Optimize RawSpan/_extracting methods
#82057
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- `RawSpan/_extracting(last:)` - `RawSpan/_extracting(droppingFirst:)` - `RawSpan/_extracting(unchecked:)`
oscbyspro
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RawSpan/_extracting methodsRawSpan/_extracting methods
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Generally speaking, we want to resolve these sorts of issues in SIL/LLVM if possible, rather than littering unsafeBitCast everywhere. If that turns out to be impossible for some reason or another, we can resort to bit casts, but we should be starting with that. CC @glessard, @meg-gupta |
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I'll be here to pick up the slack when SIL and LLVM tap out 😇 |
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Use bit casting operations to remove branches in:
RawSpan/_extracting(last:)RawSpan/_extracting(droppingFirst:)RawSpan/_extracting(unchecked:)See also: #81902
This pull request is a practical example: @stephentyrone
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Note that this optimization relies on
Int.init(bitPattern:)andUnsafeRawPointer.init?(bitPattern:)being branchless. They are not branchless at the time of writing. This contribution is but one part of an attempt to fix that.