Add a DenseMapInfo<T> for shorts.

[zturner]

Summary

Not sure why this little guy was curiously missing, but I need one.

llvm/include/llvm/ADT/DenseMapInfo.h

template<> struct DenseMapInfo<char> {
   static inline char getEmptyKey() { return ~0; }
   static inline char getTombstoneKey() { return ~0 - 1; }
   static unsigned getHashValue(const char& Val) { return Val * 37U; }
   static bool isEqual(const char &LHS, const char &RHS) {
     return LHS == RHS;
   }
 };
 
+// Provide DenseMapInfo for unsigned shorts.
+template <> struct DenseMapInfo<unsigned short> {
+  static inline unsigned short getEmptyKey() { return 0xFFFF; }
+  static inline unsigned short getTombstoneKey() { return 0xFFFF - 1; }
+  static unsigned getHashValue(const unsigned short &Val) { return Val * 37U; }
+  static bool isEqual(const unsigned short &LHS, const unsigned short &RHS) {
+    return LHS == RHS;
+  }
+};
+
 // Provide DenseMapInfo for unsigned ints.
 template<> struct DenseMapInfo<unsigned> {
   static inline unsigned getEmptyKey() { return ~0U; }
   static inline unsigned getTombstoneKey() { return ~0U - 1; }
   static unsigned getHashValue(const unsigned& Val) { return Val * 37U; }
   static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
     return LHS == RHS;
   }
static unsigned getHashValue(const unsigned long long& Val) {
     return (unsigned)(Val * 37ULL);
   }
   static bool isEqual(const unsigned long long& LHS,
                       const unsigned long long& RHS) {
     return LHS == RHS;
   }
 };
 
+// Provide DenseMapInfo for shorts.
+template <> struct DenseMapInfo<short> {
+  static inline short getEmptyKey() { return 0x7FFF; }
+  static inline short getTombstoneKey() { return -0x7FFF - 1; }
+  static unsigned getHashValue(const short &Val) { return Val * 37U; }
+  static bool isEqual(const short &LHS, const short &RHS) { return LHS == RHS; }
+};
+
 // Provide DenseMapInfo for ints.
 template<> struct DenseMapInfo<int> {
   static inline int getEmptyKey() { return 0x7fffffff; }
   static inline int getTombstoneKey() { return -0x7fffffff - 1; }
   static unsigned getHashValue(const int& Val) { return (unsigned)(Val * 37U); }
   static bool isEqual(const int& LHS, const int& RHS) {
     return LHS == RHS;
   }