diff --git a/llvm/lib/Support/DJB.cpp b/llvm/lib/Support/DJB.cpp
index 3190c7f..c696f1e 100644
--- a/llvm/lib/Support/DJB.cpp
+++ b/llvm/lib/Support/DJB.cpp
@@ -12,85 +12,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/DJB.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/ConvertUTF.h"
-#include "llvm/Support/Unicode.h"
-
-using namespace llvm;
-
-static inline uint32_t djbHashChar(char C, uint32_t H) {
-  return (H << 5) + H + C;
-}
 
 uint32_t llvm::djbHash(StringRef Buffer, uint32_t H) {
   for (char C : Buffer.bytes())
-    H = djbHashChar(C, H);
-  return H;
-}
-
-static UTF32 chopOneUTF32(StringRef &Buffer) {
-  UTF32 C;
-  const UTF8 *const Begin8Const =
-      reinterpret_cast<const UTF8 *>(Buffer.begin());
-  const UTF8 *Begin8 = Begin8Const;
-  UTF32 *Begin32 = &C;
-
-  // In lenient mode we will always end up with a "reasonable" value in C for
-  // non-empty input.
-  assert(!Buffer.empty());
-  ConvertUTF8toUTF32(&Begin8, reinterpret_cast<const UTF8 *>(Buffer.end()),
-                     &Begin32, &C + 1, lenientConversion);
-  Buffer = Buffer.drop_front(Begin8 - Begin8Const);
-  return C;
-}
-
-static StringRef toUTF8(UTF32 C, MutableArrayRef<UTF8> Storage) {
-  const UTF32 *Begin32 = &C;
-  UTF8 *Begin8 = Storage.begin();
-
-  // The case-folded output should always be a valid unicode character, so use
-  // strict mode here.
-  ConversionResult CR = ConvertUTF32toUTF8(&Begin32, &C + 1, &Begin8,
-                                           Storage.end(), strictConversion);
-  assert(CR == conversionOK && "Case folding produced invalid char?");
-  (void)CR;
-  return StringRef(reinterpret_cast<char *>(Storage.begin()),
-                   Begin8 - Storage.begin());
-}
-
-static UTF32 foldCharDwarf(UTF32 C) {
-  // DWARF v5 addition to the unicode folding rules.
-  // Fold "Latin Small Letter Dotless I" and "Latin Capital Letter I With Dot
-  // Above" into "i".
-  if (C == 0x130 || C == 0x131)
-    return 'i';
-  return sys::unicode::foldCharSimple(C);
-}
-
-static uint32_t caseFoldingDjbHashCharSlow(StringRef &Buffer, uint32_t H) {
-  UTF32 C = chopOneUTF32(Buffer);
-
-  C = foldCharDwarf(C);
-
-  std::array<UTF8, UNI_MAX_UTF8_BYTES_PER_CODE_POINT> Storage;
-  StringRef Folded = toUTF8(C, Storage);
-  return djbHash(Folded, H);
-}
-
-uint32_t llvm::caseFoldingDjbHash(StringRef Buffer, uint32_t H) {
-  while (!Buffer.empty()) {
-    unsigned char C = Buffer.front();
-    if (LLVM_LIKELY(C <= 0x7f)) {
-      // US-ASCII, encoded as one character in utf-8.
-      // This is by far the most common case, so handle this specially.
-      if (C >= 'A' && C <= 'Z')
-        C = 'a' + (C - 'A'); // fold uppercase into lowercase
-      H = djbHashChar(C, H);
-      Buffer = Buffer.drop_front();
-      continue;
-    }
-    H = caseFoldingDjbHashCharSlow(Buffer, H);
-  }
+    H = ((H << 5) + H) + C;
   return H;
 }