diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 5fcb892f7fb87d..cae79099dd6bcf 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -825,7 +825,7 @@ MicrosoftCXXABI::getRecordArgABI(const CXXRecordDecl *RD) const {
   switch (CGM.getTarget().getTriple().getArch()) {
   default:
     // FIXME: Implement for other architectures.
-    return RAA_Default;
+    return RAA_Indirect;
 
   case llvm::Triple::thumb:
     // Pass things indirectly for now because it is simple.
diff --git a/clang/test/CodeGenCXX/microsoft-abi-unknown-arch.cpp b/clang/test/CodeGenCXX/microsoft-abi-unknown-arch.cpp
new file mode 100644
index 00000000000000..bb0364186eb40e
--- /dev/null
+++ b/clang/test/CodeGenCXX/microsoft-abi-unknown-arch.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -emit-llvm %s -o - -triple=ppc64-windows-msvc | FileCheck %s
+
+// The purpose of this test is to see that we do something reasonable for
+// architectures where we haven't checked what MSVC does.
+
+struct A {
+  A() : a(42) {}
+  A(const A &o) : a(o.a) {}
+  ~A() {}
+  int a;
+};
+
+struct B {
+  A foo(A o);
+};
+
+A B::foo(A x) {
+  return x;
+}
+
+// CHECK-LABEL: define void @"?foo@B@@QEAA?AUA@@U2@@Z"(%struct.B* %this, %struct.A* noalias sret align 4 %agg.result, %struct.A* %x)