diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -843,6 +843,8 @@
   case APFloat::S_PPCDoubleDouble: Out << 'Z'; break;
   case APFloat::S_Float8E5M2:
   case APFloat::S_Float8E4M3FN:
+  case APFloat::S_Float8E5M2FNUZ:
+  case APFloat::S_Float8E4M3FNUZ:
     llvm_unreachable("Tried to mangle unexpected APFloat semantics");
   }