On 12/10/19 2:13 PM, Marek Polacek wrote:
Ville pointed out that our paren init of aggregates doesn't work for
auto a = new A(1, 2, 3);
and I think it should:
A new-expression that creates an object of type T initializes that object
as follows:
...
-- Otherwise, the new-initializer is interpreted according to the
initialization rules of [dcl.init] for direct-initialization.
so I think it follows that we should perform dcl.init#17.6.2.2.
This doesn't work with new[]; we have:
error ("parenthesized initializer in array new");
Bootstrapped/regtested on x86_64-linux, ok for trunk?
OK.
2019-12-10 Marek Polacek <pola...@redhat.com>
PR c++/92878 - Parenthesized init of aggregates in new-expression.
* init.c (build_new_1): Handle parenthesized initialization of
aggregates in new-expression.
* g++.dg/cpp2a/paren-init20.C: New test.
diff --git gcc/cp/init.c gcc/cp/init.c
index e40afe27e1a..b0331b8ba53 100644
--- gcc/cp/init.c
+++ gcc/cp/init.c
@@ -3608,10 +3608,22 @@ build_new_1 (vec<tree, va_gc> **placement, tree type,
tree nelts,
tree ie;
/* We are processing something like `new int (10)', which
- means allocate an int, and initialize it with 10. */
+ means allocate an int, and initialize it with 10.
- ie = build_x_compound_expr_from_vec (*init, "new initializer",
- complain);
+ In C++20, also handle `new A(1, 2)'. */
+ if (cxx_dialect >= cxx2a
+ && AGGREGATE_TYPE_P (type)
+ && (*init)->length () > 1)
+ {
+ ie = build_tree_list_vec (*init);
+ ie = build_constructor_from_list (init_list_type_node, ie);
+ CONSTRUCTOR_IS_DIRECT_INIT (ie) = true;
+ CONSTRUCTOR_IS_PAREN_INIT (ie) = true;
+ ie = digest_init (type, ie, complain);
+ }
+ else
+ ie = build_x_compound_expr_from_vec (*init, "new initializer",
+ complain);
init_expr = cp_build_modify_expr (input_location, init_expr,
INIT_EXPR, ie, complain);
}
diff --git gcc/testsuite/g++.dg/cpp2a/paren-init20.C
gcc/testsuite/g++.dg/cpp2a/paren-init20.C
new file mode 100644
index 00000000000..05da7604686
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/paren-init20.C
@@ -0,0 +1,54 @@
+// PR c++/92878 - Parenthesized init of aggregates in new-expression.
+// { dg-do compile { target c++2a } }
+// Test new TYPE(...).
+
+int f ();
+
+struct A
+{
+ int a;
+ int b;
+};
+
+void
+fn_A ()
+{
+ int i = 0;
+ auto y = new A(1, 2);
+ auto x = new A(++i, ++i);
+ auto z = new A(1, { ++i });
+ auto u = new A(1, f());
+}
+
+struct B
+{
+ int a;
+ int b;
+ int c = 42;
+};
+
+void
+fn_B ()
+{
+ int i = 0;
+ auto y = new B(1, 2);
+ auto x = new B(++i, ++i);
+ auto z = new B(1, { ++i });
+ auto u = new B(1, f());
+}
+
+struct C
+{
+ int a;
+ int b = 10;
+};
+
+void
+fn_C ()
+{
+ int i = 0;
+ auto y = new C(1);
+ auto x = new C(++i);
+ auto z = new C({ ++i });
+ auto u = new C(f());
+}
