[mypyc] feat: extend stararg fastpath from #19629 with star2 fastpath

Author: BobTheBuidler

mypyc/irbuild/ll_builder.py

@@ -127,6 +127,7 @@
 from mypyc.primitives.bytes_ops import bytes_compare
 from mypyc.primitives.dict_ops import (
     dict_build_op,
+    dict_copy_op,
     dict_new_op,
     dict_ssize_t_size_op,
     dict_update_in_display_op,
@@ -810,13 +811,21 @@ def _construct_varargs(
                             star_result = self.primitive_op(list_tuple_op, [value], line)
                         else:
                             star_result = self.primitive_op(sequence_tuple_op, [value], line)
+                        if is_dict_rprimitive(args[1][0].type):
+                            # even faster fastpath for decorators
+                            return star_result, self.primitive_op(dict_copy_op, [args[1][0]], line)
                         continue
                         # elif ...: TODO extend this to optimize fn(*args, k=1, **kwargs) case
                     # TODO optimize this case using the length utils - currently in review
                     star_result = self.new_list_op(star_values, line)
                 self.primitive_op(list_extend_op, [star_result, value], line)
             elif kind == ARG_STAR2:
                 if star2_result is None:
+                    if len(args) == 1:
+                        # early exit with fastpath if the only arg is ARG_STAR2
+                        # TODO: can we maintain an empty tuple in memory and just reuse it again and again?
+                        return self.new_tuple([], line), self.primitive_op(dict_copy_op, [args[0][0]], line)
+
                     star2_result = self._create_dict(star2_keys, star2_values, line)
 
                 self.call_c(dict_update_in_display_op, [star2_result, value], line=line)

mypyc/primitives/dict_ops.py

@@ -53,7 +53,7 @@
 )
 
 # Construct a dictionary from another dictionary.
-function_op(
+dict_copy_op = function_op(
     name="builtins.dict",
     arg_types=[dict_rprimitive],
     return_type=dict_rprimitive,

mypyc/test-data/irbuild-generics.test

@@ -167,17 +167,13 @@ def execute(func, args, kwargs):
     func :: object
     args :: tuple
     kwargs, r0 :: dict
-    r1 :: i32
-    r2 :: bit
-    r3 :: object
-    r4 :: int
+    r1 :: object
+    r2 :: int
 L0:
-    r0 = PyDict_New()
-    r1 = CPyDict_UpdateInDisplay(r0, kwargs)
-    r2 = r1 >= 0 :: signed
-    r3 = PyObject_Call(func, args, r0)
-    r4 = unbox(int, r3)
-    return r4
+    r0 = PyDict_Copy(kwargs)
+    r1 = PyObject_Call(func, args, r0)
+    r2 = unbox(int, r1)
+    return r2
 def f(x):
     x :: int
 L0:
@@ -703,10 +699,8 @@ def inner_deco_obj.__call__(__mypyc_self__, args, kwargs):
     r22, can_iter, r23, can_use_keys, r24, can_use_values :: list
     r25 :: object
     r26 :: dict
-    r27 :: i32
-    r28 :: bit
-    r29 :: object
-    r30 :: int
+    r27 :: object
+    r28 :: int
 L0:
     r0 = __mypyc_self__.__mypyc_env__
     r1 = var_object_size args
@@ -758,12 +752,10 @@ L9:
     r24 = CPyDict_Values(kwargs)
     can_use_values = r24
     r25 = r0.func
-    r26 = PyDict_New()
-    r27 = CPyDict_UpdateInDisplay(r26, kwargs)
-    r28 = r27 >= 0 :: signed
-    r29 = PyObject_Call(r25, args, r26)
-    r30 = unbox(int, r29)
-    return r30
+    r26 = PyDict_Copy(kwargs)
+    r27 = PyObject_Call(r25, args, r26)
+    r28 = unbox(int, r27)
+    return r28
 def deco(func):
     func :: object
     r0 :: __main__.deco_env