Revert optional type special casing

I'm not convinced that it's any better. Getting the address of None requires a memory read, so we'd have an extra memory read in the slow path.

Author: JukkaL

mypyc/codegen/emit.py

@@ -514,18 +514,7 @@ def emit_inc_ref(self, dest: str, rtype: RType, *, rare: bool = False) -> None:
         elif not rtype.is_unboxed:
             # Always inline, since this is a simple but very hot op
             if rtype.may_be_immortal or not HAVE_IMMORTAL:
-                if (
-                    HAVE_IMMORTAL
-                    and (opt := optional_value_type(rtype))
-                    and not opt.may_be_immortal
-                ):
-                    # Optimized incref of optional type avoids reading reference count
-                    # if value is None (None is immortal)
-                    self.emit_line(f"if ({dest} != Py_None) {{")
-                    self.emit_line(f"CPy_INCREF_NO_IMM({dest});")
-                    self.emit_line("}")
-                else:
-                    self.emit_line("CPy_INCREF(%s);" % dest)
+                self.emit_line("CPy_INCREF(%s);" % dest)
             else:
                 self.emit_line("CPy_INCREF_NO_IMM(%s);" % dest)
         # Otherwise assume it's an unboxed, pointerless value and do nothing.
@@ -556,18 +545,7 @@ def emit_dec_ref(
             else:
                 # Inlined
                 if rtype.may_be_immortal or not HAVE_IMMORTAL:
-                    if (
-                        HAVE_IMMORTAL
-                        and (opt := optional_value_type(rtype))
-                        and not opt.may_be_immortal
-                    ):
-                        # Optimized decref of optional type avoids reading reference count
-                        # if value is None (None is immortal)
-                        self.emit_line(f"if ({dest} != Py_None) {{")
-                        self.emit_line(f"CPy_{x}DECREF_NO_IMM({dest});")
-                        self.emit_line("}")
-                    else:
-                        self.emit_line(f"CPy_{x}DECREF({dest});")
+                    self.emit_line(f"CPy_{x}DECREF({dest});")
                 else:
                     self.emit_line(f"CPy_{x}DECREF_NO_IMM({dest});")
         # Otherwise assume it's an unboxed, pointerless value and do nothing.

mypyc/test/test_emit.py

@@ -11,7 +11,6 @@
     RTuple,
     RUnion,
     bool_rprimitive,
-    dict_rprimitive,
     int_rprimitive,
     list_rprimitive,
     none_rprimitive,
@@ -117,14 +116,6 @@ def test_emit_inc_ref_instance(self) -> None:
     def test_emit_inc_ref_optional(self) -> None:
         optional = RUnion([self.instance_a, none_rprimitive])
         self.emitter.emit_inc_ref("o", optional)
-        if HAVE_IMMORTAL:
-            self.assert_output("if (o != Py_None) {\n    CPy_INCREF_NO_IMM(o);\n}\n")
-        else:
-            self.assert_output("CPy_INCREF(o);\n")
-
-    def test_emit_inc_ref_optional_2(self) -> None:
-        optional = RUnion([dict_rprimitive, none_rprimitive])
-        self.emitter.emit_inc_ref("o", optional)
         self.assert_output("CPy_INCREF(o);\n")
 
     def test_emit_dec_ref_object(self) -> None:
@@ -172,14 +163,6 @@ def test_emit_dec_ref_instance(self) -> None:
     def test_emit_dec_ref_optional(self) -> None:
         optional = RUnion([self.instance_a, none_rprimitive])
         self.emitter.emit_dec_ref("o", optional)
-        if HAVE_IMMORTAL:
-            self.assert_output("if (o != Py_None) {\n    CPy_DECREF_NO_IMM(o);\n}\n")
-        else:
-            self.assert_output("CPy_DECREF(o);\n")
-
-    def test_emit_dec_ref_optional_2(self) -> None:
-        optional = RUnion([dict_rprimitive, none_rprimitive])
-        self.emitter.emit_dec_ref("o", optional)
         self.assert_output("CPy_DECREF(o);\n")
 
     def assert_output(self, expected: str) -> None: