Update hash function of uint64_t for DenseMap

Author: ChuanqiXu9

llvm/include/llvm/ADT/DenseMapInfo.h

@@ -137,7 +137,12 @@ template<> struct DenseMapInfo<unsigned long> {
   static inline unsigned long getTombstoneKey() { return ~0UL - 1L; }
 
   static unsigned getHashValue(const unsigned long& Val) {
-    return (unsigned)(Val * 37UL);
+    if constexpr (sizeof(Val) == 4)
+      return DenseMapInfo<unsigned>::getHashValue(Val);
+    else
+      return detail::combineHashValue(
+          DenseMapInfo<unsigned>::getHashValue(Val),
+          DenseMapInfo<unsigned>::getHashValue(Val >> 32));
   }
 
   static bool isEqual(const unsigned long& LHS, const unsigned long& RHS) {
@@ -151,7 +156,9 @@ template<> struct DenseMapInfo<unsigned long long> {
   static inline unsigned long long getTombstoneKey() { return ~0ULL - 1ULL; }
 
   static unsigned getHashValue(const unsigned long long& Val) {
-    return (unsigned)(Val * 37ULL);
+    return detail::combineHashValue(
+        DenseMapInfo<unsigned>::getHashValue(Val),
+        DenseMapInfo<unsigned>::getHashValue(Val >> 32));
   }
 
   static bool isEqual(const unsigned long long& LHS,