Stream: git-wasmtime

Topic: wasmtime / PR #3887 Add vector compare to 0 optims

Wasmtime GitHub notifications bot (Mar 07 2022 at 12:58):

FreddieLiardet opened PR #3887 from vec_comp to main:

Signed-off-by: Freddie Liardet <frederick.liardet@arm.com>

Optimization for simd comparisons to 0 vectors using dedicated instructions.

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Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

It's a tiny stylistic nit but I'd prefer to avoid this paren on its own line style; the more common S-expr formatting is something like

(let ((x ...)
      (y ...)
      (z ...))
  body)

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

The def_inst can be skipped now that we have implicit conversions -- should make this pattern look much nicer!

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

Could you add spaces between the term name and arg list parenthesis here?

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

put_in_reg also has an implicit conversion defined now, so we can do:

  (rn Reg x)

or just use rn in a context that expects a Reg and things should Just Work.

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

Tiny nit but we've mostly stuck to all-lowercase with underscores ("snake case"); would prefer noteq or not_eq here.

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

It looks like this isn't changing the matched IntCC; could we write this as just IntCC::Equal | IntCC::SignedGreaterThanOrEqual | ... => Some(cond)?

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

Could you add some comments here describing what the extractors look for? E.g. from icmp_cond_zero it's not entirely clear to me what this means: a "zero condition"? Does it change the IntCC somehow?

Wasmtime GitHub notifications bot (Mar 07 2022 at 18:17):

cfallin created PR review comment:

a more descriptive name might be good for this helper: float_cc_cmp_zero_to_vec_misc_op maybe? fcompare doesn't tell the reader what it does, other than suggest perhaps it returns an instruction or something to do a compare... also, the name does not at all suggest the connection to zero.

Wasmtime GitHub notifications bot (Mar 08 2022 at 13:50):

FreddieLiardet updated PR #3887 from vec_comp to main.

Wasmtime GitHub notifications bot (Mar 08 2022 at 17:50):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Mar 08 2022 at 17:50):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Mar 08 2022 at 17:50):

cfallin created PR review comment:

Sorry, I should've said "and similar below" to earlier comments about naming the above constructors. Could you make all of these added ones more descriptive as well? E.g. f_comp_inst doesn't give me any hint that this might have to do with zero comparisons; at best I might buess that it means "create a floating point comparison instruction", which sounds like a generic constructor.

Doc comments on each (one line is fine) to say what they do would also be helpful. Thanks!

Wasmtime GitHub notifications bot (Mar 08 2022 at 17:50):

cfallin created PR review comment:

More paren-style comments: here and below, the closing parens should be on the last line of the body, not on separate lines.

Wasmtime GitHub notifications bot (Mar 09 2022 at 15:44):

FreddieLiardet updated PR #3887 from vec_comp to main.

Wasmtime GitHub notifications bot (Mar 10 2022 at 00:19):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Mar 10 2022 at 00:20):

cfallin merged PR #3887.

Last updated: Dec 06 2025 at 06:05 UTC