--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/nested-func-12.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,48 @@
+/* PR target/88620 */
+/* { dg-do run } */
+/* { dg-options "-Ofast --param ipa-cp-eval-threshold=0 -fno-guess-branch-probability -fno-inline-small-functions" } */
+/* { dg-require-effective-target alloca } */
+
+void
+foo (int n)
+{
+  struct S { int a[n]; };
+
+  struct S
+  fn (void)
+  {
+    struct S s;
+    s.a[0] = 42;
+    return s;
+  }
+
+  auto struct S
+  fn2 (void)
+  {
+    return fn ();
+  }
+
+  struct S x;
+  fn ();
+  fn2 ();
+  x = fn ();
+
+  if (x.a[0] != 42)
+    __builtin_abort ();
+
+  if (fn ().a[0] != 42)
+    __builtin_abort ();
+
+  __typeof__ (fn ()) *p = &x;
+  if (p->a[0] != 42)
+    __builtin_abort ();
+
+  if (fn2 ().a[0] != 42)
+    __builtin_abort ();
+}
+
+int
+main (void)
+{
+  foo (1);
+}