[gcc r14-9815] c++: add fixed test [PR91079]

[Marek Polacek via Gcc-cvs]

https://gcc.gnu.org/g:2b2d3a135a43cbafadd8957e0b2543f38c390437

commit r14-9815-g2b2d3a135a43cbafadd8957e0b2543f38c390437
Author: Marek Polacek <pola...@redhat.com>
Date:   Fri Apr 5 13:40:33 2024 -0400

    c++: add fixed test [PR91079]
    
    Fixed by r12-2975.
    
            PR c++/91079
            DR 1881
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/ext/is_std_layout5.C: New test.

Diff:
---
 gcc/testsuite/g++.dg/ext/is_std_layout5.C | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/gcc/testsuite/g++.dg/ext/is_std_layout5.C 
b/gcc/testsuite/g++.dg/ext/is_std_layout5.C
new file mode 100644
index 00000000000..875f3c0948d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_std_layout5.C
@@ -0,0 +1,13 @@
+// PR c++/91079
+// DR 1881 - Standard-layout classes and unnamed bit-fields
+// { dg-do compile { target c++11 } }
+
+struct A { int a : 4; };
+struct B : A { int b : 3; };
+static_assert(__is_standard_layout(A), "");
+static_assert(!__is_standard_layout(B), "");
+
+struct C { int : 0; };
+struct D : C { int : 0; };
+static_assert(__is_standard_layout(C), "");
+static_assert(!__is_standard_layout(D), "");