FunctionSignatureOpts: don't convert non-copyable owned -> guaranteed arguments

It's not safe to insert a compensating release_value at the call site.
This release_value calls the deinit which might have been already de-virtualized in the callee.

Author: eeckstein

lib/SILOptimizer/FunctionSignatureTransforms/OwnedToGuaranteedTransform.cpp

@@ -80,6 +80,13 @@ bool FunctionSignatureTransform::OwnedToGuaranteedAnalyzeParameters() {
     if (!A.canOptimizeLiveArg()) {
       continue;
     }
+    if (A.Arg->getType().isMoveOnly()) {
+      // We must not do this transformation for non-copyable types, because it's
+      // not safe to insert a compensating release_value at the call site. This
+      // release_value calls the deinit which might have been already de-
+      // virtualized in the callee.
+      continue;
+    }
 
     // See if we can find a ref count equivalent strong_release or release_value
     // at the end of this function if our argument is an @owned parameter.

test/embedded/non-copyable-deinit.swift

@@ -0,0 +1,28 @@
+// RUN: %target-run-simple-swift(-enable-experimental-feature Embedded -O -parse-as-library -runtime-compatibility-version none -wmo -Xfrontend -disable-objc-interop) | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: OS=macosx || OS=linux-gnu
+
+var deinitCalled = false
+
+struct S: ~Copyable {
+  let s: String
+
+  @inline(never)
+  deinit {
+    precondition(!deinitCalled)
+    deinitCalled = true
+    print(s)
+  }
+}
+
+@main
+struct Main {
+  static func main() {
+    // CHECK:      1
+    _ = S(s: "1")
+    // CHECK-NEXT: done
+    print("done")
+  }
+}
+