A union can have a constexpr defaulted default constructor, if it has an

in-class initializer for one of its fields. Value-initialization of such
a type should use the in-class initializer!

The former was just a bug, the latter is a (reported) standard defect.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156274 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 54 insertions, 2 deletions

diff --git a/test/CXX/special/class.ctor/p6-0x.cpp b/test/CXX/special/class.ctor/p6-0x.cpp
index 8c8800f2de..9860317aa1 100644
--- a/test/CXX/special/class.ctor/p6-0x.cpp
+++ b/test/CXX/special/class.ctor/p6-0x.cpp
@@ -55,3 +55,42 @@ struct A {}; // expected-note {{here}}
 struct B {
   friend A::A(); // expected-error {{non-constexpr declaration of 'A' follows constexpr declaration}}
 };
+
+namespace UnionCtors {
+  union A { // expected-note {{here}}
+    int a;
+    int b;
+  };
+  union B {
+    int a;
+    int b = 5;
+  };
+  union C {
+    int a = 5;
+    int b;
+  };
+  struct D {
+    union {
+      int a = 5;
+      int b;
+    };
+    union {
+      int c;
+      int d = 5;
+    };
+  };
+  struct E { // expected-note {{here}}
+    union {
+      int a;
+      int b;
+    };
+  };
+
+  struct Test {
+    friend constexpr A::A() noexcept; // expected-error {{follows non-constexpr declaration}}
+    friend constexpr B::B() noexcept;
+    friend constexpr C::C() noexcept;
+    friend constexpr D::D() noexcept;
+    friend constexpr E::E() noexcept; // expected-error {{follows non-constexpr declaration}}
+  };
+}
diff --git a/test/CodeGenCXX/const-init-cxx11.cpp b/test/CodeGenCXX/const-init-cxx11.cpp
index 62a345a495..d1b91ba3f5 100644
--- a/test/CodeGenCXX/const-init-cxx11.cpp
+++ b/test/CodeGenCXX/const-init-cxx11.cpp
@@ -49,6 +49,17 @@ namespace StructUnion {
 
   // CHECK: @_ZN11StructUnion1fE = global {{.*}} { i32 5 }
   D f;
+
+  union E {
+    int a;
+    void *b = &f;
+  };
+
+  // CHECK: @_ZN11StructUnion1gE = global {{.*}} @_ZN11StructUnion1fE
+  E g;
+
+  // CHECK: @_ZN11StructUnion1hE = global {{.*}} @_ZN11StructUnion1fE
+  E h = E();
 }
 
 namespace BaseClass {
diff --git a/test/CodeGenCXX/member-init-anon-union.cpp b/test/CodeGenCXX/member-init-anon-union.cpp
index 1ff7537387..4db31f0b83 100644
--- a/test/CodeGenCXX/member-init-anon-union.cpp
+++ b/test/CodeGenCXX/member-init-anon-union.cpp
@@ -2,8 +2,10 @@
 
 // PR10531.
 
+int make_a();
+
 static union {
-  int a = 42;
+  int a = make_a();
   char *b;
 };
 
@@ -32,4 +34,4 @@ int g() {
 
 // CHECK: define {{.*}}@"[[CONSTRUCT_GLOBAL]]C2Ev"
 // CHECK-NOT: }
-// CHECK: store i32 42
+// CHECK: call {{.*}}@_Z6make_a