Index: llvm.test/lib/Support/APInt.cpp
===================================================================
--- llvm.test/lib/Support/APInt.cpp	(revision 65963)
+++ llvm.test/lib/Support/APInt.cpp	(working copy)
@@ -623,16 +623,29 @@ unsigned APInt::getBitsNeeded(const char
   return isNegative + tmp.logBase2() + 1;
 }
 
+// This 64-bit-to-32-bit hash was copied from
+// http://www.concentric.net/~Ttwang/tech/inthash.htm .
+static uint32_t hash6432shift(uint64_t key)
+{
+  key = (~key) + (key << 18);	// key = (key << 18) - key - 1;
+  key = key ^ (key >> 31);
+  key = key * 21;		// key = (key + (key << 2)) + (key << 4);
+  key = key ^ (key >> 11);
+  key = key + (key << 6);
+  key = key ^ (key >> 22);
+  return (uint32_t) key;
+}
+
 uint64_t APInt::getHashValue() const {
   // Put the bit width into the low order bits.
-  uint64_t hash = BitWidth;
+  uint64_t hash; // = BitWidth;
 
   // Add the sum of the words to the hash.
   if (isSingleWord())
-    hash += VAL << 6; // clear separation of up to 64 bits
+    hash = hash6432shift(VAL);
   else
-    for (unsigned i = 0; i < getNumWords(); ++i)
-      hash += pVal[i] << 6; // clear sepration of up to 64 bits
+    for (unsigned i = 0, hash = 0; i < getNumWords(); ++i)
+      hash ^= hash6432shift(pVal[i]);
   return hash;
 }