[APSInt] Use APInt::compare and APInt::compareSigned to implement APSInt::compareValue

[craig.topper]

Summary

APInt just got compare methods that return -1, 0, or 1 instead of just having ult/slt and eq.

This patch uses these methods to implement APSInt::compareValues so that we don't have to call do an equal comparison and then possibly a second less than comparison.

[hans]

lgtm

llvm/trunk/include/llvm/ADT/APInt.h

union {
     uint64_t VAL;   ///< Used to store the <= 64 bits integer value.
     uint64_t *pVal; ///< Used to store the >64 bits integer value.
   };
 
   unsigned BitWidth; ///< The number of bits in this APInt.
 
   friend struct DenseMapAPIntKeyInfo;
 
+  friend class APSInt;
+
   /// \brief Fast internal constructor
   ///
   /// This constructor is used only internally for speed of construction of
   /// temporaries. It is unsafe for general use so it is not public.
   APInt(uint64_t *val, unsigned bits) : pVal(val), BitWidth(bits) {}
 
   /// \brief Determine if this APInt just has one word to store value.
   ///

llvm/trunk/include/llvm/ADT/APSInt.h

public:
   /// sign-extending as needed.
   static bool isSameValue(const APSInt &I1, const APSInt &I2) {
     return !compareValues(I1, I2);
   }
 
   /// \brief Compare underlying values of two numbers.
   static int compareValues(const APSInt &I1, const APSInt &I2) {
     if (I1.getBitWidth() == I2.getBitWidth() && I1.isSigned() == I2.isSigned())
-      return I1 == I2 ? 0 : I1 > I2 ? 1 : -1;
+      return I1.IsUnsigned ? I1.compare(I2) : I1.compareSigned(I2);
 
     // Check for a bit-width mismatch.
     if (I1.getBitWidth() > I2.getBitWidth())
       return compareValues(I1, I2.extend(I1.getBitWidth()));
-    else if (I2.getBitWidth() > I1.getBitWidth())
+    if (I2.getBitWidth() > I1.getBitWidth())
       return compareValues(I1.extend(I2.getBitWidth()), I2);
 
     // We have a signedness mismatch. Check for negative values and do an
     // unsigned compare if both are positive.
     if (I1.isSigned()) {
       assert(!I2.isSigned() && "Expected signed mismatch");
       if (I1.isNegative())
         return -1;
     } else {
       assert(I2.isSigned() && "Expected signed mismatch");
       if (I2.isNegative())
         return 1;
     }
 
-    return I1.eq(I2) ? 0 : I1.ugt(I2) ? 1 : -1;
+    return I1.compare(I2);
   }
 
   static APSInt get(int64_t X) { return APSInt(APInt(64, X), false); }
   static APSInt getUnsigned(uint64_t X) { return APSInt(APInt(64, X), true); }
 
   /// Profile - Used to insert APSInt objects, or objects that contain APSInt
   ///  objects, into FoldingSets.
   void Profile(FoldingSetNodeID& ID) const;