Use xor as mixing function

Author: nikic

llvm/include/llvm/ADT/DenseMapInfo.h

@@ -140,9 +140,8 @@ template<> struct DenseMapInfo<unsigned long> {
     if constexpr (sizeof(Val) == 4)
       return DenseMapInfo<unsigned>::getHashValue(Val);
     else
-      return detail::combineHashValue(
-          DenseMapInfo<unsigned>::getHashValue(Val),
-          DenseMapInfo<unsigned>::getHashValue(Val >> 32));
+      return DenseMapInfo<unsigned>::getHashValue(Val) ^
+             DenseMapInfo<unsigned>::getHashValue(Val >> 32);
   }
 
   static bool isEqual(const unsigned long& LHS, const unsigned long& RHS) {
@@ -156,9 +155,8 @@ template<> struct DenseMapInfo<unsigned long long> {
   static inline unsigned long long getTombstoneKey() { return ~0ULL - 1ULL; }
 
   static unsigned getHashValue(const unsigned long long& Val) {
-    return detail::combineHashValue(
-        DenseMapInfo<unsigned>::getHashValue(Val),
-        DenseMapInfo<unsigned>::getHashValue(Val >> 32));
+    return DenseMapInfo<unsigned>::getHashValue(Val) ^
+           DenseMapInfo<unsigned>::getHashValue(Val >> 32);
   }
 
   static bool isEqual(const unsigned long long& LHS,