diff --git a/lib/Support/Dwarf.cpp b/lib/Support/Dwarf.cpp
index 9972960d373..7b94b71834d 100644
--- a/lib/Support/Dwarf.cpp
+++ b/lib/Support/Dwarf.cpp
@@ -422,8 +422,6 @@ const char *llvm::dwarf::AttributeEncodingString(unsigned Encoding) {
   case DW_ATE_signed_fixed:              return "DW_ATE_signed_fixed";
   case DW_ATE_unsigned_fixed:            return "DW_ATE_unsigned_fixed";
   case DW_ATE_decimal_float:             return "DW_ATE_decimal_float";
-  case DW_ATE_lo_user:                   return "DW_ATE_lo_user";
-  case DW_ATE_hi_user:                   return "DW_ATE_hi_user";
   }
   return nullptr;
 }
diff --git a/unittests/Support/DwarfTest.cpp b/unittests/Support/DwarfTest.cpp
index 2dccfe7ad3c..b1a23b31c1c 100644
--- a/unittests/Support/DwarfTest.cpp
+++ b/unittests/Support/DwarfTest.cpp
@@ -69,4 +69,14 @@ TEST(DwarfTest, getLanguage) {
   EXPECT_EQ(0u, getLanguage("DW_LANG_hi_user"));
 }
 
+TEST(DwarfTest, AttributeEncodingStringOnInvalid) {
+  // This is invalid, so it shouldn't be stringified.
+  EXPECT_EQ(nullptr, AttributeEncodingString(0));
+
+  // These aren't really tags: they describe ranges within tags.  They
+  // shouldn't be stringified either.
+  EXPECT_EQ(nullptr, AttributeEncodingString(DW_ATE_lo_user));
+  EXPECT_EQ(nullptr, AttributeEncodingString(DW_ATE_hi_user));
+}
+
 } // end namespace