From defc59734a00cc0f476f6a93c35fd0b313ed587a Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Tue, 10 Nov 2020 10:17:46 +0000
Subject: [PATCH] Add a llvm_unreachable to fix MSVC unhandled enum warning.
 NFCI.

---
 clang/lib/AST/ItaniumMangle.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 2cf69d34d472..1cf178fdd988 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -5028,6 +5028,8 @@ static bool isZeroInitialized(QualType T, const APValue &V) {
   case APValue::MemberPointer:
     return !V.getMemberPointerDecl();
   }
+
+  llvm_unreachable("Unhandled APValue::ValueKind enum");
 }
 
 void CXXNameMangler::mangleValueInTemplateArg(QualType T, const APValue &V) {