diff --git a/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp b/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
index 44b239894e9..76a9d2b6385 100644
--- a/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
+++ b/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
@@ -164,8 +164,7 @@ enum X86_32RelType { RT32_32, RT32_16, RT32_8 };
 
 static X86_32RelType getType32(X86_64RelType T) {
   switch (T) {
-  default:
-  //case RT64_64:
+  case RT64_64:
     llvm_unreachable("Unimplemented");
   case RT64_32:
   case RT64_32S:
@@ -175,6 +174,7 @@ static X86_32RelType getType32(X86_64RelType T) {
   case RT64_8:
     return RT32_8;
   }
+  llvm_unreachable("unexpected relocation type!");
 }
 
 static unsigned getRelocType32(MCSymbolRefExpr::VariantKind Modifier,