When value-initializing a class with no user-defined constructors but
with a non-trivial default constructor, zero-initialize the storage
and then call the default constructor. Fixes PR5800.

llvm-svn: 91548
diff --git a/clang/test/CodeGenCXX/value-init.cpp b/clang/test/CodeGenCXX/value-init.cpp
new file mode 100644
index 0000000..decfc18
--- /dev/null
+++ b/clang/test/CodeGenCXX/value-init.cpp
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 %s -triple x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s
+
+struct A {
+  virtual ~A();
+};
+
+struct B : A { };
+
+struct C {
+  int i;
+  B b;
+};
+
+// CHECK: _Z15test_value_initv
+void test_value_init() {
+  // This value initialization requires zero initialization of the 'B'
+  // subobject followed by a call to its constructor.
+  // PR5800
+
+  // CHECK: store i32 17
+  // CHECK: call void @llvm.memset.i64
+  // CHECK: call void @_ZN1BC1Ev(%struct.A* %tmp1)
+  C c = { 17 } ;
+  // CHECK: call void @_ZN1CD1Ev(%struct.C* %c)
+}