// RUN: %target-swift-frontend %s -emit-ir | %FileCheck %s

// REQUIRES: CPU=x86_64

import Swift

class C {}
sil_vtable C {}

struct JustWeak {
  weak var x: C?
}

struct NoWeak {
  var x, y: C
}

struct SomeWeak {
  var x: C
  weak var y: C?
}

struct Gen<T> {
  var x: C
  var y: T
}

// CHECK-NOT: define internal %swift.opaque* @"$s20weak_value_witnesses8JustWeakVwTK"(

// The default memcpy-ing witness is good enough for NoWeak.
// CHECK-NOT: define internal %swift.opaque* @"$s20weak_value_witnesses6NoWeakVwtk"(%swift.opaque* %dest, %swift.opaque* %src, %swift.type* %Self)

// CHECK-NOT: @"$s20weak_value_witnesses6NoWeakVwTK"

// CHECK-LABEL: define internal %swift.opaque* @"$s20weak_value_witnesses8JustWeakVwCP"
// CHECK: entry:
// CHECK:  load %swift.refcounted*, %swift.refcounted**
// CHECK:  call %swift.refcounted* @swift_retain
// CHECK:  store %swift.refcounted*
// CHECK:  load %swift.refcounted*
// CHECK:  getelementptr inbounds i8
// CHECK:  ret %swift.opaque
// CHECK:}

// CHECK-LABEL: define internal %swift.opaque* @"$s20weak_value_witnesses8SomeWeakVwCP"
// CHECK:entry:
// CHECK:  load %swift.refcounted*, %swift.refcounted**
// CHECK:  call %swift.refcounted* @swift_retain
// CHECK:  store %swift.refcounted*
// CHECK:  load %swift.refcounted*
// CHECK:  getelementptr inbounds i8
// CHECK:  ret %swift.opaque
// CHECK:}

// Weak references must be taken by swift_weakTakeInit.
// CHECK-LABEL: define internal %swift.opaque* @"$s20weak_value_witnesses8SomeWeakVwtk"(%swift.opaque* noalias %dest, %swift.opaque* noalias %src, %swift.type* %SomeWeak)
// CHECK:         call %swift.weak* @swift_weakTakeInit

// CHECK-NOT: define internal %swift.opaque* @"$s20weak_value_witnesses8SomeWeakVwTK"(

// Generic types must be taken using their value witness.
// CHECK-LABEL: define internal %swift.opaque* @"$s20weak_value_witnesses3GenVwtk"(%swift.opaque* noalias %dest, %swift.opaque* noalias %src, %swift.type* %"Gen<T>")
// CHECK:         call %swift.opaque* %initializeWithTake