python · JukkaL · Jul 11, 2025 · Jul 11, 2025 · Jul 11, 2025 · Jul 11, 2025
diff --git a/mypyc/irbuild/builder.py b/mypyc/irbuild/builder.py
@@ -129,6 +129,7 @@
 from mypyc.primitives.list_ops import list_get_item_unsafe_op, list_pop_last, to_list
 from mypyc.primitives.misc_ops import check_unpack_count_op, get_module_dict_op, import_op
 from mypyc.primitives.registry import CFunctionDescription, function_ops
+from mypyc.primitives.tuple_ops import tuple_get_item_unsafe_op
 
 # These int binary operations can borrow their operands safely, since the
 # primitives take this into consideration.
@@ -772,10 +773,15 @@ def process_sequence_assignment(
         values = []
         for i in range(len(target.items)):
             item = target.items[i]
-            index = self.builder.load_int(i)
+            index: Value
             if is_list_rprimitive(rvalue.type):
+                index = Integer(i, c_pyssize_t_rprimitive)
                 item_value = self.primitive_op(list_get_item_unsafe_op, [rvalue, index], line)
+            elif is_tuple_rprimitive(rvalue.type):
+                index = Integer(i, c_pyssize_t_rprimitive)
+                item_value = self.call_c(tuple_get_item_unsafe_op, [rvalue, index], line)
             else:
+                index = self.builder.load_int(i)
                 item_value = self.builder.gen_method_call(
                     rvalue, "__getitem__", [index], item.type, line
                 )

diff --git a/mypyc/irbuild/for_helpers.py b/mypyc/irbuild/for_helpers.py
@@ -44,6 +44,7 @@
     RTuple,
     RType,
     bool_rprimitive,
+    c_pyssize_t_rprimitive,
     int_rprimitive,
     is_dict_rprimitive,
     is_fixed_width_rtype,
@@ -75,6 +76,7 @@
 from mypyc.primitives.misc_ops import stop_async_iteration_op
 from mypyc.primitives.registry import CFunctionDescription
 from mypyc.primitives.set_ops import set_add_op
+from mypyc.primitives.tuple_ops import tuple_get_item_unsafe_op
 
 GenFunc = Callable[[], None]
 
@@ -586,7 +588,9 @@ def gen_cleanup(self) -> None:
 
     def load_len(self, expr: Value | AssignmentTarget) -> Value:
         """A helper to get collection length, used by several subclasses."""
-        return self.builder.builder.builtin_len(self.builder.read(expr, self.line), self.line)
+        return self.builder.builder.builtin_len(
+            self.builder.read(expr, self.line), self.line, use_pyssize_t=True
+        )
 
 
 class ForIterable(ForGenerator):
@@ -766,6 +770,8 @@ def unsafe_index(builder: IRBuilder, target: Value, index: Value, line: int) ->
     # so we just check manually.
     if is_list_rprimitive(target.type):
         return builder.primitive_op(list_get_item_unsafe_op, [target, index], line)
+    elif is_tuple_rprimitive(target.type):
+        return builder.call_c(tuple_get_item_unsafe_op, [target, index], line)
     else:
         return builder.gen_method_call(target, "__getitem__", [index], None, line)
 
@@ -784,11 +790,9 @@ def init(self, expr_reg: Value, target_type: RType, reverse: bool) -> None:
         # environment class.
         self.expr_target = builder.maybe_spill(expr_reg)
         if not reverse:
-            index_reg: Value = Integer(0)
+            index_reg: Value = Integer(0, c_pyssize_t_rprimitive)
         else:
-            index_reg = builder.binary_op(
-                self.load_len(self.expr_target), Integer(1), "-", self.line
-            )
+            index_reg = builder.builder.int_sub(self.load_len(self.expr_target), 1)
         self.index_target = builder.maybe_spill_assignable(index_reg)
         self.target_type = target_type
 
@@ -838,13 +842,7 @@ def gen_step(self) -> None:
         builder = self.builder
         line = self.line
         step = 1 if not self.reverse else -1
-        add = builder.int_op(
-            short_int_rprimitive,
-            builder.read(self.index_target, line),
-            Integer(step),
-            IntOp.ADD,
-            line,
-        )
+        add = builder.builder.int_add(builder.read(self.index_target, line), step)
         builder.assign(self.index_target, add, line)
 
 

diff --git a/mypyc/lib-rt/CPy.h b/mypyc/lib-rt/CPy.h
@@ -652,7 +652,7 @@ PyObject *CPyList_GetItemShortBorrow(PyObject *list, CPyTagged index);
 PyObject *CPyList_GetItemInt64(PyObject *list, int64_t index);
 PyObject *CPyList_GetItemInt64Borrow(PyObject *list, int64_t index);
 bool CPyList_SetItem(PyObject *list, CPyTagged index, PyObject *value);
-bool CPyList_SetItemUnsafe(PyObject *list, CPyTagged index, PyObject *value);
+void CPyList_SetItemUnsafe(PyObject *list, Py_ssize_t index, PyObject *value);
 bool CPyList_SetItemInt64(PyObject *list, int64_t index, PyObject *value);
 PyObject *CPyList_PopLast(PyObject *obj);
 PyObject *CPyList_Pop(PyObject *obj, CPyTagged index);
@@ -703,14 +703,13 @@ tuple_T4CIOO CPyDict_NextItem(PyObject *dict_or_iter, CPyTagged offset);
 int CPyMapping_Check(PyObject *obj);
 
 // Check that dictionary didn't change size during iteration.
-static inline char CPyDict_CheckSize(PyObject *dict, CPyTagged size) {
+static inline char CPyDict_CheckSize(PyObject *dict, Py_ssize_t size) {
     if (!PyDict_CheckExact(dict)) {
         // Dict subclasses will be checked by Python runtime.
         return 1;
     }
-    Py_ssize_t py_size = CPyTagged_AsSsize_t(size);
     Py_ssize_t dict_size = PyDict_Size(dict);
-    if (py_size != dict_size) {
+    if (size != dict_size) {
         PyErr_SetString(PyExc_RuntimeError, "dictionary changed size during iteration");
         return 0;
     }
@@ -783,7 +782,8 @@ bool CPySet_Remove(PyObject *set, PyObject *key);
 
 PyObject *CPySequenceTuple_GetItem(PyObject *tuple, CPyTagged index);
 PyObject *CPySequenceTuple_GetSlice(PyObject *obj, CPyTagged start, CPyTagged end);
-bool CPySequenceTuple_SetItemUnsafe(PyObject *tuple, CPyTagged index, PyObject *value);
+PyObject *CPySequenceTuple_GetItemUnsafe(PyObject *tuple, Py_ssize_t index);
+void CPySequenceTuple_SetItemUnsafe(PyObject *tuple, Py_ssize_t index, PyObject *value);
 
 
 // Exception operations

diff --git a/mypyc/lib-rt/list_ops.c b/mypyc/lib-rt/list_ops.c
@@ -231,15 +231,8 @@ bool CPyList_SetItemInt64(PyObject *list, int64_t index, PyObject *value) {
 }
 
 // This function should only be used to fill in brand new lists.
-bool CPyList_SetItemUnsafe(PyObject *list, CPyTagged index, PyObject *value) {
-    if (CPyTagged_CheckShort(index)) {
-        Py_ssize_t n = CPyTagged_ShortAsSsize_t(index);
-        PyList_SET_ITEM(list, n, value);
-        return true;
-    } else {
-        PyErr_SetString(PyExc_OverflowError, CPYTHON_LARGE_INT_ERRMSG);
-        return false;
-    }
+void CPyList_SetItemUnsafe(PyObject *list, Py_ssize_t index, PyObject *value) {
+    PyList_SET_ITEM(list, index, value);
 }
 
 PyObject *CPyList_PopLast(PyObject *obj)

diff --git a/mypyc/lib-rt/tuple_ops.c b/mypyc/lib-rt/tuple_ops.c
@@ -46,16 +46,17 @@ PyObject *CPySequenceTuple_GetSlice(PyObject *obj, CPyTagged start, CPyTagged en
     return CPyObject_GetSlice(obj, start, end);
 }
 
+// No error checking
+PyObject *CPySequenceTuple_GetItemUnsafe(PyObject *tuple, Py_ssize_t index)
+{
+    PyObject *result = PyTuple_GET_ITEM(tuple, index);
+    Py_INCREF(result);
+    return result;
+}
+
 // PyTuple_SET_ITEM does no error checking,
 // and should only be used to fill in brand new tuples.
-bool CPySequenceTuple_SetItemUnsafe(PyObject *tuple, CPyTagged index, PyObject *value)
+void CPySequenceTuple_SetItemUnsafe(PyObject *tuple, Py_ssize_t index, PyObject *value)
 {
-    if (CPyTagged_CheckShort(index)) {
-        Py_ssize_t n = CPyTagged_ShortAsSsize_t(index);
-        PyTuple_SET_ITEM(tuple, n, value);
-        return true;
-    } else {
-        PyErr_SetString(PyExc_OverflowError, CPYTHON_LARGE_INT_ERRMSG);
-        return false;
-    }
+    PyTuple_SET_ITEM(tuple, index, value);
 }
diff --git a/mypyc/primitives/dict_ops.py b/mypyc/primitives/dict_ops.py
@@ -289,7 +289,7 @@
 
 # check that len(dict) == const during iteration
 dict_check_size_op = custom_op(
-    arg_types=[dict_rprimitive, int_rprimitive],
+    arg_types=[dict_rprimitive, c_pyssize_t_rprimitive],
     return_type=bit_rprimitive,
     c_function_name="CPyDict_CheckSize",
     error_kind=ERR_FALSE,

diff --git a/mypyc/primitives/list_ops.py b/mypyc/primitives/list_ops.py
@@ -13,6 +13,7 @@
     object_rprimitive,
     pointer_rprimitive,
     short_int_rprimitive,
+    void_rtype,
 )
 from mypyc.primitives.registry import (
     ERR_NEG_INT,
@@ -154,7 +155,7 @@
 # that is in-bounds for the list.
 list_get_item_unsafe_op = custom_primitive_op(
     name="list_get_item_unsafe",
-    arg_types=[list_rprimitive, short_int_rprimitive],
+    arg_types=[list_rprimitive, c_pyssize_t_rprimitive],
     return_type=object_rprimitive,
     error_kind=ERR_NEVER,
 )
@@ -183,10 +184,10 @@
 # PyList_SET_ITEM does no error checking,
 # and should only be used to fill in brand new lists.
 new_list_set_item_op = custom_op(
-    arg_types=[list_rprimitive, int_rprimitive, object_rprimitive],
-    return_type=bit_rprimitive,
+    arg_types=[list_rprimitive, c_pyssize_t_rprimitive, object_rprimitive],
+    return_type=void_rtype,
     c_function_name="CPyList_SetItemUnsafe",
-    error_kind=ERR_FALSE,
+    error_kind=ERR_NEVER,
     steals=[False, False, True],
 )
 

diff --git a/mypyc/primitives/tuple_ops.py b/mypyc/primitives/tuple_ops.py
@@ -6,14 +6,14 @@
 
 from __future__ import annotations
 
-from mypyc.ir.ops import ERR_FALSE, ERR_MAGIC
+from mypyc.ir.ops import ERR_MAGIC, ERR_NEVER
 from mypyc.ir.rtypes import (
-    bit_rprimitive,
     c_pyssize_t_rprimitive,
     int_rprimitive,
     list_rprimitive,
     object_rprimitive,
     tuple_rprimitive,
+    void_rtype,
 )
 from mypyc.primitives.registry import binary_op, custom_op, function_op, load_address_op, method_op
 
@@ -29,6 +29,15 @@
     error_kind=ERR_MAGIC,
 )
 
+# This is unsafe because it assumes that the index is a non-negative integer
+# that is in-bounds for the tuple.
+tuple_get_item_unsafe_op = custom_op(
+    arg_types=[tuple_rprimitive, c_pyssize_t_rprimitive],
+    return_type=object_rprimitive,
+    c_function_name="CPySequenceTuple_GetItemUnsafe",
+    error_kind=ERR_NEVER,
+)
+
 # Construct a boxed tuple from items: (item1, item2, ...)
 new_tuple_op = custom_op(
     arg_types=[c_pyssize_t_rprimitive],
@@ -48,10 +57,10 @@
 # PyTuple_SET_ITEM does no error checking,
 # and should only be used to fill in brand new tuples.
 new_tuple_set_item_op = custom_op(
-    arg_types=[tuple_rprimitive, int_rprimitive, object_rprimitive],
-    return_type=bit_rprimitive,
+    arg_types=[tuple_rprimitive, c_pyssize_t_rprimitive, object_rprimitive],
+    return_type=void_rtype,
     c_function_name="CPySequenceTuple_SetItemUnsafe",
-    error_kind=ERR_FALSE,
+    error_kind=ERR_NEVER,
     steals=[False, False, True],
 )