diff --git a/src/lj_str.c b/src/lj_str.c
index 8e999223..d684b393 100644
--- a/src/lj_str.c
+++ b/src/lj_str.c
@@ -130,6 +130,27 @@ GCstr *lj_str_new(lua_State *L, const char *str, size_t lenx)
     lj_err_msg(L, LJ_ERR_STROV);
   g = G(L);
   /* Compute string hash. Constants taken from lookup3 hash by Bob Jenkins. */
+#if LJ_ARCH_BITS == 64 && LJ_TARGET_UNALIGNED
+  if (LJ_UNLIKELY(len > 128)) {
+    MSize i = (len-1)/16;
+    const char *ss;
+    uint64_t h1 = *(uint64_t*)(str+len-8);
+    uint64_t h2 = *(uint64_t*)(str+len-16);
+    uint64_t h3 = len;
+    ss = str;
+    for (; i; i--, ss += 16) {
+      h3 = lj_rol(h3 ^ h1, 33) + (h2 ^ 0xdeadbeef);
+      h1 = lj_rol(h1, 23); h1 -= *(uint64_t*)ss;
+      h2 = lj_rol(h2, 21); h2 -= *(uint64_t*)(ss+8);
+    }
+    h1 -= lj_rol(h3, 19);
+    h2 -= lj_rol(h1, 19);
+    h3 -= lj_rol(h2, 19);
+    h = (uint32_t)h3 - (uint32_t)(h1 >> 32);
+    a = (uint32_t)h1 - (uint32_t)(h2 >> 32);
+    b = (uint32_t)h2 - (uint32_t)(h3 >> 32);
+  } else
+#endif
   if (len >= 12) {  /* Caveat: unaligned access! */
     MSize i = (len-1)/8;
     const char *ss;