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JIT: Optimize bit-wise and operation and compare with same constant value #111933

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Merged
merged 6 commits into from
Apr 23, 2025
Merged

JIT: Optimize bit-wise and operation and compare with same constant value #111933

merged 6 commits into from
Apr 23, 2025

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varelen
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@varelen varelen commented Jan 28, 2025 •
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This pull request resolves #101000 and is based on the feedback that was given on the original PR #103868. Thanks for the previous work, it was a really great way to get started.

The code emitted for:

void Foo(int x)
{
    if ((x & 0xC000000) == 0xC000000)
        Console.WriteLine();
}

x64 (before):

and     edi, 0xC000000
cmp     edi, 0xC000000
jne     SHORT G_M000_IG04

x64 (after):

not      edi
and      edi, 0xC000000
jne      SHORT G_M000_IG04

ARM64 (before):

and	w0, w0, #0xC000000
mov	w1, #0xC000000
cmp	w0, w1
bne	G_M29168_IG04

ARM64 (after):

mvn	w0, w0
and	w0, w0, #0xC000000
cbnz	w0, G_M29168_IG04

@varelen
JIT: Optimize bit-wise and operation and compare with same constant v…
7a1ae17 
…alue

This change optimizes bit-wise and with compare patterns like '(x & <constant>) == <constant>'

Fix dotnet#101000
@ghost ghost added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Jan 28, 2025
@dotnet-policy-service dotnet-policy-service bot added the community-contribution Indicates that the PR has been added by a community member label Jan 28, 2025
@varelen varelen marked this pull request as ready for review February 4, 2025 17:19
@jakobbotsch jakobbotsch reopened this Feb 24, 2025
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Thanks for the contribution! I closed/reopened this to kick off a fresh run of the CI.

cc @dotnet/jit-contrib

EgorBo
EgorBo reviewed Feb 24, 2025
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src/coreclr/jit/lower.cpp
@@ -4346,6 +4346,16 @@ GenTree* Lowering::OptimizeConstCompare(GenTree* cmp)
}
#endif
}
else if (andOp2->IsIntegralConst() && GenTree::Compare(andOp2, op2))
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can you leave a comment of what this transformation does?

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I added a comment, hope it's okay.

This was referenced Feb 24, 2025
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EgorBo commented Feb 25, 2025

/azp run Fuzzlyn

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@JulieLeeMSFT
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@EgorBo, please review this community PR again.

@build-analysis build-analysis bot mentioned this pull request Mar 24, 2025
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@JulieLeeMSFT
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@BruceForstall, please review this community PR.

@JulieLeeMSFT JulieLeeMSFT removed the request for review from EgorBo April 14, 2025 15:54
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/azp run Fuzzlyn, runtime-coreclr outerloop

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Azure Pipelines successfully started running 2 pipeline(s).

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/ba-g unrelated failures

@BruceForstall BruceForstall merged commit a37502b into dotnet:main Apr 23, 2025
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@BruceForstall BruceForstall BruceForstall approved these changes

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JIT: Optimize "x & cns == cns" pattern
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@varelen @jakobbotsch @EgorBo @JulieLeeMSFT @BruceForstall