[llvm] [IR] Fix deprecated-enum-enum-conversion C++20 warnings; NFC (PR #203277)

[Sven van Haastregt via llvm-commits]

https://github.com/svenvh created https://github.com/llvm/llvm-project/pull/203277

This addition of enum values resulted in many warnings of the form

    warning: arithmetic between different enumeration types
    'llvm::Value::ValueTy' and 'llvm::Instruction::TermOps' is
    deprecated

>From 268716e5bf828a074624d9a34b4d8f1e7a2e817b Mon Sep 17 00:00:00 2001
From: Sven van Haastregt <sven.vanhaastregt at arm.com>
Date: Thu, 11 Jun 2026 11:23:14 +0100
Subject: [PATCH] [IR] Fix deprecated-enum-enum-conversion C++20 warnings; NFC

This addition of enum values resulted in many warnings of the form

    warning: arithmetic between different enumeration types
    'llvm::Value::ValueTy' and 'llvm::Instruction::TermOps' is
    deprecated
---
 llvm/lib/IR/Value.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index 6f71a5093e4a3..1b72717e8389e 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -13,6 +13,7 @@
 #include "llvm/IR/Value.h"
 #include "LLVMContextImpl.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/Constants.h"
@@ -123,7 +124,7 @@ void Value::deleteValue() {
 #include "llvm/IR/Value.def"
 
 #define HANDLE_INST(N, OPC, CLASS)                                             \
-  case Value::InstructionVal + Instruction::OPC:                               \
+  case addEnumValues(Value::InstructionVal, Instruction::OPC):                 \
     delete static_cast<CLASS *>(this);                                         \
     break;
 #define HANDLE_USER_INST(N, OPC, CLASS)