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[SR-10606] Slow type checking of bit-twiddling function #53006

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swift-ci opened this issue May 2, 2019 · 1 comment
Open

[SR-10606] Slow type checking of bit-twiddling function #53006

swift-ci opened this issue May 2, 2019 · 1 comment
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compiler The Swift compiler in itself improvement performance type checker Area → compiler: Semantic analysis

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@swift-ci
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swift-ci commented May 2, 2019

Previous ID SR-10606
Radar None
Original Reporter smartgo (JIRA User)
Type Improvement

Attachment: Download

Additional Detail from JIRA
Votes 0
Component/s Compiler
Labels Improvement, Performance, TypeChecker
Assignee None
Priority Medium

md5: 4478fece73f38e6a73319d8f60b2f0f6

Issue Description:

Slow type checking for the following function:

func extractBits(from word: UInt64, offset: Int, numBits: Int) -> UInt {
    return UInt((word >> offset) & ((1 << numBits) - 1))
}

Xcode 10.2.1, Swift 5.
@belkadan
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belkadan commented May 3, 2019

I'll note that you probably want UInt(bitPattern:), but the report's still important.

@swift-ci swift-ci transferred this issue from apple/swift-issues Apr 25, 2022
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compiler The Swift compiler in itself improvement performance type checker Area → compiler: Semantic analysis
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@belkadan @swift-ci