Merge pull request swiftlang#39824 from glessard/urbp-copycontents-optimization

glessard · web-flow · commit 8eea64271a4e · 2021-10-21T11:39:43.000-06:00
[stdlib] a minor optimization
diff --git a/stdlib/public/core/UnsafeRawBufferPointer.swift.gyb b/stdlib/public/core/UnsafeRawBufferPointer.swift.gyb
@@ -181,7 +181,7 @@ extension Unsafe${Mutable}RawBufferPointer: Sequence {
     }
     let destinationAddress = destination.baseAddress._unsafelyUnwrappedUnchecked
     let d = UnsafeMutableRawPointer(destinationAddress)
-    let n = Swift.min(destination.count, self.count)
+    let n = Swift.min(destination.count, s.distance(to: e))
     d.copyMemory(from: s, byteCount: n)
     return (Iterator(_position: s.advanced(by: n), _end: e), n)
   }

Original file line number	Diff line number	Diff line change
`@@ -181,7 +181,7 @@ extension Unsafe${Mutable}RawBufferPointer: Sequence {`
`181`	`181`	`}`
`182`	`182`	`let destinationAddress = destination.baseAddress._unsafelyUnwrappedUnchecked`
`183`	`183`	`let d = UnsafeMutableRawPointer(destinationAddress)`
`184`		`- let n = Swift.min(destination.count, self.count)`
	`184`	`+ let n = Swift.min(destination.count, s.distance(to: e))`
`185`	`185`	`d.copyMemory(from: s, byteCount: n)`
`186`	`186`	`return (Iterator(_position: s.advanced(by: n), _end: e), n)`
`187`	`187`	`}`