[Support] Use llvm::to_underlying in BinaryStreamWriter.h (NFC)

[kazutakahirata]

llvm::to_underlying, forward ported from C++23, conveniently packages
static_cast and std::underlying_type_t like so:

static_cast<std::underlying_type_t>(E)

[llvmbot]

@llvm/pr-subscribers-llvm-support

Author: Kazu Hirata (kazutakahirata)

Changes

llvm::to_underlying, forward ported from C++23, conveniently packages
static_cast and std::underlying_type_t like so:

static_cast<std::underlying_type_t<EnumTy>>(E)

---

Full diff: https://github.com/llvm/llvm-project/pull/163087.diff

1 Files Affected:

• (modified) llvm/include/llvm/Support/BinaryStreamWriter.h (+2-2)

diff --git a/llvm/include/llvm/Support/BinaryStreamWriter.h b/llvm/include/llvm/Support/BinaryStreamWriter.h
index dddf53bd5483c..39ce0b6e4c110 100644
--- a/llvm/include/llvm/Support/BinaryStreamWriter.h
+++ b/llvm/include/llvm/Support/BinaryStreamWriter.h
@@ -10,6 +10,7 @@
 #define LLVM_SUPPORT_BINARYSTREAMWRITER_H
 
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLForwardCompat.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/BinaryStreamArray.h"
 #include "llvm/Support/BinaryStreamError.h"
@@ -69,8 +70,7 @@ class BinaryStreamWriter {
     static_assert(std::is_enum<T>::value,
                   "Cannot call writeEnum with non-Enum type");
 
-    using U = std::underlying_type_t<T>;
-    return writeInteger<U>(static_cast<U>(Num));
+    return writeInteger(llvm::to_underlying(Num));
   }
 
   /// Write the unsigned integer Value to the underlying stream using ULEB128