[Objective-C++ IRGen] do not generate .cxx_construct 
for class that contains trivially-constructible struct ivar.
rdar://18950072

llvm-svn: 221823
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 17b0a4b..fe56552 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3005,6 +3005,19 @@
   return false;
 }
 
+static bool AllTrivialInitializers(CodeGenModule &CGM,
+                                   ObjCImplementationDecl *D) {
+  CodeGenFunction CGF(CGM);
+  for (ObjCImplementationDecl::init_iterator B = D->init_begin(),
+       E = D->init_end(); B != E; ++B) {
+    CXXCtorInitializer *CtorInitExp = *B;
+    Expr *Init = CtorInitExp->getInit();
+    if (!CGF.isTrivialInitializer(Init))
+      return false;
+  }
+  return true;
+}
+
 /// EmitObjCIvarInitializations - Emit information for ivar initialization
 /// for an implementation.
 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
@@ -3025,7 +3038,8 @@
 
   // If the implementation doesn't have any ivar initializers, we don't need
   // a .cxx_construct.
-  if (D->getNumIvarInitializers() == 0)
+  if (D->getNumIvarInitializers() == 0 ||
+      AllTrivialInitializers(*this, D))
     return;
   
   IdentifierInfo *II = &getContext().Idents.get(".cxx_construct");