot (Mar 02 2021 at 18:42):

cfallin created PR Review Comment:

I think this should be fine -- cloning the source is harmless (its live range will extend until its last use), and the explicit Writable coercion is fine with a fixed reg (we don't have a helper like writable_xmm0()). And no issues with the fixed reg use vs. src -- its live-range overlaps with src so the register allocator will know to move src elsewhere if originally in xmm0.

Wasmtime GitHub notifications bot (Mar 02 2021 at 18:43):

cfallin submitted PR Review.

Wasmtime GitHub notifications bot (Mar 02 2021 at 20:30):

abrown merged PR #2699.

Last updated: Oct 23 2024 at 20:03 UTC