Don't build an aggregate constructor loop when the constructor is trivial.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@102912 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGExprCXX.cpp

@@ -465,11 +465,13 @@ static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
                                llvm::Value *NewPtr,
                                llvm::Value *NumElements) {
   if (E->isArray()) {
-    if (CXXConstructorDecl *Ctor = E->getConstructor())
-      CGF.EmitCXXAggrConstructorCall(Ctor, NumElements, NewPtr, 
-                                     E->constructor_arg_begin(), 
-                                     E->constructor_arg_end());
-    return;
+    if (CXXConstructorDecl *Ctor = E->getConstructor()) {
+      if (!Ctor->getParent()->hasTrivialConstructor())
+        CGF.EmitCXXAggrConstructorCall(Ctor, NumElements, NewPtr, 
+                                       E->constructor_arg_begin(), 
+                                       E->constructor_arg_end());
+      return;
+    }
   }
   
   QualType AllocType = E->getAllocatedType();

test/CodeGenCXX/new.cpp

@@ -96,3 +96,13 @@ void t11() {
   // CHECK: call void @llvm.memset.p0i8.i64(
   B* b = new B();
 }
+
+struct Empty { };
+
+// We don't need to initialize an empty class.
+void t12() {
+  // CHECK: define void @_Z3t12v
+  // CHECK-NOT: br label
+  // CHECK: ret void
+  (void)new Empty[10];
+}