Tuple private scalar assignment hack: Skip make_tuple().

loopy/preprocess.py

@@ -773,6 +773,21 @@ def _hackily_ensure_multi_assignment_return_values_are_scoped_private(kernel):
 
         FIRST_POINTER_ASSIGNEE_IDX = 1  # noqa
 
+        param_dtypes = tuple(type_inf_mapper(param)
+                for param in insn.expression.parameters)
+
+        func_id = insn.expression.function
+
+        from pymbolic.primitives import Variable
+        if isinstance(func_id, Variable):
+            func_id = func_id.name
+
+        mangle_result = kernel.mangle_function(func_id, param_dtypes)
+
+        if mangle_result.target_name == "loopy_make_tuple":
+            # Skip loopy_make_tuple. This is lowered without a function call.
+            continue
+
         assignee_dtypes, = type_inf_mapper(
                 insn.expression, return_tuple=True, return_dtype_set=True)
 
@@ -806,7 +821,8 @@ def _hackily_ensure_multi_assignment_return_values_are_scoped_private(kernel):
             new_temporaries[new_assignee_name] = (
                     TemporaryVariable(
                         name=new_assignee_name,
-                        dtype=assignee_dtypes[assignee_nr],
+                        dtype=assignee_dtypes[assignee_nr].with_target(
+                            kernel.target),
                         scope=temp_var_scope.PRIVATE))
 
             from pymbolic import var
@@ -985,12 +1001,18 @@ def realize_reduction(kernel, insn_id_filter=None, unknown_types_ok=True,
                 var_name_gen(id + "_arg" + str(i))
                 for i in range(nresults)]
 
-        for name in temp_var_names:
+        from loopy.type_inference import infer_arg_and_reduction_dtypes_for_reduction_expression
+
+        _, reduction_dtypes = (
+                infer_arg_and_reduction_dtypes_for_reduction_expression(
+                    temp_kernel, expr, unknown_types_ok=False))
+
+        for name, dtype in zip(temp_var_names, reduction_dtypes):
             from loopy.kernel.data import TemporaryVariable, temp_var_scope
             new_temporary_variables[name] = TemporaryVariable(
                     name=name,
                     shape=(),
-                    dtype=lp.auto,
+                    dtype=dtype,
                     scope=temp_var_scope.PRIVATE)
 
         from pymbolic import var