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cmov: use ASM XOR for equality comparisons #920

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brxken128 opened this issue Jun 18, 2023 · 3 comments · Fixed by #925
Closed

cmov: use ASM XOR for equality comparisons #920

brxken128 opened this issue Jun 18, 2023 · 3 comments · Fixed by #925

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@brxken128
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This is how we originally did equality comparisons for x86, but for some reason #[inline(always)] caused it to break entirely.

I'd prefer to do the XOR within the ASM block as it's just more consistent, and I'll work on testing this out later today.
@brxken128 brxken128 mentioned this issue Jun 18, 2023
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@tarcieri
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We should probably stop using #[inline(always)]: rust-lang/stdarch#306

@brxken128
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We should probably stop using #[inline(always)]: rust-lang/stdarch#306

And change to just #[inline]? I thought this was best practice anyway, as LLVM/whatever will decide the rest.

This was referenced Jul 5, 2023
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@tarcieri
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tarcieri commented Jul 8, 2023 •
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Our main usage of #[inline(always)] before was as an alternative to #[target_feature] (which mandates the annotated function must be unsafe), but this lead to a lot of hard-to-debug codegen-related issues.

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cmov: XOR within the ASM block brxken128/utils
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@tarcieri @brxken128