Index: include/llvm/ADT/PointerSumType.h
===================================================================
--- include/llvm/ADT/PointerSumType.h
+++ include/llvm/ADT/PointerSumType.h
@@ -249,11 +249,11 @@
   // member.
   template <typename MemberT, typename... InnerMemberTs>
   struct Checker : Checker<InnerMemberTs...> {
-    static_assert(MemberT::Tag < (1 << NumTagBits),
+    static_assert(MemberT::Tag < (UINTMAX_C(1) << NumTagBits),
                   "This discriminant value requires too many bits!");
   };
   template <typename MemberT> struct Checker<MemberT> : std::true_type {
-    static_assert(MemberT::Tag < (1 << NumTagBits),
+    static_assert(MemberT::Tag < (UINTMAX_C(1) << NumTagBits),
                   "This discriminant value requires too many bits!");
   };
   static_assert(Checker<MemberTs...>::value,
Index: unittests/ADT/PointerSumTypeTest.cpp
===================================================================
--- unittests/ADT/PointerSumTypeTest.cpp
+++ unittests/ADT/PointerSumTypeTest.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/PointerEmbeddedInt.h"
 #include "llvm/ADT/PointerSumType.h"
 #include "gtest/gtest.h"
 using namespace llvm;
@@ -18,15 +19,29 @@
   float f;
   int i1, i2;
 
+  enum NarrowKinds { EmbeddedInt1, EmbeddedChar };
+  unsigned ei1;
+  char ec;
+
   typedef PointerSumType<Kinds, PointerSumTypeMember<Float, float *>,
                          PointerSumTypeMember<Int1, int *>,
                          PointerSumTypeMember<Int2, int *>>
       SumType;
   SumType a, b, c, n;
 
+  typedef PointerSumType<
+      NarrowKinds,
+      PointerSumTypeMember<EmbeddedInt1, PointerEmbeddedInt<unsigned, 1>>,
+      PointerSumTypeMember<EmbeddedChar, PointerEmbeddedInt<char>>>
+      NarrowSumType;
+  NarrowSumType d, e;
+
   PointerSumTypeTest()
-      : f(3.14f), i1(42), i2(-1), a(SumType::create<Float>(&f)),
-        b(SumType::create<Int1>(&i1)), c(SumType::create<Int2>(&i2)), n() {}
+      : f(3.14f), i1(42), i2(-1), ei1(1), ec('c'),
+        a(SumType::create<Float>(&f)), b(SumType::create<Int1>(&i1)),
+        c(SumType::create<Int2>(&i2)), n(),
+        d(NarrowSumType::create<EmbeddedInt1>(ei1)),
+        e(NarrowSumType::create<EmbeddedChar>(ec)) {}
 };
 
 TEST_F(PointerSumTypeTest, NullTest) {
@@ -34,6 +49,8 @@
   EXPECT_TRUE(b);
   EXPECT_TRUE(c);
   EXPECT_FALSE(n);
+  EXPECT_TRUE(d);
+  EXPECT_TRUE(e);
 }
 
 TEST_F(PointerSumTypeTest, GetTag) {
@@ -41,6 +58,8 @@
   EXPECT_EQ(Int1, b.getTag());
   EXPECT_EQ(Int2, c.getTag());
   EXPECT_EQ((Kinds)0, n.getTag());
+  EXPECT_EQ(EmbeddedInt1, d.getTag());
+  EXPECT_EQ(EmbeddedChar, e.getTag());
 }
 
 TEST_F(PointerSumTypeTest, Is) {
@@ -53,6 +72,10 @@
   EXPECT_FALSE(c.is<Float>());
   EXPECT_FALSE(c.is<Int1>());
   EXPECT_TRUE(c.is<Int2>());
+  EXPECT_TRUE(d.is<EmbeddedInt1>());
+  EXPECT_FALSE(d.is<EmbeddedChar>());
+  EXPECT_FALSE(e.is<EmbeddedInt1>());
+  EXPECT_TRUE(e.is<EmbeddedChar>());
 }
 
 TEST_F(PointerSumTypeTest, Get) {
@@ -71,12 +94,19 @@
   EXPECT_EQ(nullptr, n.get<Float>());
   EXPECT_EQ(nullptr, n.get<Int1>());
   EXPECT_EQ(nullptr, n.get<Int2>());
+
+  EXPECT_EQ(ei1, d.get<EmbeddedInt1>());
+  EXPECT_EQ('\0', d.get<EmbeddedChar>());
+  EXPECT_EQ(0U, e.get<EmbeddedInt1>());
+  EXPECT_EQ(ec, e.get<EmbeddedChar>());
 }
 
 TEST_F(PointerSumTypeTest, Cast) {
   EXPECT_EQ(&f, a.cast<Float>());
   EXPECT_EQ(&i1, b.cast<Int1>());
   EXPECT_EQ(&i2, c.cast<Int2>());
+  EXPECT_EQ(ei1, d.cast<EmbeddedInt1>());
+  EXPECT_EQ(ec, e.cast<EmbeddedChar>());
 }
 
 TEST_F(PointerSumTypeTest, Assignment) {
@@ -107,6 +137,10 @@
   EXPECT_EQ(nullptr, n.get<Float>());
   EXPECT_EQ(nullptr, n.get<Int1>());
   EXPECT_EQ(nullptr, n.get<Int2>());
+
+  d = NarrowSumType::create<EmbeddedChar>('d');
+  EXPECT_EQ(0U, d.get<EmbeddedInt1>());
+  EXPECT_EQ('d', d.get<EmbeddedChar>());
 }