Reduce restrict use even more, reduce usage

python · Fidget-Spinner · Aug 21, 2025 · Aug 21, 2025 · Aug 21, 2025 · Aug 21, 2025
commit 5584fec64e358f55ceeb58136f1d2ba16b35e8dd
diff --git a/Include/internal/pycore_ceval.h b/Include/internal/pycore_ceval.h
@@ -391,7 +391,7 @@ _PyForIter_VirtualIteratorNext(PyThreadState* tstate, struct _PyInterpreterFrame
 #define SPECIAL___AEXIT__   3
 #define SPECIAL_MAX   3
 
-/* Special counterparts of ceval functions for performance reasons */
+// Special counterparts of ceval functions for performance reasons
 PyAPI_FUNC(int) _PyEval_Mapping_GetOptionalItem(PyObject *obj, PyObject *key, PyObject **result);
 
 #if defined(_MSC_VER) && !defined(__clang__) && _Py_TAIL_CALL_INTERP
@@ -400,17 +400,18 @@ PyAPI_FUNC(int) _PyEval_Mapping_GetOptionalItem(PyObject *obj, PyObject *key, Py
 #  define Py_NO_INLINE_MSVC_TAILCALL
 #endif
 
+// Tells the compiler that this variable cannot be alised.
 #if defined(_MSC_VER) && !defined(__clang__)
-#  define Py_MSVC_RESTRICT restrict
+#  define Py_UNALIASED(var) restrict var
 #else
-#  define Py_MSVC_RESTRICT
+#  define Py_UNALIASED(var) var
 #endif
 
-// Just a scope. Hints to the programmer
+// Just a scope. Hints to the programmer and compiler
 // That any local variable defined within this block MUST
 // not escape from the current definition.
-# define Py_BEGIN_LOCALS_MUST_NOT_ESCAPE() {
-# define Py_END_LOCALS_MUST_NOT_ESCAPE() }
+# define Py_BEGIN_LOCALS_MUST_NOT_ESCAPE {
+# define Py_END_LOCALS_MUST_NOT_ESCAPE }
 
 #ifdef __cplusplus
 }

diff --git a/Objects/abstract.c b/Objects/abstract.c
@@ -225,7 +225,7 @@ PyMapping_GetOptionalItem(PyObject *obj, PyObject *key, PyObject **result)
 }
 
 Py_NO_INLINE_MSVC_TAILCALL int
-_PyEval_Mapping_GetOptionalItem(PyObject *obj, PyObject *key, PyObject **Py_MSVC_RESTRICT result)
+_PyEval_Mapping_GetOptionalItem(PyObject *obj, PyObject *key, PyObject **Py_UNALIASED(result))
 {
     return PyMapping_GetOptionalItem(obj, key, result);
 }

@@ -2228,7 +2228,7 @@ dummy_func(
             // handle any case whose performance we care about
             PyObject *super;
             Py_BEGIN_LOCALS_MUST_NOT_ESCAPE;
-            PyObject *Py_MSVC_RESTRICT stack[] = {class, self};
+            PyObject *stack[] = {class, self};
             super = PyObject_Vectorcall(global_super, stack, oparg & 2, NULL);
             Py_END_LOCALS_MUST_NOT_ESCAPE;
             if (opcode == INSTRUMENTED_LOAD_SUPER_ATTR) {
@@ -2291,7 +2291,7 @@ dummy_func(
             int method_found = 0;
             PyObject *attr_o;
             Py_BEGIN_LOCALS_MUST_NOT_ESCAPE;
-            int *Py_MSVC_RESTRICT method_found_ptr = &method_found;
+            int *method_found_ptr = &method_found;
             attr_o = _PySuper_Lookup(cls, self, name,
                                 Py_TYPE(self)->tp_getattro == PyObject_GenericGetAttr ? method_found_ptr : NULL);
             Py_END_LOCALS_MUST_NOT_ESCAPE;
@@ -3519,7 +3519,7 @@ dummy_func(
             (void)lasti; // Shut up compiler warning if asserts are off
             PyObject* res_o;
             Py_BEGIN_LOCALS_MUST_NOT_ESCAPE;
-            PyObject *Py_MSVC_RESTRICT stack[5] = {NULL, PyStackRef_AsPyObjectBorrow(exit_self), exc, val_o, tb};
+            PyObject *stack[5] = {NULL, PyStackRef_AsPyObjectBorrow(exit_self), exc, val_o, tb};
             int has_self = !PyStackRef_IsNull(exit_self);
             res_o = PyObject_Vectorcall(exit_func_o, stack + 2 - has_self,
                     (3 + has_self) | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h