Index: lib/CodeGen/TargetInfo.cpp
===================================================================
--- lib/CodeGen/TargetInfo.cpp
+++ lib/CodeGen/TargetInfo.cpp
@@ -2498,13 +2498,16 @@
   // of the second element because it might make us access off the end of the
   // struct.
   if (HiStart != 8) {
-    // There are only two sorts of types the ABI generation code can produce for
-    // the low part of a pair that aren't 8 bytes in size: float or i8/i16/i32.
+    // There are usually two sorts of types the ABI generation code can produce
+    // for the low part of a pair that aren't 8 bytes in size: float or
+    // i8/i16/i32.  This can also include pointers when they are 32-bit (X32 and
+    // NaCl).
     // Promote these to a larger type.
     if (Lo->isFloatTy())
       Lo = llvm::Type::getDoubleTy(Lo->getContext());
     else {
-      assert(Lo->isIntegerTy() && "Invalid/unknown lo type");
+      assert((Lo->isIntegerTy() || Lo->isPointerTy())
+             && "Invalid/unknown lo type");
       Lo = llvm::Type::getInt64Ty(Lo->getContext());
     }
   }
Index: test/CodeGenCXX/x86_64-arguments-nacl-x32.cpp
===================================================================
--- test/CodeGenCXX/x86_64-arguments-nacl-x32.cpp
+++ test/CodeGenCXX/x86_64-arguments-nacl-x32.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-nacl -emit-llvm -o - %s | FileCheck %s
-// RUN: %clang_cc1 -triple=x86_64-unknown-linux-gnux32 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-nacl -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 -triple=x86_64-unknown-linux-gnux32 -emit-llvm -o - %s | FileCheck %s
 
 struct test_struct {};
 typedef int test_struct::* test_struct_mdp;
@@ -42,3 +42,16 @@
 void f_struct_with_mfp_too_much(struct_with_mfp_too_much a, int x) {
   (void)a;
 }
+
+/* Struct containing an empty struct */
+typedef struct { int* a; test_struct x; double *b; } struct_with_empty;
+
+// CHECK-LABEL: define void @{{.*}}f_pass_struct_with_empty{{.*}}(i64 %x{{.*}}, double* %x
+void f_pass_struct_with_empty(struct_with_empty x) {
+  (void) x;
+}
+
+// CHECK-LABEL: define { i64, double* } @{{.*}}f_return_struct_with_empty
+struct_with_empty f_return_struct_with_empty() {
+  return {0, {}, 0};
+}