Stream: git-wasmtime

Topic: wasmtime / PR #5031 cranelift: Remove booleans

Wasmtime GitHub notifications bot (Oct 12 2022 at 17:17):

elliottt edited PR #5031 from trevor/remove-booleans to main:

Remove the boolean types from cranelift, and the associated instructions breduce, bextend, bconst, and bint. Standardize on using 1/0 for the return value from instructions that produce scalar boolean results, and -1/0 for boolean vector elements.

Fixes #3205
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Wasmtime GitHub notifications bot (Oct 12 2022 at 19:18):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 12 2022 at 19:59):

elliottt has marked PR #5031 as ready for review.

Wasmtime GitHub notifications bot (Oct 12 2022 at 20:00):

elliottt requested cfallin for a review on PR #5031.

Wasmtime GitHub notifications bot (Oct 12 2022 at 22:31):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 12 2022 at 22:48):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Oct 12 2022 at 22:48):

cfallin created PR review comment:

we can probably call this file something other than b1.clif now -- maybe conditional_values.clif or something?

Wasmtime GitHub notifications bot (Oct 12 2022 at 22:48):

cfallin created PR review comment:

s/false/0/ here (or "and require the return value to be nonzero")?

Wasmtime GitHub notifications bot (Oct 12 2022 at 22:48):

cfallin created PR review comment:

So nice to see this mess of canonicalization and type-coercion go away!

Wasmtime GitHub notifications bot (Oct 12 2022 at 22:48):

cfallin created PR review comment:

I think this could get a bit better (one instruction shorter) with

tst w0, #255
csel ...

(tst w0, #255 is an alias for ands wzr, w0, #255; if we don't have machinst support for that yet it should be easy as another ALU op, one bit different from and)

Wasmtime GitHub notifications bot (Oct 12 2022 at 22:48):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:13):

elliottt submitted PR review.

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:13):

elliottt created PR review comment:

Great point. I like the latter phrasing, and will make that change.

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:36):

elliottt submitted PR review.

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:36):

elliottt created PR review comment:

Good point, the existing name isn't really all that meaningful going forward :)

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:47):

elliottt submitted PR review.

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:47):

elliottt created PR review comment:

Would you be okay with addressing this one in follow-up PR?

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:49):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:54):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Oct 12 2022 at 23:54):

cfallin created PR review comment:

Yep, that's fine!

Wasmtime GitHub notifications bot (Oct 13 2022 at 01:52):

elliottt submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 01:52):

elliottt created PR review comment:

I went ahead and fixed it on this branch, and found a bug with the x64 lowering of select in the process!

Wasmtime GitHub notifications bot (Oct 13 2022 at 01:56):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 13 2022 at 05:17):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 05:17):

cfallin created PR review comment:

while here, a useful runtest to add might be a very slight variation on this one that intentionally tries to have nonzero bits in the upper undef bits of the i8-in-register, to make sure we're really testing just the low 8 bits; for example, by adding and wrapping:

block0(v0: i8):
  v1 = iconst.i8 255
  v2 = iadd.i8 v0, v1
  brz v2, ...

then it should branch for input arg v0 = 1 even though the register will likely contain 256...

Wasmtime GitHub notifications bot (Oct 13 2022 at 05:17):

cfallin submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 05:17):

cfallin created PR review comment:

Good catch! Just to make sure, do we have a runtest somewhere that tests with a nonzero-but-even value to catch LSB-only checks like this?

Wasmtime GitHub notifications bot (Oct 13 2022 at 09:21):

uweigand submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 09:21):

uweigand created PR review comment:

Hmm. This helper is only called for possible scalar result types of icmp and fcmp. These are specified as &Int.as_bool() and &Float.as_bool() so I thought I needed to handle multiple widths here. But looking at this again, actually the only scalar return type of as_bool has always been $B1 (and is now $I8), so it seems this is only type we need to handle here in the first place.

Wasmtime GitHub notifications bot (Oct 13 2022 at 09:21):

uweigand submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 10:37):

afonso360 submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 10:37):

afonso360 created PR review comment:

;; For conversions that fit in a register, we can use csetm.

Wasmtime GitHub notifications bot (Oct 13 2022 at 10:37):

afonso360 submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 16:26):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 13 2022 at 16:27):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 13 2022 at 16:29):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 13 2022 at 16:43):

elliottt created PR review comment:

We do in the runtests: there's a case that checks the return value with 2 as the argument to select in runtests/br.clif.

Wasmtime GitHub notifications bot (Oct 13 2022 at 16:43):

elliottt submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 16:44):

elliottt submitted PR review.

Wasmtime GitHub notifications bot (Oct 13 2022 at 16:44):

elliottt created PR review comment:

That's a great idea, I'll add that test!

Wasmtime GitHub notifications bot (Oct 13 2022 at 17:25):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 13 2022 at 22:07):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 13 2022 at 23:28):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 17 2022 at 21:07):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 17 2022 at 21:25):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 17 2022 at 21:39):

elliottt updated PR #5031 from trevor/remove-booleans to main.

Wasmtime GitHub notifications bot (Oct 17 2022 at 23:00):

elliottt merged PR #5031.

Last updated: Dec 23 2024 at 12:05 UTC