Wasmtime GitHub notifications bot (Aug 05 2022 at 18:22): Wasmtime GitHub notifications bot (Aug 05 2022 at 18:22):elliottt opened PR #4625 from trevor/x64-icmp-bool-opt to main:
- Add tests asserting existing behavior for
icmp slt- Add a peephole optimization for
x < 0<!--
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Wasmtime GitHub notifications bot (Aug 05 2022 at 18:24):elliottt edited PR #4625 from trevor/x64-icmp-bool-opt to main:
Fixes #4607
Add a peephole optimization for
icmp slt x, (iconst 0)for 32 and 64 bit values, turning them into a right shift by 31 or 63 bits respectively. This optimization only applies to the case where the result of theicmpis used directly, cases likebrz (icmp ..)will be left alone.<!--
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Wasmtime GitHub notifications bot (Aug 05 2022 at 18:27):cfallin submitted PR review.
Wasmtime GitHub notifications bot (Aug 05 2022 at 21:52):elliottt updated PR #4625 from trevor/x64-icmp-bool-opt to main.
Wasmtime GitHub notifications bot (Aug 06 2022 at 03:54):MaxGraey submitted PR review.
Wasmtime GitHub notifications bot (Aug 06 2022 at 03:54):MaxGraey created PR review comment:
Hmm, why it uses signed right shift now? It should be an unsigned shift
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:00):MaxGraey submitted PR review.
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:00):MaxGraey created PR review comment:
Is it correct? I guess it should be:
notl %edi, %edi shrl $31, %edi, %edi
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:04):MaxGraey submitted PR review.
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:04):MaxGraey created PR review comment:
Doesn't ISLE and cranelift ir always canonicalize constants on the right?
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:25):MaxGraey edited PR review comment.
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:26):MaxGraey edited PR review comment.
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:26):MaxGraey edited PR review comment.
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:27):MaxGraey edited PR review comment.
Wasmtime GitHub notifications bot (Aug 06 2022 at 04:35):MaxGraey edited PR review comment.
Wasmtime GitHub notifications bot (Aug 08 2022 at 17:56):elliottt submitted PR review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 17:56):elliottt created PR review comment:
This was with an eye towards better supporting our boolean representations, as mentioned in #3205, as
sarwill do sign extension.
Wasmtime GitHub notifications bot (Aug 08 2022 at 17:58):elliottt created PR review comment:
I've inverted it and restricted this optimization to boolean-producing instructions. Also this shouldn't affect the
test/jmpfusion, as this optimization will only fire foricmpinstructions whose results are used directly, not as the input to a branch decision. Was there another fusion case you were thinking this might invalidate?
Wasmtime GitHub notifications bot (Aug 08 2022 at 17:58):elliottt submitted PR review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:00):elliottt created PR review comment:
Not currently, hence the symmetric cases for this optimization. This is something we might look into after the mid-end optimization work has landed.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:00):elliottt submitted PR review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:14):MaxGraey submitted PR review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:14):MaxGraey created PR review comment:
I meant macro / micro fusion on the CPU side
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:15):MaxGraey deleted PR review comment.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:15):MaxGraey submitted PR review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:15):MaxGraey created PR review comment:
Got it. Thanks!
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:16):MaxGraey submitted PR review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:16):MaxGraey created PR review comment:
I see
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:21):elliottt updated PR #4625 from trevor/x64-icmp-bool-opt to main.
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:23):elliottt created PR review comment:
Given that it's not clear to me that we can use the wider boolean types with
icmp, I've switched back toshrwith a type guard on the result. Sorry about the back and forth here!
Wasmtime GitHub notifications bot (Aug 08 2022 at 18:23):elliottt submitted PR review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 19:48):elliottt has marked PR #4625 as ready for review.
Wasmtime GitHub notifications bot (Aug 08 2022 at 19:49):elliottt requested cfallin for a review on PR #4625.
Wasmtime GitHub notifications bot (Aug 09 2022 at 04:20):cfallin submitted PR review.
Wasmtime GitHub notifications bot (Aug 09 2022 at 16:45):elliottt merged PR #4625.
Last updated: Oct 23 2024 at 20:03 UTC