[llvm] [NFC] Add llvm_unreachable to getRCPrefix (PR #106822)

[Damyan Pepper via llvm-commits]

https://github.com/damyanp created https://github.com/llvm/llvm-project/pull/106822

None

>From 16c27f28977abdc8417bac75e83fba546e2a09aa Mon Sep 17 00:00:00 2001
From: Damyan Pepper <damyanp at microsoft.com>
Date: Sat, 31 Aug 2024 03:15:57 +0000
Subject: [PATCH] add llvm_unreachable

---
 llvm/lib/Target/DirectX/DXILPrettyPrinter.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/Target/DirectX/DXILPrettyPrinter.cpp b/llvm/lib/Target/DirectX/DXILPrettyPrinter.cpp
index f282eff6c002b2..0478dc2df988de 100644
--- a/llvm/lib/Target/DirectX/DXILPrettyPrinter.cpp
+++ b/llvm/lib/Target/DirectX/DXILPrettyPrinter.cpp
@@ -45,6 +45,7 @@ static StringRef getRCPrefix(dxil::ResourceClass RC) {
   case dxil::ResourceClass::Sampler:
     return "s";
   }
+  llvm_unreachable("covered switch");
 }
 
 static StringRef getFormatName(const dxil::ResourceInfo &RI) {