[gcc r10-9311] c++: Fix list-init of array of no-copy type [PR63707]

[Jason Merrill <jason@gcc.gnu.org>]

https://gcc.gnu.org/g:81fd2df5911c4b2c31960fa5ef1407d20f1ca50c

commit r10-9311-g81fd2df5911c4b2c31960fa5ef1407d20f1ca50c
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Jan 15 11:42:00 2021 -0500

    c++: Fix list-init of array of no-copy type [PR63707]
    
    build_vec_init_elt models initialization from some arbitrary object of the
    type, i.e. copy, but in the case of list-initialization we don't do a copy
    from the elements, we initialize them directly.
    
    gcc/cp/ChangeLog:
    
            PR c++/63707
            * tree.c (build_vec_init_expr): Don't call build_vec_init_elt
            if we got a CONSTRUCTOR.
    
    gcc/testsuite/ChangeLog:
    
            PR c++/63707
            * g++.dg/cpp0x/initlist-array13.C: New test.

Diff:
---
 gcc/cp/tree.c                                 | 10 +++++++++-
 gcc/testsuite/g++.dg/cpp0x/initlist-array13.C | 16 ++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 59fa0903015..59cef1770ad 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -782,7 +782,15 @@ build_vec_init_expr (tree type, tree init, tsubst_flags_t complain)
 {
   tree slot;
   bool value_init = false;
-  tree elt_init = build_vec_init_elt (type, init, complain);
+  tree elt_init;
+  if (init && TREE_CODE (init) == CONSTRUCTOR)
+    {
+      gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (init));
+      /* We built any needed constructor calls in digest_init.  */
+      elt_init = init;
+    }
+  else
+    elt_init = build_vec_init_elt (type, init, complain);
 
   if (init == void_type_node)
     {
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-array13.C b/gcc/testsuite/g++.dg/cpp0x/initlist-array13.C
new file mode 100644
index 00000000000..92fe97164cd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist-array13.C
@@ -0,0 +1,16 @@
+// PR c++/63707
+// { dg-do compile { target c++11 } }
+
+struct Child
+{
+  Child (int);
+  ~Child ();
+  Child (const Child &) = delete;
+};
+
+struct Parent
+{
+  Parent () : children {{5}, {7}} {}
+
+  Child children[2];
+};