--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/CodeGenCXX/microsoft-new.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,39 @@
+// RUN: %clang_cc1 -triple i686-pc-win32 -fms-compatibility %s -emit-llvm -o - | FileCheck %s
+
+#include <stddef.h>
+
+struct arbitrary_t {} arbitrary;
+void *operator new(size_t size, arbitrary_t);
+
+struct arbitrary2_t {} arbitrary2;
+void *operator new[](size_t size, arbitrary2_t);
+
+namespace PR13164 {
+  void f() {
+	// MSVC will fall back on the non-array operator new.
+    void *a;
+    int *p = new(arbitrary) int[4];
+    // CHECK: call i8* @"??2@YAPAXIUarbitrary_t@@@Z"(i32 16, %struct.arbitrary_t*
+  }
+
+  struct S {
+    void *operator new[](size_t size, arbitrary_t);
+  };
+
+  void g() {
+    S *s = new(arbitrary) S[2];
+    // CHECK: call i8* @"??_US@PR13164@@SAPAXIUarbitrary_t@@@Z"(i32 2, %struct.arbitrary_t*
+    S *s1 = new(arbitrary) S;
+    // CHECK: call i8* @"??2@YAPAXIUarbitrary_t@@@Z"(i32 1, %struct.arbitrary_t*
+  }
+
+  struct T {
+    void *operator new(size_t size, arbitrary2_t);
+  };
+
+  void h() {
+    // This should still call the global operator new[].
+    T *t = new(arbitrary2) T[2];
+    // CHECK: call i8* @"??_U@YAPAXIUarbitrary2_t@@@Z"(i32 2, %struct.arbitrary2_t*
+  }
+}