Index: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
@@ -732,6 +732,15 @@
       SanOpts.Mask &= ~SanitizerKind::CFIUnrelatedCast;
   }
 
+  // Ignore null checks in coroutine functions since the coroutines passes
+  // are not aware of how to move the extra UBSan instructions across the split
+  // coroutine boundaries.
+  if (D && SanOpts.has(SanitizerKind::Null))
+    if (const auto *FD = dyn_cast<FunctionDecl>(D))
+      if (FD->getBody() &&
+          FD->getBody()->getStmtClass() == Stmt::CoroutineBodyStmtClass)
+        SanOpts.Mask &= ~SanitizerKind::Null;
+
   // Apply xray attributes to the function (as a string, for now)
   if (D) {
     if (const auto *XRayAttr = D->getAttr<XRayInstrumentAttr>()) {
Index: cfe/trunk/test/CodeGenCXX/ubsan-coroutines.cpp
===================================================================
--- cfe/trunk/test/CodeGenCXX/ubsan-coroutines.cpp
+++ cfe/trunk/test/CodeGenCXX/ubsan-coroutines.cpp
@@ -0,0 +1,49 @@
+// This test merely verifies that emitting the object file does not cause a
+// crash when the LLVM coroutines passes are run.
+// RUN: %clang_cc1 -emit-obj -std=c++2a -fsanitize=null %s -o %t.o
+
+namespace std::experimental {
+template <typename R, typename... T> struct coroutine_traits {
+  using promise_type = typename R::promise_type;
+};
+
+template <class Promise = void> struct coroutine_handle;
+template <> struct coroutine_handle<void> {
+  static coroutine_handle from_address(void *) noexcept;
+  coroutine_handle() = default;
+  template <class PromiseType>
+  coroutine_handle(coroutine_handle<PromiseType>) noexcept;
+};
+template <class Promise> struct coroutine_handle : coroutine_handle<void> {
+  coroutine_handle() = default;
+  static coroutine_handle from_address(void *) noexcept;
+};
+}
+
+struct suspend_always {
+  bool await_ready() noexcept;
+  void await_suspend(std::experimental::coroutine_handle<>) noexcept;
+  void await_resume() noexcept;
+};
+
+struct task {
+  struct promise_type {
+    task get_return_object() { return task(); }
+    suspend_always initial_suspend() { return {}; }
+    suspend_always final_suspend() { return {}; }
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+};
+
+struct awaitable {
+  task await() { (void)co_await *this; }
+  bool await_ready() { return false; }
+  bool await_suspend(std::experimental::coroutine_handle<> awaiter) { return false; }
+  bool await_resume() { return false; }
+};
+
+int main() {
+  awaitable a;
+  a.await();
+}