diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index a15ad55..1d6480c 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -712,6 +712,8 @@
     return bitc::ATTR_KIND_WRITEONLY;
   case Attribute::ZExt:
     return bitc::ATTR_KIND_Z_EXT;
+  case Attribute::ImmArg:
+    return bitc::ATTR_KIND_IMMARG;
   case Attribute::EndAttrKinds:
     llvm_unreachable("Can not encode end-attribute kinds marker.");
   case Attribute::None: