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Description
Description
In the following code, both the "non-pack" and "direct" variants optimize down to return 54, but the indirect one that uses both pointer-based indirection and variadic packs still writes the value to the stack, loads it twice using InitializeWithCopy, and then adds the result.
Reproduction
func applyPointer<each T>(input: repeat UnsafePointer<each T>, op: (repeat each T) -> Int) -> Int {
op(repeat (each input).pointee)
}
func applyPointerNonPack<T, U>(input: UnsafePointer<T>, _ input2: UnsafePointer<U>, op: (T, U) -> Int) -> Int {
op(input.pointee, input2.pointee)
}
func applyDirect<each T>(input: repeat each T, op: (repeat each T) -> Int) -> Int {
op(repeat (each input))
}
func test() -> Int {
withUnsafePointer(to: 27) {
applyPointer(input: $0, $0) { ($0 + $1) }
}
}
func testNonPack() -> Int {
withUnsafePointer(to: 27) {
applyPointerNonPack(input: $0, $0) { ($0 + $1) }
}
}
func testDirect() -> Int {
applyDirect(input: 27, 27) { ($0 + $1) }
}Expected behavior
Ideally, the first variant would optimize down to return 54 like the other two.
Environment
Swift 6.1 on Compiler Explorer, also nightly version Swift version 6.2-dev (LLVM 5e7837820b1c886, Swift d5ef256).
Additional information
No response