[cxx-interop] Add silgen test to check triviality of foreign reference types.

Author: zoecarver

test/Interop/Cxx/foreign-reference/reference-counted-silgen.swift

@@ -0,0 +1,31 @@
+// RUN: %target-swift-emit-silgen %s -I %S/Inputs -enable-experimental-cxx-interop | %FileCheck %s
+//
+// XFAIL: OS=linux-android, OS=linux-androideabi
+
+import POD
+import ReferenceCounted
+
+// CHECK-LABEL: sil [ossa] @$s4main11testTrivialyyF : $@convention(thin) () -> ()
+// CHECK-NOT: retain
+// CHECK-NOT: release
+// CHECK-NOT: copy_value
+// CHECK-NOT: destroy_value
+// CHECK-NOT: begin_borrow
+// CHECK-NOT: end_borrow
+// CHECK: return
+// CHECK-LABEL: end sil function '$s4main11testTrivialyyF'
+public func testTrivial() {
+    let x = Empty.create()
+    let t = (x, x, x)
+}
+
+// CHECK-LABEL: sil [ossa] @$s4main14testNonTrivialyyF : $@convention(thin) () -> ()
+// CHECK:  copy_value %{{[0-9]+}} : $LocalCount
+// CHECK:  copy_value %{{[0-9]+}} : $LocalCount
+// CHECK:  copy_value %{{[0-9]+}} : $LocalCount
+// CHECK: return
+// CHECK-LABEL: end sil function '$s4main14testNonTrivialyyF'
+public func testNonTrivial() {
+    let x = LocalCount.create()
+    let t = (x, x, x)
+}