[RUNTIME] Better support for None (#387)

* regression test fails but it doesn't make sense to me.

python/src/triton.cc

@@ -127,6 +127,10 @@ void parse_args(py::list& args, py::list do_not_specialize, const std::string& f
       if(PyLong_Check(arg_ptr)){
         int overflow;
         long long value = PyLong_AsLongLongAndOverflow(arg_ptr, &overflow);
+        if(specialize && (value == 1)){
+          cache_key += '1';
+          continue;
+        }
         // long and int have different kernels
         if(!overflow & (std::abs(value) <= 0xffffffff)){
           cache_key += 'I';
@@ -147,10 +151,7 @@ void parse_args(py::list& args, py::list do_not_specialize, const std::string& f
         if(!specialize)
           continue;
         // values equal to 1 are specialized
-        if(value == 1)
-          cache_key += '1';
-        else
-          cache_key += 'x';
+        cache_key += 'x';
         // values divisible by small powers of 2 are specialized
         cache_key += pow2_divisor(value);
         continue;
@@ -199,6 +200,10 @@ void parse_args(py::list& args, py::list do_not_specialize, const std::string& f
         continue;
       }
       std::string ty_str = arg.attr("__class__").attr("__name__").cast<std::string>();
+      if(ty_str == "NoneType"){
+        cache_key += "None";
+        continue;
+      }
       std::string err_msg = "Received type '" + ty_str + "' for argument " + std::to_string(i) + "."
                             + " Only int, float, bool, torch.Tensor, and triton.language.constexpr are supported.";
       throw std::runtime_error(err_msg);