diff -r a507882736b2 Python/pyhash.c
--- a/Python/pyhash.c	Wed Jan 25 22:33:43 2017 +0900
+++ b/Python/pyhash.c	Wed Feb 01 18:20:50 2017 +0900
@@ -351,21 +351,19 @@ static PyHash_FuncDef PyHash_Func = {fnv
 #  define ROTATE(x, b) (uint64_t)( ((x) << (b)) | ( (x) >> (64 - (b))) )
 #endif
 
-#define HALF_ROUND(a,b,c,d,s,t)         \
-    a += b; c += d;             \
+#define HALF_ROUND(a,b,c,d,s,t)     \
+    a += b; c += d;                 \
     b = ROTATE(b, s) ^ a;           \
     d = ROTATE(d, t) ^ c;           \
     a = ROTATE(a, 32);
 
-#define DOUBLE_ROUND(v0,v1,v2,v3)       \
-    HALF_ROUND(v0,v1,v2,v3,13,16);      \
-    HALF_ROUND(v2,v1,v0,v3,17,21);      \
-    HALF_ROUND(v0,v1,v2,v3,13,16);      \
+#define ROUND(v0,v1,v2,v3)          \
+    HALF_ROUND(v0,v1,v2,v3,13,16);  \
     HALF_ROUND(v2,v1,v0,v3,17,21);
 
 
 static Py_hash_t
-siphash24(const void *src, Py_ssize_t src_sz) {
+siphash13(const void *src, Py_ssize_t src_sz) {
     uint64_t k0 = _le64toh(_Py_HashSecret.siphash.k0);
     uint64_t k1 = _le64toh(_Py_HashSecret.siphash.k1);
     uint64_t b = (uint64_t)src_sz << 56;
@@ -385,7 +383,7 @@ siphash24(const void *src, Py_ssize_t sr
         in += 1;
         src_sz -= 8;
         v3 ^= mi;
-        DOUBLE_ROUND(v0,v1,v2,v3);
+        ROUND(v0,v1,v2,v3);
         v0 ^= mi;
     }
 
@@ -404,18 +402,19 @@ siphash24(const void *src, Py_ssize_t sr
     b |= _le64toh(t);
 
     v3 ^= b;
-    DOUBLE_ROUND(v0,v1,v2,v3);
+    ROUND(v0,v1,v2,v3);
     v0 ^= b;
     v2 ^= 0xff;
-    DOUBLE_ROUND(v0,v1,v2,v3);
-    DOUBLE_ROUND(v0,v1,v2,v3);
+    ROUND(v0,v1,v2,v3);
+    ROUND(v0,v1,v2,v3);
+    ROUND(v0,v1,v2,v3);
 
     /* modified */
     t = (v0 ^ v1) ^ (v2 ^ v3);
     return (Py_hash_t)t;
 }
 
-static PyHash_FuncDef PyHash_Func = {siphash24, "siphash24", 64, 128};
+static PyHash_FuncDef PyHash_Func = {siphash13, "siphash13", 64, 128};
 
 #endif /* Py_HASH_ALGORITHM == Py_HASH_SIPHASH24 */