Add a unit test for LifetimeDependenceInsertion

Author: atrick

test/SILOptimizer/lifetime_dependence_insertion.swift

@@ -0,0 +1,48 @@
+// RUN: %target-swift-frontend %s -emit-sil \
+// RUN:   -sil-verify-all \
+// RUN:   -module-name test \
+// RUN:   -disable-experimental-parser-round-trip \
+// RUN:   -enable-experimental-feature NonescapableTypes \
+// RUN:   -Xllvm -enable-lifetime-dependence-insertion \
+// RUN:   2>&1 | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+
+@_nonescapable
+struct BV {
+  let p: UnsafeRawPointer
+  let i: Int
+
+  @_unsafeNonescapableResult
+  init(_ p: UnsafeRawPointer, _ i: Int) {
+    self.p = p
+    self.i = i
+  }
+}
+
+struct NC : ~Copyable {
+  let p: UnsafeRawPointer
+  let i: Int
+
+  // Requires a borrow.
+  borrowing func getBV() -> _borrow(self) BV {
+    BV(p, i)
+  }
+}
+
+@_silgen_name("use")
+func use(_ o : borrowing BV)
+
+// CHECK-LABEL: sil hidden @$s4test13bv_borrow_var1p1iySV_SitF : $@convention(thin) (UnsafeRawPointer, Int) -> () {
+// CHECK: [[A:%.*]] = begin_access [read] [static] %{{.*}} : $*NC
+// CHECK: [[L:%.*]] = load [[A]] : $*NC
+// CHECK:   [[R:%.*]] = apply %{{.*}}([[L]]) : $@convention(method) (@guaranteed NC) -> _scope(0) @owned BV
+// CHECK:   [[M:%.*]] = mark_dependence [unresolved] [[R]] : $BV on [[A]] : $*NC
+// CHECK:   end_access [[A]] : $*NC
+// CHECK:   %{{.*}} = apply %{{.*}}([[M]]) : $@convention(thin) (@guaranteed BV) -> ()
+// CHECK-LABEL: } // end sil function '$s4test13bv_borrow_var1p1iySV_SitF'
+func bv_borrow_var(p: UnsafeRawPointer, i: Int) {
+  var nc = NC(p: p, i: i)
+  let bv = nc.getBV()
+  use(bv)
+}